51 Ophiuchi

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]
Characteristics
Spectral type B9.5IIIe[3]
U−B color index –0.06[2]
B−V color index +0.00[2]
Astrometry
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 mas[1]
Distance410 ± 10 ly
(124 ± 4 pc)
Details
Mass3.3±0.1[5] M☉
Radius5.66±0.23[5] R☉
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
Age0.3[8] Myr
Other designations
c Oph, 51 Oph, CD–23° 13412, GC 23320, HD 158643, HIP 85755, HR 6519, SAO 185470[9]
Database references
SIMBADdata

51 Ophiuchi is a single[8] star located approximately 410[1] light years away from the Sun in the equatorial constellation of Ophiuchus, northwest of the center of the Milky Way. It is visible to the naked eye as a faint, blue-white point of light with an apparent visual magnitude of 4.81.[2] The star is moving closer to the Earth with a heliocentric radial velocity of –12 km/s.[4]

This object is notable for being "a rare, nearby example of a young planetary system just entering the last phase of planet formation".[10] 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.[11] 51 Ophiuchi is about 300,000[8] years old with 3.3 times the mass of the Sun and a polar radius 5.7 times the Sun's radius.[5] It is radiating three[6] times the Sun's luminosity from its photosphere at an effective temperature of 9,772 K.[6] The star is spinning rapidly with a projected rotational velocity of 267 km/s,[7] close to the critical rotation rate.[5]

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  2. ^ a b c d Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference apj653_1_657 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference rgcrv was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference Jamialahmadi2015 was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference aaa490_1_297 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference mnras286_3_604 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference Roberge2002 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference eScience was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference apj660_1_461 was invoked but never defined (see the help page).