UZ Pyxidis

UZ Pyxidis (HD 75021) is a semiregular variable star in the constellation Pyxis. It is located about 6,000 light-years (2,000 parsecs) away from the Earth.

UZ Pyxidis
Observation data
Epoch J2000      Equinox J2000
Constellation Pyxis
Right ascension  08h 46m 36.33187s[1]
Declination −29° 43′ 41.1989″[1]
Apparent magnitude (V) 6.99 - 7.63[2]
Characteristics
Spectral type C55J (R8)[2]
U−B color index +2.99[3]
B−V color index +2.01[3]
Variable type SRb[4]
Astrometry
Radial velocity (Rv)13.00[5] km/s
Proper motion (μ) RA: -6.49[1] mas/yr
Dec.: 1.99[1] mas/yr
Parallax (π)0.55 ± 0.35[6] mas
Distanceapprox. 6,000 ly
(approx. 2,000 pc)
Details
Luminosity5,649[7] L☉
Temperature3,325[7] K
Other designations
UZ Pyx, CD-29° 6735, HD 75021, HIP 43093, SAO 176458, GC 12117
Database references
SIMBADdata

UZ Pyxidis lies directly between α and γ Pyxidis. It has a common proper motion companion, HD 75022,[8] less than 2' away but the two are not listed in double star catalogues.

UZ Pyxidis is a carbon star. These types of stars are known for having large amounts of carbon in their atmospheres, forming carbon compounds that make the star appear strikingly red. It was first recognised as having an unusual spectrum in 1893.[9] Under the Morgan–Keenan classification of carbon stars, UZ Pyxidis' spectral type is C55; if it were a normal giant star, this would correspond to a spectral type of about K5.[10] It is also unusual in that it has very strong isotopic bands of C2 and CN.[11]

UZ Pyxidis is classified as a semiregular variable with a dominant period of 159.6 days. It varies in brightness between magnitude 6.99 and 7.63.[2] The variability was first reported in 1972,[12][8] and the variable star designation UZ Pyxidis was assigned in 1978.[13]

References
  1. van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
  2. Otero, Sebastian Alberto (15 April 2012). "VSX: Detail for UZ Pyx". The International Variable Star Index. American Association of Variable Star Observers. Retrieved 18 January 2017.
  3. Platais, I.; Pourbaix, D.; Jorissen, A.; Makarov, V. V.; Berdnikov, L. N.; Samus, N. N.; Lloyd Evans, T.; Lebzelter, T.; Sperauskas, J. (2003). "Hipparcos red stars in the HpVT2 and VIC systems". Astronomy and Astrophysics. 397 (3): 997–1010. arXiv:astro-ph/0211048. Bibcode:2003A&A...397..997P. doi:10.1051/0004-6361:20021589.
  4. Samus, N. N.; Durlevich, O. V.; et al. (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. 1. Bibcode:2009yCat....102025S.
  5. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
  6. Gaia Collaboration; Brown, A. G. A.; Vallenari, A.; Prusti, T.; De Bruijne, J. H. J.; Mignard, F.; Drimmel, R.; Babusiaux, C.; Bailer-Jones, C. A. L.; Bastian, U.; Biermann, M.; Evans, D. W.; Eyer, L.; Jansen, F.; Jordi, C.; Katz, D.; Klioner, S. A.; Lammers, U.; Lindegren, L.; Luri, X.; O'Mullane, W.; Panem, C.; Pourbaix, D.; Randich, S.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; Valette, V.; Van Leeuwen, F.; et al. (2016). "Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties". Astronomy & Astrophysics. 595: A2. arXiv:1609.04172. Bibcode:2016A&A...595A...2G. doi:10.1051/0004-6361/201629512.
  7. Bergeat, J.; Chevallier, L. (2005). "The mass loss of C-rich giants". Astronomy and Astrophysics. 429: 235–246. arXiv:astro-ph/0601366. Bibcode:2005A&A...429..235B. doi:10.1051/0004-6361:20041280.
  8. Eggen, O. J. (1972). "The classification of intrinsic variable stars. I. The red variables of type N". Astrophysical Journal. 174: 45. Bibcode:1972ApJ...174...45E. doi:10.1086/151467.
  9. Fleming, W. P. (1893). "Stars having peculiar spectra". Astronomy and Astro-Physics. 12: 546. Bibcode:1893AstAp..12..546F.
  10. Keenan, P. C.; Morgan, W. W. (1941). "The Classification of the Red Carbon Stars". The Astrophysical Journal. 94: 501. Bibcode:1941ApJ....94..501K. doi:10.1086/144356.
  11. Keenan, P. C. (1993). "Revised MK Spectral Classification of the Red Carbon Stars". Publications of the Astronomical Society of the Pacific. 105: 905. Bibcode:1993PASP..105..905K. doi:10.1086/133252.
  12. Eggen, O. J. (1972). "The classification of intrinsic variable stars. II. The red variables of S and related types". Astrophysical Journal. 177: 489. Bibcode:1972ApJ...177..489E. doi:10.1086/151725.
  13. Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (1978). "63rd Name-List of Variable Stars". Information Bulletin on Variable Stars. 1414: 1. Bibcode:1978IBVS.1414....1K.
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