R85

R85 (or RMC 85, after the Radcliffe Observatory Magellanic Clouds catalog[5]) is a candidate luminous blue variable[9] located in the LH-41 OB association[10] in the Large Magellanic Cloud.

R85

The nebula N119; R85 is the brightest of the small triangle of stars in the lower right "arm".
Credit: ESO
Observation data
Epoch J2000      Equinox J2000
Constellation Dorado
Right ascension 05h 17m 56.076s[1]
Declination −69° 16′ 03.77″[1]
Apparent magnitude (V) 10.84[2] (10.65 - 10.80[3])
Characteristics
Evolutionary stage LBV[4]
Spectral type B5 Iae[3]
Apparent magnitude (U) 10.28[2]
Apparent magnitude (B) 10.93[2]
Apparent magnitude (V) 10.84[2]
Apparent magnitude (R) 10.53[2]
Apparent magnitude (I) 10.44[2]
Apparent magnitude (J) 10.103[1]
Apparent magnitude (H) 9.980[1]
Apparent magnitude (K) 9.822[1]
U−B color index −0.65[2]
B−V color index +0.09[2]
Variable type LBV[4]
Astrometry
Radial velocity (Rv)292[5] km/s
Proper motion (μ) RA: -1.0[6] mas/yr
Dec.: -2.3[6] mas/yr
Distance160,000 ly
(50,000[7] pc)
Absolute magnitude (MV)−8.2 - −8.5[3]
Details
1960 (minimum)
Radius135[8] R☉
Luminosity350,000[3] L☉
Temperature13,500[3] K
1983 - 1990 (maximum)
Luminosity315,000[3] L☉
Temperature10,000[3] K
Other designations
HD 269321, CPD−69° 352, 2MASS J05175607-6916037, GSC 09162-00359, Sk−69°92
Database references
SIMBADdata

R85 has been shown to vary erratically in brightness with an amplitude of about 0.3 magnitudes. It shows variations on several timescales, sometimes with a distinct 400 day period. It has also shown temperature changes associated with brightness changes over several years, a characteristic of Luminous Blue Variables.[11]

Based on R85's current properties and evolutionary models, it probably started out with an initial mass of 28 M☉.[10] It is theorized to be making a bubble known as DEM L132a with its stellar wind in the nebula LHA-120 N119, along with S Doradus.[12] It has an infrared excess consistent with a stellar wind contribution.[4]

References
  1. 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: 2003yCat.2246....0C. 2246. Bibcode:2003yCat.2246....0C.
  2. 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.
  3. Van Genderen, A. M. (2001). "S Doradus variables in the Galaxy and the Magellanic Clouds". Astronomy and Astrophysics. 366 (2): 508–531. Bibcode:2001A&A...366..508V. CiteSeerX 10.1.1.459.5400. doi:10.1051/0004-6361:20000022.
  4. Bonanos, A. Z.; Massa, D. L.; Sewilo, M.; Lennon, D. J.; Panagia, N.; Smith, L. J.; Meixner, M.; Babler, B. L.; Bracker, S.; Meade, M. R.; Gordon, K. D.; Hora, J. L.; Indebetouw, R.; Whitney, B. A. (2009). "Spitzersage Infrared Photometry of Massive Stars in the Large Magellanic Cloud". The Astronomical Journal. 138 (4): 1003–1021. arXiv:0905.1328. Bibcode:2009AJ....138.1003B. doi:10.1088/0004-6256/138/4/1003. S2CID 14056495.
  5. Feast, M. W.; Thackeray, A. D.; Wesselink, A. J. (1960). "The brightest stars in the Magellanic Clouds". Monthly Notices of the Royal Astronomical Society. 121 (4): 337. Bibcode:1960MNRAS.121..337F. doi:10.1093/mnras/121.4.337.
  6. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27. Bibcode:2000A&A...355L..27H.
  7. Aldoretta, E. J.; Caballero-Nieves, S. M.; Gies, D. R.; Nelan, E. P.; Wallace, D. J.; Hartkopf, W. I.; Henry, T. J.; Jao, W.-C.; Maíz Apellániz, J.; Mason, B. D.; Moffat, A. F. J.; Norris, R. P.; Richardson, N. D.; Williams, S. J. (2015). "The Multiplicity of Massive Stars: A High Angular Resolution Survey with the Guidance Sensor". The Astronomical Journal. 149 (1): 26. arXiv:1410.0021. Bibcode:2015AJ....149...26A. doi:10.1088/0004-6256/149/1/26. S2CID 58911264.
  8. Stahl, O.; Wolf, B.; Leitherer, C.; Zickgraf, F.-J.; Krautter, J.; De Groot, M. (1984). "Variable blue supergiants in the Large Magellanic Cloud - R 84, R 85, and R 99". Astronomy and Astrophysics. 140: 459. Bibcode:1984A&A...140..459S.
  9. Richardson, Noel D.; Mehner, Andrea (2018). "The 2018 Census of Luminous Blue Variables in the Local Group". Research Notes of the American Astronomical Society. 2 (3): 121. arXiv:1807.04262. Bibcode:2018RNAAS...2c.121R. doi:10.3847/2515-5172/aad1f3. S2CID 119509358.
  10. Smith, Nathan; Tombleson, Ryan (2015). "Luminous blue variables are antisocial: Their isolation implies that they are kicked mass gainers in binary evolution". Monthly Notices of the Royal Astronomical Society. 447 (1): 598–617. arXiv:1406.7431. Bibcode:2015MNRAS.447..598S. doi:10.1093/mnras/stu2430. S2CID 119284620.
  11. Van Genderen, A. M.; Sterken, C.; De Groot, M. (1998). "Light variations of massive stars (alpha Cyg variables). XVI. The LMC supergiants R 85 (LBV) and R 110 (LBV) and the SMC supergiants R 42 and R 45". Astronomy and Astrophysics. 337: 393. Bibcode:1998A&A...337..393V.
  12. Ambrocio-Cruz, P.; Rosado, M.; Laval, A.; Le Coarer, E.; Russeil, D.; Amram, P. (2008). "Kinematic field of the S-shaped nebula N119 in the LMC". Revista Mexicana de Astronomía y Astrofísica. 44: 355. Bibcode:2008RMxAA..44..355A.
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