J/A+A/412/813 Rotation in F-stars (Reiners+, 2003)
Differential rotation in rapidly rotating F-stars
Reiners A., Schmitt J.H.M.M.
<Astron. Astrophys. 412, 813 (2003)>
=2003A&A...412..813R 2003A&A...412..813R
ADC_Keywords: Stars, F-type ; Rotational velocities
Keywords: stars: rotation - stars: late-type - stars: activity -
methods: data analysis - line: profiles
Abstract:
We obtained high quality spectra of 135 stars of spectral types F
and later and derived "overall" broadening functions in selected
wavelength regions utilizing a Least Squares Deconvolution (LSD)
procedure. Precision values of the projected rotational velocity
vsini were derived from the first zero of the Fourier transformed
profiles and the shapes of the profiles were analyzed for effects of
differential rotation. The broadening profiles of 70 stars rotating
faster than vsini=45km/s show no indications of multiplicity nor of
spottedness. In those profiles we used the ratio of the first two
zeros of the Fourier transform q2/q1 to search for deviations from
rigid rotation. In the vast majority the profiles were found to be
consistent with rigid rotation. Five stars were found to have flat
profiles probably due to cool polar caps, in three stars cuspy
profiles were found. Two out of those three cases may be due to
extremely rapid rotation seen pole on, only in one case (vsini=52km/s)
solar-like differential rotation is the most plausible explanation for
the observed profile. These results indicate that the strength of
differential rotation diminishes in stars rotating as rapidly as
vsini>50km/s.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 69 135 Projected rotational velocities
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See also:
III/226 : Rotational Velocities of Stars (Glebocki+ 2000)
J/A+A/381/105 : Rotational velocities of A-type stars. I. (Royer+, 2002)
J/A+A/393/897 : Rotational velocities of A-type stars II. (Royer+, 2002)
J/A+AS/118/545 : Rotational velocities of F dwarfs (Groot+, 1996)
J/A+A/398/647 : Rotational velocities of F and G stars (Reiners+, 2003)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD Henry Draper Catalogue (Cat. III/135) number
8- 11 I4 --- HR Bright Star Catalogue (Cat. V/50) number
14- 24 A11 --- Name Name
27- 36 A10 --- OName Other name
39- 42 F4.2 mag B-V B-V colour index (1)
44 A1 -- l_vsini Limit flag on vsini
45- 49 F5.1 km/s vsini Projected rotational velocity
51- 54 F4.1 km/s e_vsini Error on vsini
56- 59 F4.2 -- q2/q1 ? Ratio of second to first Fourier zeros
61- 64 F4.2 -- e_q2/q1 ? Error of q2/q1
66- 67 A2 -- Note Flag on shape (2)
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Note (1): B-V from Bright Star Catalogue (Cat. V/50)
Note (2): Shape flags:
b -- blended multiple (suspected)
s -- spotted star (suspected)
a -- asymmetric profile (reason unidentified)
m2 -- multiple with 2 separated components
m3 -- multiple with 3 separated components
c -- symmetric profile, but candidate for spottedness
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Acknowledgements: Ansgar Reiners
(End) Patricia Bauer CDS 24-Oct-2003