GDOR-like Patterns and UKIRT Merged Stars

 KIC 10681464 at Planet Hunters

UKIRT image

At Planet Hunters we are good at detecting patterns in the Kepler light curves. So it is not unusual to see some speculation on our more interesting star patterns with visual anomalies. In this case we are posing some questions about Gamma Doradus-like (GDOR) stars with very close in neighbors showing up on UKIRT. Is there a link between possible contamination showing up in the field of view and the actual GDOR-like pattern in the light curve? Are we seeing the effect of a background GDOR as contamination? Or is this simply a random event, coincidence with no relationship?  Taking this speculation one step further, can there be, in some instances, a gravitational link between very close in neighbors showing up in the field of view of those stars that appear to be merging? Can some of the light curve patterns be indicating a binary star system relationship?

Tom128

We are seeing a lot of contaminated stars in the Kepler field of view with GDOR-like LC patterns. Any thoughts as to why? Instead of false positive transit drops we are seeing these interesting contamination patterns.

Here are some examples taken from our PH GDOR list:
KIC 10681464 Listed on VSX as a SPB - http://talk.planethunters.org/objects/APH43125465





UKIRT



KIC 10199218 http://talk.planethunters.org/objects/APH73018369


UKIRT



KIC 5301537 http://talk.planethunters.org/objects/APH72114406


UKIRT



KIC 10728428 http://talk.planethunters.org/objects/APH53074550


UKIRT



KIC 12218729 http://talk.planethunters.org/objects/APH72010654



UKIRT



KIC 2695344 http://talk.planethunters.org/objects/APH73093495

4 months ago

djsimister

@Tom128 Not on our list but maybe Another example?

KID 5728217 http://talk.planethunters.org/objects/APH10027511


UKIRT.

4 months ago

Tom128

Yes, it seems instead of false positive transit drops we see these light curve patterns. I did not do any contamination analysis on any of these light curves, but they seem to have the same visual merged or close in neighbor. Here are a some more examples:
KIC 3441414 http://talk.planethunters.org/objects/APH22140442




UKIRT



KIC 4076350 http://talk.planethunters.org/objects/APH52022370



UKIRT



KIC 1295531 http://talk.planethunters.org/objects/APH71094127





UKIRT

4 months ago

arvintan

 here's a couple more from my collection:




KID 6782360: http://talk.planethunters.org/objects/APH52098313




KID 5689219: http://talk.planethunters.org/objects/APH10038724

4 months ago

Tom128

Here is another example of a GDOR-like LC with a close neighbor on UKIRT:

KIC 5650341



http://talk.planethunters.org/objects/APHE2000oht

UKIRT

You can follow this thread on the Planet Hunters Talk Science board here. 

KIC 5879583 Unlisted RR Lyrae Star

Contaminated Star  KIC 5879574 in Q2 at Planet Hunters

Planet Hunters forum Talk member Tom128 posted the unusual light curve above for KIC 5879574 in Kepler Q2. At that time Kian Jek commented:

Possible #contamination from KID 5879583 (not a Kepler target) but is a nearby A star. RRL lightcurve (on detrend) but class is G.

Unfortunately, the contaminator star was never followed up at Planet Hunters until recently when Talk member Cappella found  KIC 5879583 to have been targeted by Kepler in Q14.

Kian Jek:

If two years ago we'd known how to do the kind of APO/TPF contamination analysis, we'd have fingered the Type A star known then as #5 on the Skyview as the likely RRL Type A, and it would have been the 2nd RRL to be discovered through Kepler LC blending, a testament to the fidelity of Kepler's CCDs.
Here's the LC of the contaminated star, KIC 5879574, the APOs are startling - they are humongous, at nearly 100 millipixels, and you can make out that the contaminant even has Blazhko modulation:



The APO vector points roughly in the direction of our 5879583 - the green arrow is in the direction of flux maxima:





and the TPF (flipped and rotated to N is up, sky orientation) shows that the halo pixels in the same direction are the ones with the RRL modulation:

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

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.

Unlisted 1.84x RE Super-Earth Transiting KIC 8499940

Q14 light curve for KIC 8499940 at Planet Hunters

Planet Hunters forum Talk member Sean63 flagged this long period transit in Kepler Quarter 14. It is not listed on the Kepler Threshold Crossing Events (TCE)  table.

Kian Jek:

Q14 event appears to be the only transit seen in all the quarters. The modeled transit gives an estimated period of 1387 d + 540/-280, so it looks like a pretty long-period PC.

The transit curve also estimates a 1.84x RE super-earth, at 2.9AU and Teq of 158K.

Kepler Q14 also has more than its share of cosmic ray hits. Here is Kian's comments on this possibility:

 I just checked the FITS file. It's hard to tell for sure. Turns out there IS a cosmic ray hit, an isolated one but in the OA. However it is right in the middle of the transit as circled.

The others we have seen were at the very start of the dips. What the CR hit does is to cause a momentary spike. The CCD module detects these spikes and then adjusts the level to compensate for it. But because I think the circuitry is overloaded, what usually happens is that although the spike is removed, subsequent cadences are adjusted down instead, creating the impression of a dip.

I'm not sure. We'll have to look for repeats.

 
 

 You can follow the discussion on this possible planet transit on Talk here.

KIC 7944566 Unlisted Eclipsing Binary

KIC 7944566 in Q7

Planet Hunters forum Talk members have flagged this transit for KIC 7944566 as an unlisted eclipsing binary star system. It shows up in both Kepler quarters Q7 and Q12. Not listed in Kepler Threshold Crossing Events (TCE) table.

UKIRT

You can follow this system on Talk here

Possible Exomoon Candidate transiting KIC 11152511

Kepler Q4 Light curve drop for KIC 11122511

Planet Hunters Talk member Khalin flagged this drop in Quarter four and Capella recently brought the transit forward from a collection of Tom128 for further analysis by forum members. There are some anomalies with this transit that may indicate the presence of an Exomoon. Though speculative at this point and time, more analysis is required as the hunt for a valid Exomoon continues at a fever pitch in the Kepler community.

ajamyajax

 

Yeah, could always be noise. The small gap in data here is what I saw though. There is a similar one on the other side in the earlier transit event. And not much in the third. So in theory anyway, this could be a large moon with its own periodic orbit. This recent article mentions that the first such finds will likely be large moons, which also got me thinking about that here:

"Alien Moons Could Host Life Outside 'Habitable Edge'"
http://news.yahoo.com/alien-moons-could-host-life-outside-habitable-edge-115714229.html





The complete Planet Hunters forum Talk thread for this transit follows:

cappella

I found this possible PC in Tom128's famous golden junk heap collection:
Q10 - day ~935 BJD

9 days ago

cappella

Q13 - day ~1223 BJD

9 days ago

cappella

We may have a candidate here with a period of ~288 days.
Unfortunately we don't have Q7 to verify the BJD ~650 transit, but there is one in Q41.

9 days ago

ajamyajax

 

Yes, looks like the same object in transit to me. And a new one not in any studies yet as far as I could see. I get a start of 360.815 BJD and a period of 287.342 with a maximum duration around 13.68 hours. And I didn't see any APO's with a glance at NEA. Here is a chart of the last two eclipses (thru q14) which are a little better than the first:

8 days ago

zoo3hans

According to the Planetary Calculator I get a 3.0 R_Earth planet @ 0.885 au from its 1.3 R_sol star with a period around 287.3 days and a temperature of 282 K, probably in the HZ.

8 days ago

ajebson

 

Here it is phased at 287.3673:

FULL

For the stellar parameters, I used Pinsonneault to infer values from the SDSS colours:

FULL

Here's a quick transit analysis constrained to zero eccentricity:

FULL


FULL

I'm a bit dubious about the exact timing of the 935 BJD transit.
Using this, it is 3.13 x Re @ 1.25AU with a Teff of 259K

8 days ago

ajamyajax in response to ajebson

ajebson:...

I'm a bit dubious about the exact timing of the 935 BJD transit.
Using this, it is 3.13 x Re @ 1.25AU with a Teff of 259K

I noticed that also, thought this one had TTV because of it. Just a disturbance in the flux :), or could that possibly be a moon?... Speculative of course, but in the HZ would make that a really neat find for PH... So I remain optimistic, as always.

8 days ago

ajebson

There's a high point followed by a two sample gap at the end of the transit, which makes it hard to be sure wher the transit ends - is the high point just noise, etc?

8 days ago

ajamyajax

 

Yeah, could always be noise. The small gap in data here is what I saw though. There is a similar one on the other side in the earlier transit event. And not much in the third. So in theory anyway, this could be a large moon with its own periodic orbit.
This recent article mentions that the first such finds will likely be large moons, which also got me thinking about that here:

"Alien Moons Could Host Life Outside 'Habitable Edge'"
http://news.yahoo.com/alien-moons-could-host-life-outside-habitable-edge-115714229.html

7 days ago

zoo3hans

Maybe David Kipping of Harvard should be alerted about this case. I have written an email to him.

ajebson

I wonder if we should do a more systematic search of all the HZ or near-HZ candidates for transit signatures as described-- Try this one and this

Also, there is one that troyw looked at that shows interesting TDVs which could just possibly be an exomoon.

7 days ago

ajamyajax in response to zoo3hans

zoo3hans:

Maybe David Kipping of Harvard should be alerted about this case. I have written an email to him.

I just e-mailed Dr Chris Lintott, thought he would like to know.

7 days ago

ajamyajax in response to ajebson

ajebson:

I wonder if we should do a more systematic search of all the HZ or near-HZ candidates for transit signatures as described here
Also, there is one that troyw looked at that shows interesting TDVs which could just possibly be an exomoon

Brilliant idea, many possibilities. You guys would be good at this, too.

about 3 hours ago

zookeeper (Chris Lintott)

Looks like an interesting case indeed! I'll ask the team and see what else we can dig up; from a quick glance I'm reasonably sceptical about the TTV - certainly one to watch for future quarters, though.
If anyone wanted a systematic search for exomoon signatures I think that'd be great, although I remain reasonably unconvinced that the Kepler data is good enough to show such a thing - noone would be happier than I to be proved wrong, though!

You can follow this star on the Forum Talk thread here.