Astronomy:HD 192685

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Short description: B-type star in the constellation Vulpecula
HD 192685
Location of HD 192685 (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Vulpecula
Right ascension  20h 15m 15.89542s[1]
Declination +25° 35′ 31.0549″[1]
Apparent magnitude (V) 4.60 - 4.80[2]
Characteristics
Spectral type B3Ve + A7V[3]
U−B color index −0.73[4]
Variable type γ Cas[2]
Astrometry
Radial velocity (Rv)−7.00[5] km/s
Proper motion (μ) RA: +6.93[1] mas/yr
Dec.: −3.89[1] mas/yr
Parallax (π)3.29 ± 0.51[1] mas
Distanceapprox. 1,000 ly
(approx. 300 pc)
Absolute magnitude (MV)−2.56[6]
Details
A
Mass4.7[3] M☉
Luminosity3331[6] L☉
Surface gravity (log g)3.49[7] cgs
Temperature18,700[8] K
Metallicity [Fe/H]−0.10[7] dex
Rotational velocity (v sin i)160[9] km/s
Age100[3] Myr
B
Mass1.8[3] M☉
Age100[3] Myr
Other designations
QR Vul, BD+25°4165, CCDM J20153+2536AB, GC 28140, HIP 99824, HR 7739, HD 192685, SAO 88410, WDS J20153+2536AB
Database references
SIMBADdata

HD 192685, also known as QR Vulpeculae or HR 7739, is a binary star[3] about 1,000 ly away in the Vulpecula constellation. It is visible to the naked eye.

Description

The main plot is a visual band light curve for QR Vulpeculae, adapted from Pavlovski et al. (1983),[10] showing a sudden brightening. The inset plot, adapted from Lefèvre et al. (2009),[11] shows the periodic variability.

In 1982 Krešimir Pavlovski and Hrvoje Božić announced their discovery that HD 192685 is a variable star.[12] It was given its variable star designation, QR Vulpeculae, in 1985.[13] HD 192685 varies slightly in brightness and is classified as a γ Cassiopeiae variable.[2]

The stellar components have a projected separation of 70 astronomical units and have an estimated orbital period of 217 years. Component A is a Be star with a spectral type of B3Ve, having a mass 4.7 times that of the Sun, while component B has a class of A3V and is 1.8 times as massive as the Sun.[3]

In July 1982, HD 192685 was observed to have its Hα spectral line, previously a broad absorption line,[10] in emission with a central absorption core, and it was classified as a Be star.[14] In late 1982 the emission increased in strength and the star brightened rapidly and briefly by over 0.1 magnitudes.[10]

HD 192685 has excess infrared emissions (12-100 μm) which are interpreted to be free-free radiation in the gas surrounding the star.[15]


References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V.  Vizier catalog entry
  2. ↑ 2.0 2.1 2.2 Samus, N. N. 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. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Kalari, V. M.; Salinas, R.; Saez-Carvajal, C.; Oudmaijer, R. D.; Howell, S.; Caballero-Nieves, S.; Kamp, K.; Matson, R.; Scott, N. (2025-09-23). "A search for Be stars in multiple systems within the solar neighborhood". arXiv:2509.19286 [astro-ph.SR].
  4. ↑ Mermilliod, J. C. (2006). "VizieR Online Data Catalog: Homogeneous Means in the UBV System (Mermilliod 1991)". VizieR On-line Data Catalog: II/168. Originally Published in: Institut d'Astronomie 2168. Bibcode: 2006yCat.2168....0M. Vizier catalog entry
  5. ↑ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G. 
  6. ↑ 6.0 6.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.  Vizier catalog entry
  7. ↑ 7.0 7.1 Wu, Yue; Singh, H. P.; Prugniel, P.; Gupta, R.; Koleva, M. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics 525: A71. doi:10.1051/0004-6361/201015014. Bibcode: 2011A&A...525A..71W. 
  8. ↑ Hohle, M.M.; Neuhäuser, R.; Schutz, B.F. (2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten 331 (4): 349. doi:10.1002/asna.200911355. Bibcode: 2010AN....331..349H.  Vizier catalog entry
  9. ↑ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (2002). "Rotational Velocities of B Stars". The Astrophysical Journal 573 (1): 359–365. doi:10.1086/340590. Bibcode: 2002ApJ...573..359A. 
  10. ↑ 10.0 10.1 10.2 Pavlovski, K.; Bozic, H.; Harmanec, P.; Horn, J.; Koubsky, P. (14 November 1983). "Sudden Brightening of the Recently Discovered Be Star HR 7739". Information Bulletin on Variable Stars 2431 (1): 1. ISSN 0374-0676. Bibcode: 1983IBVS.2431....1P. 
  11. ↑ Lefèvre, L.; Marchenko, S. V.; Moffat, A. F. J.; Acker, A. (November 2009). "A systematic study of variability among OB-stars based on HIPPARCOS photometry". Astronomy and Astrophysics 507 (2): 1141–1201. doi:10.1051/0004-6361/200912304. Bibcode: 2009A&A...507.1141L. 
  12. ↑ Pavlovski, Pavlovski; Božić, Hrvoje (1982). "UBV Photometry of some Be stars: progress report". Hvar Observatory Bulletin 6 (1): 45–51. Bibcode: 1982HvaOB...6...45P. 
  13. ↑ Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Perova, N. B. (March 1985). "The 67th Name-List of Variable Stars". Information Bulletin on Variable Stars 2681: 1–32. Bibcode: 1985IBVS.2681....1K. 
  14. ↑ Green, Daniel W. E. (July 14, 1982). "2 Vul AND HR 7739". IAU Circular (IAU Central Bureau for Astronomical Telegrams) (3710): 2. Bibcode: 1982IAUC.3710....2B. http://www.cbat.eps.harvard.edu/iauc/03700/03710.html#Item2. Retrieved 11 December 2012. 
  15. ↑ Cote, J. (July 1987). "B and A type stars with unexpectedly large colour excesses at IRAS wavelengths". Astronomy and Astrophysics 181 (1): 83. ISSN 0004-6361. Bibcode: 1987A&A...181...77C. 



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