Showing posts with label Dwarf Nova. Show all posts
Showing posts with label Dwarf Nova. Show all posts

Saturday, April 13, 2013

Mystery Star KIC 9406652 at Planet Hunters


Q10 Time plot for KIC 9406652 by Kian Jek

Forum Talk member Penn_gwenn flagged this star in Kepler Q2. It immediately attracted interest from forum members, Zoo3hans, Kian Jek, Nighthawk_black, Cappella and others as a possible Dwarf nova or Heartbeat binary. You can see superhump-like features in the time plot above. KIC 9406652 is currently being investigated by the Kepler Guest Observer program for further analysis. No one quite knows what exactly this star is.

Kian Jek

I believe this might be genuine. There are APOs of around 20-30 millipixels in the source FITS file, but the brightening points in the direction of the target. And there is no apparent source in that direction. The APOs represents the flux shifting away from the brighter neighbor IMO:



I suspect this could be an SS Cygni type of dwarf nova, from the shape and frequency of the outbursts - they are more frequent and do not exhibit the super-outbursting behavior of the SU UMa types we've seen previously. There are superhumps noted during the descending limbs of an outburst, sometimes stretching into the quiescent periods, with a period of approximately 6 hours. I'll do a little more poking around.


The region from which I took the sample to find the superhump period is here:

and here's where it comes from, in Q10:

Backing up a bit, here's the entire light curve:

What just occurred to me is that the lowest flux levels seen here are true minimas - they are not due to data gap problems - the flux level of ~0.5 seems to be the actual base flux level, and therefore this DN seems to spend a lot of its time at about 2x its lowest brightness. This type of behavior is perhaps more accurately described as a UGZ or a Z Camelopardalis type of dwarf novae rather than a UGSS (or SS Cygni type).
 Caveat: I am not a real astrophysicist. EIKAAILOW™ (Everything I Know About Astrophysics I Learned On Wikipedia).
This is interesting because IIRC we have already found 2 examples of UGSU and 1 UGSS (although they are background DNs) and this one, which seems like a real target, is a UGZ, and thus completes all the major types of dwarf novae discovered by citizen scientists in the Kepler FOV.

Daryll LaCourse (Nighthawk_black):
Keppixseries from the target pixel files support this interpretation; the outbursts flood the optimal aperture and to a lesser extent the surrounding halo pixels:

Q5:

FULL

Q10:

FULL

You can follow this star on Planet Hunters forum Talk here.

Tuesday, July 24, 2012

Dwarf Novae Candidates at Planet Hunters KIC 11412044, KIC 5565606, KID 10678185

Comment by Kian Jek:

"So far, Planet Hunters have found three background dwarf novae (DN) candidates in the Kepler public data, and we have worked out some basic characterizations of their properties as well as locations:

KIC 11412044 (see here)
KIC 5565606 (see here)
KIC 10678168 (see here) - the actual DN is suspected to be KIC 10678185

These were discovered at various times in the past with various contributions from many of us - I am just summarizing these here (on 6/30/2012) in the expectation that anybody trying to do a Google search of any of these Kepler IDs will be directed to this thread and continue to the discussions. If you have found these stars independently and plan to conduct some research on them, I simply request that you acknowledge our prior work and contributions. Please send correspondence to Meg Schwamb <megan.schwamb AT yale.edu>"

 KIC 11412044

 KIC 5565606


KIC 10678168 contaminated by suspected DN  KID 10678185




Monday, July 23, 2012

KIC 9715425 - Eruptive Variable Star

KIC 9715425 /APH22027710 is a spectral type A star, as listed at Planet Hunters, but may actually be a type B at 11199 (K). Tentatively tagged as a Gamma Doradus, it has eruptions through the quarters. First identified by Planet Hunters members one year ago.


This is what Talk member Kian Jek has to say about this star:

"This is an unusual one. There are no obvious APOs or contamination of any sort, so these spikes are a bit of a mystery. The pulsations continue right through these outbursts. In fact the pulsations resemble superhumps... could this yet be some strange species of dwarf nova? The double headed outburst at 340 appears to resemble the larger one at 600."

More ongoing updates at Planet Hunters here.

An Automated Search for Transiting Exocomets- HD 182952 (KIC 8027456)

A team of astronomers led by Grant M. Kennedy , discovered a potential third comet system in the Kepler prime field data of HD 182952 (KIC...