Friday, June 3, 2011

Following in Kepler's Footsteps

Carnival of Space...Happy 200th episode, webisode, Bi-centenial (no that's years) or as we say in Australia - 200 Gamer!! Congratulations!!!, what a triumph for social media, education outreach for astronomy and all round great fun.

As its the 200th edition, I thought I better pull out all stops and put together a bumper post!

As an amateur astronomer, I consider myself exactly that, amateur, someone who has the passion, the toys, but hasn't got around to the 4 years of study at Swinburne Astronomy. However the contribution from amateur astronomers is still important, as they can do things at their own pace, share their passion, go after targets of opportunity, targets not likely chased by other professional observatories, and assist the real scientists who know how to do the scary math.

So when the Kepler team published an inviting list of 1235 transit candidates, it was only a matter of time before these "private detectives" started poking around.

Anyone can be involved in the Kepler Hunt, and today I'll cover three different levels where each and everyone of you could assist in bagging a transit, and help share the load of the monumental task of following up the data generated by the Kepler research. By Kepler, of course, I am referring to the space telescope named after 17th century astronomer and mathematician Johannes Kepler, which is currently photographing (continuously) 160,000 stars.

This week, I bagged a transit on one of the 1235 candidates in the publicly released Kepler data. Out of respect for the program, I'll leave the science in its proper place - the TRESCA ETD (Exoplanet Transit Database).

The importance of this is quite interesting as the target has a 6 hour transit, and a thirty day orbit, which means that the transit is only visible to earth based telescopes three times a year.....the next window is in August. The only people likely to pick up what is, lets be honest, probably a fairly low value target, is the amateur community. However ....... data is data!!

Given the number of multiple planet systems and other crazy configurations discovered so far, a single hot Jupiter crossing near the equator every 30 days is possibly - completely boring. However for an Amateur - a real test of skill, patience and sense of accomplishment and involvement in the program.

The challenges of this target were interesting:
1) The transit was 6 hours long, almost impossible to get a complete transit lightcurve - So I focused on the Egress which was well positioned.

2) The depth of the transit was a bit of an unknown - It looked big in the Kepler Data lightcurve in the MAST database.....but as Kepler is a space telescope there is no atmospheric extinction to worry about, they don't use comparison stars and they measure direct flux variation in parts per million - hard to know what that would look like down here. So I took a punt and picked the biggest depth, in the best position I could find on the given night - KOI 189b.

3) There were no AAVSO reference stars in the FOV. In exoplanet research there is much less reliance on cataloged reference stars as the photometry is based more on total flux, compensation for airmass, extinction, and camera noise etc. However basic differential photometery can still produce reasonable results, as my recent run on HAT-P-3b confirmed.

4) towards the end of the run, the Moon rose and messed around with my sky glow background values, causing some additional noise in the signal.

All good learnings for the future.

Bagging Transits
The are three levels of involvement in Kepler exoplanet research: Citizen science, Serious Amateur, Guest Observer. (I guess there is a fourth being on the actual Kepler Team).

Zooniverse has teamed up with the Kepler Team to provide yet another element to their hugely popular Citizen Science program, first pioneered by Galaxy Zoo. A veritable army of 429,000 members have an account, some look at the Kepler light curves, classify the star type and use an adjustable rectangular overlay to highlight any observed transits. This is a lot of fun and teaches you a lot about the many different star types and has the mandatory comment, share and chat functions. Every now and then they will throw in a known target and cheer you on for correctly identifying it. In addition to the 80 odd newly discovered transits, hundreds of eclipsing binaries have also been identified.

Join up today and bag a transit yourself!

Serious Amateurs participate in exoplanet research and contribute to the TRESCA ETD. This work was pioneered by legendary amateur Exo-hunter Bruce Gary, who deveolped somewhat of a cult following. Finding it difficult to maintain a growing database of Lightcurves, he teamed up with the Czech Astronomical Society who already had a scalable repository for light curves - and it even deals with the Scary Math for you!!!

Kepler Guest Observer Program is for professional astronomers to submit proposals for new observations that sit outside the core Kepler Mission Goals:
* Provide a statistically significant value for the frequency of Earth-size and larger planets in and near the habitable zone;
* Characterize the size and orbital distributions of such planets;
* Identify correlations between the presence and characteristics of planetary systems with stellar properties of the host star.

The Kepler Team maintain a database of lightcurves in MAST Multimission Archive at Space Telescope Institute. MAST contains all the lightcurves including the "public list" of transit candidates, some of this data is proprietry, and can be made available to guest observers. They publish a list of the 1235 "public targets" that were covered in Boruki et. al. 2011 These are made available for professionals and amateurs alike, to formulate their own research and leverage the wider Astronomy community.

(note: earth sized planets are so tiny their transits are only a few 10,000ths of a magnitude and are out of reach for earth based amateur scopes)

Collaborative efforts like Zooniverse / is one such example of the broader astronomy community using this data.

For me, my target KOI 189b, was listed as "No Obs" in the comments field, certainly sounded like an invitation ;-)

So here's to the Carnival of Space that keeps driving my interest to new and higher levels of involvement, in the great unanswered questions.

The work pays off, sometimes in very unexpected ways. This FMO flew through the field of view as I was doing some test images mid transit about an hour and a half before I got serious about the Egress. At 600 arcsecs/min its possibly a Geo-Stationary satellite, but a little unusual to say the least.

Happy 200th - Carnival of Space!!!


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