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“Without Planet Hunters, none of the subsequent discoveries would have been possible.”

An interview with PH Tom Jacobs, by Rebekah and Jennifer Kahn

Thomas Lee Jacobs is a long-time Planet Hunters member who recently coauthored “Likely Transiting Exocomets Detected by Kepler,” a paper in which the first exocomets were discovered by the transit method through his persevering efforts in reviewing over 200,000 light curves.  Published in Monthly Notices of the Royal Astronomical Society, you can read that paper here: . This is not Tom’s first scholarly paper, having previously been listed as coauthor of nine other papers, in which he explored eclipsing binaries, long period exoplanet orbits, and Jupiter size exoplanets in the Habitable Zone. And he tells us “there are more in the works.”  With such a record of scholarly accomplishments as a citizen scientist, we thought his views of the past, present and future of PH would be worth listening to.  And yes, he is a real citizen scientist; having graduated with a non-science degree from the University of Washington in Business Administration, his rewarding day job is working as an employment consultant for workers with intellectual disabilities.

PH: Could you tell us what attracted you to Planet Hunters when it was founded seven years ago?  Were you already an amateur astronomer?  Had you already been involved in exoplanets, and what other astronomy interests did you have then or now?

TJ: I originally was drawn to citizen science projects created by the Zooniverse Citizen Science Alliance at MoonZoo and moved over to Planet Hunters when it was launched in December of 2010. The idea of looking for planets outside of our solar system when there was only a handful of known exoplanet discoveries at the time was intriguing. We all know now that the NASA Kepler space telescope has revolutionized astronomy and astrophysics, but at the launch of Planet Hunters there were many unknowns. I think back to that period of time as being similar to the “Wild West”, as everything was fresh and uncharted and little was known about what we would find together as Planet Hunters members. For me, I started at ground zero with no background in astronomy and my college major was in business not science.

PH: What has been your experience with Planet Hunters, then and now?

TJ: As mentioned, I became a member of Planet Hunters around 2010 and attended the first Kepler Science Conference in 2011. At Planet Hunters “Talk” I began learning from other members with more experience and insight into the light curves. Kian Jek (kianjin) was one of the most respected members at the time. There were many stalwart surveyors and contributors and I list only a few- Gerald Green, Hans Martin Schwengeler, Daryll LaCourse, Alan Schmitt, Troy Winarski, Mark Omohundro, Johann Sejpka, Ivan Terentev and Robert Gagliano. What they all have in common is dedication, perseverance and a great love for finding new and unusual events in the light curves. Kian, Daryll and I attended the first Kepler Science Conference in 2011. At that time, Planet Hunters was very novel to the astronomical community. Non-science folks, making meaningful discoveries by visual survey of the Kepler data, still had a ways to go to being acceptable in science papers. Of course, this has all changed as we fast forward to today and Planet Hunters has made significant discoveries. It is safe to say that without Planet Hunters coming on to the scene, some of the more unusual astrophysical discoveries would still remain dormant in the Kepler data. Just think of Boyajian’s star, KIC 8462852.

If you do not have an advanced mathematical and science background do not worry. I do not have one either and can only perform the most basic analysis of the Kepler light curves. What I do have is the treasure hunter zeal and a practiced eye that lends well for surveying and looking for unusual patterns in the data. Currently, I survey the Kepler K2 data using Alan Schmitt’s LcTools light curve viewer and work in collaboration with Daryll and two veteran astronomers, Saul Rappaport and Andrew Vanderburg. Daryll and I perform the initial identification and screening and Saul and Andrew do all the heavy lifting (analysis).  I have since been a coauthor on 10 Kepler science papers with more in the works.

PH: What were some of the early obstacles that PH had to overcome?

TJ: I think you both will agree that the original concept and design for Planet Hunters using crowd-sourcing techniques to identify interesting events quickly became obsolete. Some obstacles for analysis were not having access to the real KIC nomenclature, access to the Kepler data and having a fast, high resolution light curve viewer showing the entire observation period. This resulted in an independent subsystem of light curve analysis and sharing in the Planet Hunters “Talk” section.

PH: Well, we can remember that, at the time, things were moving along rather rapidly and everyone in the exoplanet community was learning on the fly.

TJ: One has to also acknowledge that in 2010 this was all new territory and the learning curve evolved over time. Without Planet Hunters, none of the subsequent discoveries would have been possible.

PH: And individual Planet Hunters not only made these discoveries, but also developed the analytical tools that enabled them.  Can you tell us about that?

TJ: Yes. As you know, Alan Schmitt’s LcTools program was created to address the shortfall I mentioned of not having a fast, high resolution light curve viewer.  His programs now provide a complete set of analytical tools. One can quickly scan individual light curves in ten seconds or less (actually an almost instantaneous scrolling feature) with excellent light curve resolution.

This year, I generated the Kepler DR25 long cadence light curves and they are available on his site, linked to my Gmail Google Drive as zip files for the LcTools viewer.

PH: Well, we hope to interview Mr. Schmitt for PH in the future and learn more from his perspective also.  Now, you have been a significant force in making many PH discoveries.   What particular outlook do you bring to the search for other worlds and how does this align with the PH mission and exoplanetary discovery as a whole?

TJ: I would consider myself more of a Kepler pattern recognition treasure hunter veteran and an individual who can perform only the most basic light curve analysis. I leave the heavy lifting to the skilled veterans.

PH: But you have been a coauthor on several important papers and part of so many exoplanet discoveries.  Surely there is a bit more to it?

TJ: There are some tools available online for a more detailed look and many planet hunters are adept in doing so. I am not one of them. What I have found is over the course of many years one can develop an eye for what is an interesting event and what may be simply noise or artifacts in the light curves. Though periodicity is a key tell for real astrophysical events, machine searches are well suited to beat the trained citizen scientist making visual surveys. However, single (less so now), aperiodic and new light curve patterns of real astrophysical events give the visual surveyor a real edge in this area.

PH: So, even in these new days of neural networks and machine ‘deep learning’ that characterize light curves with great accuracy, there is still a place for citizen scientists and Planet Hunters?

TJ: A machine will only find known patterns. The visual surveyor travels into uncharted areas finding new and unusual events.

PH: Such as your recent exocomets find, for sure!  Well, what is your process for finding and analyzing light curves and what resources do you use?

TJ: When I survey a light curve, the first thing I do is look for unusual or known light curve patterns. Depending on how they appear will give the surveyor an idea if the events are real, the star owns the events, if there are third body events and/or if there is contamination. The next thing to check is the actual FOV. PanSTARRS is relatively new site though there are others:

I will not list all the K2 and Kepler main field online archives search sites as they are well known. The IRSA/WISE site is also a great resource of looking for WISE band 4 IR that is a great tell for “Dippers.”  Of course, Andrew Vanderburg’s site is a must see for K2. He has a page for each K2 light curve that shows background contamination such as BGEBs:

PH: What future projects do you think PH should pursue? And what are some suggestions for improvement?

TJ: I would be interested in learning more about how Planet Hunters will be working with the new TESS data when it becomes operational later this year (hopefully).   Educating and training its members to work more independently and developing close relationships with veteran science team members with timely feedback would be of significant help.  There will be quite a bit of excellent data to analyze and citizen scientists will need strong advocates in the professional astronomical community to ensure the data is accessible to the public similar to the Kepler data, though I have been told that the data will be accessible similar to K2.

PH: Can you point to any particular discoveries or experiences over the last seven years that you particularly enjoyed or are especially proud of?

In January of last year, I took on a very large project of downloading and visually surveying all 201,250 light curves of the Kepler prime-field stars in Ames Data Release 25. Alan Schmitt and I collaborated in downloading the stars. This was a dream that I had envisioned while surveying at Planet Hunters. What until January was not in place to do this was the technology, team, experience and time. The survey took five months and I kind of went off the charts devoting most of my free time to visually surveying before and after my day job working as a Special Projects manager for AtWork! in Bellevue, Washington helping people with intellectual disabilities find paid employment in their community. I have been doing this rewarding work for over 21 years. The visual survey was completed in May and a rich harvest of interesting finds was discovered. The discovery that stands out and is likely my high-water mark for surveying is the exocomet paper recently published last fall. These are the first exocomet candidates ever discovered using transit photometry. Without the team effort, the comets would still be lurking in the Kepler data. That is the power of visually surveying, team effort and a love of finding new and usual things in the light curves. Thank you Planet Hunters and Happy Hunting!

Thank you, Tom.  We appreciate your work, explanation of your outlook and methods, and recommendations for the future. In particular, we hope that your thoughts might stimulate some further discussion on this blog.  Reminiscences of our successful past are welcome, but practical suggestions for our future would be truly exciting.


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