Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · astro-ph/9709186

The mass of the white dwarf in the old nova BT Mon

D. A. Smith·V. S. Dhillon·T. R. Marsh
View original source ↗Read source document ↗Export metadata ↓

Abstract

We present spectrophotometry of the eclipsing old nova BT Mon (Nova Mon 1939). By detecting weak absorption features from the secondary star, we find its radial velocity semi-amplitude to be K_R = 205+/-5 km/s and its rotational velocity to be vsin i = 138+/-5 km/s. We also measure the radial velocity semi-amplitude of the primary star to be K_R = 170+/-10 km/s. From these parameters we obtain a mass of 1.04+/-0.06 M_sun for the white dwarf primary star and a mass of 0.87+/-0.06 M_sun for the G8V secondary star. The inclination of the system is found to be 82.2+/-3.2 deg and we estimate that the system lies at a distance of 1700+/-300pc. The high mass of the white dwarf and our finding that BT Mon was probably a fast nova together constitute a new piece of evidence in favour of the thermonuclear runaway model of classical nova outbursts. The emission lines are single peaked throughout the orbital cycle, showing absorption around phase 0.5, high velocity S-wave components and large phase offsets in their radial velocity curves. In each of these respects, BT Mon is similar to the SW Sex stars. We also find quasi-periodic flaring in the trailed spectra, which makes BT Mon a candidate intermediate polar.

Explore related subjects

astro-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D. A. Smith, V. S. Dhillon, T. R. Marsh. 1997-09-22. The mass of the white dwarf in the old nova BT Mon. https://doi.org/10.1046/j.1365-8711.1998.00743.x

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2024

Deformation procedure for scalar fields in cosmology

This work offers an extension of the deformation procedure introduced in field theory to the case of standard cosmology in the presence of real scalar field in flat space-time. The procedure is shown to work for many models, which give rise to several different cosmic scenarios, evolving under the presence of first-order differential equations which solve the corresponding equations of motion very appropriately.

astro-ph↗
arXiv2023

Dark Energy is the Cosmological Quantum Vacuum Energy of Light Particles-The Axion and the Lightest Neutrino

We uncover the general mechanism producing the dark energy(DE). This is only based on well known quantum physics and cosmology. We show that the observed DE originates from the cosmological quantum vacuum of light particles which provides a continuous energy distribution able to reproduce the data. Bosons give positive contributions to the DE while fermions yield negative contributions. As usual in field theory, ultraviolet divergences are subtracted from the physical quantities. The subtractions respect the symmetries of the theory and we normalize the physical quantities to be zero for the Minkowski vacuum. The resulting finite contributions to the energy density and the pressure from the quantum vacuum grow as log a(t) where a(t) is the scale factor, while the particle contributions dilute as 1/a^3(t), as it must be for massive particles. The DE equation of state P = w(z)H turns to be w(z)<-1 with w(z) asymptotically reaching the value -1 from below.A scalar particle can produce the observed DE through its quantum cosmological vacuum provided:(i)its mass is of the order of 10^{-3} eV = 1 meV,(ii) it is very weakly coupled and (iii) it is stable on the time scale of the age of the universe. The axion vacuum thus appears as a natural candidate. The neutrino vacuum (especially the lightest mass eigenstate) can give negative contributions to the DE. We find that w(z=0) is slightly below -1 by an amount ranging from [-1.5 10^{-3}] to [-8 10^{-3}] and we predict the axion mass to be in the range between 4 and 5 meV. We find that the universe will expand in the future faster than the de Sitter universe, as an exponential in the square of the cosmic time. DE arises from the quantum vacua of light particles in FRW cosmological space time in an analogous way to the Casimir effect in Minkowski spacetime with non trivial boundaries.

astro-ph↗