X Persei

Quality 0.50 · 0 views · Updated 2 months ago

Variable star in the constellation Perseus

title: "X Persei" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["perseus-(constellation)", "o-type-giants", "b-type-main-sequence-stars", "neutron-stars", "x-ray-binaries", "objects-with-variable-star-designations", "pulsars", "durchmusterung-objects", "hipparcos-objects", "bright-star-catalogue-objects", "henry-draper-catalogue-objects", "gamma-cassiopeiae-variable-stars", "be-stars"] description: "Variable star in the constellation Perseus" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/X_Persei" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Variable star in the constellation Perseus ::

| image= |image=Perseus constellation map.svg |float=center |alt= |label= |position=right |width=280 |mark=Red circle.svg |mark_width=10 |mark_link=X Per |x=381|y=940 |caption=Location of X Per (circled in red, in the middle of the green dash) | epoch=J2000.0 | constell=Perseus | ra= | dec= | appmag_v=6.03 - 7.00 | class=O9.5IIIe-B0Ve | b-v=+0.137 | u-b=−0.790 | variable=γ Cas + X-ray pulsar | radial_v=−50.00 | prop_mo_ra=−1.397 | prop_mo_dec=−2.254 | parallax=1.2342 | p_error=0.0562 | parallax_footnote = | dist_pc= | absmag_v=−3.47 | reference = | period_unitless = 250.3 days | axis_unitless = 2.2 AU | eccentricity = | inclination = 23 - 30 | node = | periastron = | periarg = | periarg_primary = | k1 = | k2 = | component1 = Donor | source= | mass=15.5 | radius=6.5 | luminosity=29,000 | temperature= 29,500 | metal= | gravity=4.0 | rotational_velocity=215 | age_myr= 5 | names=X Persei, HR 1209, HIP 18350, HD 24534, BD+30°591, WDS J03554+3103, AAVSO 0349+30, 4U 0352+309, 2MASS J03552309+3102449, Gaia DR2 168450545792009600 |Simbad = X+Persei

X Persei is a high-mass X-ray binary system located in the constellation Perseus, approximately 950 parsecs away. It is catalogued as 4U 0352+309 in the final Uhuru catalog of X-ray objects.

::figure[src="https://upload.wikimedia.org/wikipedia/commons/9/9f/XPerLightCurve.png" caption="visual band]] [[light curve]] for X Persei, adapted from Lutovinov ''et al.'' (2012)"] ::

The conventional star component of 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 Cassiopeiae variable, and the visual range is magnitude 6 - 7. In 1989 and 1990, the spectrum of X Persei changed from a Be star to a normal B class star while it faded significantly. This appears to have been caused by the loss of the excretion disk. The disk has since reformed and shows strong emission lines.

The system also contains a neutron star which is a pulsar with an unusually long period of 837 seconds. The pulsar has shown period changes that are associated with mass transfer from the more massive primary star. Between 1973 and 1979 it was seen to increase its rate of spin, associated with a strong x-ray flare and presumed strong mass transfer. Since then the spin has been slowing despite small x-ray flares.

The combination of a neutron star and OB emission line star places X Persei in the Be/X-ray binary class of stars.

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. It is a background red giant and a candidate long period variable with the variable star designation V397 Persei.

References

References

  1. (2013). "Interstellar Abundances toward X Per, Revisited". The Astrophysical Journal.
  2. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S.
  3. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ˜55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten.
  4. {{cite DR2. 168450545792009600
  5. (1997). "Fundamental parameters, helium abundance and distance of X Persei". Monthly Notices of the Royal Astronomical Society.
  6. (2007). "Joint Hα and X-Ray Observations of Massive X-Ray Binaries. III. The Be X-Ray Binaries HDE 245770 = A0535+26 and X Persei". The Astrophysical Journal.
  7. (2001). "The Orbit of X Persei and Its Neutron Star Companion". The Astrophysical Journal.
  8. (2014). "Long-term Optical Observations of the Be/X-Ray Binary X Per". The Astronomical Journal.
  9. (1994). "Catalogue des composantes d'etoiles doubles et multiples (CCDM) premiere edition - Catalogue of the components of double and multiple stars (CCDM) first edition". Com. De l'Observ. Royal de Belgique.
  10. {{cite DR2. 168450545792008448
  11. (June 2012). "Strong outburst activity of the X-ray pulsar X Persei during 2001–2011". Monthly Notices of the Royal Astronomical Society.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

perseus-(constellation)o-type-giantsb-type-main-sequence-starsneutron-starsx-ray-binariesobjects-with-variable-star-designationspulsarsdurchmusterung-objectshipparcos-objectsbright-star-catalogue-objectshenry-draper-catalogue-objectsgamma-cassiopeiae-variable-starsbe-stars