SN 2011fe is a bit bluer than SN 1994D
RHM's picture
Posted: September 12, 2011 - 1:16pm
Yes, you're absolutely right. The graph below shows that while SN 2011fe is tracking SN 1994D pretty well in V, R and I passbands, it's a bit brighter in the B-band. What exactly does that mean? It's not clear yet. I'd like to see a comparison of the spectra
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Mon Sep 19, 2011 5:40 am
by Ann
It does appear to be blue. As to what it means, my instinctive guess would be that it is slightly brighter than the other supernova, SN 1994D.
Ann
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Mon Sep 19, 2011 2:14 pm
by neufer
Ann wrote:
It does appear to be blue. As to what it means, my instinctive guess would be that it is slightly brighter than the other supernova, SN 1994D.
<<I am jazzed up. I finally got a picture of the supernova SN 2011fe in the Pinwheel Galaxy last night using only a telephoto lens on a tracking mount. The path starts at bright Mizar and zigzags its way up to the supernova, which lies just beyond the arrow tip in the Pinwheel Galaxy in this photo taken last night (Sept. 16). Alkaid and Mizar are the two stars at the end of the Big Dipper's Handle. Details: 150mm lens, f/2.8, ISO 800 and 2-minute exposure. (Photo: Bob King)
The moon is now nearly at last quarter and doesn’t flood the sky with light like it does around full phase. This provides us all with another round of opportunities to see the supernova before it fades. For almost a week, it’s been humming along at magnitude 9.9. As you can tell from the before-and-after sequence above, it’s hard to miss!
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Tue Sep 20, 2011 1:38 am
by Ann
It's fading!!!
On Mon, 19 Sep 2011 22:40:34 GMT, SN 2011fe was at magnitude 10.0!
And hey, Art, that's a nice Bob King image of the end part of the handle of the Big Dipper and M101. The picture is actually in color! At first it's very hard ot miss that it is actually in color, but check out that unmistakable, although subtle, blue halo around Alkaid! :jumping up and down smilie: There is a hint of blue in the halo around Mizar too, but it is even subtler, and rightly so, because Alkaid really is much bluer than Mizar!
Note, too, the one obviously yellow-looking star in this image, the second one from Alcor in "the wiggly path to the supernova" in this image. The yellow star is 83 Ursa Majoris or IQ Ursa Majoris. I like the name, IQ Ursa Majoris! Although my favorite IQ star is IQ Aurigae, a star classified as an A0pSi star which is as blue as a B4 star!
Still, IQ Ursa Majoris is interesting enough. It is classified as a M2III star, so it is really cool and quite bright, too. It is about 300 times the luminosity in yellow-green light, but since a star of spectral class M2 peaks well into the infrared part of the spectrum, the bolometric (total) energy output of this star is likely several thousand times that of the Sun.
It's so much fun to discover that what looked like a black and white image is really a color picture, and then it's even more fun to try to read its colors! :jumping up and down: :jumping up and down:
Ann
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Tue Sep 20, 2011 3:07 am
by neufer
Ann wrote:
It's fading!!!
On Mon, 19 Sep 2011 22:40:34 GMT, SN 2011fe was at magnitude 10.0!
It should be noted that SN 2011fe got to a visual magnitude comparable with that of the brightest (blue hypergiant) stars of the Large Magellanic Cloud which is over a hundred times closer to us than M101
http://en.wikipedia.org/wiki/S_Doradus wrote:
<<S Doradus is the brightest star in the Large Magellanic Cloud, a satellite of the Milky Way. A hypergiant, it is one of the most luminous stars known (sometimes more luminous than −10 absolute magnitude), but so far away that it is invisible to the naked eye. This star belongs to its own eponymous S Doradus class of variable stars (these classes are usually named after their prototypes); also designated as the class luminous blue variable or LBV. S Doradus exhibits long, slow changes in brightness, punctuated by occasional outbursts.>>
<<The brightest star in the Large Magellanic Cloud (LMC), one of the brightest stars known, and the prototype for the class of variable known as S Doradus stars (luminous blue variables). It lies in the young open cluster NGC 1910 on the northern rim of the LMC's central bar.
S Doradus has a spectrum very similar to that of P Cygni (see P Cygni profile), another variable of the same type. These stars are extremely massive (at least 60 solar masses) and luminous, using up their nuclear fuel so fast that their lifetimes can't exceed a few million years; they will then explode as supernovae. The very high luminosity also results in an enormous radiation pressure at the star's surface, which tends to blow away significant portions of the stellar mass by way of an intense stellar wind and, occasionally, in the form of an ejected gaseous shell. The light curve of S Doradus also points to a long period (40-year) eclipsing variable behavior.
Recent observations of S Dor have shown that its optical spectrum now resembles that of an F-type supergiant, with a rich complex of absorption lines. Despite nearly 50 years of spectroscopic monitoring, such a spectrum has never previously been seen for S Dor despite many occasions when the star was equally bright. Such F-type spectra have, however, been seen in other luminous blue variables, including Var B in M33 during a recent outburst, and in Eta Carina during an outburst in 1893. The singly ionized metal lines arise in a layer moving away from the star (toward us) at 50 km/s, consistent with the lines forming in a "pseudo photosphere" originating in the stellar wind. The temperature suggested by the F-type spectrum is as cool as an LBV can get.>>
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Tue Sep 20, 2011 3:32 am
by Beyond
I don't know if the super nova was really all that bright. It blew itself up, didn't it
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Tue Sep 20, 2011 3:46 am
by neufer
Beyond wrote:
I don't know if the super nova was really all that bright. It blew itself up, didn't it
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Wed Sep 21, 2011 12:35 am
by Ann
On Tue, 20 Sep 2011 23:19:56 GMT, the supernova was still at magnitude 10.0.
Art, I love your "about-to-explode" ever bluer woman!
Ann
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Wed Sep 21, 2011 3:26 am
by Beyond
That came from one of those Willy Wonka Chocolate Factory movies, but i don't remember which one. She ate an experimental blueberry chocolate something or other, that they were told not to eat because it had some strange side effects. As you can see--she was rather disobedient and became a human blueberry, A very-very mini blueberry nova. Just one of many things that went on, until they were wittled down to the winner that would take over running the chocolate factory from Willy Wonka.
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Thu Sep 22, 2011 3:14 am
by Ann
On Thu, 22 Sep 2011 03:00:40 GMT, the supernova was still at magnitude 10.0. It is not fading rapidly, that's for sure.
Beyond, thanks for the info about the blue woman! A "blueberry nova", indeed!
Ann
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Sat Sep 24, 2011 6:06 am
by Ann
On Sat, 24 Sep 2011 05:30:23 GMT, the supernova was still magnitude 10.0.
You can't accuse it of fading slowly.
Ann
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Mon Sep 26, 2011 12:39 am
by Ann
Wow! I was lazy here! I didn't check out the supernova yesterday. I should have, because it's really fading now! On Sun, 25 Sep 2011 23:22:18 GMT, SN 2011fe was "only" magnitude 10.5!
Ann
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Mon Sep 26, 2011 1:47 am
by Beyond
It's 'pooped'. After expending all that energy, it's retiring from it's supernova job and getting ready to take up something easier for the rest of it's life.
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Mon Sep 26, 2011 3:18 am
by Ann
Beyond wrote:It's 'pooped'. After expending all that energy, it's retiring from it's supernova job and getting ready to take up something easier for the rest of it's life.
I guess it will go to the great green pastures of the retired supernovae in the sky!
Ann
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Mon Sep 26, 2011 5:08 pm
by Ann
They measured it again on Mon, 26 Sep 2011 03:08:46 GMT. It's still 10.5.
Ann
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Tue Sep 27, 2011 5:12 pm
by Ann
On Tue, 27 Sep 2011 03:06:55 GMT, the supernova was still mag. 10.5.
I don't know about the rest of you, but I find these leaps and jumps and plunges in brightness, interspersed with plateaus, confusing.
The light curve of Supernova 2011fe, a mesa-like shape?
Ann
Re: BA: AstroAlert: Type Ia supernova in M101!
Posted: Tue Sep 27, 2011 7:18 pm
by rosettastoned
Umm, after browsing through this thread I don't see so many jumps and plunges in your many reports Ann. In fact I seem to recall the word 'boring' a couple of times ;P
Follows the early predicted behaviour very well, but I can't seem(or is it can't be bothered?) to find an actual published spectra of this SN. Anyone got a link, maybe?
Haven't thought about the colour of 1as to be the same all over, but this is really the first SN I've observed, and I guess as a SN virgin I don't have any foundation for an opinion
btw: thx for the reports Ann, I'm too lazy to look for these things myself
I said the 'terminology' was good - referring to tickety-boo. I DIDN"T listen to the video, so i have no idea what the tune is like.
