51 Ophiuchi

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51 Ophiuchi
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension 17h 31m 24.95413s[1]
Declination −23° 57′ 45.5136″[1]
Apparent magnitude (V) 4.81[2]
Spectral type B9.5IIIe[3]
U−B color index –0.06[2]
B−V color index +0.00[2]
Radial velocity (Rv)–12[4] km/s
Proper motion (μ) RA: 5.24[1] mas/yr
Dec.: -25.72[1] mas/yr
Parallax (π)8.04 ± 0.24[1] mas
Distance410 ± 10 ly
(124 ± 4 pc)
Mass~4[5] M
Luminosity3.12[6] L
Temperature9,772[6] K
Metallicity [Fe/H]–0.25[6] dex
Rotational velocity (v sin i)267 ± 5[7] km/s
Other designations
c Oph, HD 158643, HIP 85755, HR 6519, SAO 185470, CD–23° 13412 [8]
Database references

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".[9] 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.[5]

Dust and gas disk[edit]

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.[9][10]

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.[11] 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.[10] 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.[9]

See also[edit]


  1. ^ a b c d e 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
  2. ^ a b c 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.
  3. ^ 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
  4. ^ 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
  5. ^ a b 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
  6. ^ a b c 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
  7. ^ 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
  8. ^ "c Oph -- Be Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-22
  9. ^ a b c "Twin Keck telescopes probe dual dust disks", e! Science News, September 24, 2009, retrieved 2009-10-01
  10. ^ a b 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
  11. ^ 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