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Rho Herculis

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Binary star in the constellation Hercules
Rho Herculis
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
ρ Her A
Right ascension 17 23 40.972
Declination +37° 08′ 45.33″
Apparent magnitude (V) 4.510
ρ Her B
Right ascension 17 23 40.718
Declination +37° 08′ 48.44″
Apparent magnitude (V) 5.398
Characteristics
ρ Her A
Spectral type A0IIIpHgMn
U−B color index −0.06
B−V color index +0.00
ρ Her B
Spectral type B9.5IVn
Astrometry
ρ Her A
Radial velocity (Rv)−21.0 ± 2 km/s
Proper motion (μ) RA: −38.6 mas/yr
Dec.: 9.2 mas/yr
Parallax (π)8.3380 ± 0.3358 mas
Distance390 ± 20 ly
(120 ± 5 pc)
ρ Her B
Radial velocity (Rv)−19.3 ± 2 km/s
Proper motion (μ) RA: −38.6 mas/yr
Dec.: 9.2 mas/yr
Parallax (π)9.0354 ± 0.1135 mas
Distance361 ± 5 ly
(111 ± 1 pc)
Details
A
Mass4.00/2.93 M☉
Temperature9,118 K
Metallicity 0.0 dex
Rotational velocity (v sin i)75 km/s
B
Mass3.27 M☉
Surface gravity (log g)3.6 cgs
Temperature8,755 K
Rotational velocity (v sin i)291 km/s
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. Parallax measurements published in Gaia Data Release 2 put the system at some 360-390 light-years (111-121 parsecs) away.

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. They are also referred to, rarely, as Rho Herculis and Rho Herculis. Rho Herculis A is itself a close binary which has been resolved using speckle interferometry, with the two components separated by 0.252″.

The two visual components have very similar spectral types, between A0 and B9. Rho Herculis A is generally assigned a giant luminosity class, with Rho Herculis B most often considered to be a main sequence star. Rho Herculis A has been considered to be an Ap star, with unusually strong silicon or mercury and manganese absorption lines in its spectrum, but this is now considered to be dubious.

References

  1. ^ 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. ^ 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. ^ Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99. Bibcode:1966CoLPL...4...99J.
  4. ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication: 0. Bibcode:1953GCRV..C......0W.
  5. ^ Zacharias, N. (2012). "The fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)". VizieR On-line Data Catalog. Bibcode:2012yCat.1322....0Z.
  6. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  7. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  8. ^ "Multiple Star Catalog". Cerro Tololo Inter-American Observatory. Archived from the original on 2018-12-01. Retrieved 2018-11-30.
  9. ^ Gebran, M.; Farah, W.; Paletou, F.; Monier, R.; Watson, V. (2016). "A new method for the inversion of atmospheric parameters of A/Am stars". Astronomy and Astrophysics. 589: A83. arXiv:1603.01146. Bibcode:2016A&A...589A..83G. doi:10.1051/0004-6361/201528052. S2CID 118549566.
  10. ^ Royer, F.; Grenier, S.; Baylac, M. -O.; Gómez, A. E.; Zorec, J. (2002). "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin I". Astronomy and Astrophysics. 393 (3): 897–911. arXiv:astro-ph/0205255. Bibcode:2002A&A...393..897R. doi:10.1051/0004-6361:20020943.
  11. Mason, Brian D.; Hartkopf, William I.; Gies, Douglas R.; Henry, Todd J.; Helsel, John W. (2009). "The High Angular Resolution Multiplicity of Massive Stars". The Astronomical Journal. 137 (2): 3358. arXiv:0811.0492. Bibcode:2009AJ....137.3358M. doi:10.1088/0004-6256/137/2/3358. S2CID 119268845.
  12. Skiff, B. A. (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)". VizieR On-line Data Catalog. Bibcode:2014yCat....1.2023S.
  13. Abt, H. A.; Cardona, O. (1984). "The nature of the visual companions of AP and AM stars". The Astrophysical Journal. 276: 266. Bibcode:1984ApJ...276..266A. doi:10.1086/161610.
  14. Renson, P.; Manfroid, J. (2009). "Catalogue of Ap, HgMn and Am stars". Astronomy and Astrophysics. 498 (3): 961. Bibcode:2009A&A...498..961R. doi:10.1051/0004-6361/200810788.
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