Epoch J2000 Equinox J2000
|Right ascension||17h 31m 24.95413s|
|Declination||−23° 57′ 45.5136″|
|Apparent magnitude (V)||4.81|
|U−B color index||–0.06|
|B−V color index||+0.00|
|Radial velocity (Rv)||–12 km/s|
|Proper motion (μ)|| RA: 5.24 mas/yr |
Dec.: -25.72 mas/yr
|Parallax (π)||8.04 ± 0.24 mas|
|Distance||410 ± 10 ly |
(124 ± 4 pc)
|Metallicity [Fe/H]||–0.25 dex|
|Rotational velocity (v sin i)||267 ± 5 km/s|
51 Ophiuchi (51 Oph) is a star located approximately 410 light years away in the constellation Ophiuchus, northwest of the center of the Milky Way. It is notable for being "a rare, nearby example of a young planetary system just entering the last phase of planet formation". There is uncertainty about the stellar classification of this star. It has the nominal classification of B9.5IIIe, a B-type giant star with emission lines. However, it has also been classified as an A0 II-IIIe star and as a Herbig Ae/Be star.
Dust and gas disk
51 Ophiuchi has a disk of dust and gas that appears to be a young debris disk and is probably a planetary system in the late stages of formation. This system resembles Beta Pictoris, a well known star with a large debris disk, in several ways: spectral type, the presence of an edge-on disk with both gas and dust, and the presence of variable blue-shifted absorption lines suggesting in-falling comets.
The distance to 51 Ophiuchi is much greater than the distance to Beta Pictoris, and its debris disk is relatively compact. As a consequence, the disk around 51 Ophiuchi requires an interferometer to resolve, in contrast to that of Beta Pictoris, which has been observed using visual spectrum imaging. Recent observations of 51 Ophiuchi made with the Keck Interferometer Nuller at the W. M. Keck Observatory show that the disk has two components: a central cloud of large particles (exozodiacal dust) surrounded by a much larger cloud of small silicate particles extending to about 1,000 astronomical units. The inner disk has a radius approximately four times the distance between the sun and the Earth, with a density of around 100,000 times that of the dust in the Solar System.
- van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357
- Johnson, H. L.; et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99). Bibcode:1966CoLPL...4...99J.
- Manoj, P.; et al. (December 2006), "Evolution of Emission-Line Activity in Intermediate-Mass Young Stars", The Astrophysical Journal, 653 (1): 657–674, arXiv:astro-ph/0608541, Bibcode:2006ApJ...653..657M, doi:10.1086/508764
- Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E
- Berthoud, M. G.; et al. (May 2007), "Near-IR CO Overtone Emission in 51 Ophiuchi", The Astrophysical Journal, 660 (1): 461–468, Bibcode:2007ApJ...660..461B, doi:10.1086/512056
- Saffe, C.; et al. (October 2008), "Spectroscopic metallicities of Vega-like stars", Astronomy and Astrophysics, 490 (1): 297–305, arXiv:0805.3936, Bibcode:2008A&A...490..297S, doi:10.1051/0004-6361:200810260
- Dunkin, S. K.; Barlow, M. J.; Ryan, Sean G. (April 1997), "High-resolution spectroscopy of Vega-like stars - I. Effective temperatures, gravities and photospheric abundances", Monthly Notices of the Royal Astronomical Society, 286 (3): 604–616, Bibcode:1997MNRAS.286..604D, doi:10.1093/mnras/286.3.604
- "c Oph -- Be Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-22
- "Twin Keck telescopes probe dual dust disks", e! Science News, September 24, 2009, retrieved 2009-10-01
- Stark, Christopher C.; et al. (2009), "51 Ophiuchus: A Possible Beta Pictoris Analog Measured with the Keck Interferometer Nuller", Astrophysical Journal, 703 (2): 1188–1197, arXiv:0909.1821, Bibcode:2009ApJ...703.1188S, doi:10.1088/0004-637X/703/2/1188
- Smith, B. A.; Terrile, R. J. (1984), "A circumstellar disk around Beta Pictoris", Science, 226 (4681): 1421–1424, Bibcode:1984Sci...226.1421S, doi:10.1126/science.226.4681.1421, PMID 17788996