89 Herculis

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89 Herculis
Hercules constellation map.svg
Red circle.svg

Location of 89 Her (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
Right ascension 17h 55m 25.18892s[1]
Declination 26° 02′ 59.9738″[1]
Apparent magnitude (V) 5.36[2] (5.34 - 5.54[3])
Evolutionary stage post-AGB
Spectral type F2Ibe[4]
U−B color index −0.34[2]
B−V color index +0.34[2]
Variable type SRd[3]
Radial velocity (Rv) −28.5[5] km/s
Proper motion (μ) RA: 4.34[1] mas/yr
Dec.: 5.89[1] mas/yr
Parallax (π) 0.76 ± 0.23[1] mas
Distance approx. 4,000 ly
(approx. 1,300 pc)
Absolute magnitude (MV) −6.5[6]
Mass 1.0[7] M
Radius 71.0[7] R
Luminosity 8,350[7] L
Surface gravity (log g) 0.55[4] cgs
Temperature 6,550[4] K
Metallicity −0.5[4]
Rotational velocity (v sin i) 23[8] km/s
Other designations
89 Her, V441 Her, HR 6685, BD +26° 3120, HD 163506, FK5 1468, HIP 87747, SAO 85545, GC 24382, AAVSO 1751+26
Database references
Exoplanet Archive data

89 Herculis is a fifth-magnitude star in the constellation Hercules. Located about 4,000 light years away, it is among a rare class of post-AGB stars - low mass stars in the last stages of their lives, highly inflated to appear as supergiants.[4]

89 Her is a spectroscopic binary system with the pair surrounded by a dusty disc. The system shows variable brightness and spectral line profiles.[9] The companion has a very low mass and luminosity and orbits the primary in 288 days.[4]

89 Her is classified as a semiregular variable star, V441 Her, varying from magnitude 5.3 to 5.5 in around 68 days.[3]


  1. ^ a b c d e Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752free to read. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  2. ^ a b c Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D. 
  3. ^ a b c Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S. 
  4. ^ a b c d e f Hillen, M.; Verhoelst, T.; Van Winckel, H.; Chesneau, O.; Hummel, C. A.; Monnier, J. D.; Farrington, C.; Tycner, C.; Mourard, D.; Ten Brummelaar, T.; Banerjee, D. P. K.; Zavala, R. T. (2013). "An interferometric study of the post-AGB binary 89 Herculis. I. Spatially resolving the continuum circumstellar environment at optical and near-IR wavelengths with the VLTI, NPOI, IOTA, PTI, and the CHARA Array". Astronomy & Astrophysics. 559: A111. arXiv:1308.6715free to read. Bibcode:2013A&A...559A.111H. doi:10.1051/0004-6361/201321616. 
  5. ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W. 
  6. ^ Kipper, Tõnu (2011). "On the Optical Spectrum of 89 Her". Baltic Astronomy. 20: 65. Bibcode:2011BaltA..20...65K. 
  7. ^ a b c Hillen, M.; Menu, J.; Van Winckel, H.; Min, M.; Gielen, C.; Wevers, T.; Mulders, G. D.; Regibo, S.; Verhoelst, T. (2014). "An interferometric study of the post-AGB binary 89 Herculis. II. Radiative transfer models of the circumbinary disk". Astronomy & Astrophysics. 568: A12. arXiv:1405.1960free to read. Bibcode:2014A&A...568A..12H. doi:10.1051/0004-6361/201423749. 
  8. ^ Hoffleit, Dorrit; Jaschek, Carlos (1991). "The Bright star catalogue". New Haven. Bibcode:1991bsc..book.....H. 
  9. ^ Burki, G.; Mayor, M.; Rufener, F. (1980). "Study of the Variable F-Type Supergiants HD161796 and HD163506 in Radial Velocity and Photometry". Astronomy and Astrophysics Supplement. 42: 383. Bibcode:1980A&AS...42..383B. 

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