Advanced

Determination of accurate stellar radial-velocity measures

Gullberg, Dag and Lindegren, Lennart LU (2002) In Astronomy & Astrophysics 390(1). p.383-395
Abstract
Wavelength measurements in stellar spectra cannot readily be interpretedas true stellar motion on the sub-km s<SUP>-1</SUP> accuracy level dueto the presence of many other effects, such as gravitational redshiftand stellar convection, which also produce line shifts. Following arecommendation by the IAU, the result of an accurate spectroscopicradial-velocity observation should therefore be given as the``barycentric radial-velocity measure'', i.e. the absolute spectralshift as measured by an observer at zero gravitational potential locatedat the solar-system barycentre. Standard procedures for reducingaccurate radial-velocity observations should be reviewed to take intoaccount this recommendation. We describe a procedure to... (More)
Wavelength measurements in stellar spectra cannot readily be interpretedas true stellar motion on the sub-km s<SUP>-1</SUP> accuracy level dueto the presence of many other effects, such as gravitational redshiftand stellar convection, which also produce line shifts. Following arecommendation by the IAU, the result of an accurate spectroscopicradial-velocity observation should therefore be given as the``barycentric radial-velocity measure'', i.e. the absolute spectralshift as measured by an observer at zero gravitational potential locatedat the solar-system barycentre. Standard procedures for reducingaccurate radial-velocity observations should be reviewed to take intoaccount this recommendation. We describe a procedure to determineaccurate barycentric radial-velocity measures of bright stars, based ondigital cross-correlation of spectra obtained with the ELODIEspectrometer (Observatoire de Haute-Provence) with a synthetic templateof Fe I lines. The absolute zero point of the radial-velocity measuresis linked to the wavelength scale of the Kurucz (1984) Solar Flux Atlasvia ELODIE observations of the Moon. Results are given for the Sun and42 stars, most of them members of the Hyades and Ursa Major clusters.The median internal standard error is 27 m s<SUP>-1</SUP>. The externalerror is estimated at around 120 m s<SUP>-1</SUP>, mainly reflecting theuncertainty in the wavelength scale of the Solar Flux Atlas. For the Sunwe find a radial-velocity measure of +257+/- 11 m s<SUP>-1</SUP>referring to the full-disk spectrum of the selected Fe I lines. Based onobservations made at Observatoire de Haute-Provence (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
stars: kinematics, methods: data analysis, techniques: radial velocities, open clusters and associations
in
Astronomy & Astrophysics
volume
390
issue
1
pages
383 - 395
publisher
EDP Sciences
external identifiers
  • wos:000176980000042
  • scopus:0036647888
ISSN
0004-6361
DOI
10.1051/0004-6361:20020660
language
English
LU publication?
yes
id
e8751aae-c057-4875-827d-2c4c7e987960 (old id 130342)
date added to LUP
2007-07-13 10:13:41
date last changed
2017-01-01 07:12:45
@article{e8751aae-c057-4875-827d-2c4c7e987960,
  abstract     = {Wavelength measurements in stellar spectra cannot readily be interpretedas true stellar motion on the sub-km s&lt;SUP&gt;-1&lt;/SUP&gt; accuracy level dueto the presence of many other effects, such as gravitational redshiftand stellar convection, which also produce line shifts. Following arecommendation by the IAU, the result of an accurate spectroscopicradial-velocity observation should therefore be given as the``barycentric radial-velocity measure'', i.e. the absolute spectralshift as measured by an observer at zero gravitational potential locatedat the solar-system barycentre. Standard procedures for reducingaccurate radial-velocity observations should be reviewed to take intoaccount this recommendation. We describe a procedure to determineaccurate barycentric radial-velocity measures of bright stars, based ondigital cross-correlation of spectra obtained with the ELODIEspectrometer (Observatoire de Haute-Provence) with a synthetic templateof Fe I lines. The absolute zero point of the radial-velocity measuresis linked to the wavelength scale of the Kurucz (1984) Solar Flux Atlasvia ELODIE observations of the Moon. Results are given for the Sun and42 stars, most of them members of the Hyades and Ursa Major clusters.The median internal standard error is 27 m s&lt;SUP&gt;-1&lt;/SUP&gt;. The externalerror is estimated at around 120 m s&lt;SUP&gt;-1&lt;/SUP&gt;, mainly reflecting theuncertainty in the wavelength scale of the Solar Flux Atlas. For the Sunwe find a radial-velocity measure of +257+/- 11 m s&lt;SUP&gt;-1&lt;/SUP&gt;referring to the full-disk spectrum of the selected Fe I lines. Based onobservations made at Observatoire de Haute-Provence},
  author       = {Gullberg, Dag and Lindegren, Lennart},
  issn         = {0004-6361},
  keyword      = {stars: kinematics,methods: data analysis,techniques: radial velocities,open clusters and associations},
  language     = {eng},
  number       = {1},
  pages        = {383--395},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {Determination of accurate stellar radial-velocity measures},
  url          = {http://dx.doi.org/10.1051/0004-6361:20020660},
  volume       = {390},
  year         = {2002},
}