XX Tauri


XX Tauri
Location of XX Tauri (circled in red)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Taurus
Right ascension 05h 19m 24.467s[1]
Declination +16° 43′ 01.02″[1]
Apparent magnitude (V) 5.9p — 18.5p[2]
Distance3500[3] pc
Variable type nova
Other designations
Nova Tau 1927, AAVSO 0513+16
Database references
The light curve of XX Tauri, plotted from Harvard plate data,[4] (shown in blue) and AAVSO data (shown in green).

XX Tauri (Nova Tauri 1927) was a nova, which appeared in the constellation Taurus in 1927. It was discovered by Arnold Schwassmann and Arno Arthur Wachmann at Hamburg Observatory on an objective prism photographic plate taken on 18 November 1927. Subsequent examination of pre-discovery photographic plates taken at the Harvard College Observatory showed that the peak brightness, magnitude 5.9, occurred on 1 October 1927, at which point it may have been faintly visible to the naked eye.[5] By 1988 it had faded below magnitude 19.8.[6]

XX Tauri faded three magnitudes from peak brightness in just 43 days, making it a "fast nova". Its post eruption light curve shows small amplitude (~0.1 magnitude) variations of timescales of days, hours and minutes, which makes the determination of the orbital period of the binary system comprising the nova difficult. The orbital period may be 0.136±0.002 days.[7]

In 1984 a small (radius 2.2 arc second) nova remnant surrounding XX Tau was discovered using the Hale Telescope.[8] The expansion of that remnant has been used to derive a distance estimate of 3500 parsecs.[3]


  1. ^ a b Webbink, R.F.; Hazen, M.L.; Hoffleit, D. (July 2002). "Coordinates and Identifications of Harvard Variables". Information Bulletin on Variable Stars. 5298: 1. Retrieved 25 December 2020.
  2. ^ Downes, Ronald; Webbink, Ronald F.; Shara, Michael M. (April 1997). "A Catalog and Atlas of Cataclysmic Variables-Second Edition". Publications of the Astronomical Society of the Pacific. 109: 345–440. doi:10.1086/133900. Retrieved 25 December 2020.
  3. ^ a b Shafter, A.W. (September 1997). "On the Nova Rate in the Galaxy". The Astrophysical Journal. 487: 226–236. doi:10.1086/304609. Retrieved 26 December 2020.
  4. ^ Harwood, Margaret (March 1928). "Nova Tauri 1927". Harvard College Observatory Bulletin (856): 12. Retrieved 26 December 2020.
  5. ^ Duerbeck, Hilmar W. (March 1987). "A Reference Catalogue and Atlas of Galactic Novae". Space Science Reviews. 45 (1–2): 1–14. doi:10.1007/BF00187826. Retrieved 25 December 2020.
  6. ^ Szkody, Paula (August 1994). "BVRGK Observations of Northern Hemisphere Old Novae". The Astronomical Journal. 108: 639. doi:10.1086/117098. Retrieved 26 December 2020.
  7. ^ Rodr ́ıguez-Gil, P.; Torres, M.A.P. (February 2005). "Time-resolved photometry of the nova remnants DM Gem, CP Lac, GI Mon, V400 Per, CT Ser and XX Tau". Astronomy and Astrophysics. 431: 289–296. doi:10.1051/0004-6361:20041112. Retrieved 26 December 2020.
  8. ^ Cohen, J.G. (May 1985). "Nova shells. II. Calibration of the distance scale using novae". The Astrophysical Journal. 292: 90–103. doi:10.1086/163135. Retrieved 26 December 2020.