V420 Aurigae is a high-mass
star with an inferred
compact companion. Closely orbiting each other every 0.8 days, they are a source of X-ray emission.[6]
These coordinates were identified as an X-ray source using the
Uhuru satellite in 1978, then associated with the star V420 Aurigae by V. F. Polcaro and associates in 1984.[12] The spectrum of the star shows rapid variation in the lines of singly-ionized iron and
Balmer line emission, with these varying on a time scale of less than 300 seconds. This lends support to the presence of a compact companion.[13] The system displays an
infrared excess, suggesting it has an orbiting circumstellar envelope of gas and possibly dust.[4] The system appears to be positioned at the center of an irregular, wispy nebula that was detected in the infrared band. One of the two filaments in this nebula appears to be connected with the system.[12]
References
^"/ftp/cats/more/HIP/cdroms/cats". Centre de Données astronomiques de Strasbourg. Strasbourg astronomical Data Center. Retrieved 15 October 2022.
^
abcdPolcaro, V. F.; et al. (May 1990), "BD +37 1160 : a probable optical counterpart of the X-ray source 1H 0521+373", Astronomy and Astrophysics, 231: 354–364,
Bibcode:
1990A&A...231..354P.
^
abPercy, John R.; et al. (February 2004), "Short-Period Variable Be Stars Discovered or Confirmed through Self-Correlation Analysis of Hipparcos Epoch Photometry", The Publications of the Astronomical Society of the Pacific, 116 (816): 178–183,
Bibcode:
2004PASP..116..178P,
doi:
10.1086/382246,
S2CID120898311.
^Halbedel, Elaine M. (September 1996), "Rotational Velocity Determinations for 164 Be and B Stars", Publications of the Astronomical Society of the Pacific, 108: 833,
Bibcode:
1996PASP..108..833H,
doi:10.1086/133804,
S2CID119944672.
^Rossi, C.; et al. (September 1991), "Rapid variability of BD +37 1160, a possible optical counterpart of the X-ray source 1H 0521+373.", Astronomy and Astrophysics, 249: L19,
Bibcode:
1991A&A...249L..19R.
Further reading
Norci, L.; et al. (December 2006), "Is the X-ray Transient HD 34921 (4U 0515+38) a B[e] Star?", Stars with the B[e] Phenomenon. ASP Conference Series, Vol. 355, Proceedings of the Conference Held 10-16 July, 2005, at the Isle of Vlieland, The Netherlands, vol. 355, San Francisco: Astronomical Society of the Pacific, p. 289,
Bibcode:
2006ASPC..355..289N.
Polcaro, V. F.; et al. (2007), St.-Louis, Nicole; Moffat, Anthony F.J. (eds.), "The Very Unusual HMXRB HD 34921", Massive Stars in Interactive Binaries, ASP Conference Series 367, vol. 367, San Francisco: Astronomical Society of the Pacific, p. 471,
Bibcode:
2007ASPC..367..471P.
Waagen, Elizabeth O. (October 2016), "Observations of V420 Aur (HD 34921) needed to support spectroscopy", AAVSO Alert Notice 554, vol. 554, p. 1,
Bibcode:
2016AAN...554....1W.
Polcaro, V. F.; et al. (2006), Meurs, E. J. A.; Fabbiano, G. (eds.), "The Be/X-ray transient HD34921", Populations of High Energy Sources in Galaxies Proceedings of the 230th Symposium of the International Astronomical Union, Held in Dublin, Ireland 15-19 August 2005, vol. 1, Cambridge: Cambridge University Press, pp. 49–50,
Bibcode:
2006IAUS..230...49P,
doi:10.1017/S1743921306007824.