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Title: Novae in globular clusters

Journal Article · · Astrophysical Journal
 [1];  [2];  [3]
  1. Department of Astronomy, Keio University, Hiyoshi, Yokohama 223-8521 (Japan)
  2. Department of Earth Science and Astronomy, College of Arts and Sciences, University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902 (Japan)
  3. European Space Astronomy Centre, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain)

We present the first light-curve analysis of Population II novae that appeared in M31 globular clusters. Our light-curve models, based on the optically thick wind theory, reproduce well both the X-ray turn-on and turnoff times with the white dwarf (WD) mass of about 1.2 M {sub ☉} for M31N 2007-06b in Bol 111 and about 1.37 M {sub ☉} for M31N 2010-10f in Bol 126. The transient supersoft X-ray source CXO J004345 in Bol 194 is highly likely a nova remnant of 1.2-1.3 M {sub ☉} WD. These WD masses are quite consistent with the temperatures deduced from X-ray spectra. We also present the dependence of nova light curves on the metallicity in the range from [Fe/H] = 0.4 to –2.7. Whereas strong optically thick winds are accelerated in Galactic disk novae owing to a large Fe opacity peak, only weak winds occur in Population II novae with low Fe abundance. Thus, nova light curves are systematically slow in low Fe environment. For an extremely low Fe abundance normal nova outbursts may not occur unless the WD is very massive. We encourage V or y filter observation rather than R as well as high cadence X-ray monitorings to open quantitative studies of extragalactic novae.

OSTI ID:
22348556
Journal Information:
Astrophysical Journal, Vol. 779, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
Country of Publication:
United States
Language:
English