200 likes | 287 Views
Results of HARPS-N observations of the transiting system Qatar-1 in GAPS. E. Covino M. Esposito, M. Barbieri, S. Desidera, L. Mancini, V. Nascimbeni, J. Southworth, A. Sozzetti, R.Claudi, K. Biazzo, N. Lanza, G. Piotto, & GAPS team.
E N D
Results of HARPS-N observations of the transiting system Qatar-1in GAPS E. Covino M. Esposito, M. Barbieri, S. Desidera, L. Mancini, V. Nascimbeni, J. Southworth, A. Sozzetti, R.Claudi, K. Biazzo, N. Lanza, G. Piotto, & GAPS team GREAT-ESF Gaia and Exoplanets Workshop – Turin 5-7/Nov/2012 GREAT-ESF Gaia and Exoplanets Workshop
What can we learn from RM effect observations? The shape of the RM anomaly depends on the trajectory of the transiting planet. Gaudi & Winn (2007)
Why is the RM effect interesting? is connected with the planet migration mechanism • Type II migration: disk-planet interaction small eccentricity and inclination • roughly explains semi-major axis distribution (Ida & Lin 2004) • cannot explain eccentric planets • Jumping Jupiter model: multiple-planet interaction + scattering • Kozai migration: perturbation by off-plane massive companion possible large eccentricity and inclination • explain eccentricity distribution when combined with Type II migration models
Observational panorama ~60 systems with RM effect measured Most planets are aligned (||<30º). Misaligned planets seem more frequent around slightly more evolved stars or hotter than ~6000K (Winn et al. 2010), though still an open issue (Moutou et al. 2011).
Motivation of the GAPS RM effect subprogram • derived via the RM effect is an important constraint on spin-orbit alignment and a basic parameter to characterize planetary orbits and test planet migration models • Study tidal interaction with host star of close-in GPs • Confirmation of transiting planet candidates Study of RM effect for transiting planets provides clues on architecture and orbital evolution of planetary systems
The GAPS RM-effect subprogram: targets This sub-program of GAPS is aimed to determine/improve fundamental orbital parameters for transiting planets, i.e. derive the spin-orbit misalignement through observation of the Rossiter-McLaughlin (RM) effect Selected Targets include stars with: V<13, DEC>-30 and VsinI>1km/s spanning a range of stellar and planet properties Excluded objects with: RM effect already measured Kepler targets
HARPS-N observations of the transiting system Qatar-1 Hot Jupiter orbiting a (V~12.8mag) metal-rich K-dwarf star in about 2.4 days (Alsubai 2010) • Obtained 11 spectra (exp-time=900s, S/N~30 at 6000Å, σRV~4.5m/s) covering transit on September 3: RM effect successfully detected • Out-of-transit data gathered in six following nights (Sep 5, 6, 7, 8, 9, 11): new RVC solution
Observed R-M effect RVC from Alsubai (2010)
Qatar-1 spectroscopic orbit New orbital solution based on HARPS-N data consistent with a circular orbit P=1.42002449±0.0000010 d
Qatar-1 spectroscopic characterization Results from MOOG: Teff=4820±50 K Logg=4.43±0.10 ξ=0.90±0.05 km/s logn(FeI)=7.68±0.09 logn(FeII)=7.68±0.06 [FeI/H]=0.25±0.10 [FeII/H]=0.25±0.12 vsini=2.5±0.5 km/s
Ancillary data: transit R-band photometry Asiago 1.82m tel.: Date RMS (mmag) 29/05/2011 3.4 (0.95) 24/08/2012 2.6 (1.04) Calar Alto 1.23m tel.: Date RMS (mmag) 25/08/2011 1.62 21/07/2012 0.82 10/09/2012 0.87 AsiagoCA Alsubai ETD AsiagoCA Alsubai ETD
Qatar-1 RM effect model Adopted model as in Queloz et al. (2000), based on the following assumptions: average line profile as from CCF; stellar disc modelled by a 2000x2000 matrix, each element contributing with a Gaussian line profile (macroturbulence), characterized by a given velocity along the line-of-sight due to stellar rotation and limb-darkening coefficients (Claret 2004). Total profile resulting from convolution with HARPS-N instrumental profile The model considers the actual area of the disc that is occulted during an exposure and the phase smearing due to the planet's displacement.
Qatar-1 phase-smearing in RM effect The model takes into account the actual area of the disc that is occulted during each (900s) exposure and the phase smearing due to the planet's displacement. Total transit duration ~1.62 hours
Qatar-1 phase-smearing in RM effect The model takes into account the actual area of the disc that is occulted during each (900s) exposure and the phase smearing due to the planet's displacement. Total transit duration ~1.62 hours
Qatar-1 system properties • New RVC solution consistent with a circular orbit • Orbit well aligned within uncertainties with star spin axis • Determination of star Teff, log g, [Fe/H], vsinI from • Estimated star Prot ~20 days yields agegyro of ~1.3 Gyr (for B-V=0.9, usingEq. 3 of Barnes 2007) • Porb much shorter than stellar Prot implies that tidal interaction is causing angular momentum to be tranferred from planet orbit to the star, and planet is going to be engulfed.
Conclusions • New RVC solution consistent with a circular orbit • Orbit aligned within the uncertainties with spin axis • System properties derived • Planet is going to be engulfed by the star • Test of HARPS-N performances
Ancillary data: transit R-band photometry Asiago 1.82m tel.: Date RMS (mmag) 29/05/2011 3.4 (0.95) 24/08/2012 2.6 (1.04) Calar Alto 1.23m tel.: Date RMS (mmag) 25/08/2011 1.62 21/07/2012 0.82 10/09/2012 0.87 AsiagoCA Alsubai ETD