Rho Herculis

Rho Herculis
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
ρ Her A
Right ascension 17h 23m 40.972s[1]
Declination +37° 08′ 45.33″[1]
Apparent magnitude (V) 4.510[1]
ρ Her B
Right ascension 17h 23m 40.718s
Declination +37° 08′ 48.44″[1]
Apparent magnitude (V) 5.398[1]
Characteristics
ρ Her A
Spectral type A0III[2]
U−B color index −0.06[3]
B−V color index +0.00[3]
ρ Her B
Spectral type B9.5IVn[2]
Astrometry
ρ Her A
Radial velocity (Rv)−21.0 ± 2[4] km/s
Proper motion (μ) RA: −38.6[5] mas/yr
Dec.: 9.2[5] mas/yr
Parallax (π)8.29 ± 0.33[6] mas
Distance390 ± 20 ly
(121 ± 5 pc)
ρ Her B
Radial velocity (Rv)−19.3 ± 2[4] km/s
Proper motion (μ) RA: −38.6[1] mas/yr
Dec.: 9.2[1] mas/yr
Other designations
BD+37° 2878, HIP 85112, ADS 10526 AB, CCDM J17236+3708AB
ρ Her A: HD 157779, HR 6485, SAO 66001
ρ Her B: HD 157778, HR 6484, SAO 66000
Database references
SIMBADρ Her
ρ Her A
ρ Her B

Rho Herculis (ρ Her, ρ Herculis) is a double star in the constellation of Hercules. The apparent magnitudes of the components are 4.510 and 5.398, respectively.[1] Parallax measurements by Hipparcos put the system at some 390 light-years (121 parsecs) away.[6]

The two stars of Rho Herculis are separated by four arcseconds, and are known as Rho Herculis A and B, respectively. A is an A-type giant star, while B is a B-type subgiant star.[2] They are rarely referred to as Rho1 Herculis and Rho2 Herculis.

References

  1. 1 2 3 4 5 6 7 8 Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
  2. 1 2 3 Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". The Astrophysical Journal Supplement Series. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
  3. 1 2 Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4. Bibcode:1966CoLPL...4...99J.
  4. 1 2 Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Bibcode:1953GCRV..C......0W.
  5. 1 2 Zacharias, N. (2012). "The fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)". VizieR On-line Data Catalog. Bibcode:2012yCat.1322....0Z.
  6. 1 2 van Leeuwen, F.; et al. (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.
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