Hydrodynamical simulations of convection-related stellar micro-variability
(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)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/616114
- author
- Svensson, Fredrik LU and Ludwig, Hans-Günter LU
- organization
- publishing date
- 2005
- 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
- 1609-042X
- 0379-6566
- 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<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.}}, author = {{Svensson, Fredrik and Ludwig, Hans-Günter}}, booktitle = {{European Space Agency, (Special Publication) ESA SP}}, issn = {{1609-042X}}, 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}}, }