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OBSERVING BLOG by Alan MacRobert
Supernova in M82 Reaches Its Peak
Supernova 2014J in M82 has finally
stopped brightening, at about magnitude 10.5. The galaxy and supernova are
visible in amateur telescopes in the northeast during
evening.
Last updated January 31st Shortly after its discovery, Yi Cao and colleagues at Caltech took a spectrum that suggested it was two weeks away from reaching its peak brightness in the first few days of February. This and other spectra showed it to be a Type Ia supernova — an exploded white dwarf — with debris expanding at up to 20,000 kilometers per second. Because it appears reddened, it must also be dimmed by dust along our line of sight. By one estimate, it would be two magnitudes brighter if we were seeing it in the clear. M82 is a near neighbor as galaxies go, at a distance of 11 or 12 million light-years. It's a favorite for amateur astronomers and researchers alike with its thick dust bands, sprays of hydrogen gas, and bright center undergoing massive star formation. The supernova is not in the central star-forming region but off to one side, 58 arcseconds to the west-southwest. Remarkably, the supernova went undiscovered for nearly a week as it brightened. Prediscovery unfiltered CCD images by Koichi Itagaki of Yamagata, Japan, show nothing at its location to as faint as magnitude 17.0 through January 14.5. But it was magnitude 14.4 on January 15.6, 13.9 on January 16th, 13.3 on January 17th, 12.2 on January 19th, and 11.9 on January 20th. (Images.) So the actual explosion occurred (from Earth's viewpoint) late on January 14th or early on the 15th Universal Time. It received the name Supernova 2014J once its nature was confirmed. It originally went by the preliminary designation PSN J09554214+6940260. M82 is well up in the northeast by 7 or 8 p.m. (for observers at mid-northern latitudes). The waxing crescent Moon begins to light the evening sky noticeably after about February 2nd or 3rd, so don't wait. Here's a comparison-star chart from the AAVSO. On the chart north is up, east is left, and the field is ½° wide; star magnitudes are given to the nearest tenth with the decimal point omitted. The galaxy shows up as an elongated swarm of faint dots. (If you want other parameters, you can make your own chart using the AAVSO Variable Star Plotter; for star name enter SN 2014J.) Here's the preliminary AAVSO light curve with photometry in the B, V, and R bands (blue, "visual," and red light) as well as eyeball estimates (shown black). So far the light curve is developing just as expected for a reddened Type Ia supernova. Italian observer Gianluca Masi hosted an online supernova-imaging session with his Virtual Telescope Project on January 25th. Click on the link to see a replay of the hour-long event. Here's a wide-field view of M81 and M82 including the supernova, for a broader perspective. . A Flukey Find The first people to recognize the supernova were a group of students — Ben Cooke, Tom Wright, Matthew Wilde and Guy Pollack, assisted by teaching fellow Stephen J. Fossey — taking a quick image at the University of London Observatory (within the London city limits!) on the evening of January 21st at 19:20 UT. "The discovery was a fluke," says a university press release, —a 10-minute telescope workshop for undergraduate students that led to a global scramble to acquire confirming images and spectra. The original press release, and a BBC story repeating it, claimed that this is the nearest supernova since Supernova 1987A in the Large Magellanic Cloud. In fact, SN 1993J in M81 was at essentially the same distance within the uncertainties, and two subsequent supernovae, SN 2004am and SN 2008iz (an obscured radio supernova), occurred within M82 itself. However, this is said to be the nearest Type Ia supernova since 1972. That's the kind so valuable for measuring the size and expansion rate of the universe. Despite the dimming and reddening, astronomers hope that SN 2014J will provide new details about exactly what happens in these "standard-candle" explosions. Update: Supernova in Another Messier Galaxy Don't get your hopes up, but another supernova, SN 2014L, has appeared in M99 in Coma Berenices high in the late-night sky. It was only magnitude 15.7 as of January 28.4 UT, way too faint for most amateur scopes, but it was only about magnitude 17.2 when discovered on January 26th. More information and images. It was still being reported at the same magnitude 15.7 as of January 29.4 UT. M99 is a spiral galaxy about 50 million light-years away in the Virgo Cluster, four times as far as M82. It has hosted three previous known supernovae (1967H, 1972Q, and 1986I) and the odd lesser outburst PTF 10fqs.
Posted by Alan MacRobert, January 31, 2014
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First comments (from 20)
Backyard astronomy
Posted by Anthony Barreiro January 22, 2014 At 11:08 AM
PST
This is very exciting news, thanks. I'm glad I
happened to check the S&T website today. Tonight, Wednesday January 22, was
already going to be interesting, with Algol at minimum brightness at 2220 PST,
Europa and Europa's shadow transiting Jupiter from 2018 to 2352 PST, and
Jupiter's great red spot at the central meridian at 2232 PST. We're having a
drought here in California, so the weather has been remarkably good for
skywatching. I'll add M82's supernova to my list for tonight. By the way, Sky
and Telescope used to send out occasional email alerts for special events like
supernovae. Do you still do this? Do I need to sign up
again?on-line video of M82 SN
Posted by Ron January 22, 2014 At 11:25 AM PST
Check out this video on youtube. they have the SN live and even
talk about (lack of) them in M82 and don't recognize a new star is right there
on the image!
https://www.youtube.com/watch?v=ePOrciuULH0&feature=share&t=21m36sNearest Supernova?
Posted by Jon Hanford January 23, 2014 At 06:18 AM
PST
Not only was SN1993J in M81 at about the same
distance, two supernovae have appeared in M82 since 1987, SN2004am and
SN2008iz(a radio supernova). SN2004am, a Type II-P SN, appeared very close to
the position of the current SN:
http://astro.berkeley.edu/bait/public_html/2004/sn2004am.html Additional info on
these two supernovae in M82 can be found here: http://arxiv.org/abs/1207.1889
http://www3.mpifr-bonn.mpg.de/staff/abrunthaler/m82.shtmla special supernova
Posted by Paul Vondra January 23, 2014 At 09:23 PM
PST
My 86-year-old mother passed away this afternoon,
peacefully, at home, after suffering a second stroke on Monday. She never
regained consciousness. Unscientific though it is, I will always think of this
as her Special Guidelight as she sets sail across that Vast and Unknown Sea. I
live in Pittsburgh where it has been cloudy and bitterly cold since I first
heard of the supernova yesterday but I intend to set up my scope the first clear
chance i get regardless of the temp. to see it. The only other supernova I've
ever seen was the one in M101 a year or two back and I'm hoping this one may get
a little brighter.a special supernova
Posted by Bruce Mayfield January 24, 2014 At 05:15 AM
PST
Paul, sorry to read of your loss. I lost my mother
a few years back. While we know scientifically that astronomical and human
events are unrelated, seeing something special at a time of great loss can bring
comfort, so I hope you are able to personally observe SN2014J, and may your
heart be warmed when you do. But science alone doesn’t offer much hope though.
Reflecting on these verses were some of the many that brought me hope and
comfort when my mother passed; Job 14:14,15 and Acts 24:15.Max Mag of M82 SN
Posted by Tom Hoffelder January 24, 2014 At 02:50 PM
PST
Happy to see the "very tentative" prediction of mag
10.1 as the maximum. I have seen other sources saying as bright as 8. They must
be ignoring the reddening caused by dust.M82 supernova
Posted by John Mahlberg January 24, 2014 At 06:55 PM
PST
I could just barely glimpse the super nova tonight
through a 90 MM scope in central Colorado.M82 Supernova
Posted by mrvair January 25, 2014 At 09:38 AM PST
Events like this supernova remind me of Psalms
19:1.M82 Supernova
Posted by Bruce January 25, 2014 At 04:15 PM PST
That's one of my favorite verses too Mrvair. I hope to see this,
but only have 10x50 binoculars. In a fairly dark sky, what appartent magnatude
would this SN have to reach to be detectable?M82 Supernova in Binoculars
Posted by Hal Lane January 25, 2014 At 07:48 PM PST
Bruce, This PDF: "Limiting Magnitude in Binoculars"
http://www.cloudynights.com/documents/limiting.pdf answers your question: "what
appartent magnatude would this SN have to reach to be detectable [in 10x50
binos]?" -- but you'll have to do a bit of reading to find it... Note that the
author of the paper used a tripod and averted vision (looking very slightly away
from the object being looked for) for their tests... In the PDF the 3rd page has
a list of useful abbreviations used in the paper. Please post whether you were
able to see 2014J or not, and the circumstances (sky darkness, etc.) of your
attempt! - Hal Lane
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