Altair Research Articles

Rotating Stellar Atmospheres and the Energy Distribution of Altair

AbstractModels of rotating stellar atmospheres have been constructed for masses appropriate to middle and late A stars, and some of the photometric properties of these models are discussed. A specific model for the rapidly rotating star Altair has been constructed matching the observed radius, luminosity, and projected rotational velocity. It is found that the energy distribution predicted for the model agrees well with that observed for Altair, after the latter has been corrected for line blanketing.

Starry Skies for Autumn

> SEPTEMBER brings the beginning of autumn in the Northern Hemisphere, and the evening skies show the star groups that are characteristic of this time of year. High in the south shines the star Altair, marking the constellation of Aquila, the eagle. Still higher is Cygnus, the swan, with Deneb as the brightest star. A little to the west stands Vega, in Lyra, the lyre. These stars can be located with the aid of the accompanying maps, which depict the heavens as they appear about 11:00 p.m., your own kind of daylight saving time, at the beginning of September. By the middle of the month they will look the same about 10:00 p.m. They present a similar aspect around 9:00 p.m. about Sept. 30. Both Cygnus and Lyra are divided between the northern and southern sky maps. Vega is the brightest star shown, and it can be easily located high in the west. Deneb is almost directly overhead, and Altair is lower, slightly toward the southwest.