Intrinsic spectral blueshifts in rapidly rotating stars?
Madsen, Søren LU ; Dravins, Dainis LU
; Ludwig, Hans-Günter
LU
and Lindegren, Lennart
LU
(2003)
In Astronomy & Astrophysics
411(3).
p.581-586
- Abstract
- Spectroscopic radial velocities for several nearby open clusters suggestthat spectra of (especially earlier-type) rapidly rotating stars aresystematically blueshifted by 3 km s<SUP>-1</SUP> or more, relative tothe spectra of slowly rotating ones. Comparisons with astrometricallydetermined radial motions in the Hyades suggests this to be an absoluteblueshift, relative to wavelengths naively expected from stellar radialmotion and gravitational redshift. Analogous trends are seen also inmost other clusters studied (Pleiades, Coma Berenices, Praesepe, alphaPersei, IC 2391, NGC 6475, IC 4665, NGC 1976 and NGC 2516). Possiblemechanisms are discussed, including photospheric convection, stellarpulsation, meridional circulation, and... (More)
- Spectroscopic radial velocities for several nearby open clusters suggestthat spectra of (especially earlier-type) rapidly rotating stars aresystematically blueshifted by 3 km s<SUP>-1</SUP> or more, relative tothe spectra of slowly rotating ones. Comparisons with astrometricallydetermined radial motions in the Hyades suggests this to be an absoluteblueshift, relative to wavelengths naively expected from stellar radialmotion and gravitational redshift. Analogous trends are seen also inmost other clusters studied (Pleiades, Coma Berenices, Praesepe, alphaPersei, IC 2391, NGC 6475, IC 4665, NGC 1976 and NGC 2516). Possiblemechanisms are discussed, including photospheric convection, stellarpulsation, meridional circulation, and shock-wave propagation, as wellas effects caused by template mismatch in determining wavelengthdisplacements. For early-type stars, a plausible mechanism is shock-wavepropagation upward through the photospheric line-forming regions. Suchwavelength shifts thus permit studies of certain types of stellaratmospheric dynamics and - irrespective of their cause - may influencededuced open-cluster membership (when selected from common velocity) anddeduced cluster dynamics (some types of stars might show fortuitousvelocity patterns). (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/130445
- author
- Madsen, Søren
LU
; Dravins, Dainis
LU
; Ludwig, Hans-Günter
LU
and Lindegren, Lennart
LU
- organization
- publishing date
- 2003
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- methods: data analysis, techniques: astrometry, spectroscopy, radial velocities, stars: rotation, open clusters and associations: general
- in
- Astronomy & Astrophysics
- volume
- 411
- issue
- 3
- pages
- 581 - 586
- publisher
- EDP Sciences
- external identifiers
-
- wos:000186571300035
- scopus:0344513387
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361:20031396
- language
- English
- LU publication?
- yes
- id
- f6fee6e4-fc73-4578-b51e-764db3877eec (old id 130445)
- date added to LUP
- 2016-04-01 16:33:31
- date last changed
- 2024-01-11 10:16:37
@article{f6fee6e4-fc73-4578-b51e-764db3877eec,
abstract = {{Spectroscopic radial velocities for several nearby open clusters suggestthat spectra of (especially earlier-type) rapidly rotating stars aresystematically blueshifted by 3 km s<SUP>-1</SUP> or more, relative tothe spectra of slowly rotating ones. Comparisons with astrometricallydetermined radial motions in the Hyades suggests this to be an absoluteblueshift, relative to wavelengths naively expected from stellar radialmotion and gravitational redshift. Analogous trends are seen also inmost other clusters studied (Pleiades, Coma Berenices, Praesepe, alphaPersei, IC 2391, NGC 6475, IC 4665, NGC 1976 and NGC 2516). Possiblemechanisms are discussed, including photospheric convection, stellarpulsation, meridional circulation, and shock-wave propagation, as wellas effects caused by template mismatch in determining wavelengthdisplacements. For early-type stars, a plausible mechanism is shock-wavepropagation upward through the photospheric line-forming regions. Suchwavelength shifts thus permit studies of certain types of stellaratmospheric dynamics and - irrespective of their cause - may influencededuced open-cluster membership (when selected from common velocity) anddeduced cluster dynamics (some types of stars might show fortuitousvelocity patterns).}},
author = {{Madsen, Søren and Dravins, Dainis and Ludwig, Hans-Günter and Lindegren, Lennart}},
issn = {{0004-6361}},
keywords = {{methods: data analysis; techniques: astrometry; spectroscopy; radial velocities; stars: rotation; open clusters and associations: general}},
language = {{eng}},
number = {{3}},
pages = {{581--586}},
publisher = {{EDP Sciences}},
series = {{Astronomy & Astrophysics}},
title = {{Intrinsic spectral blueshifts in rapidly rotating stars?}},
url = {{https://lup.lub.lu.se/search/files/4708466/624149.pdf}},
doi = {{10.1051/0004-6361:20031396}},
volume = {{411}},
year = {{2003}},
}