Volume 622, February 2019
|Number of page(s)||16|
|Section||Stellar structure and evolution|
|Published online||19 February 2019|
A UV and optical study of 18 old novae with Gaia DR2 distances: mass accretion rates, physical parameters, and MMRD⋆
INAF – Ossservatorio Astronomico di Trieste, Via Tiepolo 11, 34143 Trieste, Italy
2 European Southern Observatory, Karl Schwarzschild-Str. 2, 85748 Garching, Germany
Accepted: 25 December 2018
We combine the results of our earlier study of the UV characteristics of 18 classical novae (CNe) with data from the literature and with the recent precise distance determinations from the Gaia satellite to investigate the statistical properties of old novae. All final parameters for the sample include a detailed treatment of the errors and their propagation. The physical properties reported here include the absolute magnitudes at maximum and minimum, a new maximum magnitude versus rate of decline (MMRD) relation, and the inclination-corrected 1100–6000 Å accretion disk luminosity. Most importantly, these data have allowed us to derive a homogenous set of accretion rates in quiescence for the 18 novae. All novae in the sample were super-Eddington during outburst, with an average absolute magnitude at maximum of −7.5 ± 1.0. The average absolute magnitude at minimum corrected for inclination is 3.9 ± 1.0. The median mass accretion rate is log Ṁ1 M⊙ = −8.52 (using 1 M⊙ as WD mass for all novae) or log ṀMWD = −8.48 (using the individual WD masses). These values are lower than those assumed in studies of CNe evolution and appear to attenuate the need for a hibernation hypothesis to interpret the nova phenomenon. We identified a number of correlations among the physical parameters of the quiescent and eruptive phases, some already known but others new and even surprising. Several quantities correlate with the speed class t3 including, unexpectedly, the mass accretion rate (Ṁ). This rate correlates also with the absolute magnitude at minimum corrected for inclination, and with the outburst amplitude, providing new and simple ways to estimate Ṁ through its functional dependence on (more) easily observed quantities. There is no correlation between Ṁ and the orbital period.
Key words: novae, cataclysmic variables / ultraviolet: stars / stars: distances / accretion, accretion disks
Based mainly on INES data from the IUE satellite. Other UV data utilized in this paper were obtained from the Multimission Archive at the Space Telescope Science Institute (MAST), see Paper I. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
© ESO 2019
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