Spitzer and WISE view of G79.29+0.46, the H II-region DR15 (bright object lower left) and the IRDC G79.3+0.3 (dark clouds)[6]
| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cygnus |
| Right ascension | 20h31m 42.2847s[1] |
| Declination | +40° 21′ 59.0744″[1] |
| Apparent magnitude (V) | 15.1[2] |
| Characteristics | |
| Spectral type | B:I[e][3] |
| Astrometry | |
| Radial velocity (Rv) | 39.02±7.30[1] km/s |
| Proper motion (μ) | RA: −2.925[1] mas/yr Dec.: −5.339[1] mas/yr |
| Parallax (π) | 0.5725 ± 0.0596 mas[1] |
| Distance | approx. 5,700 ly (approx. 1,700 pc) |
| Absolute magnitude (MV) | −10[4] |
| Details | |
| Luminosity | 2.51×105[5] L☉ |
| Temperature | 20,400[5] K |
| Other designations | |
GAL 079.29+00.46, GRS G079.29 +00.46, HBHA 4203-09, IRAS 20298+4011, 2MASS J20314228+4021591, WISE J203142.22+402159.0 | |
| Database references | |
| SIMBAD | data |
G79.29+0.46 is a luminous blue variable star candidate located in the Cygnus X star formation region.[1][5] In the infrared and at radio wavelengths a prominent circular nebula can be seen. This nebula was formed by past mass-loss episodes of the LBV candidate.[6]
G79.29+0.46 was first reported as a suspected LBV by Higgs, Wendker & Landecker in 1993 with the DRAO Synthesis Telescope, which identified a nebula around a star that was a wind-blown shell.[7] As an LBV candidate, it has a spectrum with many emission lines, H-alpha being the strongest. The spectrum is similar to other LBVs and Be supergiants. The strength of the H-alpha line suggest very dense winds around this star.[3] The star is currently losing mass at a rate of 1.4×10−6 M☉/year and it is surrounded by a dusty envelope with a temperature of 40 to 1,200 K.[5] The star is considered only a candidate LBV because it has not shown variability in the optical or near-infrared over 20 years. It has been suggested that it is a LBV in the quiescent stage.[5]
From radio and infrared images a detached shell can be seen that shows evidence of two mass-loss episodes.[6] This shell has a mass of 1.51 M☉ and a radius of 0.66 parsecs,[5] and it contains carbon monoxide[8] and ammonia.[6]
![Spitzer and WISE view of G79.29+0.46, the H II-region DR15 (bright object lower left) and the IRDC G79.3+0.3 (dark clouds)[6]](http://en.wikipedia.org/wiki/File:G79.29%2B0.46.png)
