How to tell an eclipsing binary from transiting planet

• by matt1977

  This appears to be an eclipsing binary when comparing it to the exemplars and looking at the hashtags others have given it. But how does one tell the difference between an eclipsing binary and a rapidly transiting planet? Is it due to the near straight line around a brighitness of 1?

  I've only recently signed up and am still trying to figure things out.

  Thanks.

  Posted October 27, 2015 12:31 AM

• by davidbundy77

  See my answer here http://talk.planethunters.org/#/boards/BPH0000006/discussions/DPH0000yf3

  Posted October 27, 2015 5:52 PM

• by matt1977

  Thanks David. So that explanation means that whatever is transiting APH0000uji is highly unlikely to be a planet as well, but also not likely an eclipsing binary? What would explain that phenomenon?

  Posted October 27, 2015 8:32 PM

• by davidbundy77

  This is also an eclipsing binary, but quite a wierd one, because the ragged secondary eclipses are much longer than the smooth primary eclipses. I would interpret this as follows:

  The stars are similar in brightness, because the depths are about the same, but one star must be much larger than the other. The primary eclipses occur when the smaller star is completely eclipsed by the larger star. In the secondary eclipses the smaller star passes slowly in front of the larger star. I am guessing that flare activity on the small star causes the ragged shape of the dip in brightness.

  Edit: Also, the orbit must be eccentric with the major axis pointed roughly towards the Earth. This is why the secondary transit is much longer than the primary. The size difference may not be so large after all.

  Posted October 27, 2015 9:10 PM

• by matt1977

  Thanks again. It makes the process much more enjoyable to understand what I'm looking at.

  Posted October 28, 2015 1:06 AM

• by ajamyajax

  Re 210832801: the larger star in this eccentric binary system could be an interesting A-type main-sequence star, if the colors are right here. According to Wiki these stars are young as could be the system then so more flaring seems likely. I'm also posting a chart with MAST data correction just to show the otherwise normal transit events without the fine-tuning that might also show flares (if not glitches or a small corrective issue).

  s1=2245.155 p1=28.055 d1=0.32 (7.68 hours or so)

  s2=2256.20 p2=28.055 d2=1.5 (36.0 hours or so)

  EPIC, 2MASS, J mag, H mag, K mag, J - H, H - K, (J-H spectral type, stellar mass est) (H-K spectral type, stellar mass est)

  210832801 , 2MASS J03355337+2022076 , 9.778 , 9.719 , 9.685 , 0.059 , 0.034 , ('A7V', 1.76) , ('A1V', 2.2)

  https://en.wikipedia.org/wiki/A-type_main-sequence_star

  
  

  

  ...

  Update: I asked Andrew who said this is a corrections problem meaning not flares, unfortunately. But an interesting idea to watch for next time.

  Posted October 28, 2015 1:15 AM

• by davidbundy77

  Use this eclipsing binary simulator to visualise how this light curve happens. Try using high eccentricity.

  Posted October 28, 2015 4:26 PM

• by ACS_LPSP in response to davidbundy77's comment.

  davidbundy77 thank you very much for the wonderful simulators eclipsing binary stars and extrasolar planets! I'll try to respond to your message. Probably really changes in TYC 1242-639-1 light curve caused by the eccentricity of the orbit of the system components. That is my interpretation. But I'm just mastering your program so used like to know how I am right in the construction of this binary system.
  
  

  Posted April 25, 2016 10:18 PM