Query : 2009A&A...499..615D

2009A&A...499..615D - Astronomy and Astrophysics, volume 499, 615-621 (2009/5-4)

On the possibility of detecting extrasolar planets' atmospheres with the Rossiter-McLaughlin effect.


Abstract (from CDS):

The detection of extrasolar planets' atmospheres requires very demanding observations. For planets that cannot be spatially separated from their host stars, i.e. the vast majority of planets, the transiting planets are the only ones to allow their atmospheres to be probed. This is possible from transmission spectroscopy or from measurements taken during the secondary eclipse. An alternative is to measure of the Rossiter-McLaughlin effect, which is sensitive to the size of the planetary radius. Since the radius is wavelength-dependent due to contributions of strong planetary absorption lines, this opens a path toward also probing planetary atmospheres with ground-based high-resolution spectroscopy. The major goal of our numerical simulations is to provide a reliable estimate of the amplitude of the wavelength-dependent Rossiter-McLaughlin effect. Our numerical simulations provide detailed phase-resolved synthetic spectra modeling the partly eclipsed stellar surface during the transit. With these spectra we can obtain Rossiter-McLaughlin curves for different wavelength regions and for a wavelength-dependent planetary radius. Curves from regions with high and low contributions of absorption lines within the planetary atmosphere can be compared. Observable quantities are derived from these differential effects. We applied our simulations to HD209458. Our numerical simulations show that a detailed treatment of the limb-darkening for the synthetic spectra is important for a precise analysis. Compared to a parameterized limb-darkening law, systematic errors of 6m/s occur. The wavelength dependency of the planetary atmospheres over the NaD-doublet produces a differential effect in the Rossiter-McLaughlin curve of 1.5m/s for a star with a rotation velocity of 4.5km/s, which increases to 4m/s for twice the rotation velocity. As a tool for probing planetary atmospheres the Rossiter-McLaughlin effect requires phase-resolved, high signal-to-noise, high-resolution spectra taken with a stabilized spectrograph in order to obtain reliable results for slowly rotating (<10 m/s) planet host stars. Stars with spectral type earlier than about F5 are a bit less demanding since the typically higher rotation velocity increases the amplitude of the effect to about 15m/s for a star with vsini=25km/s.

Abstract Copyright:

Journal keyword(s): planetary systems - techniques: radial velocities - line: profiles - stars: rotation - stars: individual: HD 209458

Simbad objects: 6

goto Full paper

goto View the references in ADS

Number of rows : 6
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 HD 17156b Pl 02 49 44.4866941172 +71 45 11.632197644           ~ 175 1
2 BD+57 793b Pl 04 21 52.7044170433 +57 49 01.892074012           ~ 203 1
3 Ross 905b Pl 11 42 11.0933874353 +26 42 23.658083337           ~ 739 1
4 HD 147506b Pl 16 20 36.3579144486 +41 02 53.109043943           ~ 240 1
5 HD 209458 V* 22 03 10.7727465312 +18 53 03.549393384   8.21 7.63     F9V 1070 1
6 HD 209458b Pl 22 03 10.7729598762 +18 53 03.548248479           ~ 1743 1

To bookmark this query, right click on this link: simbad:objects in 2009A&A...499..615D and select 'bookmark this link' or equivalent in the popup menu


© Université de Strasbourg/CNRS

    • Contact