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Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Sat Jan 25, 2014 10:31 pm
by BDanielMayfield
Personally, being flippant, I don’t give a flying flip about the “big rip”.
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Nitpicker wrote:BDanielMayfield wrote:Since it is expected to brighten for another two weeks, and since a supernova can breifly out-shine an entire galaxy, how bright can we expect this to become? Will this become a naked eye object?
According to what I have just read about Normal Type Ia supernovae, they all have an absolute magnitude of around -19.3, meaning that this one will have an apparent magnitude of about +8.5. So, visible in binoculars, but not to the unaided eye.
8.5 = -19.3 - 5 (1- log10[3,700,000pc])
Edit: this formula is not particularly accurate for objects beyond the Milky Way.
Nitpicker, thank you for that answer, which appeals to my mathematical side. So then the formula for apparent magnitude, given distance and absolute magnitude, would be:
M(app) = M(abs)-5*(1 – log10[D]), with distance in parsecs, and not taking any reddening factors into account.
Reddening must be quite strong in the exploding cigar though as shown by the infrared image Ann posted. One estimate I read mentioned 10.1 as a predicted maximum for SN 2014J.
Please excuse my ignorance of something that I ought to know, but at a fairly dark site what might the limits of a pair of 10x50 binoculars be?
Dirty Harry: "A man’s got to know his limitations.”
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Sat Jan 25, 2014 10:47 pm
by geckzilla
There's dust in M82, sure, but all this talk about it being super reddened seems unfounded. It's possible that it's at the periphery of the galaxy with a minimal amount of dust surrounding it. Until some measurements and analysis from someone experienced with such things are done it doesn't make sense to continue with this assumption.
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Sat Jan 25, 2014 10:51 pm
by neufer
BDanielMayfield wrote:
Personally, being flippant, I don’t give a flying flip about the “big rip”.
If you ran around all over the place in purple tights you might feel differently.
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Sat Jan 25, 2014 10:57 pm
by neufer
geckzilla wrote:
<<There's dust in M82, sure, but all this talk about it being super reddened seems unfounded. It's possible that it's at the periphery of the galaxy with a minimal amount of dust surrounding it. Until some measurements and analysis from someone experienced with such things are done it doesn't make sense to continue with this assumption.>>
http://astrobob.areavoices.com/2014/01/25/m82-supernova-2014j-update-see-it-live-this-afternoon/ wrote:
M82 supernova 2014J update
Astrobob, January 25, 2014
<<The recent bright supernova SN 2014J discovered in the M82, the Cigar Galaxy, earlier this week has brightened up to magnitude 10.5 by some estimates. While I saw it last night at 11.5, I’m not complaining. Beginning and amateur astronomers the world over have been out braving the cold to get a look at this stellar beacon.
Lots more data on the supernova has been pouring in. Here’s what we know so far:
* SN 2014J is a Type Ia-HV supernova. HV stands for high-velocity and indicates that explosive gases have been rushing outward from the obliterated star at exceptional speeds. Early measurements on Jan. 22 clocked clouds of gas at over 20,000 km/sec.
* Astronomers estimate it was discovered about a week before maximum brightness. That would indicate a peak on or around Jan. 29.
* SN 2014J is “highly reddened”, meaning that there is a great deal of dust in the host galaxy it has to shine through for its light to reach us. Without reddening, the explosion would be even brighter.
* White dwarf stars – one of which was the progenitor of this M82 supernova – are typically made of carbon and oxygen, the waste products left by the fusion of hydrogen and helium during the star’s lifetime. Once a star becomes a white dwarf it’s done fusing elements, so it twiddles its thumbs cooling off over the next trillion years.
BUT … when it explodes as a supernova, waste carbon and oxygen fuse in the fury of heat and pressure to create a new element, silicon. That’s exactly what astronomers are seeing now in SN 2014J’s spectrum, a map of the star’s light made with a spectrograph. Spectrographs spread out a star’s light to “fingerprint” the elements of which it’s composed. Silicon is also produced “naturally” by fusion in the cores of supergiant stars, some of which can explode as Type II supernovae.
Silicon combined with oxygen is the most common compound in Earth’s crust. Next time you admire an agate or feel the sand between your toes, look up and thank a supernova.>>
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Sat Jan 25, 2014 11:15 pm
by geckzilla
It's a graph without any analysis. I have no way of knowing if that's typical or unusual.
Edit: I see your edit and raise you another edit. Thank you for the Astrobob reference.
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Sun Jan 26, 2014 1:03 am
by BDanielMayfield
This is exciting news because unlike so many SNs this one is both relatively close AND it was detected prior to reaching maximum brightness. This potentially puts it within range of great numbers of people with binoculars and small telescopes, IF it isn’t dimmed too much by dust. That’s why discussing how bright and when the peak brightness may occur is so significant. It’s not so much about science, but the fun of actually being able to see one of these rare events for oneself.
So per Nitpicker’s calculation this SN could reach mag. 8.5 if it wasn’t reddened. The estimate I heard was that it might reach 10.1, and the AstroBob article Art posted said that it has already reached “10.5 by some estimates.” Since each whole magnitude drop is 2.5 times brighter then this object is now only 5 times dimmer than a crude estimate of its maximum possible brightness, and it’s still brightening!
For those who also want to try finding this for yourself, here’s a link to the Sky & Tel. article about observing this, which contains links to a finder chart and other websites covering this event:
http://www.skyandtelescope.com/observin ... 77661.html
Bruce
Edit: a change of two full magnitudes would be 2.5 • 2.5 = a 6.25 fold change in mag.
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Sun Jan 26, 2014 6:40 am
by Ann
geckzilla wrote:There's dust in M82, sure, but all this talk about it being super reddened seems unfounded. It's possible that it's at the periphery of the galaxy with a minimal amount of dust surrounding it. Until some measurements and analysis from someone experienced with such things are done it doesn't make sense to continue with this assumption.
I don't think anyone has suggested that the supernova is
super-reddened, but the official accounts I have seen all say that it is
reddened. The fact that it is reddened means that it is not expected to become as bright as it would have if it had been (more or less) non-reddened.
How bright this supernova will become depends on how reddened it is and how intrinsically bright it is.
Supernovae Type Ia do vary in intrinsic peak brightness.
But indeed, this new supernova is not
super-reddened.
Art gave us a fine example earlier in this thread of a supernova that was indeed
super-reddened.
Ann
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Sun Jan 26, 2014 7:27 am
by Nitpicker
BDanielMayfield wrote:
Nitpicker wrote:BDanielMayfield wrote:Since it is expected to brighten for another two weeks, and since a supernova can breifly out-shine an entire galaxy, how bright can we expect this to become? Will this become a naked eye object?
According to what I have just read about Normal Type Ia supernovae, they all have an absolute magnitude of around -19.3, meaning that this one will have an apparent magnitude of about +8.5. So, visible in binoculars, but not to the unaided eye.
8.5 = -19.3 - 5 (1- log10[3,700,000pc])
Edit: this formula is not particularly accurate for objects beyond the Milky Way.
Nitpicker, thank you for that answer, which appeals to my mathematical side. So then the formula for apparent magnitude, given distance and absolute magnitude, would be:
M(app) = M(abs)-5*(1 – log10[D]), with distance in parsecs, and not taking any reddening factors into account.
Reddening must be quite strong in the exploding cigar though as shown by the infrared image Ann posted. One estimate I read mentioned 10.1 as a predicted maximum for SN 2014J.
Please excuse my ignorance of something that I ought to know, but at a fairly dark site what might the limits of a pair of 10x50 binoculars be?
I understand that that formula is less accurate for extra-galactic objects, due to spacetime curvature, redshifting and time dilation.
Edit:Possibly dust too.
A good observer might be able to just see a mag 10 object with binoculars from a dark site.
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Sun Jan 26, 2014 1:29 pm
by BDanielMayfield
Thank you Ann and Nitpicker for those very helpful posts.
Ann, that article about the maximum magnitudes that type Ia Supernova can display was interesting. So these “standard candles” have some variability, but it’s reassuring that the variability wasn’t too large. The main conclusion of that paper was that, depending on the White Dwarf progenitor’s metallicity, a Ia SN can vary by 0.2 or at most 0.3 magnitudes.
Nitpicker, armed with your info that a mag. 10 object might just possibly be seen in my binos I think I’m going to alter my strategy for seeing this SN. I need to “phone a friend” who has a small telescope. Tonight I have a rare good weather window and if we can find SN 2014J in a telescope first finding it in binoculars should then be a little easier.
Bruce
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Sun Jan 26, 2014 5:30 pm
by Anthony Barreiro
BDanielMayfield wrote:Thank you Ann and Nitpicker for those very helpful posts.
Ann, that article about the maximum magnitudes that type Ia Supernova can display was interesting. So these “standard candles” have some variability, but it’s reassuring that the variability wasn’t too large. The main conclusion of that paper was that, depending on the White Dwarf progenitor’s metallicity, a Ia SN can vary by 0.2 or at most 0.3 magnitudes.
Nitpicker, armed with your info that a mag. 10 object might just possibly be seen in my binos I think I’m going to alter my strategy for seeing this SN. I need to “phone a friend” who has a small telescope. Tonight I have a rare good weather window and if we can find SN 2014J in a telescope first finding it in binoculars should then be a little easier.
Bruce
As with any other telescope, you will be able to see dimmer objects in bigger binoculars. Mounted 70 mm binoculars could easily detect a 10th magnitude star. Hand-held 50 mm binoculars could probably show it, if the sky is clear and dark, and your eyes are dark adapted. 25 mm binoculars, no way. I think it's always worth trying!
Through hazy and moderately light polluted skies at Chabot observatory last night I saw M82 and the supernova faintly through an 8 inch schmidt cassegrain. Through Chabot's flagship 36 inch cassegrain M82 showed a lot of detail and the supernova stood out like a lighthouse! Very dramatic. Visitors who were not experienced observers and may have learned what a supernova is while they were standing in line were able to see it easily and understand it. The consensus was that 12 million light years is pretty far away.
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Tue Jan 28, 2014 5:11 am
by BillBixby
rstevenson wrote:geckzilla wrote:Wait, Rob. Where are you trying to go in 20 years at .999999999999 c?
Remember, I'd get to M82 in 20 of
my years in the ship, but back here on Earth, you stick-in-the-muds will experience about 12 million years. If M82 turns out to be boring, I'll come back in another 20 years (ignoring the humungous accelerations and decelerations involved, just to keep things simple) and we can all catch up on who won all the Super Bowls I missed. Then I'll sit down to watch Super Bowl 24002014. (I leave as a challenge for the reader converting that to Roman Numerals.)
Rob
Rob, I have decided to attempt your challenge (because it is there). 24002014 in Roman Numerals (RN): But, first...
Let's add some commas for conventionalism. 24,002,014 (Makes it easier for me to see the target. Plus they will be used, by me, in the completed answer, so the answer may be more easily read. I don't think the Romans had a comma back then though I bet they wish they had.)
The Binary answer, as shown in a Google web search would be 0b1011011100011110111011110
Nitpicker said the correct discussion for the then current Super Bowl based upon a vision of the Super Bowl of the distant future being played by robots (perhaps also with an alternative, lingerie-clad league). It would therefore be in hexadecimal: Super Bowl 16E3DDE.
Anyway, I brushed-up on my Roman Numerals at
http://www.mathsisfun.com/roman-numerals.html and discovered that I shall be breaking the rule of using more than three of the same characters in a row (have to love the comma). Per the website, above, numbers greater than 1,000 are formed by placing a dash over the symbol, meaning "times 1,000", but these are not commonly used: M̅ equals a million, so:
M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅,MMXIV
Note the last five (v) characters (2014) do not have the dash over them and I chose not to include a comma. Just pretend the number has no commas, at all, and the answer I came up with may be correct. I had this all set up in Word to transfer here with the dash over the M. However, since the big bang transfer the dash and the M seem to have experienced some red shift using the Ancient Roman Numeral system. It may not be shifted to extremely as the dash over the letter concept appears to have been added in the middle ages. It would have taken a lot more of the letter M had the dash not become available.
Rob, thank you for the challenge.
Bill
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Tue Jan 28, 2014 6:49 am
by Nitpicker
BillBixby wrote:
M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅,MMXIV
A worthy effort. Personally, I'd
cheat be creative and "double-bar a 24", viz:
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Tue Jan 28, 2014 1:06 pm
by rstevenson
... only on the Asterisk!
Rob
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Tue Jan 28, 2014 3:21 pm
by Chris Peterson
Nitpicker wrote:A worthy effort. Personally, I'd
cheat be creative and "double-bar a 24", viz:
I'd
cheat in a different way.
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Tue Jan 28, 2014 5:13 pm
by BillBixby
Nitpicker wrote:BillBixby wrote:
M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅,MMXIV
A worthy effort. Personally, I'd
cheat be creative and "double-bar a 24", viz:
I like it, very much. Is it acknowledged usage or inspired?
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Tue Jan 28, 2014 9:49 pm
by Nitpicker
BillBixby wrote:Nitpicker wrote:BillBixby wrote:
M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅, M̅ M̅ M̅,M̅ M̅ M̅,MMXIV
A worthy effort. Personally, I'd
cheat be creative and "double-bar a 24", viz:
I like it, very much. Is it acknowledged usage or inspired?
Inspired by laziness. I imagine people were assassinated on the floor of the ancient Roman Senate for lesser crimes.
Supernova in M82 At Its Peak
Posted: Wed Feb 05, 2014 4:51 am
by neufer
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Thu Feb 06, 2014 6:30 am
by geckzilla
Chris Peterson wrote:geckzilla wrote:Time dilation. How does it even work?
I recommend one of two approaches. Either don't think about it at all, or think about it quite hard. It's casual thinking about things like that which will mess you up.
Unfortunately I've taken the unrecommended approach and have a question that I don't suppose can be answered simply, but does time dilation affect light itself? For a particle of light, would no time seem to pass between the time it left one position and arrived at another?
Re: APOD: Bright Supernova in M82 (2014 Jan 24)
Posted: Thu Feb 06, 2014 10:42 am
by Nitpicker
geckzilla wrote:Chris Peterson wrote:geckzilla wrote:Time dilation. How does it even work?
I recommend one of two approaches. Either don't think about it at all, or think about it quite hard. It's casual thinking about things like that which will mess you up.
Unfortunately I've taken the unrecommended approach and have a question that I don't suppose can be answered simply, but does time dilation affect light itself? For a particle of light, would no time seem to pass between the time it left one position and arrived at another?
Time dilation does become rather unintuitive at the speed of light, because information about an event at a certain place and time (an event in spacetime) cannot be conveyed faster than the speed of light.
Imagine the event of a photon radiated from a star 10 light years away, 10 years ago. From our perspective, the photon arrives now with information of the event from 10 years ago. From the perspective of the photon, it
is the event, moving through spacetime.
Not sure if this helps. I tried to avoid discussions about a clock moving with the photon, compared with a clock on Earth, as time and light are so intertwined.
Fauxtons
Posted: Thu Feb 06, 2014 1:27 pm
by neufer
Nitpicker wrote:
Imagine the event of a photon radiated from a star 10 light years away, 10 years ago. From our perspective, the photon arrives now with information of the event from 10 years ago. From the perspective of the photon, it is the event, moving through spacetime.
If an electron & positron collide to produce two quantum entangled photons
moving in opposite directions do they share the same perspective
Re: Fauxtons
Posted: Thu Feb 06, 2014 9:02 pm
by Nitpicker
neufer wrote:Nitpicker wrote:
Imagine the event of a photon radiated from a star 10 light years away, 10 years ago. From our perspective, the photon arrives now with information of the event from 10 years ago. From the perspective of the photon, it is the event, moving through spacetime.
If an electron & positron collide to produce two quantum entangled photons
moving in opposite directions do they share the same perspective
Please don't mess with my fragile and tenuous understanding of relativity.
