A brand new supernova in NGC 6946 is bright enough to see in modest-sized telescopes. Here's how to find it.
|Live webinar, May 19th! If you're unable to view the supernova through your own telescope, Gianluca Masi will show the exploding star live online on his Virtual Telescope Project website on Friday, May 19th, starting at 4:30 p.m. CDT (21:30 UT). Be sure to check it out.
Last night, Utah amateur Patrick Wiggins discovered a possible bright supernova in the spiral galaxy NGC 6946 in Cygnus. If confirmed, 2017 eaw will become the 10th supernova found in this explosion-rich galaxy in the past century, reaffirming its reputation for fireworks of the grandest kind.
It was Wiggins's third supernova, and he found it by comparing a CCD image made on May 14.24 UT through his 0.35-m f/5.5 reflector near Erda, Utah, with one taken several years ago and another from May 12th. Nothing showed on either image, leading him to suspect a supernova.
To be sure, he watched the new object for over an hour to see if it moved. Faint asteroids have masqueraded as supernovae before, but this one didn't budge. Italian astronomer Gianluca Masi did a check for known asteroids in the vicinity and none were listed. For the moment then, it appears we have a brand new stellar blowup in our night sky.
Through a combination of good fortune and hard work, Wiggins happened to catch the star during the early stage of the blast. He estimated its magnitude at 12.8. Others have since confirmed the discovery and pinned the star's brightness at 12.6, bright enough to spot in telescopes as small as 6 inches!
The new supernova is located 61″ west and 143″ north of the galaxy's nucleus at R.A. 20h 34m 44.24s, Dec. +60° 11′ 35.9″, not far from two stars of similar brightness indicated on the map. Although spectra have yet to confirm whether it's a Type Ia (white dwarf detonation) or Type II (a massive star collapsing and exploding), Wiggins's early catch likely means that AT 2017 eaw will almost certainly continue to brighten.
(Update, May 14: Good news! According to ATel #10376, a spectrum taken of the object "is consistent with that of a young type IIP supernova at one week before the maximum light." This means that our "new star" was a massive supergiant that is no more.)
During the last supernova blast in 2008, SN 2008S hovered around magnitude 16 at best; the brightest explosion occurred in 1980 when SN 1980K peaked around magnitude around 11.4. Wouldn't that be nice if it happened again? Timing's perfect for viewing the star. By 10:30 p.m. local time from mid-northern latitudes, the galaxy is already 25° up in the northeastern sky, and the Moon doesn't rise till after midnight.
I'll have additional news as it arrives in my e-mail. You can also check David Bishop's excellent Latest Supernovae site for fresh updates. Congratulations to Patrick! He joins a long line of Fireworks Galaxy supernovae discoverers, which includes American astronomer George Ritchey, inventor of the Ritchey–Chrétien telescope design, who uncovered the first stellar blast in the galaxy, SN 1917A, on July 19, 1917, and got the ball rolling.
How much time does it take a single individual to find a supernova? In an e-mail communication with Wiggins, I learned he had searched on 292 nights since his last discovery in June 2015. Each night typically involves taking more than 500 images and examining each one for a potential "new star." The patience, determination and sheer grit involved in amateur discovery in the context of today's robotic search programs is nothing short of heroic.