I work with neutron stars from the theoretical point of view. Now I am starting some calculations involving white dwarfs and I wish to know the present state of the art of the observational aspects of these compact stars.
The most recent reference I can find is from 2015, and states that RX J0045.4 , a white dwarf in the Andromeda Galaxy, is about 1.3 solar masses. It is, as all such stars must be to have their mass measured, part of a binary system, and is subject to relatively frequent nova-like bursts, due to the accretion of about 0.1 Earth-mass per year from its companion. It is possible that more massive white dwarfs have been observed since then, but I haven't seen any mention of them, and the paper announcing its discovery suggests that RX J0045.4 is probably the only white dwarf of such mass in M31, since it is already so close to the Chandrasekhar Limit. If so, finding still more massive white dwarfs may not be possible until we can observe such stars in much more distant galaxies.
In case you want to see the original paper, it can be accessed at https://ntrs.nasa.gov/search.jsp?R=20150008360
A recent summary of 3637 WD masses from SDSS spectra by Kepler et al. 2016 (see Article White Dwarf Mass Distribution
) find a mass range between 0.35 - 1.3 solar masses. Masses are computed from the WD mass-radius relation, and depends on estimates of surface gravity g = GM/R^2 and surface temperature T (also called effective temperature), via the Stefan-Boltzmann relation for stars, L ~ R^2T^4, and for which a distance is estimated for each star in the sample. While no WD has been found to exceed Chandrasekhar's maximum WD limit of 1.44 solar masses, there are models of rotating and/or magnetized WDs that could marginally increase that value.
Wikipedia gives RE J0317-853 as the most massive quoting this source:
http://adsabs.harvard.edu/abs/1998AAS...191.1511B
Hi George
Thanks. I have heard about white dwarf masses exceding the Chandrasekhar limit of 1.4 solar masses. With high internal magnetic field, exotic composition, high speed rotation and so on. I am looking for to find such information.
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