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CATEGORIES:Exoplanet Seminars
SUMMARY:Reassessing the Evidence for Time Variability in t
 he Atmosphere of the Exoplanet HAT-P-7b - Maura La
 lly (Cornell)
DTSTART;TZID=Europe/London:20240305T130000
DTEND;TZID=Europe/London:20240305T140000
UID:TALK210832AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/210832
DESCRIPTION:We reassess the claimed detection of variability i
 n the atmosphere of the hot Jupiter HAT-P-7 b\, re
 ported by Armstrong et al. (2016). Although astron
 omers expect hot Jupiters to have changing atmosph
 eres\, variability is challenging to detect. We lo
 oked for time variation in the phase curves of HAT
 -P-7 b in Kepler data using similar methods to Arm
 strong et al. (2016)\, and identified apparently s
 ignificant variations similar to what they found. 
 Numerous tests show the variations to be mostly ro
 bust to different analysis strategies. However\, w
 hen we injected unchanging phase curve signals int
 o the light curves of other stars and searched for
  variability\, we often saw similar levels of vari
 ations as in the HAT-P-7 light curve. Fourier anal
 ysis of the HAT-P-7 light curve revealed backgroun
 d red noise from stellar supergranulation on times
 cales similar to the planet's orbital period. Test
 s of simulated light curves with the same level of
  noise as HAT-P-7's supergranulation show that thi
 s effect alone can cause the amplitude and phase o
 ffset variability we detect for HAT-P-7 b. Therefo
 re\, the apparent variations in HAT-P-7 b's atmosp
 here could instead be caused by non-planetary sour
 ces\, most likely photometric variability due to s
 upergranulation on the host star.
LOCATION:Ryle seminar room + ONLINE - Details to be sent by
  email
CONTACT:Dr Emily Sandford
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