Bad Astronomy

Naked eye nova!

The skies may seem unchanging, but that’s not really the case. If you have a keen eye and knowledge of the heavens, you see quite a bit of (dare I say it?) evolution.

Case in point: in the constellation of Scorpius (not Scorpio, please), there is a bright nova going on right now. If you’re not familiar with the constellation you wouldn’t notice it, but to those who peruse the skies it sticks out like, well, like a star that’s had a massive explosive event!

Ian Musgrave has the observing details. At magnitude 3.7 or so it’s not glaringly obvious, but it’s the brightest of its kind seen in quite some time. Here’s a map with the position marked (there is nothing on the map at the nova’s spot because my software doesn’t have the nova on it, of course):

This map is for my location at about 6:00 a.m., so YMMV. You can find online sky maps at Your Sky or Heavens Above. But if you go out early in the morning, you’ll see Jupiter blazing away (I marked it on the map above as well), and the nova is a few degrees south of it. It’s very near the bright star Epsilon Scorpii in the middle of the scorpion’s body.

A nova happens when a white dwarf – the very dense remnant of a star like the Sun after it blows off its outer layers, leaving its core exposed to space – is in a binary system, that is, orbiting another normal star. The physics is complex, but matter form the normal star can be drawn off and land on the white dwarf. It piles up, and eventually gets so hot and compressed it explodes like a nuclear bomb. The flash is intense, and the glow can last for weeks.

White dwarfs are usually very faint, and the flash sudden, so what we see on Earth is a relatively blank patch of sky suddenly get bright over the course of hours. It can release thousands or even hundreds of thousands the Sun’s energy output, and last for days. Distance may dim the light, but not the knowledge of what we are seeing.

So if you rise early (or bed late) in the next few days, cast your eyes to the scorpion, and think about what fires lie in its heart.