QS Telescopii

QS Telescopii is a faint, well-studied^[4] binary star system in the southern constellation Telescopium.^[7] It is composed of a white dwarf and main sequence donor star, locked into a close, circular orbit facing one another. Known as polars, material from the donor star does not form an accretion disk around the white dwarf, but rather streams directly onto it.^[6] This is due to the presence of the white dwarf's strong magnetic field. The pair undergo frequent shifts between a high and low accretion states, and it shifts between single and double accretion poles. The main pole is partially self-eclipsing.^[4]

QS Telescopii

A visual band light curve for QS Telescopii, adapted from Rosen et al. (1996)[1]
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Telescopium
Right ascension	19h 38m 35.816s[2]
Declination	−46° 12′ 57.11″[2]
Characteristics
Spectral type	M4.5±0.5[3]
Variable type	AM Her[4]
Astrometry
Radial velocity (Rv)	110 km/s
Proper motion (μ)	RA: +35.150 mas/yr[2] Dec.: −25.496 mas/yr[2]
Parallax (π)	5.3378 ± 0.0834 mas[2]
Distance	611 ± 10 ly (187 ± 3 pc)
Orbit[5]
Period (P)	2.33 h
Eccentricity (e)	0.0
Details
White Dwarf
Mass	0.71[6] M☉
Temperature	17,500[6] K
Other designations
QS Tel, EUVE J1938-46.2, RE 1938-461, AAVSO 1931-46[7]
Database references
SIMBAD	data

The pair orbit each other with a period of 2.33^[5] hours in a circular orbit. The donor star is a small red dwarf with an estimated stellar classification of M4−5.^[3] The white dwarf primary has 71% of the mass of the Sun and an effective temperature of 17,500 K.^[6] It has a magnetic field strength of 50–80 MG. The system is a source for X-ray emission.^[4]

See also

• Variable stars
• Polar (cataclysmic variable)
• AM Herculis

References

1. Rosen, S. R.; Mittaz, J. P. D.; Buckley, D. A.; Layden, A. C.; Clayton, K. L.; McCain, C.; Wynn, G. A.; Sirk, M. M.; Osborne, J. P.; Watson, M. G. (June 1996). "Accretion mode changes in QS Tel (RE 1938 — 461): EUVE, ROSAT and optical observations". Monthly Notices of the Royal Astronomical Society. 280 (4): 1121–1142. Bibcode:1996MNRAS.280.1121R. doi:10.1093/mnras/280.4.1121. hdl:2381/38963.
2. 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.
3. Knigge, Christian (December 2006). "The donor stars of cataclysmic variables". Monthly Notices of the Royal Astronomical Society. 373 (2): 484–502. arXiv:astro-ph/0609671. Bibcode:2006MNRAS.373..484K. doi:10.1111/j.1365-2966.2006.11096.x. S2CID 2616606.
4. Traulsen, I.; Reinsch, K.; Schwope, A. D.; Burwitz, V.; et al. (2011). "XMM-Newton observations of the X-ray soft polar QS Telescopii". Astronomy and Astrophysics. 529 (A116): 7. arXiv:1103.4575. Bibcode:2011A&A...529A.116T. doi:10.1051/0004-6361/201016352. S2CID 119187792.
5. Augusteijn, T.; et al. (June 2010). "Cataclysmic variables from the Calán-Tololo Survey - II. Spectroscopic periods". Monthly Notices of the Royal Astronomical Society. 405 (1): 621–637. Bibcode:2010MNRAS.405..621A. doi:10.1111/j.1365-2966.2010.16487.x.
6. Gerke, Jill R.; et al. (2006). "Polars Changing State: Multiwavelength Long-Term Photometry and Spectroscopy of QS Telescopii, V834 Centauri, and BL Hydri". Publications of the Astronomical Society of the Pacific. 118 (843): 678–86. arXiv:astro-ph/0603097. Bibcode:2006PASP..118..678G. doi:10.1086/503753. S2CID 14857705.
7. "QS Tel". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-11-25.

Further reading

• Romero-Colmenero, E.; et al. (August 2005). Hameury, J.-M.; Lasota, J.-P. (eds.). An eclipsing geometry for the polar QS Tel. The Astrophysics of Cataclysmic Variables and Related Objects, Proceedings of ASP Conference. Vol. 330. San Francisco: Astronomical Society of the Pacific. p. 429. Bibcode:2005ASPC..330..429R.

• Romero-Colmenero, E.; et al. (March 2004). "Spectroscopic and polarimetric observations of QS Tel". Astronomische Nachrichten. 325 (3): 214. Bibcode:2004AN....325..214R. doi:10.1002/asna.200310216.

• Rosen, S. R.; et al. (April 2001). "Multiwavelength monitoring of QS Tel". Monthly Notices of the Royal Astronomical Society. 322 (3): 631–642. Bibcode:2001MNRAS.322..631R. doi:10.1046/j.1365-8711.2001.04141.x.

• de Martino, D.; et al. (January 1998). "Insights into the accretion flow in QS Telescopii (RE1938-461) from HST observations". Astronomy and Astrophysics. 329: 571–578. Bibcode:1998A&A...329..571D.

• Rosen, S. R.; et al. (June 1996). "Accretion mode changes in QS Tel (RE 1938-461): EUVE, ROSAT and optical observations". Monthly Notices of the Royal Astronomical Society. 280 (4): 1121–1142. Bibcode:1996MNRAS.280.1121R. doi:10.1093/mnras/280.4.1121. hdl:2381/38963.

• Clayton, K. L.; et al. (1996). Evans, A.; Wood, Janet H. (eds.). Recent progress on the polar QS Tel: the HST results. Cataclysmic variables and related objects. Proceedings of the 158th colloquium of the International Astronomical Union (IAU); held at Keele; United Kingdom; June 26-30; 1995; Dordrecht. Astrophysics and Space Science Library. Kluwer Academic Publishers. p. 225. Bibcode:1996ASSL..208..225C. doi:10.1007/978-94-009-0325-8_68.

• de Martino, D.; Buckely, D. A. H.; Mouchet, M.; Mukai, K. (June 1995). "UV observations of the polar system RE 1938-461". Astronomy and Astrophysics. 298: L5. Bibcode:1995A&A...298L...5D.

• Rosen, S.; et al. (1995). Buckley, D. A. H.; Warner, B. (eds.). EUVE Spectrophotometry of QS Tel (RE1938-461): The Second Pole Becomes Active. Cape Workshop on Magnetic cataclysmic variables; Proceedings of the Cape Workshop, held in Cape Town, 23-27 January 1995. Astronomical Society of the Pacific Conference Series. Vol. 85. San Francisco: Astronomical Society of the Pacific. p. 279. Bibcode:1995ASPC...85..279R.

• Schwope, A. D.; et al. (January 1995). "Two-pole accretion in the high-field polar RXJ 1938.6-4612". Astronomy and Astrophysics. 293: 764–776. Bibcode:1995A&A...293..764S.

• Ferrario, L.; et al. (May 1994). "The Polarization and Magnetic Field of REJ1938-461 during its Low State". Monthly Notices of the Royal Astronomical Society. 268 (1): 128. Bibcode:1994MNRAS.268..128F. doi:10.1093/mnras/268.1.128.

• Warren, John K.; et al. (September 1993). "Extreme Ultraviolet Explorer Observations of the Magnetic Cataclysmic Variable RE 1938-461". Astrophysical Journal Letters. 414: L69. Bibcode:1993ApJ...414L..69W. doi:10.1086/186998.

• Warren, J. K.; et al. (December 1992). EUVE Observations of the Magnetic Cataclysmic Variable RE1938-461. American Astronomical Society, 181st AAS Meeting. Bulletin of the American Astronomical Society. Vol. 24. p. 1250. Bibcode:1992AAS...181.8007W. 80.07.