II Lupi

II Lupi
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lupus
Right ascension 15h 23m 05.075s[1]
Declination −51° 25′ 58.73″[1]
Characteristics
Spectral type C[2]
Apparent magnitude (I) 10.18[3]
Apparent magnitude (J) 5.92[4]
Apparent magnitude (K) 1.79[4]
Variable type Mira[5]
Astrometry
Distance500[6] pc
Absolute magnitude (MV)−5.15[7]
Details
Radius547[2] R☉
Luminosity8,800[6] L☉
Temperature2,400[6] K
Other designations
II Lup, IRAS 15194-5115, 2MASS J15230507-5125587
Database references
SIMBADdata

II Lupi (IRAS 15194-5115) is a Mira variable and carbon star located in the constellation Lupus. It is the brightest carbon star in the Southern Hemisphere at 12 μm.

In 1987, the infrared source IRAS 15194-5115 was identified as an extreme carbon star. It was seen to be strongly variable at optical and infrared wavelengths. It is very faint visually, 15th or 16th magnitude in a red filter and below 21st magnitude in a blue filter, but at mid-infrared wavelengths (N band) it is the third-brightest carbon star in the sky.[8] A star at the location had earlier been catalogued as WOS 48, a possible S-type star, on the basis of strong LaO bands in its spectrum.[9]

On the basis of infrared photometry,[10] IRAS 15194-5115 was given the variable star designation II Lupi in 1995, although the variability type was still unknown.[11] More detailed infrared photometry confirmed that II Lupi was a Mira variable and showed regular variations with a period of 675 days over 18 years. The mean magnitude also dimmed and brightened during that time and has been characterised as a 6,900-day secondary period although less than a full cycle was observed. The secondary period could be interpreted as an isolated or irregular obscuration event in a dust shell surrounding the star.[12]

References

  1. 1 2 Cutri, R. M; Skrutskie, M. F; Van Dyk, S; Beichman, C. A; Carpenter, J. M; Chester, T; Cambresy, L; Evans, T; Fowler, J; Gizis, J; Howard, E; Huchra, J; Jarrett, T; Kopan, E. L; Kirkpatrick, J. D; Light, R. M; Marsh, K. A; McCallon, H; Schneider, S; Stiening, R; Sykes, M; Weinberg, M; Wheaton, W. A; Wheelock, S; Zacarias, N (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". VizieR On-line Data Catalog: II/246. Originally published in: 2003y Cat.2246....0C. 2246. Bibcode:2003yCat.2246....0C.
  2. 1 2 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.
  3. ↑ . Bibcode:2005yCat.2263....0T. Missing or empty |title= (help)
  4. 1 2 Whitelock, Patricia A; Feast, Michael W; Marang, Freddy; Groenewegen, M. A. T (2006). "Near-infrared photometry of carbon stars". Monthly Notices of the Royal Astronomical Society. 369 (2): 751. arXiv:astro-ph/0603504. Bibcode:2006MNRAS.369..751W. doi:10.1111/j.1365-2966.2006.10322.x.
  5. ↑ 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.
  6. 1 2 3 Schöier, F. L; Ramstedt, S; Olofsson, H; Lindqvist, M; Bieging, J. H; Marvel, K. B (2013). "The abundance of HCN in circumstellar envelopes of AGB stars of different chemical type". Astronomy & Astrophysics. 550: A78. arXiv:1301.2129. Bibcode:2013A&A...550A..78S. doi:10.1051/0004-6361/201220400.
  7. ↑ Guandalini, R; Cristallo, S (2013). "Luminosities of carbon-rich asymptotic giant branch stars in the Milky Way". Astronomy & Astrophysics. 555: A120. arXiv:1305.4203. Bibcode:2013A&A...555A.120G. doi:10.1051/0004-6361/201321225.
  8. ↑ Meadows, P. J; Good, A. R; Wolstencroft, R. D (1987). "The identification of IRAS 15194-5115 with a bright extreme carbon star". Monthly Notices of the Royal Astronomical Society (ISSN 0035-8711). 225: 43P. Bibcode:1987MNRAS.225P..43M. doi:10.1093/mnras/225.1.43P.
  9. ↑ Westerlund, B. E; Olander, N (1978). "S stars in the southern Milky Way". Astronomy and Astrophysics Supplement Series. 32: 401. Bibcode:1978A&AS...32..401W.
  10. ↑ Le Bertre, T (1992). "Carbon-star lightcurves in the 1-20 micron range". Astronomy and Astrophysics Supplement Series (ISSN 0365-0138). 94: 377. Bibcode:1992A&AS...94..377L.
  11. ↑ Kazarovets, E. V; Samus, N. N (1995). "The 72nd Name-List of Variable Stars". Information Bulletin on Variable Stars. 4140: 1. Bibcode:1995IBVS.4140....1K.
  12. ↑ Feast, Michael W; Whitelock, Patricia A; Marang, Freddy (2003). "The case for asymmetric dust around a C-rich asymptotic giant branch star". Monthly Notices of the Royal Astronomical Society. 346 (3): 878. arXiv:astro-ph/0308417. Bibcode:2003MNRAS.346..878F. doi:10.1111/j.1365-2966.2003.07136.x.
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