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Hyades dynamics from N-body simulations: Accuracy of astrometric radial velocities from Hipparcos

Madsen, Søren LU (2003) In Astronomy & Astrophysics 401(2). p.565-576
Abstract
The internal velocity structure in the Hyades cluster as seen byHipparcos is compared with realistic N-body simulations using the NBODY6code, which includes binary interaction, stellar evolution and theGalactic tidal field. The model allows to estimate reliably the accuracyof astrometric radial velocities in the Hyades as derived by Lindegrenet al. (cite{lindegren00}) and Madsen et al. (cite{madsen02}) fromHipparcos data, by applying the same estimation procedure on thesimulated data. The simulations indicate that the current clustervelocity dispersion decreases from 0.35 km s<SUP>-1</SUP> at the clustercentre to a minimum of 0.20 km s<SUP>-1</SUP> at 8 pc radius (2-3 coreradii), from where it slightly increases... (More)
The internal velocity structure in the Hyades cluster as seen byHipparcos is compared with realistic N-body simulations using the NBODY6code, which includes binary interaction, stellar evolution and theGalactic tidal field. The model allows to estimate reliably the accuracyof astrometric radial velocities in the Hyades as derived by Lindegrenet al. (cite{lindegren00}) and Madsen et al. (cite{madsen02}) fromHipparcos data, by applying the same estimation procedure on thesimulated data. The simulations indicate that the current clustervelocity dispersion decreases from 0.35 km s<SUP>-1</SUP> at the clustercentre to a minimum of 0.20 km s<SUP>-1</SUP> at 8 pc radius (2-3 coreradii), from where it slightly increases outwards. A clear negativecorrelation between dispersion and stellar mass is seen in the centralpart of the cluster but is almost absent beyond a radius of 3 pc. Itfollows that the (internal) standard error of the astrometric radialvelocities relative to the cluster centroid may be as small as 0.2 kms<SUP>-1</SUP> for a suitable selection of stars, while a total(external) standard error of 0.6 km s<SUP>-1</SUP> is found when theuncertainty of the bulk motion of the cluster is included. Attempts tosee structure in the velocity dispersion using observational data fromHipparcos and Tycho-2 are inconclusive.Based on observations by the ESA Hipparcos satellite, and on the N-bodycode NBODY6 by Sverre Aarseth, publicly available atftp://ftp.ast.cam.ac.uk/pub/sverre/ (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
methods: N-body simulations, data analysis, techniques: astrometry, stars: kinematics, open clusters and associations: general, open clusters and associations: individual: Hyades
in
Astronomy & Astrophysics
volume
401
issue
2
pages
565 - 576
publisher
EDP Sciences
external identifiers
  • wos:000181708800019
  • scopus:0037388523
ISSN
0004-6361
DOI
10.1051/0004-6361:20030147
language
English
LU publication?
yes
id
2bab516b-fe32-4fc4-8eaa-d367a434c011 (old id 130553)
date added to LUP
2007-07-13 14:08:02
date last changed
2017-01-01 06:42:30
@article{2bab516b-fe32-4fc4-8eaa-d367a434c011,
  abstract     = {The internal velocity structure in the Hyades cluster as seen byHipparcos is compared with realistic N-body simulations using the NBODY6code, which includes binary interaction, stellar evolution and theGalactic tidal field. The model allows to estimate reliably the accuracyof astrometric radial velocities in the Hyades as derived by Lindegrenet al. (cite{lindegren00}) and Madsen et al. (cite{madsen02}) fromHipparcos data, by applying the same estimation procedure on thesimulated data. The simulations indicate that the current clustervelocity dispersion decreases from 0.35 km s&lt;SUP&gt;-1&lt;/SUP&gt; at the clustercentre to a minimum of 0.20 km s&lt;SUP&gt;-1&lt;/SUP&gt; at 8 pc radius (2-3 coreradii), from where it slightly increases outwards. A clear negativecorrelation between dispersion and stellar mass is seen in the centralpart of the cluster but is almost absent beyond a radius of 3 pc. Itfollows that the (internal) standard error of the astrometric radialvelocities relative to the cluster centroid may be as small as 0.2 kms&lt;SUP&gt;-1&lt;/SUP&gt; for a suitable selection of stars, while a total(external) standard error of 0.6 km s&lt;SUP&gt;-1&lt;/SUP&gt; is found when theuncertainty of the bulk motion of the cluster is included. Attempts tosee structure in the velocity dispersion using observational data fromHipparcos and Tycho-2 are inconclusive.Based on observations by the ESA Hipparcos satellite, and on the N-bodycode NBODY6 by Sverre Aarseth, publicly available atftp://ftp.ast.cam.ac.uk/pub/sverre/},
  author       = {Madsen, Søren},
  issn         = {0004-6361},
  keyword      = {methods: N-body simulations,data analysis,techniques: astrometry,stars: kinematics,open clusters and associations: general,open clusters and associations: individual: Hyades},
  language     = {eng},
  number       = {2},
  pages        = {565--576},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {Hyades dynamics from N-body simulations: Accuracy of astrometric radial velocities from Hipparcos},
  url          = {http://dx.doi.org/10.1051/0004-6361:20030147},
  volume       = {401},
  year         = {2003},
}