J/PASP/109/759 Rotational Velocities of Intermediate-mass MS Stars (Wolff+ 1997)
Rotational Velocities of Intermediate-mass Main Sequence Stars
Wolff S.C., Simon T.
<Publ. Astron. Soc. Pac. 109, 759 (1997)>
=1997PASP..109..759W 1997PASP..109..759W
ADC_Keywords: Rotational velocities; Stars, normal; Spectroscopy
Description:
Rotational velocities are reported for intermediate-mass main-sequence
stars selected from Gray (1986, Gray and Garrison 1987, 1989a, 1989b).
Measured rotational velocities, with photometric data from SIMBAD, are
given in table1.dat for 249 stars. The measurements are based on new,
high-S/N CCD spectra from the Coude Feed Telescope of the Kitt Peak
National Observatory. Published velocities for 294 stars are provided
in table2.dat.
Abstract:
(from Publ. Astron. Soc. Pac. 109, 759 (1997))
We analyze these rotation rates for a dependence on both mass and age.
We compare the average rotation speeds of the field stars with mean
velocities for young stars in Orion, the Α Persei cluster, the
Pleiades, and the Hyades. The average rotation speeds of stars more
massive than ∼1.6 Msol experience little or no change during the
evolutionary lifetimes of these stars on the zero age main sequence
(ZAMS) or within the ZAMS band. Less massive stars in the range
between 1.6 Msol and 1.3 Msol also show little decline in mean
rotation rate while they are on the main sequence, and at most
a factor of two decrease in velocity as they evolve off the main
sequence. The e-folding time for the loss of angular momentum by
the latter group of stars is at least 1-2 billion years. This
inferred characteristic time scale for spindown is far longer than
the established rotational braking time for solar-type stars with
masses below ∼1.3 Msol. We conclude from a comparison of the trends
in rotation with trends in chromospheric and coronal activity that
the overall decline in mean rotation speed along the main sequence,
from ∼2 Msol down to ∼1.3 Msol, is imposed during the pre-main-sequence
phase of evolution, and that this pattern changes little thereafter
while the star resides on the main sequence. The magnetic activity
must therefore play only a minor role in determining the rotation
rates of the intermediate-mass stars, either because a solar-like
dynamo is weak or absent, or else the geometry of the magnetic field
is appreciably less effective in removing angular momentum from these
stars.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 45 249 Measured rotational velocities
table2.dat 46 294 Published rotational velocities
--------------------------------------------------------------------------------
See also:
III/22 : Rotation of Evolving A and F Stars (Danziger+ 1972)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- HD HD number
8- 12 F5.2 mag B-V *B-V color index
14- 18 F5.3 mag beta *Hβ index
19- 24 F6.3 mag b-y *b-y color index
26- 30 F5.3 mag c1 *c1 index
32- 36 F5.2 mag mag Absolute magnitude MV
38 A1 --- l_vsini [<]? Limit flag on V*Sin(i)
40- 42 I3 km/s vsini Measured V*Sin(i)
44- 45 I2 --- bin *? Bin in Fig. 3(a), color-magnitude
--------------------------------------------------------------------------------
Note on B-V, beta, b-y, c1:
Photometric data from SIMBAD.
Note on bin:
A blank indicates that the star lies beyond the terminal age main
sequence (TAMS).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- HD HD number
8- 11 F4.2 mag B-V B-V color index
13- 17 F5.3 mag beta Hβ index
19- 23 F5.3 mag b-y b-y color index
25- 29 F5.3 mag c1 c1 index
31- 35 F5.2 mag mag Absolute magnitude MV
37 A1 --- l_vsini [<]? Limit flag on V*Sin(i)
39- 41 I3 km/s vsini Published V*Sin(i)
43- 44 I2 --- bin *? Bin in Fig. 3(a), color-magnitude
46 I1 --- ref *[1-5] Reference code
--------------------------------------------------------------------------------
Note on bin:
A blank indicates that the star lies beyond the terminal age main
sequence (TAMS).
Note on ref:
1 = Slettebak et al. 1975ApJS...29..137S 1975ApJS...29..137S
2 = Kraft 1967ApJ...150..551K 1967ApJ...150..551K
3 = Danziger and Faber 1972A&A....18..428D 1972A&A....18..428D
4 = Soderblom 1983ApJS...53....1S 1983ApJS...53....1S
5 = Benz and Mayor 1984A&A...138..183B 1984A&A...138..183B
--------------------------------------------------------------------------------
Acknowledgment:
The ADC thanks Dr. Simon for providing the data tables as LaTeX files.
J.A. Watko [SSDOO/ADC] converted the tables to ASCII.
References:
Benz W., Mayor M. 1984. Astron. Astrophys. 138, 183. (1984A&A...138..183B 1984A&A...138..183B)
Danziger I.J., Faber S.M. 1972. Astron. Astrophys. 18, 428.
(1972A&A....18..428D 1972A&A....18..428D, CDS Cat. III/22)
Gray R.O. 1986. Thesis, U. Toronto.
Gray R.O., Garrison R.F. 1987. Astrophys. J. Suppl. 65, 581.
(1987ApJS...65..581G 1987ApJS...65..581G)
Gray R.O., Garrison R.F. 1989a. Astrophys. J. Suppl. 69, 301.
(1989ApJS...69..301G 1989ApJS...69..301G)
Gray R.O., Garrison R.F. 1989b. Astrophys. J. Suppl. 70, 623.
(1989ApJS...70..623G 1989ApJS...70..623G)
Kraft R.P. 1967b. Astrophys. J. 150, 551. (1967ApJ...150..551K 1967ApJ...150..551K)
Slettebak A., Collins G.W., Boyce P.B., White N.M., Parkinson T.D.
1975. Astrophys. J. Suppl. 29, 137. (1975ApJS...29..137S 1975ApJS...29..137S)
Soderblom D.R. 1983 Astrophys. J., Suppl. 53, 1 (1983ApJS...53....1S 1983ApJS...53....1S)
Wolff S.C., Simon T. 1997. Publ. Astron. Soc. Pac. 109,759.
(1997PASP..109..759W 1997PASP..109..759W)
(End) Julie Anne Watko [SSDOO/ADC] 08-Jan-1998