A Nova aka a New Star is a sudden outburst on the surface of a white dwarf (remnant of a dead star) when it pulls enough material from its companion in a binary system. The companion is usually a star that is in close orbit with this white dwarf. Due to the latter’s strong gravitational pull, material (mostly hydrogen) from the surface of the star is pulled and wrapped around the white dwarf. This material keeps piling up on the surface of the white dwarf, which eventually raises the surface temperature to millions of degrees. This temperature is sufficient to start an uncontrolled nuclear reaction for the hydrogen atoms and leads to an explosion on the surface of the white dwarf, which is called the thermonuclear runaway in astronomy.
In theory, this phenomenon keeps happening again and again until the accumulated mass reaches a critical stage which destroys the white dwarf itself. This is why the study of novae is extremely important. This process synthesizes various elements and tell us about the chemistry of our solar system and sheds a light on the evolution of stars. Moreover, lithium found on Earth or anywhere in the Universe is primarily produced by nova explosions, as predicted by these explosion models.
Researchers from Arizona State University, the University of Minnesota, and The Ohio State University found a nova on June 12, 2021, called V1674 which is the fastest to date, and published their findings in the Research Notes of the American Astronomical Society (RNAAS). Usually, the nova (brightening of the white dwarf due to the explosion) stays visible to telescopes for a few days to a few months, but this one faded in a day. It was extremely bright because it was visible to the naked eye. Along with its speed, wobbling was also witnessed in this system which tells us a lot about the geometry of the binary orbit, and it does affect the overall brightness of the event as well as the speed. Understanding such systems literally tells us where we came from, because of the elements they synthesize. After all, “we all are made of star-stuff”.
Source: RNASS press release
