Observation and analysis of the youngest transiting planet candidate Stefanie Rätz Research Fellow, ESA, ESTEC, Noordwijk, The Netherlands

YETI – Young Exoplanet Transit Initiative Search for transiting planets in young open clusters Main goal: Search for close-in, young planets and Brown Dwarfs with the transit method Young, open star clusters provide an ideal environment because they have a relatively high number of stars of same age, metallicity and distance Can give constraints on: –Limits for time scales of planet formation and migration –Effect of age, environment and metallicity on frequency of planets –Evolutionary models of planets and Brown Dwarfs Additional scientific output: –Constraints on Metallicity, age, distance –Large number of variable stars could be analyzed Different clusters in a range of Myr were selected Neuhäuser et. al. (2011)

Transit Observation we launched an international observing campaign Strategy: collecting data from m telescopes spread worldwide at different longitudes  Aim: Observations 24/7 three runs per year per cluster in two or three subsequent years: typically one to two weeks long

Gunma Astronomical Observatory 1.5-m telescope Xinglong Observatory 90/60 cm Byurakan 1.0 and 2.6 telescopes Stara Lesna Astronomical Institute 0.6-m telescope Jena Astrophysical Institute 0.9/0.6-m telescope Sierra Nevada 1.5-m telescope Gettysburg Collage Observatory 0.4-m telescope Llano del Hato Observatory 1-m Schmidt telescope Tenagra II 0.8-m telescope Stony Brook 14““ telescope Lulin Lulin Observatory 1m Telescope Nainital State Observatory 1-m telescope Rozhen 0.6 and 2-m telescopes Torun 60 cm telescope Calar Alto 2.2-m telescope Swarthmore 0.6-m telescope Observatorio Cerro Armazones two 5.9’’ telescopes Mauna Kea Univ. of Hawaii 2.2m telescope

25 Ori cluster (Briceño et al. 2007) Well defined group of at least 200 low-mass pre-main-sequence stars Concentrated within ~1° of the early-B star 25 Ori in Orion OB1a The parallaxes of the Hipparcos stars yield a mean distance of 323 pc Low mass members follow a well- defined band in the color-magnitude Diagram  isochronal age ~7-10 Myrs disk lifetime: ~ Myrs, hence 25 Ori cluster at the very age, when planet formation finishes Most populated cluster in this age range known within 500 pc  excellent laboratory to study the early evolution of sun-like stars, protoplanetary disks, and planet formation 3 Myrs 10 Myrs 1 Myr 30 Myrs100 Myrs

Observations Start of the monitoring of 25 Ori: January 2010 –Observations from three different Observatories beginning of 2010 –University Observatory Jena: 15 nights Season 1 (winter 2010/2011): –2010 Dec. 10 – 17, 2011 Jan. 14 – 24, 2011 Feb. 16 – 28 –Observations from 13 different Observatories –University Observatory Jena: 52 nights Season 2 (winter 2011/2012 ): –2011 Dec. 05 – 16, 2012 Jan. 09 – 18, 2012 Jan. 31– Feb. 09 –Observations from 12 different Observatories –University Observatory Jena: 42 nights Season 3 (winter 2011/2012 ): –2012 Dec. 04 – 14, 2013 Jan. 08 – 18, 2013 Feb. 10 – 17 –Observations from 7 different Observatories –University Observatory Jena: 5 nights

Duty Cycle: 54.5%

First Transit candidate

Barnes et al. 2013

Observations Start of the monitoring of 25 Ori: January 2010 Season 1 (winter 2010/2011): 52 clear nights including 13 transits Season 2 (winter 2011/2012): 42 clear nights including 11 transits Season 3 (winter 2012/2013): only 5 observing nights Follow-up observations on the Observatorio de Sierra Nevada, Spain –5 transit observations in 2013 Nov-Dec After each season all transits were combined

Barnes et al. 2013: a precessing planet transiting a gravity-darkened star

Gravity Darkening Fast rotation  star is oblate (larger radius at the equator than at the poles)  poles have a higher surface gravity, and thus, higher temperature and brightness

Outlook

Gaps in the observations were interpolated with 3rd order polynomials (continuity of the data points)

before

see Poster M. Kitze (EP-5)

Thank you for your attention !!!