Primary X Per | Companion 4U 0352+309 | |
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X Persei is a binary star system located in the constellation Perseus, approximately 950 parsecs away.
The optical star X Persei has been classified either as an O-type giant or a B-type main sequence star. It is a Be star, rotating rapidly, and at times surrounded by a disk of expelled material. This qualifies it as a Gamma Cassiopeia variable, and the visual range is magnitude 6 - 7. There is a faint optical companion separated by 22.5" which the Catalog of Components of Double and Multiple Stars refers to as X Persei B.
X Persei A is in orbit with a neutron star, which is catalogued as 4U 0352+309 in the final Uhuru catalog of X-ray objects. It is a pulsar with an unusually long period of 837 seconds.
References
X Persei Wikipedia(Text) CC BY-SA