Night Sky by Mark R. Chartrand & Helmut K. Wimmer

Author:Mark R. Chartrand & Helmut K. Wimmer
Language: eng
Format: azw3
Tags: Sky Observation, Nature
ISBN: 9781466864757
Publisher: Macmillan
Published: 2001-04-14T00:00:00+00:00

CEPHEUS

Cephei Cep The King

“Cepheus” is a two-syllable word, as is “Perseus.” Cepheus was the father of Andromeda and husband of Cassiopeia, with whom he ruled ancient Aethiopia (here). Although some people can see a man here, most refer to it as a lopsided house.

α is Alderamin, “right arm.” This A7IV star of magnitude 2.44 is at a distance of 52 lt-yr. About 5,000 years from now, the north pole of Earth will point close to Alderamin.

β, Alfirk, “the flock,” is a B2III star 980 lt-yr away. It is slightly variable around magnitude 3.15.

γ is Errai, “the shepherd.” At 51 lt-yr this K1IV star has a magnitude of 3.20.

δ is not named but is famous as the prototype of Cepheid variable stars. These have a correlation between the period of variation and the average absolute magnitude; thus they are invaluable as distance indicators. (See here.) δ Cep is 1,300 lt-yr away, and like all other Cepheid variables changes in spectral type as it changes in magnitude. δ goes from F5 to G2 and from 3.51 to 4.42 magnitude during its period of 5.37 days. Cepheids are supergiant stars; δ is 30 times the size of our Sun.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.