Astronomy:II Lupi

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Short description: Star in the constellation Lupus
II Lupi
IILupLightCurve.png
A near-infrared (J band) light curve for II Lupi, adapted from Lykou et al. (2018)[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Lupus
Right ascension  15h 23m 05.073s[2]
Declination −51° 25′ 58.76″[2]
Characteristics
Spectral type C[3]
Apparent magnitude (I) 10.18[4]
Apparent magnitude (J) 5.92[5]
Apparent magnitude (K) 1.79[5]
Variable type Mira[6]
Astrometry
Proper motion (μ) RA: −12.992[2] mas/yr
Dec.: −13.119[2] mas/yr
Parallax (π)1.5633 ± 0.2138[2] mas
Distanceapprox. 2,100 ly
(approx. 640 pc)
Absolute magnitude (MV)−5.15[7]
Details
Mass2.2[2] M☉
Radius547[3] R☉
Luminosity8,900[8] L☉
Surface gravity (log g)0.06[2] cgs
Temperature2,800[8] K
Age942[2] Myr
Other designations
II Lup, IRAS 15194-5115, 2MASS J15230507-5125587, WOS 48, Gaia DR2 5889797405925371392
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.[9] 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.[10]

On the basis of infrared photometry,[11] IRAS 15194-5115 was given the variable star designation II Lupi in 1995, although the variability type was still unknown.[12] More detailed infrared photometry confirmed that II Lupi was a Mira variable and showed regular variations with a period of 575 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.[13]

II Lupi has a strong stellar wind averaging 10−5 solar masses per year.[14]

References

  1. ↑ Lykou, Foteini; Zijlstra, A. A.; Kluska, J.; Lagadec, E.; Tuthill, P. G.; Avison, A.; Norris, B. R. M.; Parker, Q. A. (October 2018). "The curious case of II Lup: a complex morphology revealed with SAM/NACO and ALMA". Monthly Notices of the Royal Astronomical Society 480 (1): 1006–1021. doi:10.1093/mnras/sty1903. Bibcode: 2018MNRAS.480.1006L. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 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. doi:10.1051/0004-6361/200913771. Bibcode: 2010A&A...523A..18D. 
  4. ↑ DENIS Consortium (2003). "VizieR Online Data Catalog: The DENIS database (DENIS Consortium, 2003)". VizieR On-line Data Catalog. Bibcode: 2003yCat....102002T. 
  5. ↑ 5.0 5.1 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): 751–782. doi:10.1111/j.1365-2966.2006.10322.x. Bibcode: 2006MNRAS.369..751W. 
  6. ↑ Samus, N. N. 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. ↑ Guandalini, R; Cristallo, S (2013). "Luminosities of carbon-rich asymptotic giant branch stars in the Milky Way". Astronomy & Astrophysics 555: A120. doi:10.1051/0004-6361/201321225. Bibcode: 2013A&A...555A.120G. 
  8. ↑ 8.0 8.1 Ramstedt, S.; Olofsson, H. (2014). "The 12CO/13CO ratio in AGB stars of different chemical type. Connection to the 12C/13C ratio and the evolution along the AGB". Astronomy & Astrophysics 566: A145. doi:10.1051/0004-6361/201423721. Bibcode: 2014A&A...566A.145R. 
  9. ↑ 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 225: 43p–49p. doi:10.1093/mnras/225.1.43P. Bibcode: 1987MNRAS.225P..43M. 
  10. ↑ 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. 
  11. ↑ Le Bertre, T (1992). "Carbon-star lightcurves in the 1-20 micron range". Astronomy and Astrophysics Supplement Series 94: 377. Bibcode: 1992A&AS...94..377L. 
  12. ↑ 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. 
  13. ↑ 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. doi:10.1111/j.1365-2966.2003.07136.x. Bibcode: 2003MNRAS.346..878F. 
  14. ↑ Smith, C. L.; Zijlstra, A. A.; Fuller, G. A. (2015). "A molecular line survey of a sample of AGB stars and planetary nebulae". Monthly Notices of the Royal Astronomical Society 454 (1): 177–200. doi:10.1093/mnras/stv1934. Bibcode: 2015MNRAS.454..177S. 



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