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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 In European Space Agency, (Special Publication) ESA SP 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
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Exoplanets, Granulations, Variability, Astrometry
in
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
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
2007-11-25 17:06:09
date last changed
2017-03-12 03:29:23
@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},
  keyword      = {Exoplanets,Granulations,Variability,Astrometry},
  language     = {eng},
  pages        = {979--984},
  publisher    = {European Space Agency},
  title        = {Hydrodynamical simulations of convection-related stellar micro-variability},
  volume       = {560},
  year         = {2005},
}