XX Pyxidis

XX Pyxidis is a star located in the constellation Pyxis. It is one of the more-studied members of a class of stars known as Delta Scuti variables[3]—short period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology.[5] Astronomers made more sense of its pulsations when it became clear that it is also a binary star system. The main star is a white main sequence star of spectral type A4V that is around 1.85±0.05 times as massive as the Sun. Its companion is most likely a red dwarf star of spectral type M3V, around 0.3 times as massive as the Sun. The two are very close—possibly only 3 times the diameter of the Sun between them—and orbit each other every 1.15 days. The brighter star is deformed into an egg-shape,[3] and pulsates in several overlapping modes 26-76 times per day.[6]

XX Pyxidis

Visual band light curves for XX Pyxidis, adapted from Arentoft et al. (2001)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Pyxis
Right ascension 08h 58m 39.04s[2]
Declination −24° 35′ 10.6 ″[2]
Apparent magnitude (V) 11.49
Characteristics
Spectral type A4V + M3V[3]
Variable type Delta Scuti variable
Astrometry
Proper motion (μ) RA: -13.830[4] mas/yr
Dec.: 6.985[4] mas/yr
Parallax (π)1.4301 ± 0.0341 mas[4]
Distance2,280 ± 50 ly
(700 ± 20 pc)
Details
Mass1.85 ± 0.05[3] M☉
Other designations
XX Pyxidis, CD-24 7599, GSC 06589-00261, 2MASS, Gaia DR2 5652782998603093632
Database references
SIMBADdata

References
  1. Arentoft, T.; Sterken, C.; Handler, G. (September 2001). "Low-frequency variability and binarity of the δ Scuti star XX Pyx". Monthly Notices of the Royal Astronomical Society. 326: 192–202. doi:10.1046/j.1365-8711.2001.04594.x. Retrieved 2 March 2022.
  2. "XX Pyxidis", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 5 September 2015
  3. Aerts, C.; Handler, G.; Arentoft, T.; Vandenbussche, B.; Medupe, R.; Sterken, C. (2002). "The δ Scuti star XX Pyx is an ellipsoidal variable". Monthly Notices of the Royal Astronomical Society. 333 (2): L35–L39. Bibcode:2002MNRAS.333L..35A. doi:10.1046/j.1365-8711.2002.05627.x.
  4. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. Gaia EDR3 record for this source at VizieR.
  5. Templeton, Matthew (16 July 2010). "Delta Scuti and the Delta Scuti Variables". Variable Star of the Season. AAVSO (American Association of Variable Star Observers). Retrieved 5 September 2015.
  6. Bedding, Timothy R.; et al. (2020), "Very regular high-frequency pulsation modes in young intermediate-mass stars", Nature, 581 (7807): 147–151, arXiv:2005.06157, doi:10.1038/s41586-020-2226-8, PMID 32405022, S2CID 218613877


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