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Hydrodynamical simulations of convection-related stellar micro-variability

Svensson, Fredrik LU and Ludwig, Hans-Günter LU (2005) 13th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun 560. p.979-984
Abstract
We used a series of CO<sup>5</sup>BOLD hydrodynamical model atmospheres covering stellar objects from white dwarfs to red giants to derive theoretical estimates of the photometric and photocentric stellar variability in wavelength-integrated light across the Hertzsprung-Russell diagram. We validated our models against solar measurements from the SoHO/VIRGO instrument. Within our set of models we find a systematic increase of the photometric as well as photocentric variability - which turn out to be closely connected - with decreasing surface gravity. The estimated absolute levels of the photocentric variability do not affect astrometric observations on a precision level expected to be achieved by the GAIA mission - with the... (More)
We used a series of CO<sup>5</sup>BOLD hydrodynamical model atmospheres covering stellar objects from white dwarfs to red giants to derive theoretical estimates of the photometric and photocentric stellar variability in wavelength-integrated light across the Hertzsprung-Russell diagram. We validated our models against solar measurements from the SoHO/VIRGO instrument. Within our set of models we find a systematic increase of the photometric as well as photocentric variability - which turn out to be closely connected - with decreasing surface gravity. The estimated absolute levels of the photocentric variability do not affect astrometric observations on a precision level expected to be achieved by the GAIA mission - with the exception of close-by giants. The case of supergiants remains to be investigated. In view of the ongoing debate about the photometric non-detection of p-modes in Procyon by the Canadian MOST satellite we remark that we obtain a factor of approximately equals 3 in amplitude between the granular background "noise" in the Sun and Procyon. This statement refers to a particular representation of temporal power spectra as discussed in Sect. 5. (Less)
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author
and
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Exoplanets, Granulations, Variability, Astrometry
host publication
European Space Agency, (Special Publication) ESA SP
volume
560
pages
979 - 984
publisher
European Space Agency
conference name
13th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun
conference location
Hamburg, Germany
conference dates
2004-07-05 - 2004-07-09
external identifiers
  • wos:000231306900198
  • other:CODEN: ESPUD4
  • scopus:23844531326
ISSN
0379-6566
1609-042X
language
English
LU publication?
yes
id
adcd9b75-b1b4-4890-a324-0ebb71b94494 (old id 616114)
alternative location
http://front.math.ucdavis.edu/0409.1714
date added to LUP
2016-04-01 11:58:45
date last changed
2024-06-04 03:23:09
@inproceedings{adcd9b75-b1b4-4890-a324-0ebb71b94494,
  abstract     = {{We used a series of CO&lt;sup&gt;5&lt;/sup&gt;BOLD hydrodynamical model atmospheres covering stellar objects from white dwarfs to red giants to derive theoretical estimates of the photometric and photocentric stellar variability in wavelength-integrated light across the Hertzsprung-Russell diagram. We validated our models against solar measurements from the SoHO/VIRGO instrument. Within our set of models we find a systematic increase of the photometric as well as photocentric variability - which turn out to be closely connected - with decreasing surface gravity. The estimated absolute levels of the photocentric variability do not affect astrometric observations on a precision level expected to be achieved by the GAIA mission - with the exception of close-by giants. The case of supergiants remains to be investigated. In view of the ongoing debate about the photometric non-detection of p-modes in Procyon by the Canadian MOST satellite we remark that we obtain a factor of approximately equals 3 in amplitude between the granular background "noise" in the Sun and Procyon. This statement refers to a particular representation of temporal power spectra as discussed in Sect. 5.}},
  author       = {{Svensson, Fredrik and Ludwig, Hans-Günter}},
  booktitle    = {{European Space Agency, (Special Publication) ESA SP}},
  issn         = {{0379-6566}},
  keywords     = {{Exoplanets; Granulations; Variability; Astrometry}},
  language     = {{eng}},
  pages        = {{979--984}},
  publisher    = {{European Space Agency}},
  title        = {{Hydrodynamical simulations of convection-related stellar micro-variability}},
  url          = {{http://front.math.ucdavis.edu/0409.1714}},
  volume       = {{560}},
  year         = {{2005}},
}