EDP Sciences
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Volume 390, Number 1, July IV 2002
Page(s) 109 - 119
Section Stellar clusters and associations
DOI http://dx.doi.org/10.1051/0004-6361:20020713

A&A 390, 109-119 (2002)
DOI: 10.1051/0004-6361:20020713

Rotation of stars in NGC 6134

A comparison of $\delta$ Scuti stars and non-variable stars
M. B. Rasmussen1, H.Bruntt1, S. Frandsen1, E. Paunzen2 and H. M. Maitzen2

1  Institute for Physics and Astronomy, University of Aarhus, Bygn. 520, 8000 Aarhus C, Denmark
2  Institut für Astronomie der Universität Wien, Türkenschanzstrasse 17, 1180 Wien, Austria

(Received 14 February 2002 / Accepted 24 April 2002)

We present results of spectroscopic observations of selected stars in the southern open cluster NGC 6134. We have determined the rotational velocities of the six known $\delta$ Scuti stars in NGC 6134 as well as several other non-variable stars with similar colour temperature in order to investigate if $v\sin i$ and variability is somehow connected: we find no such correlation. We also compare the distribution of $v\sin i$ of $\delta$ Scuti stars and non-variable stars with four other well-studied open clusters to look for any systematic behaviour, but we find no conclusive evidence for $v\sin i$ and variability to be connected. We have also used the spectra to carry out an abundance analysis of the $\delta$ Scuti stars in NGC 6134 to confirm the high metal content of the cluster. We find $[{\rm Fe/H}] = +0.38\pm0.05$ which is in agreement with the result obtained from Strömgren photometry. We also present $\Delta a$ photometry of the cluster, but we find no chemical peculiar stars based on this index.

Key words: stars: oscillations -- stars: variable: $\delta$ Scuti -- stars: rotation -- open clusters and associations: individual: NGC 6134, NGC 3680

Offprint request: S. Frandsen, srf@ifa.au.dk

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