J/ApJ/832/30 Raman scattering cross sections for H2 (Oklopcic+, 2016)
Raman scattering by molecular hydrogen and nitrogen in exoplanetary atmospheres.
Oklopcic A., Hirata C.M., Heng K.
<Astrophys. J., 832, 30-30 (2016)>
=2016ApJ...832...30O 2016ApJ...832...30O (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics
Keywords: molecular processes; planets and satellites: atmospheres;
radiative transfer; scattering; techniques: spectroscopic
Abstract:
An important source of opacity in exoplanet atmospheres at short
visible and near-UV wavelengths is Rayleigh scattering of light on
molecules. It is accompanied by a related, albeit weaker process-Raman
scattering. We analyze the signatures of Raman scattering imprinted in
the reflected light and the geometric albedo of exoplanets, which
could provide information about atmospheric properties. Raman
scattering affects the geometric albedo spectra of planets in the
following ways. First, it causes filling-in of strong absorption lines
in the incident radiation, thus producing sharp peaks in the albedo.
Second, it shifts the wavelengths of spectral features in the
reflected light causing the so-called Raman ghost lines. Raman
scattering can also cause a broadband reduction of the albedo due to
wavelength shifting of a stellar spectrum with red spectral index.
Observing the Raman peaks in the albedo could be used to measure the
column density of gas, thus providing constraints on the presence of
clouds in the atmosphere. Observing the Raman ghost lines could be
used to spectroscopically identify the main scatterer in the
atmosphere, even molecules like H2 or N2, which do not have
prominent spectral signatures in the optical wavelength range. If
detected, ghost lines could also provide information about the
temperature of the atmosphere. In this paper, we investigate the
effects of Raman scattering in hydrogen- and nitrogen-dominated
atmospheres. We analyze the feasibility of detecting the signatures of
Raman scattering with the existing and future observational
facilities, and of using these signatures as probes of exoplanetary
atmospheres.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 38 56 Raman scattering cross sections for H2
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1 I1 --- Ji [0/9] Initial rotational quantum number for
ground vibrational level
3- 4 I2 --- Jf [0/11] Final rotational quantum number
6 I1 --- vf [0/1] Final vibrational quantum number
8- 24 E17.10 cm+6 CS [4e-48/10e-45] Cross section coefficient
26- 38 F13.7 cm-1 delnu [-1815.5/5927.8] Raman shift
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 15-Feb-2017