Astronomy:R85

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Short description: Candidate luminous variable star in the constellation Dorado
R85
Eso9931d.jpg
The nebula N119; R85 is the brightest of the small triangle of stars in the lower right "arm".
Credit: ESO
Observation data
Equinox J2000.0]] (ICRS)
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 (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.

A visual band light curve for R85, plotted from ASAS-SN data[11]

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.[12]

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.[13] It has an infrared excess consistent with a stellar wind contribution.[4]

References

  1. 1.0 1.1 1.2 1.3 1.4 Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E. et al. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues 2246: II/246. Bibcode2003yCat.2246....0C. http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=II/246. 
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 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. Bibcode2002yCat.2237....0D. 
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Van Genderen, A. M. (2001). "S Doradus variables in the Galaxy and the Magellanic Clouds". Astronomy and Astrophysics 366 (2): 508–531. doi:10.1051/0004-6361:20000022. Bibcode2001A&A...366..508V. 
  4. 4.0 4.1 4.2 Bonanos, A. Z.; Massa, D. L.; Sewilo, M.; Lennon, D. J.; Panagia, N.; Smith, L. J.; Meixner, M.; Babler, B. L. et al. (2009). "Spitzersage Infrared Photometry of Massive Stars in the Large Magellanic Cloud". The Astronomical Journal 138 (4): 1003–1021. doi:10.1088/0004-6256/138/4/1003. Bibcode2009AJ....138.1003B. 
  5. 5.0 5.1 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. doi:10.1093/mnras/121.4.337. Bibcode1960MNRAS.121..337F. 
  6. 6.0 6.1 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27. Bibcode2000A&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. et al. (2015). "The Multiplicity of Massive Stars: A High Angular Resolution Survey with the Guidance Sensor". The Astronomical Journal 149 (1): 26. doi:10.1088/0004-6256/149/1/26. Bibcode2015AJ....149...26A. 
  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. Bibcode1984A&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. doi:10.3847/2515-5172/aad1f3. Bibcode2018RNAAS...2..121R. 
  10. 10.0 10.1 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. doi:10.1093/mnras/stu2430. Bibcode2015MNRAS.447..598S. 
  11. "ASAS-SN Variable Stars Database". ASAS-SN. https://asas-sn.osu.edu/variables/lookup. 
  12. 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. Bibcode1998A&A...337..393V. 
  13. 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. Bibcode2008RMxAA..44..355A.