HD 168607
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| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 21m 14.889s |
| Declination | −16° 22′ 31.76″ |
| Apparent magnitude (V) | 8.25v |
| Characteristics | |
| Spectral type | B9Ia+[1] |
| U−B color index | 0.63 |
| B−V color index | 1.35 |
| J−K color index | 1.085 |
| Variable type | alpha cygni |
| Astrometry | |
| Radial velocity (Rv) | -30 km/s |
| Proper motion (μ) | RA: -0.27 mas/yr Dec.: -1.01 mas/yr |
| Parallax (π) | 1.85 ± 1.29 mas |
| Distance | approx. 2,000 ly (approx. 500 pc) |
| Absolute magnitude (MV) | −8.4[1] |
| Details | |
| Luminosity | 240,000[1] L☉ |
| Surface gravity (log g) | 1.0[1] cgs |
| Temperature | 9,300[1] K |
| Database references | |
| SIMBAD | data |
| Other designations | |
HD 168607 is a blue hypergiant and luminous blue variable (LBV) star located in the constellation of Sagittarius, easy to see with amateur telescopes. It forms a pair with HD 168625, also a blue hypergiant and possible luminous blue variable, that can be seen at the south-east of M17, the Omega Nebula.
Physical Properties
HD 168607 is usually assumed to be at the same distance of the Omega Nebula (2.2 kiloparsecs, 7,200 light years, from the Sun) and may be physically associated with HD 168625.[2] Assuming this distance is correct, this star [3] is 240,000 times brighter than our Sun with a surface temperature of 9300 °K.[3] Its apparent magnitude has a variation of 0.25-0.30 m. with a period of 64 days; however, unlike other LBVs, no eruptions have been detected so far.[4]
Unlike its neighbour HD 168625, no nebula has been found around this star.[5]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Bibcode: 1992A&A...264...88V
- ↑ Chentsov, E.L.; Gorda, E.S. (2004). "Spatial Closeness of the White Hypergiants HD 168607 and HD 168625". Astronomy Letters 30: 145–180. Bibcode:2004AstL...30..461C. doi:10.1134/1.1774398.
- ↑ 3.0 3.1 van Genderen, A.M. (2001). "S Doradus variables in the Galaxy and the Magellanic Clouds". Astronomy & Astrophysics 366: 508–531. Bibcode:2001A&A...366..508V. doi:10.1051/0004-6361:20000022.
- ↑ Sterken, C.; Arentoft, T.; Duerbeck, E.; Brogt (1999). "Light variations of the blue hypergiants HD 168607 and HD 168625 (1973-1999)". Astronomy & Astrophysics 349: 532–536. Bibcode:1999A&A...349..532S.
- ↑ Hutsemekers, D.; vanDrom, E.; Gosset, E.; Melnick, J. (1994). "A dusty nebula around the luminous blue variable candidate HD 168625". Astronomy and Astrophysics 2904: 906–914. Bibcode:1994A&A...290..906H.
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