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Rotation of stars in NGC 6134. A comparison of delta Scuti stars and non-variable stars
We present results of spectroscopic observations of selected stars inthe southern open cluster NGC 6134. We have determined the rotationalvelocities of the six known delta Scuti stars in NGC 6134 as well asseveral other non-variable stars with similar colour temperature inorder to investigate if v sin i and variability is somehow connected: wefind no such correlation. We also compare the distribution of v sin i ofdelta Scuti stars and non-variable stars with four other well-studiedopen clusters to look for any systematic behaviour, but we find noconclusive evidence for v sin i and variability to be connected. We havealso used the spectra to carry out an abundance analysis of the deltaScuti stars in NGC 6134 to confirm the high metal content of thecluster. We find [Fe/H] = +0.38+/-0.05 which is in agreement with theresult obtained from Strömgren photometry. We also present Delta aphotometry of the cluster, but we find no chemical peculiar stars basedon this index. Based in part on observations obtained at the EuropeanSouthern Observatory at La Silla and UTSO-Las Campanas, Chile.
| Estimation of spectral classifications for bright southern stars with interesting Stromgren indices
This paper investigates the degree of success with which uvby photometrycan be applied to predict spectral classifications for 947 A, F, and Gstars brighter than an apparent magnitude of 8.3 and with four-colorindices indicating some kind of interesting, unusual, or peculiarspectrum. One or several possible spectral classifications are estimatedfor each star from photometry alone, double stars are distinguished, andthe estimates are compared with published classifications. The resultsshow that the framework provided by uvby photometry can be extended toinclude most G and K stars, reddened stars, peculiar stars, and certaintypes of double star.
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