Direct Observations of Rotationally Distorted Stars
نویسندگان
چکیده
We present infrared interferometric angular size measurements for rapidly rotating stars which indicate non-circular projected disk brightness distributions. For the A7IV-V star Altair, assuming that the apparent oblateness of the photosphere is due to the star's rapid rotation, a rigorous evaluation of the observation data in the context of a rigidly rotating Roche model shows that an estimate of v sin i == 210 ± 13 km S-l can be derived that is independent of spectroscopic techniques. Altair is the first main sequence star for which direct observations of an oblate photosphere have been reported, and the first star for which v sin i has been established from observations of the star's photospheric geometry. Future prospects for this technique are considered, and a prospective catalog of 67 rotationally oblate targets is presented.
منابع مشابه
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