Friday, February 23, 2007

Supernova 1987A

23 February 1987,
7:35 UT
Anomalously high neutrino counting rates observed in the Kamiokande, IMB, and Baksan neutrino detectors
23 February 1987,
10:30 UT
Robert McNaught photographs the Large Magellanic Cloud. When he develops the plate, a bright new star shows up.
24 February 1987,
5:30 UT
Astronomer Ian Shelton at the Las Campanas Observatory, Chile, sees with his naked eyes a new star in the Large Magellanic Cloud.

Do you remember the Supernova in the Large Magellanic Cloud in February 1987?

Last weekend, I climbed down into the cellar of my parent's house, and it was still there, in a pile of yellowed magazines: The old copy of the March 23, 1987 TIME magazine with the long cover story about Supernova 1987A, which had exploded four weeks before, on February 23, 1987.

Just having finished school, I did my military service at that time, and was casually reading TIME to work on my English. The Supernova news had fascinated me, I knew it was the first in our cosmic vicinity that could be seen with the naked eye since the days of Kepler, and I was deeply disappointed that it was visible only in the Southern Sky. But this four-page story compensated my quite a bit - it was well written, and you can still read it online. The thrill of this exciting event was one of the reasons I started to study physics later that year...

I hope at least some of our readers have a conscious memory about things scientific that happened 20 years ago ;-) I'll be glad to read your memories of SN1987A!

Plenty of fascinating physics and great photos are related to Supernova 1987A - see e.g. here:

By the way, what has happened to the neutrino signal of 02:52 UT from the Montblanc detector?



  1. Where was I? In a fitting circumstance, I was taking a graduate stellar evolution (late evolution: novae, supernovae) course at UCSC taught by Stan Woolsey, and the IR astronomy group in which I was working at NASA-Ames was snagged to take their spectrometers to Christchurch to observe SN1987a from the Kuiper Airborne Observatory (KAO). Even though I've flown on the KAO a dozen times, I was only a programmer/data analyst and my boss/group couldn't justify the expense of a large travel like that for me, plus I couldn't be away from my courses that long. So I stayed behind and dreamed ...

  2. Sadly, I can't remember anything about SN1987. But then, I was only 11 at this time. This must have been so exciting for the astronomers!

    Is there some kind of a worldwide master plan for astronomers in case there's a supernovae coming up?



  3. Where is SN1987a's remnant neutron star or black hole? Neither one would be a subtle thing to observe or an object easy to invisibly uncreate.

    How could the entire iron core of Sanduleak -62 202 photodisintegrate?

  4. Uncle Al: Why are you so sure it is not there? If its spin rate is small or it has a small magnetic field, the neutron star would not be easily detectable.

  5. I remember that Time issue (impressive cover), but I don't recall the details of the article. It was my freshman year of college and all freshmen got subscriptions to Time as part of our "liberal arts" curriculum. Sometimes I had time to read it cover to cover but usually I didn't. Wow, twenty years! I'm old!!

  6. I don't remember the hype surrounding the observation of supernova 1987, despite having a faint interest in astronomy at that time. Twenty years is a long time for useless memories to fade away :) I do remember seeing Halley's Comet with my naked eyes just the year before, in 1986.

  7. Oh, yes! I was a physics undergrad at the time (in Sydney) and I remember how excited everyone was. I'm not sure about SN1987, but even in those days there were definitely international plans for switching observations quickly when something like that turned up. But because there was so much less automation (and no computers to speak of) things usually needed arranging in advance. I remember the Neptune encounter at the Parkes telescope (I was doing night shifts there) - NASA was there weeks before laying wires all over the building.

  8. Hi Chicken!

    Now that you mention it, I also remember Halley's. I had a friend back then who was very into stargazing (childhood romance). He moved shortly after that though, never heard of him again. I wonder what he's doing today. He was kind of the prototype for the nerdy kid. At this time though, I was still in my phase of becoming a famous writer, it took one more decade for me to discover physics. Best,


  9. Back in 1987, I guess I was in the first year of my postdoc at Yale. The really cool thing, of course, was seeing anomalous neutrino bursts in several different neutrino detectors. Neutrinos are darn hard to catch; the idea of seeing them from a source 170,000 light years away was mindboggling to me.

    The next time something like this happens, people will be better prepared. From the paper "The future of supernova neutrino detection" by Burrows, Klein and

    By a series of independent decisions, an international network of massive underg
    round neutrino detectors is being established whose collective sensitivity to supernova neutrinos will be unprecedented. Individually and in coordinated fashion, these detectors could provide temporal, energetic, angular, and flavor information for any stellar collapse in our Galaxy, the Large Magellanic Cloud, or the Small Magellanic Cloud.

    Gravitational wave detectors can also look for signals! This is what Tiffany Summerscales at Penn State is working on - along with other people.

  10. Hi Stefan, great post

    Bee, the Swift Explorer BAT is a wide Field-Of-View (FOV) coded-aperture gamma ray imager that produces arcminute GRB positions onboard within 10 seconds. The spacecraft executes a rapid autonomous slew that points the focusing telescopes at the BAT position in typically ~ 50s.

    Swift supernovae

    PS - Stefan could open the last link: star death from uoregon

  11. For me nothing stands out.

    Although I do have an interest in Supernova events. So from your article I had been incubating on this subject from what I had read of your post here.

  12. Dear all,

    thank you very much for sharing your stories from all over the world :-) It's great to see that we have readers with so interesting backgrounds!

    Dear John,

    i was completely stunned at that time when I heard about the neutrino signal from the supernova. Thank you for the reference, and for the link. I wasn't aware that LIGO could pick up gravitational waves from nearby supernovae - amazing..

    Hi chickenbreeder,

    when Halley came back in 1985/86, that was what got me really interested in astronomy. I rememeber that earlier in 1985, I had typed pages of BASIC code for a small program that could plot charts of the sky at any point on earth, at any time, in my C64 computer. Printing out these maps and comparing them to the sky was how I learned to recognize the constellations - funny geeky way to learn about the stars... But Halley, then, was quite a disappointment for me, since it was visible only as a foggy blob, with no remarkable tail. I don't remember if I had seen it with naked eyes. The frist night I was trying to spot it using my fathers binoculars, in late December 1985, I missed it because I had misunderstood the labeling on the map I had used and looked for the comet at a position where it was the next day. Later, I realized that the small, unremarkable cloudy thing I had seen and ignored was, indeed, Halley's comet!

    Hi Quasar,

    the server was temporary down, now the link should work again..

  13. Dear Stefan, The people who I was working for at NASA-Ames at the time of SN 1987A were using the C64 to control the star guiding system on the Kuiper Airbone Observatory - we had our Apple II collecting the data, and sending it to the Macintosh Plus for data analysis (that was my part). I guess we were 'pushing the envelope' ?

  14. Bee: I also remember Halley's.
    Stefan: But Halley, then was quite a disappointment for me, since it was visible only as a foggy blob.

    Good to know that I was not the only one seeing it, so it was not an optical illusion. Yes, it wasn't as spectacular as I had imagined, but it definitely has a distinctive look that's different from any other stars/planets.

    Comets are cool because they promise to come back, unlike a supernova (or childhood romance) that only happens once out of the blue. As the saying goes, "what happened only once might as well have never happened at all". (I guess this saying has a German origin.)

  15. Dear Amara,

    The people who I was working for at NASA-Ames at the time of SN 1987A were using the C64

    wow, I would have never guessed that! I mean, in 1987 the C64 was already a bit outdated ;-) But that's a really cool application to know about!

    Best, Stefan

    Hi chickenbreeder

    "what happened only once might as well have never happened at all". (I guess this saying has a German origin.)

    There is the German saying "einmal ist keinmal" - "once is never" ;-) ... But I'll have to get really really old to see Halley's comet again....

  16. Stefan- I found the situation on the KAO funny because the C64 was controlling the star tracker, to fix the telescope on the star, so then in a large sense, it was controlling the movements of the plane.

    The telescope was fun to watch too, because, in order to be perfectly fixed, it rode on a cushion of air, so upon watching it, you have a sense that the plane (a very noisy cargo jet) was revolving around the telescope.

    Calculating the flight path looked to me an interesting exercise too. The navigator needed to calculate a trajectory to avoid any restricted military space, at the same time of having the object be as close to zenith as possible, at the same time of keeping us at our maximum altitude of 41,000 ft, at the same time of making a path that returned us to Moffett Field before the 7.5 hour limit of the pilots' legal flying time ended. Usually we flew triangle-shaped routes over the Pacific Ocean 1/3 of the way to Hawaii and back.

    We were always the people who were using the 'outdated' equipment (we collected the old personal computers of everyone else), carrying our Apple IIs and Mac Plus and Commodores around with the spectrometers to various telescopes. This was the day before laptops, remember, so with these computers, we were 'portable'. I told some people at Apple Computer how we were using their computers, thinking that they might like to use it for PR, but they were not interested, strangely. (Although that was in Apple's aimless years of the later 80s and early 90s when they almost went out of business, so maybe I can understand their lack of interests in the scientists work !)

  17. Hi Amara,

    thank you - that C64 story is really fascinating! Right, it was an easily portable computer :-)...

    If I think about it, compared to my quite "boring" path through theoretical physics, where the most exciting "external" adventure have been some trips to CERN and working in an office with a view into the computing centre's big machine hall, I envy you a bit for your participation in an experiment such as the Kuiper telescope... Experimentalists can travel to much cooler places :-) or hotter, if you think of HESS... ;-)

    BTW, do you have any connection to the SOFIA telescope on the Jumbo?

    Best, stefan

  18. Stefan: I was a scientific programmer for more than 15 years working for astronomers (collecting my degrees, with my jobs driving my education), so my work seemed pretty normal at the time. My life, on the other hand makes me think that an AI with the sense of humor of David Lynch and Federico Fellini is pulling the strings.

    Your question: The only connections are that some acquaintances who worked on the KAO are now working on SOFIA, and I remember when most of the SOFIA work moved from NASA Ames to JPL in the earlier 1990s. I lost track of the torturous road that that project has been on since, however. It should have been finished by now, but seems to be constantly suffering financial support. On that, here is recent report I found. If anyone has more recent news of its status, I would be interested.

  19. One more comment on SOFIA. I see from the photo of your link where the telescope will be located on the plane. I remember a large discussion (earlier 1990s) of where the telescope will be mounted, and I remember that 'over-the'wing' was considered a poor location due to the turbulent eddies there. Were the eddies around the wing found to be not so turbulent? Maybe the telesope has a particular design to circumvent the air conditions around the wing? I am puzzled.

  20. Sorry, still not awake. I was confusing SIRTF (now Spitzer) with SOFIA for moving to JPL. A lot of the expertise of the SOFIA work likely stayed in the SF Bay area.

  21. Well I dont remember anything about it...But I was born on that day! Which is pretty awesome to be born under a supernova! I was born a star! lol It didnt bring me THAT much luck, But I am blessed!

  22. I was wondering if I can make a question. It´s about the plot magnitude vs redshift for supernovas 1a(I´m desperate now, finding no answer after more than 2 hours...). These two graphics that are supposed to be the same, but they are not. After the calculation I get the first one:
    diferencia entre

    -Bottom of

    -Page 7 of

    Maybe the answer is that in the second case, the magnitude definition includes a filter transmission function?

  23. Hi Charles,

    I am not sure what your question is about specifically? I am not an expert on this, but the "Union" Plot probably has more data points than the original 1998 compilation? Then, the Union plot uses a different scale for the ordinate than the 1998 plot you are referring to – check equation 2 on page 12 in the Union paper. It seems the shift by "−M" is by the "standard candle" luminosity M = −19.3. Can't say more about technical details...

    Cheers, Stefan.

  24. Thank you be Bee for publishing the comment; thanks Stefan for answering. I can´t believe how much time I spend on this...I had paid no attention to the x scale...I just saw two different curves. In the second case, a log_10 scale is used. In a log_10 scale, I get the curve of the second link (or at least, a very similar on m ( z ) = 5 * log_10 (z + z^2/2) for omega_M = 0, omega_lambda = 1). Best,



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