Sunday, November 15, 2015

Lyra . MV Lyrae nova-like star

VY Sculptor star observation
Graph Astro Keel, UK

MV Lyrae a nova-like star consisting of a red dwarf and a white dwarf.

Originally classified as a VY Sculptoris star due to spending most time at maximum brightness, since around 1979 the system has been dominantly at minimum brightness, with periodic outbursts. Its nature is still not fully understood. Wikipedia

For an example of a scientific report on observing MV Lyrae see
Pavlenko, E. P. (Crimean Astrophysical Observatory, Nancy, Ukraine)
Shugarov, S. Yu. (Sternberg State Astronomical Institute, Moscow, Russia)
Photometric study of the nova-like variable MV Lyrae during an enormous outburst in 1997. Astronomy and Astrophysics 343, 909–915 (1999).  Harvard link PDF
VY Sculptoris star is a nova-like variable that occasionally shows a sudden drop in brightness, reminiscent of a *Z Camelopardalis star. Oxford Dictionary of Astronomy

Nova-like stars
Cataclysmic (Explosive or Nova-like) Variables
These are variable stars that show outbursts which are caused by thermonuclear burst processes on the surface (novae) or deep in the interior of the star (supernovae).

The majority of explosive and nova-like systems are close binaries, which are often made up of a white dwarf and normal star companion.

The stars have strong mutual effects on each others development. A normal star, similar to our Sun, will lose mass onto the white dwarf by accretion because the white dwarf is incredibly dense and has huge gravitational potential.

Classic nova outbursts are caused by sudden nuclear fusion of hydrogen-rich material on the surface of the white dwarf. White Dwarfs are the cinders of our stars like the sun, hydrogen fusion is only possible when fresh fuel is accreted onto its surface, and the normal star in close binary system does this.
Astro Keele UK

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