The Very Influential Natalie Batalha

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Natalie Batalha, project scientist for the Kepler mission and a leader of NASA’s NExSS initiative on exoplanets, was just selected as one of Time Magazine’s 100 most influential people in the world. (NASA, TIME Magazine.)

I’d like to make a slight detour and talk not about the science of exoplanets and astrobiology, but rather a particular exoplanet scientist who I’ve had the pleasure to work with.

The scientist is Natalie Batalha, who has been lead scientist for NASA’s landmark Kepler Space Telescope mission since soon after it launched in 2009, has serves on numerous top NASA panels and boards, and who is one of the scientists who guides the direction of this Many Worlds column.

Last week, Batalha was named by TIME Magazine as one of the 100 most influential people in the world. This is a subjective (non-scientific) calculation for sure, but it nonetheless seems appropriate to me and to doubtless many others.

Batalha and the Kepler team have identified more than 2500 exoplanets in one small section of the distant sky, with several thousand more candidates awaiting confirmation.  Their work has once and for all nailed the fact that there are billions and billions of exoplanets out there.

“NASA is incredibly proud of Natalie,” said Paul Hertz, astrophysics division director at NASA headquarters, after the Time selection was announced.

“Her leadership on the Kepler mission and the study of exoplanets is helping to shape the quest to discover habitable exoplanets and search for life beyond the solar system. It’s wonderful to see her recognized for the influence she has had on the world – and on the way we see ourselves in the universe.”

And William Borucki, who had the initial idea for the Kepler mission and worked for decades to get it approved and then to manage it, had this to say about Batalha:

“She has made major contributions to the Kepler Mission throughout its development and operation. Natalie’s collaborative leadership style, and expert knowledge of the population of exoplanets in the galaxy, will provide guidance for the development of successor missions that will tell us more about the habitability of the planets orbiting nearby stars.”

Batalha has led the science mission of the Kepler Space Telescope since it launched in 2009. (NASA)

As a sign of the perceived importance of exoplanet research, two of the other TIME influential 100 are discoverers of specific new worlds.  They are Guillem Anglada-Escudé (who led a team that detected a planet orbiting Proxima Centauri) and Michael Gillon (whose team identified the potentially habitable planets around the Trappist-1 system.)

But Batalha, and no doubt the other two scientists, stress that they are part of a team and that the work they do is inherently collaborative. It absolutely requires that many others also do difficult jobs well.

For Batalha, working in that kind of environment is a natural fit with her personality and skills.  Having watched her at work many times, I can attest to her ability to be a strong leader with extremely high standards, while also being a kind of force for calm and inclusiveness.

We worked together quite a bit on the establishing and running of this column, which is part of the NASA Nexus for Exoplanet System Science (NExSS) initiative to encourage interdisciplinary thinking and collaboration in exoplanet science.

It was NASA’s astrobiology senior scientist Mary Voytek who set up the initiative and saw fit to start this column, and it was Batalha (along with several others) who helped guide and focus it in its early days.

I think back to her patience.  I was visiting her at NASA’s Ames Research Center in Silicon Valley and talking shop — meaning stars and planets and atmospheres and the like.  While I had done a lot of science reporting by that time, astronomy was not a strong point (yet.)

So in conversation she made a reference to stars on the Hertzsprung-Russell diagram and I must have had a somewhat blank look to me.  She asked if I was familiar with Hertzsprung-Russell and I had to confess that I was not.

Not missing a beat, she then went into an explanation of what is a basic feature of astronomy, and did it without a hint of impatience.  She just wanted me to know what the diagram was and what it meant, and pushed ahead with good cheer to bring me up to speed — as I’m sure she has done many other times with many people of different levels of exposure to the logic and complexities of her very complex work.

(Incidently, the Hertzsprung-Russell diagram plots each star on a graph measuring the star’s brightness against its temperature or color.)

I mention this because part of Batalha’s influence has to do with her ability to communicate with individuals and audiences from the lay to the most scientifically sophisticated.  Not surprisingly, she is often invited to be a speaker and I recommend catching her at the podium if you can.

By chance — or was it chance? — the three exoplanet scientists selected for the Time 100 were at Yuri Milner’s Breakthrough Discuss session Thursday when the news came out. On the left is Anglada-Escude, Batalha in the middle and Gillon on the right.

Batalha was born in Northern California with absolutely no intention of being a scientist.  Her idea of a scientist, in fact, was a guy in a white lab coat pouring chemicals into a beaker.

As a young woman, she was an undergrad at the University of California at Berkeley and planned on going into business.  But she had always been very good and advanced in math, and so she toyed with other paths.  Then, one day, astronaut Rhea Setton came to her sorority.  Setton had been a member of the same sorority and came to deliver a sorority pin she had taken up with during on a flight on the Space Shuttle.

“That visit changed my path,” Batalha told me.  “When I had that opportunity to see a woman astronaut, to see that working for NASA was a possibility, I decided to switch my major — from business to physics.”

After getting her BA in physics from UC Berkeley, she continued in the field and earned a PhD in astrophysics from  UC Santa Cruz. Batalha started her career as a stellar spectroscopist studying young, sun-like stars. Her studies took her to Brazil, Chile and, in 1995, Italy, where she was present at the scientific conference when the world learned of the first planet orbiting another star like our sun — 51 Pegasi b.

It had quite an impact.  Four years later, after a discussion with Kepler principal investigator Borucki at Ames about challenges that star spots present in distinguishing signals from transiting planets, she was hired to join the Kepler team.  She has been working on the Kepler mission ever since.

Asked how she would like to use her now publicly acknowledged “influence,” she returned to her work on the search for  habitable planets, and potentially life, beyond earth.

“We’ve seen that there’s such a keen public interest and an enormous scientific interest in terms of habitable worlds, and we have to keep that going,” she said. “This is a very hard problem to solve, and we need all hands on deck.”

She said the effort has to be interdisciplinary and international to succeed, and she pointed to the two other time 100 exoplanet hunters selected.  One is from Belgium and the other is working in the United Kingdom, but comes from Spain.

When the nominal Kepler mission formally winds down in September, she says she looks forward to more actively engaging with the exoplanet science Kepler has made possible.

The small planets identified by Kepler as one one year ago that are small and orbit in the region around their star where water can exist as a liquid. NASA Ames/N. Batalha and W. Stenzel

Batalha’s role in the NASA NExSS initiative offers a window into what makes her a leader — she excels at making things happen.

Voytek and Shawn Domogal-Goldman of Goddard founded and oversee the group.  They then chose Batalha two other leaders (Anthony Del Genio of the Goddard Institute for Space Studies and Dawn Gelino of NASA Exoplanet Science Institute ) to be the hands-on leaders of the 18 groups of scientists from a wide variety of American universities.

(Asked why she selected Batalha, Voytek replied, “TIME is recognizing what motivated us to select her as one of the leaders for….NExSS. Her scientific and leadership excellence.”)

This is the official NExSS task:  “Teams will help classify the diversity of worlds being discovered, understand the potential habitability of these worlds, and develop tools and technologies needed in the search for life beyond Earth. Scientists are developing ways to identify habitable environments on these worlds and search for biosignatures, or signs of life.  Central to the work of NExSS is understanding how biology interacts with the atmosphere, surface, oceans, and interior of a planet, and how these interactions are affected by the host star.”

She has encouraged and helped create the kinds of collaborations that these tasks have made essential, but also helped identify upcoming problems and opportunities for exoplanet research and has started working on ways to address them.  For instance, it became clear within the NExSS group and larger community  that many, if not most exoplanet researchers would not be able to effectively apply for time to use the James Webb Space Telescope (JWST) for several years after it launched in late 2018.

To be awarded time on the telescope, researchers have to write detailed descriptions of what they plan to do and how they will do it. But how the giant telescope will operate in space is not entirely know — especially as relates to exoplanets.  So it will be impossible for most researchers to make proposals and win time until JWST is already in space for at least two of its five years of operation.

Led by Batalha, exoplanet scientists are now hashing out a short list of JWST targets that the community as a whole can agree should be the top priorities scientifically and to allow researchers to learn better how JWST works.  As a result, they would be able to propose their own targets for research much more quickly  in those early years of JWST operations.   It’s the kind of community consensus building that Batalha is known for.

She also has an important roles in the NASA Astrophysics Advisory Committee and hopes to use the skills she developed working with Kepler on the upcoming Transiting Exoplanet Survey Satellite (TESS) mission.

Batalha preparing for the Science Walk in San Francisco on Earth Day.

A mother of four (including daughter Natasha, who is on her way to also becoming an accomplished astrophysicist), Batalha is active on Facebook sharing her activities, her often poetic thoughts, and her strong views about scientific and other issues of the day.

She was an active participant, for instance, in the National March for Science in San Francisco, posting photos and impressions along the way.  I think it’s fair to say her presence was noticed with appreciation by others.

And that returns us to what she considers to be some of her greatest potential “influence” — being an accomplished, high ranking and high profile NASA female scientist.

“I don’t have to stand up and say to young women ‘You can do this.’  You can just exist doing your work and you become a role model.  Like Rhea Setton did with me.”

And it is probably no coincidence that four other senior (and demanding) positions on the Kepler mission are filled by women — two of whom were students in classes taught some years ago by Natalie Batalha.

 

 

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Some Spectacular Images (And Science) From The Year Past

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A rose made of galaxies

This is a golden era for space and planetary science, a time when discoveries, new understandings, and newly-found mysteries are flooding in.  There are so many reasons to find the drama intriguing:  a desire to understand the physical forces at play, to learn how those forces led to the formation of Earth and ultimately us, to explore whether parallel scenarios unfolded on planets far away, and to see how our burgeoning knowledge might set the stage for exploration.

But always there is also the beauty; the gaudy, the stimulating, the overpowering spectacle of it all.

Here is a small sample of what came in during 2016:

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The Small Magellanic Cloud, a dwarf galaxy that is a satellite of our Milky Way galaxy, can be seen only in the southern hemisphere.  Here, the Hubble Space Telescope captured two nebulas in the cloud. Intense radiation from the brilliant central stars is heating hydrogen in each of the nebulas, causing them to glow red.

Together, the nebulas are called NGC 248 and are 60 light-years long and 20 light-years wide. It is among a number of glowing hydrogen nebulas in the dwarf satellite galaxy, which is found approximately 200,000 light-years away.

The image is part of a study called Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE). Astronomers are using Hubble to probe the Milky Way satellite to understand how dust is different in galaxies that have a far lower supply of heavy elements needed to create that dust.  {NASA.ESA, STSci/K. Sandstrom (University of California, San Diego), and the SMIDGE team}

This picture combines a view of the southern skies over the ESO 3.6-metre telescope at the La Silla Observatory in Chile with images of the stars Proxima Centauri (lower-right) and the double star Alpha Centauri AB (lower-left) from the NASA/ESA Hubble Space Telescope. Proxima Centauri is the closest star to the Solar System and is orbited by the planet Proxima b, which was discovered using the HARPS instrument on the ESO 3.6-metre telescope.

Probably the biggest exoplanet news of the year, and one of the major science stories, involved the discovery of an exoplanet orbiting Proxima Centauri, the star closest to our own.

This picture combines a view of the southern skies over the European Space Observatory’s 3.6-metre telescope at the La Silla Observatory in Chile with images of the stars Proxima Centauri (lower-right) and the double star Alpha Centauri AB (lower-left).

The planet Proxima Centauri b is thought to lie within the habitable zone of its star.  Learning more about the planet, the parent star and the two other stars in the Centauri system has become a focus of the exoplanet community.

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We all know about auroras that light up our far northern skies, but there’s no reason why they wouldn’t exist on other planets shielded by a magnetic field — such as Jupiter.  Astronomers using the Hubble Space Telescope have found them on the poles of our solar system’s  largest planet, and produced far ultraviolet light images taken as the Juno spacecraft approached the planet.

Auroras are formed when charged particles in the space surrounding the planet are accelerated to high energies along the planet’s magnetic field. When the particles hit the atmosphere near the magnetic poles, they cause it to glow like gases in a fluorescent light fixture. Jupiter’s magnetosphere is 20,000 times stronger than that of Earth.

The full-color disk of Jupiter in this image was separately photographed at a different time by Hubble’s Outer Planet Atmospheres Legacy (OPAL) program, a long-term Hubble project that annually captures global maps of the outer planets.

Inside the Crab Nebula

Peering deep into the core of the Crab Nebula, this close-up image reveals the heart of one of the most historic and intensively studied remnants of a supernova, an exploding star. The inner region sends out clock-like pulses of radiation and tsunamis of charged particles embedded in magnetic fields.

The neutron star at the very center of the Crab Nebula has about the same mass as the sun but compressed into an incredibly dense sphere that is only a few miles across. Spinning 30 times a second, the neutron star shoots out detectable beams of energy that make it look like it’s pulsating.

The NASA Hubble Space Telescope image is centered on the region around the neutron star (the rightmost of the two bright stars near the center of this image) and the expanding debris surrounding it. Intricate details of glowing gas are shown in red and the blue glow is radiation given off by electrons spiraling at nearly the speed of light in the powerful magnetic field around the crushed stellar core.

Observations of the Crab supernova were recorded by Chinese astronomers in 1054 A.D. The nebula, bright enough to be visible in amateur telescopes, is located 6,500 light-years away in the constellation Taurus.  (NASA, ESA)

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The Gemini Planet Imager provides some of the earliest high-resolution, high-contrast direct imaging of exoplanets.  Using a coronagraph inside the telescope to block out the light of the star, the GPI can then allow researchers to see the region surrounding that star — in other words, where exoplanets might be.

This image includes a wide-angle view of the star HD 106906 taken by the Hubble Space Telescope and a close-up view from the Planet Imager, which operates on the Gemini South telescope in Chile’s Atacama Desert.  The image reveals a disturbed system of comets near the star, which may be responsible for the orbit of the the unusually distant giant planet (upper right).

The GPI Exoplanet Survey is operated by a team of astronomers from the University of California at  Berkeley and 23 other institutions, and is targeting 600 young stars to understand how planetary systems evolve over time.

Paul Kalas of UC Berkeley is responsible for the image and led the team that wrote about it. That paper actually came out in the Astrophysical Journal in late 2015 but, hey, that’s almost 2016.

Astronomers have regularly found a galaxy or star that is the furthest from us ever to be detected.  But the record is there to be broken, and in 2016 it was astronomers from the Great Observatories Origins Deep Survey (GOODS) who made the discovery.

Galaxy GN-z11, shown in the inset, was imaged as it was 13.4 billion years in the past, just 400 million years after the big bang.  That means the universe was only three percent of its current age when the light left that galaxy.

The galaxy has many blue stars that are bright and young, but it looks red in this image because its light has been stretched to longer spectral wavelengths by the expansion of the universe.

(NASA, ESA, P. Oesch (Yale University), G. Brammer ( STScI)), P. van Dokkum (Yale University), and G. Illingworth (University of California, Santa Cruz)

Biggest announce of discovred exoplanets by Kepler. (No, those are not real images, but still...)

No, these are not images of actual exoplanets, but they represent the continuing work of one of NASA’s most pioneering and productive missions, the Kepler Space Telescope. In May the Kepler team announced the detection of 1284 more planets or planet candidates as part of its newest catalog, the largest number announced at once in the mission.

To date, Kepler has identified unconfirmed 4,696 planet candidates, 2,331 confirmed planets, and 21 confirmed small planets in a habitable zone. In addition, the follow-on K2 mission has identified 458 candidate planets and 173 confirmed.

The Kepler spacecraft stared fixedly at a small portion of the sky for four years, looking to identify miniscule dimmings in the brightness of stars that would indicate that a planet was passing between the telescope and the star. In this way, Kepler has established a census of exoplanets that has been extrapolated to show the presence of billions and billions of planets around other stars.

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The 21-foot array that will collect photons for the James Webb Space Telescope was finished and put on display in November at the Goddard Space Flight Center. It will be the largest mirror to go into space, and will likely make the JWST into the most powerful and far-seeing observatory ever.

It will observe in the infrared portion of the spectrum because its goals include peering deep into the past of the universe, which is now most visible in the infrared. This means the JWST will have to be cooled to -364 degrees F, just 50 degrees above absolute zero.  To achieve that temperature, it’s insulated from the sun by five membrane layers, each no thicker than a human hair. Placing those membranes was finished in November, marking an end to construction of the telescope “mirror.”

The project has been enormously ambitious, and with that has come long delays and budget overruns that almost resulted in it being scrapped. Just this month, some early vibrating tests – designed to simulate launch conditions – experienced an anomaly that NASA engineers are working on now.  The JWST is scheduled to launch in late 2018.

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This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position of Jupiter’s moon Europa. The plumes, photographed by NASA’s Hubble’s Space Telescope Imaging Spectrograph, were seen in silhouette as the moon passed in front of Jupiter.

While the plumes spitting out of Saturn’s moon Enceladus are much better known now — the Cassini spacecraft flew through them in 2015, after all — the growing scientific consensus that Europa also has some plumes may be of even greater importance.  That moon is much larger, its ice-covered oceans have been determined to hold more water than all the oceans of Earth, and those oceans have clearly been around for a long time.

Hubble’s ultraviolet sensitivity allowed for the detection of the plumes, which rise more than 100 miles above Europa’s icy surface. The image of Europa, superimposed on the Hubble data, is assembled from data from the Galileo and Voyager missions. (NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center.)

compounds being created in the xxx nebula

How the fundamentals needed for life are created in space has been a longstanding mystery.  The cosmos, after all, began with hydrogen and helium, and that was about it.  But life needs carbon atoms connected to hydrogen, oxygen, nitrogen and other elements

Astronomers and astrochemists have been making progress in recent years and now understand the basics of how the heavier elements are formed in space.  New data from the European Space Agency’s Herschel Space Observatory has gone further and has established that ultraviolet light from stars plays a key role in creating these molecules.  Previously, scientists thought that turbulence created by “shock” events was the driving force.

This image is of the Orion nebula, where scientists studied carbon chemistry of a major star-forming region. Herschel probed an area of the electromagnetic spectrum — the far infrared, associated with cold objects — that no other space telescope has reached before so it could take into account the entire Orion Nebula instead of individual stars.

The result was a better understanding of how carbon and hydrogen reach the states necessary to bond and form the basic carbon chemistry of the cosmos (and of life.)

Within the inset image, the emission from ionized carbon atoms (C+), overlaid in yellow, was isolated and mapped out from spectrographic data.

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Following a successful close flyby of Enceladus, the NASA-ESA Cassini spacecraft captured this image of the moon with Saturn’s rings beyond.

The image was taken in visible light with the Cassini spacecraft wide-angle camera when it was about 106,000 miles away from Enceladus. That flyby turned into a fly-through as well, when Cassini entered the plumes of water vapor and dust that shoot out of the bottom of the moon.

Scientists already know that an array of organic and other chemicals are in the plumes, but the field is awaiting word about the presence (or absence) of molecular hydrogen, which is formed when water comes into contact with rocks in hydrothermal vents.  Many think that Enceledus is habitable and should be tested for signs of life because biosignatures could potentially exist in the relatively easy-to-access geysers.

moon-halo-5-13-2016-yuri-beletsky-chile-pano

While Yuri Beletsky is a staff astronomer at the Las Campanas Observatory in Chile, he is also a noted astrophotographer who specializes in capturing the beauty of nighttime scenes — usually connecting the celestial with the terrestrial.

In this 2016 photo, the moon is surrounded by a halo caused by the presence of millions of ice crystals in the upper atmosphere.  Great conditions for an astrophotographer, but pretty much useless for an astronomer.

The star within the halo is Regulus, brightest object in the constellation Leo the Lion. On the left outside the halo is Procyon from Canis Minor and on the right is the planet Jupiter.

As is so often the case in this line of endeavor, it’s quite a sight to see.

 

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The Ever More Puzzling, And Intriguing, “Tabby’s Star.”

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Star debris illustration
Did Tabby’s star going through periodic and deep dimmings because of dust and debris clouds that pass edbetween it and the mirror of the Kepler Space Telescope?  That was an earlier explanation for the highly unusual behavior of the star, but new research makes that answer less likely. Artist drawing by NASA/JPL-Caltech/T. Pyle

Substantial, sun-like stars are not supposed to dim.  They start with gravity and pressure induced nuclear reactions, and then they burn brighter and brighter until they either explode (go supernova) or burn all their fuel and become small, enormously dense, and not very bright “white dwarfs.”

Of course, the transit technique of searching for exoplanets looks precisely for dimmings — of stars caused by the passage of an exoplanet.  But those are tiny reductions in the star’s brightness and short-lived.  So if a star is dimming significantly over a much longer period of time, something unusual is going on.

And that is apparently exactly what is happening with the current poster child for mysterious stars — KIC 8462852 or “Tabby’s star,” named after the Yale University postdoc who, with the help of citizen scientists, discovered it,  Tabetha Boyajian.

First written up last fall, the big news was data from the Kepler Space Telescope showed that the star had experienced two major and dissimilar dips in brightness — a highly unusual and perplexing phenomenon.  The dips appeared much too large to represent the passage of an exoplanet, so explanations tended towards the baroque — a swarm of comets, a vast dust cloud, even an alien megastructure (proposed as a last possible explanation.)  The observation was first identified by citizen planet hunters working with Boyajian, making it an even more compelling finding.

Now the mystery has grown stranger still.  A paper made public last week based on a different kind of Kepler imaging (full-frame imaging) found not two but one enormous dip in the light curve, as well as a surprising and significant dimming the of star over the four year observing period of the space telescope.  The paper has been submitted for publication in American Astronomical Society journals.

Benjamin Montet of Caltech and Joshua Simon of the Observatories of the Carnegie Institution of Washington, analyzed the full-field images taken by Kepler every three months (rather than the hourly images studied by Boyajian et al,) and concluded that something strange was indeed going on.

Their conclusion: “No known or proposed stellar phenomena can fully explain all aspects of the observed light curve.”

 

Photometry of KIC 8462852 as measured from the FFI data. The four colors and shapes (green squares, black circles, red diamonds, and blue triangles) represent measurements from the four separate channels the starlight reaches as the telescope rolls. The four subpanels show ux from each particular detector individually. The main gure combines all observations together; we apply three linear osets to the data from dierent channels to minimize the scatter to a linear t to the rst 1100 days of data. In all four channels, the photometry is consistent with a linear decrease in ux for the rst three years of the mission, followed by a rapid decrease in ux of  2:5% over the next six months. The light gray curve represents one possible Kepler long cadence light curve consistent with the FFI photometry created by tting a spline to the FFI photometry as described in Section 4. The large dips observed by Boyajian et al. (2016) are visible but narrow relative to the cadence of FFI observations. The long cadence data behind this gure are available online.
Photometry of KIC 8462852 as measured from the full-frame imaging (FFI) data. The four colors and shapes (green squares, black circles, red diamonds, and blue triangles) represent measurements from the four separate channels the starlight reaches as the telescope rolls.  In all four channels, the photometry is consistent with a decrease in starlight for the first three years of the mission, followed by a rapid decrease in flux of  2:5% over the next six months. The large dips observed by Boyajian et al. (2016) are visible
but less broad relative to the FFI observations. (B. Montet and J. Simon)

Expanding a bit, Montet told Gizmodo:  “We spent a long time trying to convince ourselves this wasn’t real. We just weren’t able to.”

A paper describing the results from these full-frame observations went up recently on the prior to printing site arXiv.    The site allows members of the astronomy world to offer critiques, and so the results as now released may not be final.

But the story line does seem pretty clear — that Tabby’s star had one very large period of light dimming and had a secular decline in the light it was sending out over the four years of the Kepler mission.

Boyajian, a newly-appointed Louisiana State University researcher and professor, said that she considers the original findings to be entirely compatible with the newest results, with differences based on how the light was being captured (the once-monthly full-frame Kepler images versus the continuous imaging done of more than 100,000 stars.)

What has also become increasingly clear is that the dimming is not the result of an instrument glitch, and that the surrounding stars are not exhibiting the same unusual behavior.

“As far as we know, dimming is not something stars do; they get larger and brighter,” she said.  “Especially on these remarkably fast time scales, the dimmings are unprecedented for any kind of star.”

Boyajian had initially favored the theory that the light was being blocked by a large swarm of comets, but she said the new results make that more unlikely.  She said it is similarly unlikely that the dimmings are the result of some internal dynamics of the star.  So is it all the result of some alien megastructure, the “explanation” that initially brought a lot of attention to Tabby’s star.  I think we can assume it is not.

But given the data now available, it has become extremely difficult to find an explanation that checks all the boxes.  And that’s why Boyajian and her colleagues began a kickstarter campaign to raise $100,000 for another year of observing through the telescopes of the private Las Cumbres Observatory Global Telescope Network.

As she explained it, one of the telescopes will image the star at least two hours per night for the next year.  And if a significant dimming is observed, larger ground-based telescopes will be available to look more closely.

It’s a waiting game now, which is exciting itself,” she said. “It’s only a guess, but based on Kepler light curves, we might see something interesting next spring.”

(My earlier story on Tabby and her star can be found here:  Tabby’s Star)

Tabetha Boyajian was the driving force behind bringing the mysterious star xxxx to public attention. It had initially been identified as peculiar by the citizen scientists of xxx.
Tabetha Boyajian was the driving force behind bringing the mysterious star KIC 8462852 to public attention. It had initially been identified as peculiar by the citizen scientists of Planet Hunters, which is part of the Oxford University based “Zooniverse” Citizen Science Alliance.

 

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The Still Mysterious “Tabby’s Star”

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Artist rendering of star xxx, and the unexplain ed objects close to it. KNown as "Tabby's" star
Artist rendering of dusty comets approaching star KIC8462852, an interpretation of the mysterious objects that periodically block out substantial amounts of the star’s light. Known informally as “Tabby’s” star, it was discovered by citizen scientists using Kepler Space Telescope data, and they are looking for ways to continue their work. (NASA/JPL-Caltech)

It’s been eight months since citizen “Planet Hunters”  working with Yale postdoc Tabetha Boyajian announced the discovery of a most unusual star, or rather a star where something most unusual was intermittently and erratically happening.

The puzzle began with some light curve data, taken over a four year period, by the Kepler Space Telescope  The citizen planet hunters pored through reams of data sent back by Kepler looking for signals of planetary transits — the ever-so-slight dimmings of the star caused by the crossing or an orbiting exoplanet.

But the light curve for KIC 8462852 showed dimmings that were anything but slight, and anything but regular.  The Planet Hunters flagged the star for Boyajian’s groups attention, and the mystery star was born.

Theories on what was causing the very large dips ranged from a host of enormous comets, to a violently exploding planet, to an asteroid belt or the presence of close by stars, from an artifact of Kepler’s camera to, finally, an alien megastructure.  (The last was offered by Penn State astronomer Jason Wright as a kind of “Hail Mary” explanation if and when the others are found wanting.  But that’s what got the press.)

Despite years of concerted observing, theorizing and analyzing, Boyajian, Wright the citizen planet hunters and others intrigued by the mystery say they are no closer to an explanation for whatever is passing in front of the star (now informally called “Tabby’s star.”)  NASA has ruled out a technical glitch in the Kepler data, and a range of astronomers have found fault with all the explanations put forward.

But while the quite tantalizing mystery remains, efforts to learn more about the star may have to wind down soon.  The primary Kepler mission is over, so it will provide no more data for this star.  Other space telescopes will not be looking, nor will the major ground-based observatories.  And  the first SETI searches for signals coming from the star has found nothing unusual.

So with options dwindling to learn more, Boyajian, her citizen astronomers and others have begun a grassroots effort to raise $100,000 to buy time at a network of smaller ground-based telescopes around the world.

“All the models so far have major problem. So to go forward, we need new data ,” Boyajian said this week.  “There’s a huge amount of interest in this star, and we’re trying to use that interest to help solve a real mystery.”

 The unusual light curves for "Tabby's Star," which feature some extremely large dips and other smaller ones. The X-axis label “Kepler day” means days following the Kepler launch. (NASA/Kepler Space Telescope) The unusual light curves for "Tabby's Star," which feature some extremely large dips and other smaller ones. The X-axis label “Kepler day” means days following the Kepler launch. (NASA/Kepler Space Telescope)
The unusual light curves for “Tabby’s Star,” which feature some extremely large dips and other smaller ones. The X-axis label “Kepler day” means days following the Kepler launch. (NASA/Kepler Space Telescope)

KIC 8462852 is an otherwise ordinary F-type star, slightly larger and hotter than our sun . It burns some 1500  light-years away.  Of all the 150,000 stars monitored during the Kepler mission, it is the only one to show these kinds of highly unusual light curves and, presumably, to have such massive astrophysical objects (or fields or other phenomena) nearby.

During a TED talk, Boyajian described the recent history of observing the star.

The Planet Hunters, she said,  first detected something unusual in the star’s light curve in 2009 –a dip of 1 percent dip that lasted a week. This is roughly comparable to a sign produced by a Jupiter-sized planet transiting the star. Orbiting planets produce symmetric dips and the one they found was definitely asymmetric, like something that could be the result of the passing of an irregularly-shaped object like a comet.

The light from the star remained steady for two years, then it suddenly took a 15 percent plunge that lasted for a week.

Another two years passed without incident but in 2013 the star began flickering with a complex series of uneven, unnatural looking dips that lasted 100 days. During the deepest of these dips, the intensity of the light coming from the star dropped 20 percent. According to Boyajian it would take an object 1,000 times the area of the Earth transiting the distant star to produce such a dramatic effect.

What’s causing these unusual and strong signals.  The jury remains very much out.

The Kepler field of study, observed by the space telescope nonstop for almost five years. (NASA)
The Kepler field of study, observed by the space telescope nonstop for almost five years. (NASA)

But the process of applying for grants and space telescope time is both very slow and highly competitive. So the group has decided on a different, self-financing path.  This is how they described their current and future plans on their “www.wherestheflux.com” website:

We have initiated observations on the Las Cumbres Observatory Global Telescope Network (LCOGT). LCOGT is a privately run global telescope network specifically designed for time domain astronomy, meaning that their network of telescopes is positioned strategically around the globe to ensure continuous monitoring of an object.

Our observation plan is as follows. From the 4 years of Kepler data, we know that the dips in the light curve are not periodic, so we need continuous monitoring throughout the year since we cannot predict when it will dip again. We also know that how much the brightness drops is also variable from dip-to-dip. The LCOGT data will not have the precision Kepler had, but will have plenty of sensitivity to detect the observed dips in this star.

What’s more, since we are observing this star from the ground we are also able to tailor our observation plan to reveal detailed information on whatever object(s) are passing in front of the star to make the dips! One way this will be done is by observing the star at different wavelengths, or colors, of light. These new observations will monitor the star’s brightness at an assortment of colors!

In addition to this, the data from the LCOGT are space processed in real time, so when data are seen to pass below a brightness threshold, it will trigger more observations in the LCOGT network. Our science team will then alert for observations to be taken at larger facilities to get a better look.

The observatory has gifted this program 200 hours to begin the project on their new 0.4-meter telescope network, which will take us to the end of the summer.

Tabetha Boyajian, a postdoc at Yale and soon to be on the faculty of Louisiana State University.
Tabetha Boyajian, a postdoc at Yale and soon to be on the faculty of Louisiana State University. She has been working to unravel the mysteries of KIC 8462852 since

It’s not at all easy to apply for and win the stiff competition for observing time on a major public telescope, and that reality led to the outreach effort aimed those interested in collecting more Tabby’s Star data. The Planet Hunters citizen scientist group was brought together by Yale professor Debra Fischer, herself a professional planet hunter. The group is part of the Oxford University based “Zooniverse” Citizen Science Alliance.

As I will discuss in a later column, I have my doubts about some of the big-dollar, high-profile individual and foundation efforts to jump-start space travel and space science. They can be wonderful, but they sometimes feel like efforts to get the proverbial camel’s nose into the tent, and NASA and its budget are ultimately the tent.  (I’m not thinking here of commercial space efforts like resupplying the International Space Station, although they too depend on NASA to an important financial and technical degree.)

But grassroots private efforts like this one to learn more about Tabby’s star are, to me at least, quite  different.   This is hardly the first time a private group of enthusiasts has asked the interested public to help with their research and (hopefully) it will not be the last.  At the proper scale and with proper goals, they seem generally like a most valuable part of future space science.

And if this particular effort does end up solving the Tabby’s star puzzle in the months and years ahead — or at least giving some strong possible explanations — it will strenghten the case for public citizen science of all kinds.

 

 

 

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A Flood of Newly Confirmed Exoplanets

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Artist renderings of exoplanets previously detected by the Kepler Space Telescope (NASA)
Artist renderings of exoplanets previously detected by the Kepler Space Telescope (NASA)

In the biggest haul ever of new exoplanets, scientists with NASA’s Kepler mission announced the confirmation of 1,284 additional planets outside our solar system — including nine that are relatively small and within the habitable zones of their host stars.  That almost doubles the number of these treasured rocky planets that orbit their stars at distances that could potentially support liquid water and potentially life.

Prior to today’s announcement, scientists using Kepler and all other exoplanet detection approaches had confirmed some 2,100 planets in 1,300 planetary systems.  So this is a major addition to the exoplanets known to exist and that are now available for further study by scientists.

These detections comes via the Kepler Space Telescope, which collected data on tiny decreases in the output of light from distant stars during its observing period between 2009 and 2013.  Those dips in light were determined by the Kepler team to be planets crossing in front of the stars rather than impostors to a 99 percent-plus probability.

As Ellen Stofan, chief scientist at NASA Headquarters put it,  “This gives us hope that somewhere out there, around a star much like ours, we can eventually discover another Earth.”

he histogram shows the number of planet discoveries by year for more than the past two decades of the exoplanet search. The blue bar shows previous non-Kepler planet discoveries, the light blue bar shows previous Kepler planet discoveries, the orange bar displays the 1,284 new validated planets. (NASA Ames/W. Stenzel; Princeton University/T. Morton)
The histogram shows the number of planet discoveries by year for more than the past two decades of the exoplanet search. The blue bar shows previous non-Kepler planet discoveries, the light blue bar shows previous Kepler planet discoveries, the orange bar displays the 1,284 new validated planets.
(NASA Ames/W. Stenzel; Princeton University/T. Morton)

The primary goals of the Kepler mission are to determine the demographics of exoplanets in the galaxy, and more specifically to determine the population of small, rocky planets (less than 1.6 times the size of Earth) in the habitable zones of their stars.  While orbiting in such a zone by no means assures that life is, or was, ever present, it is considered to be one of the most important criteria.

The final Kepler accounting of how likely it is for a star to host such an exoplanet in its habitable zone won’t come out until next year.  But by all estimations, Kepler has already jump-started the process and given a pretty clear sense of just how ubiquitous exoplanets, and even potentially habitable exoplanets, appear to be.

“They say not to count our chickens before they’re hatched, but that’s exactly what these results allow us to do based on probabilities that each egg (candidate) will hatch into a chick (bona fide planet),” said Natalie Batalha, co-author of the paper in the Astrophysical Journal and the Kepler mission scientist at NASA’s Ames Research Center.

“This work will help Kepler reach its full potential by yielding a deeper understanding of the number of stars that harbor potentially habitable, Earth-size planets — a number that’s needed to design future missions to search for habitable environments and living worlds.”

Batalha said that based on observations and statistics the Kepler mission has produced so far, we can expect that there are some 10 billion relatively small, rocky  (and potentially habitable) planets in our galaxy.  And with those numbers in mind, she said, the closest is likely to be in the range of 11 light years away.

She said that all of the exoplanets found in habitable zones are in the “exoplanet Hall of Fame.”  But she said two of the newly announced planets in habitable zones, Kepler 1286b and Kepler 1628b, joined two previous exoplanets of particular interest either because of their size (close to that of Earth) or their Earth-like distance from suns rather like ours.

Batalha said a new and finely-tuned software pipeline has been developed to better analyze the data collected during those four years of Kepler observations.  Asked if the final Kepler catalogue of exoplanets, expected to be finished next summer, would increase the current totals of exoplanets found, she replied:  “It wouldn’t surprise me if we had hundreds more to add.”

Since Kepler launched in 2009, 21 planets less than twice the size of Earth have been discovered in the habitable zones of their stars. The orange spheres represent the nine newly validated planets announcement on May 10, 2016. The blue disks represent the 12 previous known planets. These planets are plotted relative to the temperature of their star and with respect to the amount of energy received from their star in their orbit in Earth units. (NASA Ames/N. Batalha and W. Stenzel)
Since Kepler launched in 2009, 21 planets less than twice the size of Earth have been discovered in the habitable zones of their stars. The orange spheres represent the nine newly validated planets announcement on May 10, 2016. The blue disks represent the 12 previous known planets. These planets are plotted relative to the temperature of their star and with respect to the amount of energy received from their star in their orbit in Earth units. (NASA Ames/N. Batalha and W. Stenzel)

Once the Kepler exoplanet list is updated, scientists around the world will begin to study some of the most surprising, enticing, and significant finds.  Kepler can tell scientists only the location of a planet, its mass and its distance from the host star.  So the job of further characterizing the planets — and ultimately determining if any are indeed potentially habitable — requires other telescopes and techniques.

Nonetheless, Kepler’s ability to give scientists a broad picture of the distribution of exoplanets — to find large numbers of them rather than, as pre-Kepler, one or two at a time — has been revolutionary.  It has also been remarkably speedy, thanks in large part to an automated system of analyzing transit data devised by Tim Morton, a research scientist at Princeton University,

“Planet candidates can be thought of like bread crumbs,” Morton said in a NASA teleconference. “If you drop a few large crumbs on the floor, you can pick them up one by one. But, if you spill a whole bag of tiny crumbs, you’re going to need a broom. This statistical analysis is our broom.”

Kepler identified another 1,327 candidates that are very likely to be exoplanets, but didn’t meet the 99 percent certainty level required to be deemed an exoplanet.

A large percentage of the newly confirmed planets are either “super-Earths” or “sub-Neptunes” — planets in a size range absent in our solar system.  Initially, the widespread presence of exoplanets of these dimensions was a puzzle to the exoplanet community,  but now the puzzle is more why they are absent in our system.

Despite the abundance of these exoplanets — which are believed to be mostly gas or ice giants — scientists are convinced there are considerably more rocky, even Earth-sized planets that current telescopes can’t detect.

 The size distribution of discovered exoplanet has been a surprise to scientists. The blue bars on the histogram represent all previously verified exoplanets by size. The orange bars on the histogram represent Kepler's 1,284 newly validated planets. (NASA Ames/W. Stenzel)
The size distribution of discovered exoplanet has been a surprise to scientists. The blue bars on the histogram represent all previously verified exoplanets by size. The orange bars on the histogram represent Kepler’s 1,284 newly validated planets. (NASA Ames/W. Stenzel)

 

The primary Kepler mission focused on one small piece of the sky — about 0.25 percent of it — and a distant part at that. It watched nonstop for transiting planets in that space for four years, watching unblinkingly at some 150.000 stars. The result has been a treasure trove of data that can then be broadened statistically to tell us about the entire galaxy.

So Kepler has revolutionized our understanding of the galaxy and what’s in it, and has proven once and for all that exoplanets are common.  But the individual planets that it has detected are unlikely to be the ones that allow for breakthroughs in terms of sniffing out what chemicals are in their atmospheres — an essential process for determining if a potentially habitable planet actually has some of the ingredients for life.

This is because Kepler was looking far into the cosmos, between 600 and 3,000 light years from our sun.  While the telescope identified almost 5,000 “candidate planets” during its four years of primary operation — and now more than 2,200 confirmed planets — the planets are generally considered too distant for the more precise follow-up observing needed to understand their atmospheres and chemical make-ups.

This work will fall to ground-based telescopes looking at nearer stars, and to future generations of American and European space telescopes using the transit method of detection pioneered by Kepler. (See graphic above.)  The next space satellite in line is NASA’s Transiting Exoplanet Survey Satellite  (TESS), which is scheduled to launch in 2017 and will focus on planets orbiting much closer and brighter stars.  The long-awaited James Webb Space Telescope, due to launch in 2018, also has the potential to study exoplanets with a precision, and in wavelengths, not available before.

NASA has begun development of the more sophisticated Wide Field Infrared Survey Satellite (WFIRST) to further exoplanet research in the 2020s,  and has set up formal science and technology definition teams to plan for a possible flagship exoplanet mission for the 2030s.  That mission would potentially have the power and techniques to determine whether an exoplanet actually has the components, or the presence, of life.

 

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