This Record-Fast Nova Could Be Seen With The Naked Eye For A Day And Then Vanished

This Record-Fast Nova Could Be Seen With The Naked Eye For A Day And Then Vanished ...

Some stars are bright but short. These persistent novae streak around the sky, one flaring into naked eye view every few years, but it was a recent brief appearance of just such a 'new star' that gave astronomers a chance to investigate the mysteries of the Universe.

Seidji Ueda, a Japanese amateur astronomer, was the first to raise the alarm across the world.

Amateurs are always looking for galactic novae, since it's one of the few areas where they may contribute to actual science. Since 1911, the American Association of Variable Star Observers (AAVSO) has been the central clearinghouse for novae observations and light curves.

The'star' was a galactic nova near Hercules the Hero's northern border with Sagitta and Aquila, just off the galactic plane on the night of 21 June 2021. Soon, the nova had a name:V1674 Her orNova Herculis 2021.

Known novae are usually visible for days or weeks before disappearing from view. Examples of recent memorable novae includeNova Delphini 2013 andNova Centauri 2013.

Nova Herculis 2021 had a surprise in store: It topped out, flirting with naked-eye brightness at magnitude +6, before disappearing from view in just one day. Twenty-four hours after its eruption, the nova had faded a hundredfold, setting a new 3-day high set by Nova V838 Herculis in 1991.

When a dense white dwarf star siphons material off a main sequence companion, Novae are formed. The material becomes compressed on the surface of the white dwarf, which can ignite under the force of nuclear fusion in a violent flash.

Novae can erupt many times in what's known as a recurrent nova. They can also build up and evolve into supernovae, which can be seen throughout the Universe.

"The white dwarf that exploded is huge and expanding in mass toward a Supernova 1A explosion," according to astronomer Sumner Starrfield of the University of Minnesota. "It ejected far less mass than necessary to be accrete by the white dwarf and initiate an explosion."

Novae are important because they bring heavier elements back into the cosmos, and Type IA supernovae are used as standard candles to measure extra-galactic distances.

Nova Herculis 2021 is known for a 501-second 'wobble,' which runs across the visible and x-ray spectrum and may vary from bright to faint magnitudes. This, along with variations in the energetic wind ejected by the nova into the surrounding interstellar medium, appears to be influenced by the white dwarf star's orbital period versus its companion.

Nova Herculis 2021 is an estimated 4,750 parsecs (15,500 light-years) distant.

"We are continuing to investigate this system since it has not returned to its previous state," says Starrfield. "We know that it has a 500-second oscillation likely the white dwarf rotation period, and an about 3.6 hour rotation period that is probably the rotation period of the binary."

The Large Binocular Telescope on Mount Graham in Arizona was used to observe Nova Herculis 2021, along with its multi-object double and PEPSI spectrograph.

Investigating novae might also be a way to approaching the 'cosmological lithium problem,' and the origin of lithium abundance in metal-rich stars such as our Sun.

"Both theory and observations have now shown that classical novae are the lithium producers in the galaxy," says Starrfield. "A long-standing issue has been why there is more lithium in stars like the Sun than produced by the Big Bang."

Nova Herculis is a fascinating discovery to follow in our strange stellar menagerie.

In the American Astronomical Society's Research Notes, you may find information on the University of Minnesota and Ohio State University's Nova Herculisout.

Universe Today published this article as part of its original publication. Read the original article.

You may also like: