The southern hemisphere 5.9-day Cepheid T Antliae, sometimes suspected to be a Type II pulsator, is demonstrated to be a classical Cepheid lying in a previously undetected open cluster. The Cepheid has been studied using published photometric databases in conjunction with new brightness estimates obtained from the Harvard College Observatory plate collection. The star exhibits a progressive increase in pulsation period consistent with a Population I Cepheid in the third crossing of the instability strip. Superimposed upon the evolutionary period changes are subtle trends that are reasonably indicative of orbital motion about an unseen companion, with an orbital period of order 42 years. Centered near the Cepheid is a faint, anonymous, open cluster that may be associated with T Antliae. Spectral types from an objective prism plate of the field, in conjunction with data from the Hipparcos/Tycho mission, are consistent with an intermediate-aged cluster with a distance, reddening, and age consistent with the possible membership of T Antliae. New photometric and spectroscopic data of the Cepheid and cluster are needed to strengthen the case. The research described here was made possible by an AAS Small Research Grant.
American Astronomical Society Meeting Abstracts #200
- Pub Date:
- May 2002