Planet Hunters Talk

KIC 9153357 - Three Possible Candidates

  • ProtoJeb21 by ProtoJeb21

    I happened to notice a few interesting looking events with Planet Hunters subject APH00018nr, so I booted up LcViewer to see what was there. It turns out that there are THREE likely transit events - all of which I can't find a match for. Here's the list:

    -Transit 1: BKJD 1524.549587, duration of 4.904103 hrs, depth of 1932 ppm, sigma of 8.381 (shocking high for a single transit of this size)

    -Transit 2: BKJD 1536.033405, duration of 3.923311 hrs, depth of 1579 ppm, sigma of 4.756 (not terrible)

    -Transit 3: BKJD 1542.4088, duration of 5.884988 hrs, depth of 1549 ppm, sigma of 11.739 (a lot higher than I expected!)

    Based on the LcViewer data I can neither confirm nor deny the planetary status of these three dips. All look great, but I can confirm that they are NOT from the same object. @zoo3hans @ajamyajax what are your thoughts on this?

    Posted

  • ajamyajax by ajamyajax in response to ProtoJeb21's comment.

    Hi ProtoJeb21, I looked but didn't see much there. Shallow single transit events are always just possible transits to me anyway. And maybe you remember this from EE, but in my view if they aren't obvious transits, they probably aren't going anywhere as planets anyway. However maybe zoo3hans will see more, or you or he can get a nice periodic fold in LcViewer. Hope so! Good luck and thanks for contributing here.

    p.s. any scientist replies to your exomoon candidates yet? If not, I hope you don't give up. Just be confident you are right and then keep asking around until someone takes an interest.

    Posted

  • zoo3hans by zoo3hans in response to ProtoJeb21's comment.

    Well, unless the signals are periodic I would not care too much about those dips. In my opinion the reaction wheel problems increased considerably in Q16 and Q17, so nearly all light curve show some spurious "transits" during these dates. I see no entries in the TCE list for this star either.

    Posted

  • ProtoJeb21 by ProtoJeb21

    @zoo3hans I was so hoping for a break from spacecraft roll glitches like those in the K2 data. Next time I'll try to do analysis in the early to mid quarters just to make sure I don't find any more false transit possibilities.

    @ajamyajax Yes, David Kipping did get back to me and suggested that I use TTVFast for the timing variations. He doesn't have an explanation for the huge duration variations, which aren't expected to be caused by extra planets or even moons... as far as we know. However, I have yet to get TTVFast because I can't figure out which files I need to get from GitHub. In addition, I've been pretty caught up with K2 data analysis alongside a few other users on Exoplanet Explorers. We've already found several four-candidate (and even a five-candidate) systems, mainly around red dwarfs.

    Posted

  • ajamyajax by ajamyajax in response to ProtoJeb21's comment.

    All right, sounds like progress to me. And glad you all are finding lots of new planets! When you have the time, maybe try TTV Fast here and ask one of the authors if the latest (just the link I have saved):

    https://github.com/ericagol/TTVFaster

    "TTVFast: An efficient and accurate code for transit timing inversion problems"

    Katherine M. Deck, Eric Agol, Matthew J. Holman, David Nesvorny

    http://arxiv.org/abs/1403.1895


    Update: this is new: I just ran 'pip install ttvfast', and got ttvfast 0.3.0 installed just fine. This might be easier than the C version, if you are familiar with python.

    https://pypi.python.org/pypi/ttvfast

    Posted

  • ProtoJeb21 by ProtoJeb21 in response to ajamyajax's comment.

    I'm not only unfamiliar with Python, I don't even have it. I do just about all my coding (which is 99% Kerbal Space Program planet packs) with Notepad++. I may try the C version, as it was the one David K suggested.

    Posted