HD 192685

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HD 192685
Vulpecula constellation map.svg
Red circle.svg
Location of HD 192685 (circled)
Observation data
Epoch J2000       Equinox J2000
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  mas [1]
Distance approx. 1,000  ly
(approx. 300  pc)
Absolute magnitude  (MV)−2.56 [6]
Details
A
Mass 4.7 [3]   M☉
Luminosity 3331 [6]   L☉
Surface gravity (log g)3.49 [7]   cgs
Temperature 18,700 [8]   K
Metallicity [Fe/H]−0.10 [7]   dex
Rotational velocity (v sin i)160 [9]  km/s
Age 100 [3]   Myr
B
Mass 1.8 [3]   M☉
Age 100 [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
SIMBAD data

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.

Contents

Description

The main plot is a visual band light curve for QR Vulpeculae, adapted from Pavlovski et al. (1983), showing a sudden brightening. The inset plot, adapted from Lefevre et al. (2009), shows the periodic variability. QRVulLightCurve.png
The main plot is a visual band light curve for QR Vulpeculae, adapted from Pavlovski et al. (1983), showing a sudden brightening. The inset plot, adapted from Lefèvre et al. (2009), 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 2 3 4 5 Van Leeuwen, F. (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. S2CID   18759600. Vizier catalog entry
  2. 1 2 3 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.
  3. 1 2 3 4 5 6 7 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. arXiv: 1606.08053 . Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID   119231169.
  6. 1 2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID   119257644. Vizier catalog entry
  7. 1 2 Wu, Yue; Singh, H. P.; Prugniel, P.; Gupta, R.; Koleva, M. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics. 525: A71. arXiv: 1009.1491 . Bibcode:2011A&A...525A..71W. doi:10.1051/0004-6361/201015014. S2CID   53480665.
  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. arXiv: 1003.2335 . Bibcode:2010AN....331..349H. doi:10.1002/asna.200911355. S2CID   111387483. Vizier catalog entry
  9. ↑ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (2002). "Rotational Velocities of B Stars". The Astrophysical Journal. 573 (1): 359–365. Bibcode:2002ApJ...573..359A. doi: 10.1086/340590 .
  10. 1 2 3 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. Bibcode:1983IBVS.2431....1P. ISSN   0374-0676.
  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. Bibcode:2009A&A...507.1141L. doi: 10.1051/0004-6361/200912304 .
  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 (3710). IAU Central Bureau for Astronomical Telegrams: 2. Bibcode:1982IAUC.3710....2B . 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. Bibcode:1987A&A...181...77C. ISSN   0004-6361.
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