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The Rotation of Pre-Main Sequence Stars

Published online by Cambridge University Press:  30 March 2016

Leonard V. Kuhi  and
Stuart Vogel
Leonard V. Kuhi
Affiliation:
Department of Astronomy, University of CaliforniaBerkeley, California 94720
Stuart Vogel
Affiliation:
Department of Astronomy, University of CaliforniaBerkeley, California 94720

Extract

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Kraft (1970) obtained the rotational velocities for large numbers of stars located in the field and in clusters of different ages. He noted that (a) among the field stars those stars with strong Call K emission had larger rotational velocities than those without; (b) stars in the Hyades and Pleiades (which are much younger than the field) had both larger rotational velocities and stronger Call K emission than field stars; (c) there was a pronounced break at spectral type early F in v sini as a function of spectral type and (d) the distribution of angular momentum per unit, mass J(M⊚) was proportional to M0.57 for main sequence stars with mass M > 1.5 Mʘ. This distribution predicted a v sini of ˜75 km/sec for stars of lower mass (e.g. G type) but such high velocities were not seen in the Pleiades nor in the sun. This implied a more rapid deceleration of v sini for lower mass stars and led to estimates of the e-folding time of ˜4×l08 years for stars of 1.2 M⊚ to reduce their v sini from that of the Pleiades to that of the Hyades and ˜4×l09 years to go from the Hyades to the sun’s v sini. We note also that the age of the Pleiades is approximately equal to the pre-main sequence lifetime of a 1.0 M0 star so that the zero-age main sequence cannot have J(M) α M0.57 for ˜1 M0 stars. Skumanich (1972) showed that both the Call k emission and the rotational velocity decayed as the (age)-½ for main-sequence stars.

Type
Joint Commission Meetings
Information
Highlights of Astronomy , Volume 5: Highlights of Astronomy. As presented at the XVIIth General Assembly of the IAU, 1979 , 1980 , pp. 835 - 837
Copyright
Copyright © Cambridge University Press 1980

References

Carroll, J.A. 1933, Monthly Notices Roy Astron. Soc. 93, 508.Google Scholar
Cohen, M. and Kuhl, L.V. 1979, Astrophys. J. Suppl. (in press).Google Scholar
Herbig, G.H. 1957, Astrophys. J. 125, 612.Google Scholar
Iben, I. and Talbot, R.J. 1966, Astrophys. J. 144, 968.Google Scholar
Kraft, R.P. 1970, in Spectroscopie Astrophysics (Herbig, G.H., ed), University of California Press, Berkeley, p. 385.CrossRefGoogle Scholar
Kuhi, L.V. 1978, Moon and Planets 19, 199.Google Scholar
Skumanich, A. 1972, Astrophys. J. 171, 565.CrossRefGoogle Scholar