HD 192685

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

HD 192685

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	B3V[3]
U−B color index	−0.73[4]
B−V color index	−0.18[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
Mass	8.0[7] M☉
Luminosity	3331[6] L☉
Surface gravity (log g)	3.49[8] cgs
Temperature	18,700[9] K
Metallicity [Fe/H]	−0.10[8] dex
Rotational velocity (v sin i)	160[10] km/s
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

Description

The main plot is a visual band light curve for QR Vulpeculae, adapted from Pavlovski et al. (1983),^[11] showing a sudden brightening. The inset plot, adapted from Lefèvre et al. (2009),^[12] shows the periodic variability.

HD 192685 varies slightly in brightness and is classified as a γ Cassiopeiae variable.^[2]

From October to December 1982 the Hydrogen alpha absorption line increased in emission strength by 30%.^[11] The line is partially filled by redshifted emission.^[13]

HD 192685 has excess infrared emissions (12-100 μm) which are interpreted to be free-free radiation in the gas surrounding the star.^[14]

Companions

It has at least one companion with separation 0.55" and magnitude 7.55,^[15] and may also be a long-period spectroscopic binary.^[16]

References

1. 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. 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. Walker, G. A. H.; Yang, S.; Witt, A. N.; Fahlman, G. G. (Aug–Sep 1980). "The extinction of HD 200775 by dust in NGC 7023". Publications of the Astronomical Society of the Pacific. 92: 414. Bibcode:1980PASP...92..411W. doi:10.1086/130687.
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. 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. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873. Vizier catalog entry
8. 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.
9. 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
10. 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.
11. 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.
12. 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.
13. Green, Daniel W. E. (July 14, 1982). "2 Vul AND HR 7739". IAU Circular. 3710. IAU Central Bureau for Astronomical Telegrams. Retrieved 11 December 2012.
14. 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.
15. Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976. Vizier catalog entry
16. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Vizier catalog entry

External links

• Robin Leadbeater (translation). "Processing the spectrum of the star HD192685". PROCESSING LHIRES SPECTRA.
• HD 192685 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images