2008A&A...481L..83L -
Astronomy and Astrophysics, volume 481, L83-86 (2008/4-2)
Rayleigh scattering in the transit spectrum of HD189733b.
LECAVELIER DES ETANGS A., PONT F., VIDAL-MADJAR A. and SING D.
Abstract (from CDS):
The transit spectrum of the exoplanet HD189733b has recently been obtained between 0.55 and 1.05µm. Here we present an analysis of this spectrum. We develop first-order equations to interpret absorption spectra. In the case of HD189733b, we show that the observed slope of the absorption as a function of wavelength is characteristic of extinction proportional to the inverse of the fourth power of the wavelength (∝λ–4). Assuming an extinction dominated by Rayleigh scattering, we derive an atmospheric temperature of 1340±150K. If molecular hydrogen is responsible for the Rayleigh scattering, the atmospheric pressure at the planetary characteristic radius of 0.1564 stellar radius must be 410±30mbar. However the preferred scenario is scattering by condensate particles. Using the Mie approximation, we find that the particles must have a low value for the imaginary part of the refraction index. We identify MgSiO3 as a possible abundant condensate whose particle size must be between ∼10–2 and ∼10–1µm. For this condensate, assuming solar abundance, the pressure at 0.1564 stellar radius is found to be between a few microbars and few millibars, and the temperature is found to be in the range 1340-1540K, and both depend on the particle size.
Abstract Copyright:
∼
Journal keyword(s):
stars: planetary systems - scattering - techniques: spectroscopic - stars: individual: HD 189733b
CDS comments:
Paragraph.5 HD 18973b is a misprint for HD 189733b.
(Ref) Object type as listed in the reference "Ref"
(acronym) Object type linked to the acronym according to the original reference
() Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases
Other object types:
Pl?
(),
Pl
(),
*
(HD)
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
(wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
position angle (in degrees North celestial pole to East)
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
(wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
position angle (in degrees North celestial pole to East)
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
(wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
position angle (in degrees North celestial pole to East)
References (1141 between 1850 and 2021) (Total 1141)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
Follow
new references on this object
Annotations :
Annotations allow a user to add a note or report an error concerning the astronomical object and its data. It requires registration to post a note. See description . Please, have a look at Best practices. The list of all annotations to SIMBAD objects can be found here .
To bookmark this query, right click on this link: simbad:objects in 2008A&A...481L..83L and select 'bookmark this link' or equivalent in the popup menu