R85
Candidate luminous variable star in the constellation Dorado
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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.
 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 |
| Distance | 160,000 ly (50,000[7] pc) |
| Absolute magnitude (MV) | −8.2 – −8.5[3] |
| Details | |
| 1960 (minimum) | |
| Radius | 135[8] R☉ |
| Luminosity | 350,000[3] L☉ |
| Temperature | 13,500[3] K |
| 1983 - 1990 (maximum) | |
| Luminosity | 315,000[3] L☉ |
| Temperature | 10,000[3] K |
| Other designations | |
| HD 269321, CPD−69°352, 2MASS J05175607-6916037, GSC 09162-00359, Sk−69°92 | |
| Database references | |
| SIMBAD | data |
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]