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Burst of brightness makes rare recurrent nova visible in the night sky

A small star gorging on gas has gone thermonuclear.

Eric Mack Contributing Editor
Eric Mack has been a CNET contributor since 2011. Eric and his family live 100% energy and water independent on his off-grid compound in the New Mexico desert. Eric uses his passion for writing about energy, renewables, science and climate to bring educational content to life on topics around the solar panel and deregulated energy industries. Eric helps consumers by demystifying solar, battery, renewable energy, energy choice concepts, and also reviews solar installers. Previously, Eric covered space, science, climate change and all things futuristic. His encrypted email for tips is ericcmack@protonmail.com.
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Eric Mack
2 min read
nova3-1024x576.jpg

Artist's portrayal of a classical nova explosion.

 K. Ulaczyk/Warsaw University Observatory

This year's majestic Perseid meteor shower isn't the only spectacular sight in the evening sky this week. A rare recurrent nova is undergoing an outburst, and some sky watchers say it can be seen with the naked eye if you know where to look.

A nova is different from a supernova, which is basically a sort of death spasm for a massive star. A nova, on the other hand, typically occurs when a white dwarf in a binary system sucks up a whole bunch of gas from its larger partner until it reaches a critical mass that triggers a thermonuclear explosion. When a star does this repeatedly, it's a recurrent nova.

There are just seven confirmed recurrent novae in the Milky Way, and one of them is RS Ophiuchi, which is currently putting our whole galaxy on blast.

The small star suddenly brightened 600-fold on Sunday, according to Tony Phillips at Spaceweather.com. Observations on Monday show it continued to grow a bit brighter and is still shining.

"At 5th magnitude, the current outburst is visible to the unaided eye, albeit just barely. Binoculars or a telescope will allow you to see it with ease," Phillips writes. "Look south after sunset. Ophiuchus hangs high in the sky just above the better known constellations Scorpius and Sagittarius."

If you miss the show this time, you might get another chance but you'll have to be patient. RS Ophiuchi only has an outburst about once every 15 to 20 years.

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