Possible Nova in Sagittarius

A flaring star discovered independently by two Japanese observers has brightened to near 9th magnitude — putting it within easy range of most backyard telescopes.

Observers are a-twitter with news that a likely nova has flared into prominence in northwest Sagittarius. Now nearing 9th magnitude, it's within reach of backyard observers with modest telescopes.

The star, designated PNV J17522579-2126215 by the IAU's Central Bureau for Astronomical Telegrams, was first reported yesterday by two independent observers. In Yamagata, Japan, Koichi Itagaki saw on images taken June 26th with an 8-inch reflector and CCD camera. A day earlier, Yukio Sakurai of Mito, Japan, had recorded it with his DSLR camera and a 180-mm telephoto lens.

Since then others have followed up with new observations. Initially reported at magnitude 10.2 by Itagaki, the star appears to have brightened a bit. Last night Ernesto Guido, Giovanni Sostero, and Nick Howes imaged the star remotely using a 20-inch telescope in New Mexico and determined that it had a red-light magnitude of 8.9.

Although fresh observations are streaming into the American Association of Variable Star Observers, astronomers are not yet ready to call this a true nova. László Kiss and others in Hungary took spectra using Gothard Observatory's 20-inch telescope but found no strong emissions lines. This suggests the outburst is from a low-intensity dwarf nova. But more results should determine its true nature.

Meanwhile, in order to see this flaring star, you'll need a clear view toward the south. It'll help if your light pollution isn't too bad. But try now if you can, because in a few days the nearly full Moon will bulldoze its way into this part of the sky.

The chart at right shows the general location of PNV J17522579-2126215, which is at right ascension 17^h 52^m 25.8^s, declination –21° 26′ 21.6″. It's about 2° northwest of the Trifid Nebula (Messier 20) in a patch of sky relatively free of clutter from the Milky Way's star clouds. Click on the chart to reveal a detailed finder chart, which was provided to S&T by the AAVSO's Mike Simonsen.