Rho Ophiuchi
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 16h 25m 35.118s[1][2] |
| Declination | −23° 26′ 49.81″ |
| Apparent magnitude (V) | 4.63[1][3] |
| Characteristics | |
| Spectral type | B2/B3V (ρ Oph A);[4] B2 V (ρ Oph B)[5][6] |
| Apparent magnitude (U) | 4.30[1][3] |
| Apparent magnitude (B) | 4.85[1][3] |
| Apparent magnitude (V) | 4.63[1][3] |
| Apparent magnitude (R) | 4.27[1][3] |
| Apparent magnitude (I) | 3.96[1][3] |
| Apparent magnitude (J) | 3.74[1][3] |
| Apparent magnitude (H) | 3.56[1][3] |
| Apparent magnitude (K) | 3.51[1][3] |
| U−B color index | -0.55 |
| B−V color index | +0.23 |
| Variable type | ?? |
| Astrometry | |
| Proper motion (μ) | RA: -5.53[1][2] mas/yr Dec.: -21.74 mas/yr |
| Parallax (π) | 9.03[1][2] ± 0.90 mas |
| Distance | 360 (ρ Oph AB)[2] ly (111 (ρ Oph AB) pc) |
| Absolute magnitude (MV) | -0.70 |
| Orbit | |
| Period (P) | 2,000 yr |
| Semi-major axis (a) | 344 AU[7] |
| Details | |
| Mass | 9 / 8 M☉ |
| Luminosity | 4,900 / 2,100 L☉ |
| Temperature | 27,200 K |
| Rotation | +300 |
| Other designations | |
Rho Ophiuchi (ρ Ophiuchi) is a multiple star system in the constellation Ophiuchus.[1] It consists of at least two blue subgiants, ρ Oph A and ρ Oph B, both of which are of class B.[7] ρ Oph AB is a visual binary, and the sky-projected distance between ρ Oph A and ρ Oph B is 3.1" (or 344 AU at the 111 pc distance of ρ Oph AB).[7]
Two to three other blue subgiants, ρ Oph C and ρ Oph DE, are found to be related to the star system, with sky-projected distances to ρ Oph AB of ~ 17,000 and ~ 19,000 AU, respectively. ρ Oph C and ρ Oph D are also of class B.
The apparent brightness of the star system has been dimmed by about 2 magnitudes, as a result of interstellar extinction, due to its location within the Ophiuchus cloud. The star system, ρ Oph AB, is located about 360 light years away.[2]
References
- 1 2 3 4 5 6 7 8 9 10 11 12 13 "rho Oph, SIMAD".
- 1 2 3 4 5 "van Leeuwen, F. 2007, Hipparcos, the New Reduction of the Raw Data".
- 1 2 3 4 5 6 7 8 9 "Ducati, J. R. 2002, CDS/ADC Collection of Electronic Catalogues".
- ↑ "rho Oph A, SIMBAD".
- ↑ "rho Oph B, SIMBAD".
- ↑ "Houk, N. and Smith-Moore, M. 1988, Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Declinations -26°.0 to -12°.0.".
- 1 2 3 "Cordiner, M. A., Fossey, S. J., Smith, A. M. and Sarre, P. J. 2013, ApJ, 764, L10".