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An Unusually Active SU UMa-Type Dwarf Nova

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Taichi Kato of Kyoto University and Yoji Osaki of the University of Tokyo recently published a paper on an unusual dwarf nova spotted by Planet Hunters’ volunteers that was contaminating the photometric aperture of a Kepler target star. A dwarf nova is a binary star system where one of the pair is a normal star and the other is a white dwarf. The objects orbit so closely that material from the  star is falling onto the white dwarf with an accretion disk of material around the white dwarf. The light from the system is dominated by the accretion disk. Thus changes in brightness reflect the temperature and state of the accretion disk.  This is the 2nd Planet Hunters dwarf nova/cataclysmic variable find to be published in the astronomical literature. Congratulations to the volunteers involved.  The first Planet Hunters discovery  paper was published in the Fall of last year, and you can read more about that object here.

Drs. Kato and Osaki found the discussions about this light curve from  a volunteer curated blog that highlights interesting finds from Talk and the Talk thread about this interesting source . They went on to follow-up the find and  further investigate the dwarf nova combining  ground based,  space-based telescope data, and the Kepler light curve.  They found that this dwarf nova exhibited unusual features in the light curve (brightness of the accretion disk) for having a very short orbital period of the companion star.

Congratulations to all involved in this intriguing find. You can read about the study in detail with the preprint of the paper available here.


A mysterious object no more

This post is by Tabby Boyajian, one of the Planet Hunters science team at Yale

As you all know, planethunter volunteers use archive data taken with the Kepler space telescope to classify lightcurves and identify transiting planets. Since the launch of the Planethunters citizen science program, we have contributed five scientific publications reporting on the discovery of dozens of candidate and confirmed exoplanetary systems – otherwise undiscovered by the Kepler team.

The design of the project is expanding with the opportunity for Planethunter volunteers to support astronomers interested in using Kepler data for scientific research unrelated to the main exoplanet goals of the Kepler mission. We have dubbed this as our own ‘Guest Scientist’ program. The idea is that guest scientists participate in Planethunters Talk forum and make requests for the public to collect particular light curves, such as signatures of moons or rings, pulsators, variable stars, flare stars, cataclysmic variables, or microlensing events.

This schematic, by Planet Hunter Daryll LaCourse, shows off our new discovery.

This schematic, by Planet Hunter Daryll LaCourse, shows off our new discovery. (Click to make larger)

We are delighted to announce that the first paper presenting results associated with the Planethunters Guest Scientist program has been accepted for publication in the Astrophysical Journal! In this paper, the lead scientists Doug Gies and Zhao Guo from Georgia State University and Steve Howell and Martin Still from NASA AMES follow up on a mysterious object in the Kepler field identified by Planethunters, later confirming it to be an unusual type of cataclysmic variable. They perform an in-depth analysis on the Kepler lightcurve as well as observations made at the Kitt Peak National Observatory 4-m Mayall telescope and RC spectrograph. The result is a newly published paper, so take a momtent to read ‘KIC 9406652: An Unusual Cataclysmic Variable in the Kepler Field of View’ or to check out the planethunters talk thread where the object was first discovered and discussed:

Thanks you all for your enthusiasm and contributions to the scientific community. We have several other projects underway so keep an eye out for updates in the future!