AE Aquarii

AE Aquarii is a cataclysmic variable binary star of the DQ Herculis type. Based upon parallax measurements, the system is located at a distance of about 280 light-years (86 parsecs) from the Earth.[1] Because of its unique properties, this system has been subject to a number of scientific studies.[3]

AE Aquarii

Artistic illustration of the AE Aquarii system
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Aquarius
Right ascension 20h 40m 09.16206s[1]
Declination −00° 52′ 15.0618″[1]
Apparent magnitude (V) 11.6[2]
Characteristics
Spectral type White dwarf + K4–5 V[3]
B−V color index −1.2[2]
Variable type DQ Her
Astrometry
Radial velocity (Rv)−53[4] km/s
Proper motion (μ) RA: +73.95[1] mas/yr
Dec.: +12.40[1] mas/yr
Parallax (π)11.61 ± 2.72[1] mas
Distanceapprox. 280 ly
(approx. 90 pc)
Absolute magnitude (MV)~6.6[5]
Orbit[6]
Period (P)9.88 hours
Semi-major axis (a)2.34 ± 0.02 R☉
Inclination (i)70 ± 3°
Details
A
Mass0.63 ± 0.05[6] M☉
Radius0.01[7] R☉
Rotation33.08 sec[8]
B
Mass0.37 ± 0.04[6] M☉
Radius0.79[6] R☉
Other designations
2E 2037.5-0102, GCRV 71273, 1RXS J204009.4-005216, AN 342.1931, 2E 4404, GSC 05177-00636, SBC7 826, 1AXG J204011-0052, RJHA 119, CSI-01-20376, CDS 1178, HIP 101991, 1E 2037.5-0102, 1ES 2037-01.0, 2MASS J20400915-0052151, AAVSO 2035-01.[2]
Database references
SIMBADdata

The AE Aquarii system consisting of an ordinary star in a close orbit around a magnetic white dwarf; the pair orbit each other with a period of 9.88 hours. The white dwarf primary has 63% of the Sun's mass but a radius of only about 1% of the Sun. As of 2009, it has the shortest known spin period of any white dwarf, completing a full revolution every 33.08 seconds. This spin is decreasing at a rate of 1.78 ns per year, which is unusually high.[3] The secondary star has a stellar classification of K4-5 V, making it a main sequence star that is generating energy at its core through the thermonuclear fusion of hydrogen. It has about 37% of the Sun's mass but 79% of the Sun's radius.

This system displays flare activity that has been observed across multiple bands of the electromagnetic spectrum, including X-rays. Mass is being lost from the secondary star, most of which is being flung out of the system by the rapidly spinning magnetic primary. The X-ray luminosity is likely being caused by the accretion of mass onto the white dwarf, which is occurring at an estimated rate of about 7.3 × 1010 kg per second.[3]

See also

References
  1. van Leeuwen, F. (November 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.
  2. "V* AE Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved July 22, 2008.
  3. Mauche, Christopher W. (November 2009), "Chandra High-Energy Transmission Grating Spectrum of AE Aquarii", The Astrophysical Journal, 706 (1): 130–141, arXiv:0910.0084, Bibcode:2009ApJ...706..130M, doi:10.1088/0004-637X/706/1/130, S2CID 16457151
  4. Evans, D. S. (June 20–24, 1966). Batten, Alan Henry; Heard, John Frederick (eds.). "The Revision of the General Catalogue of Radial Velocities". Determination of Radial Velocities and Their Applications, Proceedings from IAU Symposium. University of Toronto: International Astronomical Union. 30: 57. Bibcode:1967IAUS...30...57E.
  5. From apparent magnitude and parallax.
  6. Echevarría, J.; et al. (July 2008). "High-dispersion absorption-line spectroscopy of AE Aqr". Monthly Notices of the Royal Astronomical Society. 387 (4): 1563–1574. arXiv:0804.0291. Bibcode:2008MNRAS.387.1563E. doi:10.1111/j.1365-2966.2008.13248.x. S2CID 11324791.
  7. Itoh, Kei; et al. (2005). "Density diagnostics of the hot plasma in AE Aquarii with XMM-NEWTON" (PDF). Proceedings of 'The X-ray Universe 2005', el Escorial, Madrid, Spain. 639 (1): 397–404. arXiv:astro-ph/0412559. Bibcode:2006ApJ...639..397I. doi:10.1086/499152. S2CID 14578720.
  8. Patterson, Joseph (December 15, 1979). "Rapid oscillations in cataclysmic variables. III. An oblique rotator in AE Aquarii". Astrophysical Journal. 234: 978. Bibcode:1979ApJ...234..978P. doi:10.1086/157582.

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