Query : 2004A&A...415..325R

2004A&A...415..325R - Astronomy and Astrophysics, volume 415, 325-329 (2004/2-3)

First signatures of strong differential rotation in A-type stars.


Abstract (from CDS):

We reanalyzed high quality spectra of 158 stars of spectral types A0-F1 and vsin i between 60 and 150km/s. Using a Least Squares Deconvolution technique we extracted high S/N broadening profiles and determined the loci of the Fourier transform zeros q1 and q2 where the S/N-ratio was high enough. The values of vsin i were redetermined and found to be consistent with the values derived by Rouer et al., (2002A&A...381..105R). For 78 stars q2 could be determined and the ratio q2/q1 was used as a shape parameter sensitive for solar-like differential rotation (Equator faster than Pole). 74 of the 78 stars have values of q2/q1 consistent with solid body rotation; in four of the 78 cases, values of q2/q1 are not consistent with rigid rotation. Although these stars may be binaries, none of the profiles shows signatures of a companion. The Fourier transforms do not indicate any distortions and the broadening profiles can be considered due to single objects. One of those candidates may be an extremely rapid rotator seen pole-on, but for the other three stars of spectral types as early as A6, differential rotation seems to be the most plausible explanation for the peculiar profiles.

Abstract Copyright:

Journal keyword(s): stars: rotation - stars: early-type - stars: activity

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
1 HD 6869 ** 01 08 33.83381 -46 40 04.7340           F0V 46 0
2 HD 44892 * 06 23 42.7645543008 -16 28 01.881208776   6.86 6.57     A9/F0IV 32 0
3 HD 60555 * 07 33 52.3633899264 -28 34 03.825695820   7.06 6.76     A5/7V+(F) 26 0
4 HD 109238 * 12 33 22.2465760896 -19 47 32.945772912   6.548 6.254     F0IV/V 36 0

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