J/A+A/607/A25 beta Pic HARPS spectrum (Vidal-Madjar+, 2017)
Fe I in the beta Pictoris circumstellar gas disk.
I. Physical properties of the neutral iron gas.
Vidal-Madjar A., Kiefer F., Lecavelier des Etangs A., Bourrier V.,
Ehrenreich D., Ferlet R., Hebrard G.
<Astron. Astrophys. 607, A25 (2017)>
=2017A&A...607A..25V 2017A&A...607A..25V (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Spectroscopy
Keywords: planetary systems - circumstellar matter
Abstract:
The young planetary system beta Pictoris is surrounded by a
circumstellar disk of dust and gas. Because both dust and gas have a
lifetime shorter than the system age, they need to be replenished
continuously. The gas composition is partly known, but its location
and its origin are still a puzzle. The gas source could be the
exocomets (or so-called falling and evaporating bodies, FEBs), which
are observed as transient features in absorption lines of refractory
elements (Mg, Ca, and Fe) when they transit in front of the star at
several tens of stellar radii.
Nearly 1700 high-resolution spectra of beta Pictoris have been
obtained from 2003 to 2015 using the HARPS spectrograph. In these
spectra, the circumstellar disk is always detected as a stable
component among the numerous variable absorption signatures of
transiting exocomets.
Summing all the 1700 spectra allowed us to reach a signal-to-noise
ratio higher than 1000, which is an unprecedentedly high number for a
beta Pictoris spectrum. It revealed many weak Fe I absorption lines of
the circumstellar gas in more than ten excited states. These weak
lines bring new information on the physical properties of the neutral
iron gas in the circumstellar disk. The population of the first
excited levels follows a Boltzmann distribution with a slope
consistent with a gas temperature of about 1300K; this temperature
corresponds to a distance to the star of ∼38 Rstar and implies a
turbulence of ksi∼0.8km/s.
Description:
The beta Pictoris system has been monitored with the HARPS
spectrograph mounted on the 3.6m telescope of La Silla (ESO Chile)
from 2003 to 2015 on a (mostly) regular basis (except between 2004
and 2007 and in 2012).
Objects:
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RA (2000) DE Designation(s)
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05 47 17.09 -51 03 59.4 beta Pic = HR 2020
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 73 1 Spectrum informations
spectrum.fits 2880 1730 FITS spectrum
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See also:
J/A+A/299/557 : Light variations on Beta Pic (Lecavelier des Etangs+, 1995)
J/A+A/542/A18 : βPic Harps radial velocity data (Lagrange+, 2012)
J/ApJ/823/108 : A dust model for bet Pic from 0.58 to 870um (Ballering+, 2016)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 11 F5.2 s RAs Right ascension (J2000)
13 A1 --- DE- Declination sign (J2000)
14- 15 I2 deg DEd Declination (J2000)
17- 18 I2 arcmin DEm Declination (J2000)
20- 23 F4.1 arcsec DEs Declination (J2000)
25- 30 I6 --- Nx Number of lines
32- 35 I4 Kibyte size Size of FITS file
37- 49 A13 --- FileName Name og the spectrum file
51- 73 A23 --- Title Title of the file
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Acknowledgements:
Alfred Vidal-Madjar, alfred(at)iap.fr
(End) Patricia Vannier [CDS] 12-Oct-2017