U Antliae

U Antliae (U Ant) is a variable star in the constellation Antlia. It is a carbon star surrounded by two thin shells of dust.

U Antliae
Location of U Antliae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Antlia
Right ascension  10h 35m 12.852s[1]
Declination −39° 33′ 45.32″[1]
Apparent magnitude (V) 5.27 - 6.04[2]
Characteristics
Evolutionary stage AGB
Spectral type C-N3[3] (C5,3[4])
U−B color index 7.10[5]
B−V color index 2.84[5]
Variable type LB[6]
Astrometry
Radial velocity (Rv)41.00[7] km/s
Proper motion (μ) RA: −31.372±0.228[8] mas/yr
Dec.: 2.371±0.267[8] mas/yr
Parallax (π)3.5717 ± 0.2043[8] mas
Distance910 ± 50 ly
(280 ± 20 pc)
Absolute magnitude (MV)−1.87[9]
Details
Radius325[10] R☉
Luminosity8,000[11] L☉
Temperature2,800[11] K
Other designations
HR 4153, HD 91793, HIP 51821, CD−38°6579, 2MASS J10351285-3933453, PPM 287864, AAVSO 1030–39, SAO 201533
Database references
SIMBADdata

ALMA image of the dust shells around U Antliae

U Antliae is an extremely red C-type carbon star. These cool stars on the asymptotic giant branch are further reddened by strong mass loss and dust that forms around the star. U Antliae is calculated to have an effective surface temperature of 2,800 K, although the light that reaches us has an appearance more like that from a black body with a temperature of 2,300 K surrounded by dust at a temperature of 72 K.[11] It emits most of its radiation in the infrared and although it is only about 500 times brighter than the sun at visual wavelengths,[9] its bolometric luminosity is 8,000 times higher than the Sun's.[11]

U Antliae and is an irregular variable star with an apparent magnitude that varies between 5.27 and 6.04. Approximately 900 light years from Earth, it is surrounded by two shells of dust, thought to have been ejected 14,000 and 10,000 years ago.[12] The exact origin and structure of the shells is uncertain, possibly due to enhanced mass loss during thermal pulses, possibly due to interaction of the stellar wind with interstellar material.[11]

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.Vizier catalog entry
  2. Otero, Sebastian (3 November 2011). "U Antliae". AAVSO Website. American Association of Variable Star Observers. Retrieved 25 July 2014.
  3. De Mello, A. B.; Lorenz-Martins, S.; De Araújo, F. X.; Bastos Pereira, C.; Codina Landaberry, S. J. (2009). "NSCC—A New Scheme of Classification of C-Rich Stars Devised from Optical and Infrared Observations". The Astrophysical Journal. 705 (2): 1298. arXiv:0910.4086. Bibcode:2009ApJ...705.1298D. doi:10.1088/0004-637X/705/2/1298.
  4. Yamashita, Y. (1975). "The C-classification of spectra of carbon stars. II". Tokyo. 15: 47. Bibcode:1975AnTok..15...47Y.
  5. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  6. 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.
  7. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
  8. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  9. Alksnis, A.; Balklavs, A.; Dzervitis, U.; Eglitis, I. (1998). "Absolute magnitudes of carbon stars from HIPPARCOS parallaxes". Astronomy and Astrophysics. 338: 209. Bibcode:1998A&A...338..209A.
  10. De Beck, E.; Decin, L.; De Koter, A.; Justtanont, K.; Verhoelst, T.; Kemper, F.; Menten, K. M. (2010). "Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles. II. CO line survey of evolved stars: Derivation of mass-loss rate formulae". Astronomy and Astrophysics. 523: A18. arXiv:1008.1083. Bibcode:2010A&A...523A..18D. doi:10.1051/0004-6361/200913771.
  11. Kerschbaum, F.; Ladjal, D.; Ottensamer, R.; Groenewegen, M. A. T.; Mecina, M.; Blommaert, J. A. D. L.; Baumann, B.; Decin, L.; Vandenbussche, B.; Waelkens, C.; Posch, T.; Huygen, E.; De Meester, W.; Regibo, S.; Royer, P.; Exter, K.; Jean, C. (2010). "The detached dust shells of AQ Andromedae, U Antliae, and TT Cygni". Astronomy and Astrophysics. 518: L140. arXiv:1005.2689. Bibcode:2010A&A...518L.140K. doi:10.1051/0004-6361/201014633.
  12. Izumiura, H.; Waters, L. B. F. M.; de Jong, T.; Loup, C.; Bontekoe, Tj. R.; Kester, D. J. M. (1997). "A double dust shell surrounding the carbon star U Antliae". Astronomy and Astrophysics. 323: 449–60. Bibcode:1997A&A...323..449I.
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