QX Andromedae

QX Andromedae
	Location of QX Andromedae (circled) in NGC 752
Observation data; Epoch J2000 Equinox J2000
Constellation	Andromeda
Right ascension	01h 57m 57.7818s
Declination	+37° 48′ 22.4500″
Apparent magnitude (V)	11.28 – 11.5 variable
Characteristics
Spectral type	F6
Apparent magnitude (B)	11.77
Apparent magnitude (R)	11.23
Apparent magnitude (G)	11.2929
Apparent magnitude (J)	10.393
Apparent magnitude (H)	10.225
Apparent magnitude (K)	10.163
Variable type	W UMa
Astrometry
Radial velocity (Rv)	11.70±0.27 km/s
Proper motion (μ)	RA: 10.016±1.295 mas/yr ; Dec.: −11.926±0.281 mas/yr
Parallax (π)	2.2376 ± 0.0676 mas
Distance	1,460 ± 40 ly ; (450 ± 10 pc)
Orbit
Period (P)	0.4121716 days
Semi-major axis (a)	2.89±0.04 M☉
Inclination (i)	54.6±0.2°
Details
Primary
Mass	1.47±0.05 M☉
Radius	1.46±0.02 R☉
Surface gravity (log g)	4.27±0.03 cgs
Temperature	6,440 K
Age	1.34±0.06 Gyr
Secondary
Mass	0.45±0.02 M☉
Radius	0.88±0.02 R☉
Surface gravity (log g)	4.20±0.03 cgs
Temperature	6420±20 K
Age	1.34±0.06 Gyr
Other designations
	2MASS J01575777+3748224, RX J015758.0+374820, TYC 2816-1950-1
Database references
SIMBAD	data

QX Andromedae (often abbreviated to QX And) is an eclipsing binary in the constellation Andromeda. It varies from a maximum apparent visual magnitude of 11.28 to a minimum of 11.50. Since it is impossible to specify the onset time of the eclipses, it is classified as a W Ursae Majoris variable star.^[2] It is also observed as an X-ray source^[8] and is a member of the open cluster NGC 752.^[7]

System

As a whole, the QX Andromedae system emits light like a stellar blackbody, with a F6 spectral type.^[2] The two stars in the system complete an orbit every 9.892 hours; they are so close that their envelopes are touching each other. Their temperature is similar, but they have different radius and mass.^[6] Since they belong to an open cluster, the age of this system is equal to the cluster estimated age (1.34±0.06 billion years).^[7]

Variability

A visual band light curve of QX Andromedae, adapted from Ren *et al.* (2011)^[9]

The light curve of QX Andromedae shows almost equal eclipses; the primary eclipse occurs when the less massive star pass in front of the other one. The brightness variations are rather small for this system given the low orbital inclination of 55°.^[6]

References

^ ^a ^b ^c ^d ^e ^f 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.
^ ^a ^b ^c ^d ^e N. N. Samus; O. V. Durlevich; et al. "QX And database entry". Combined General Catalog of Variable Stars (2017 ed.). CDS. Retrieved 2018-11-12.
^ ^a ^b Norton, A. J.; Wheatley, P. J.; West, R. G.; Haswell, C. A.; Street, R. A.; Collier Cameron, A.; Christian, D. J.; Clarkson, W. I.; Enoch, B.; Gallaway, M.; Hellier, C.; Horne, K.; Irwin, J.; Kane, S. R.; Lister, T. A.; Nicholas, J. P.; Parley, N.; Pollacco, D.; Ryans, R.; Skillen, I.; Wilson, D. M. (2007). "New periodic variable stars coincident with ROSAT sources discovered using SuperWASP". Astronomy and Astrophysics. 467 (2): 785. arXiv:astro-ph/0702631. Bibcode:2007A&A...467..785N. doi:10.1051/0004-6361:20077084. S2CID 16358048.
^ ^a ^b ^c Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
^ Bilir, S.; Karataș, Y.; Demircan, O.; Eker, Z. (2005). "Kinematics of W Ursae Majoris type binaries and evidence of the two types of formation". Monthly Notices of the Royal Astronomical Society. 357 (2): 497–517. arXiv:astro-ph/0411291. Bibcode:2005MNRAS.357..497B. doi:10.1111/j.1365-2966.2005.08609.x.
^ ^a ^b ^c ^d Djurašević, G.; Yılmaz, M.; Baștürk, Ö.; Kılıçoğlu, T.; Latković, O.; Çalıșkan, Ş.; Christian, D. J.; Enoch, B.; Gallaway, M.; Hellier, C.; Horne, K.; Irwin, J.; Kane, S. R.; Lister, T. A.; Nicholas, J. P.; Parley, N.; Pollacco, D.; Ryans, R.; Skillen, I.; Wilson, D. M. (2011). "Physical parameters of close binaries QX Andromedae, RW Comae Berenices, MR Delphini, and BD +079° 3142". Astronomy and Astrophysics. 525: A66. arXiv:1011.3677. Bibcode:2011A&A...525A..66D. doi:10.1051/0004-6361/201014895. S2CID 119289612.
^ ^a ^b ^c ^d Agüeros, M. A.; Bowsher, E. C.; Bochanski, J. J.; Cargile, P. A.; Covey, K. R.; Douglas, S. T.; Kraus, A.; Kundert, A.; Law, N. M.; Ahmadi, A.; Arce, H. G. (July 2018). "A New Look at an Old Cluster: The Membership, Rotation, and Magnetic Activity of Low-mass Stars in the 1.3 Gyr Old Open Cluster NGC 752". The Astrophysical Journal. 862 (1): 33. arXiv:1804.02016. Bibcode:2018ApJ...862...33A. doi:10.3847/1538-4357/aac6ed. S2CID 119438236.
^ Belloni, T.; Verbunt, F. (January 1996). "Soft X-rays from the intermediate-age open cluster NGC 752". Astronomy and Astrophysics. 305: 806. Bibcode:1996A&A...305..806B.
^ Ren, A. B.; Zhang, X. B.; Luo, C. Q.; Luo, Y. P.; Deng, L. C.; Luo, Z. Q. (April 2011). "CCD Photometry of the W UMa type star QX Andromeda". New Astronomy. 16 (3): 194–198. Bibcode:2011NewA...16..194R. doi:10.1016/j.newast.2010.08.007. Retrieved 11 October 2021.