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CATEGORIES:Exoplanet Seminars
SUMMARY:The TOI-561 system: a low density ultra-short peri
 od super-Earth and three mini-Neptunes - Gaia Lace
 delli (Padova)
DTSTART;TZID=Europe/London:20201020T130000
DTEND;TZID=Europe/London:20201020T140000
UID:TALK152632AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/152632
DESCRIPTION:Multi-planet systems offer a unique opportunity fo
 r comparative exoplanetology\, having originated f
 rom the same protoplanetary disk and evolved in th
 e same environment.  This makes them appealing tar
 gets to test theoretical planetary formation and e
 volution scenarios.\nIn this seminar I will descri
 be the multi-planet system orbiting the old\, meta
 l-poor star TOI-561. The system has been character
 ised using TESS photometry and high precision HARP
 S-N radial velocity (RV) data. We  found  that  TO
 I-561  hosts  four  transiting  planets\,  namely 
  an  ultra-short period (USP) super-Earth and thre
 e mini-Neptunes.  In fact\, after the identificati
 on of three transiting candidates by TESS\, we dis
 covered two additional external planets based on R
 V analysis. We confirmed and characterised the two
  inner TESS candidates\, but we showed that the th
 ird candidate can not be confirmed by RVs\, and wo
 uld make the system dynamically unstable. We demon
 strated that the two transits initially associated
  with this candidate are instead due to single tra
 nsits of the two additional planets discovered in 
 the RV data\, that also have a predicted strong\, 
 anti-correlated transit time variation signal. Wit
 h a density of ∼3 g cm−3\, which is consistent wit
 h a water-dominated composition\, the inner super-
 Earth is the lowest density USP planet known to da
 te.
LOCATION:ONLINE - Details to be sent by email
CONTACT:Dr Annelies Mortier
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