History of supernova observation

The known history of supernova observation goes back to 185 CE, when supernova SN 185 appeared, the oldest appearance of a supernova recorded by humankind. Several additional supernovae within the Milky Way galaxy have been recorded since that time, with SN 1604 being the last supernova to be observed.cite conference
first=D. H. | last=Clark | coauthors=Stephenson, F. R.
title = The Historical Supernovae
booktitle = Supernovae: A survey of current research; Proceedings of the Advanced Study Institute
pages = 355–370
publisher = Dordrecht, D. Reidel Publishing Co.
date = June 29, 1981
location = Cambridge, England
url = http://adsabs.harvard.edu/abs/1982sscr.conf..355C
accessdate = 2006-09-24 ]

Since the development of the telescope, the field of supernova discovery has expanded to other galaxies. These occurrences provide important information on the distances of galaxies. Successful models of supernova behavior have also been developed, and the role of supernova in the star formation process is now increasingly understood.

Early history

In 185 CE, Chinese astronomers recorded the appearance of a bright star in the sky, and observed that it took about eight months to fade from the sky. It was observed to sparkle like a star and did not move across the heavens like a comet. These observations are consistent with the appearance of a supernova, and this is believed to be the oldest recorded by humankind. SN 185 may have also possibly been recorded in Roman literature, though no records have survived. [cite journal
last = Stothers | first = Richard | title=Is the Supernova of CE 185 Recorded in Ancient Roman Literature
journal=Isis | year=1977 | volume=68 | issue=3
pages=443447
url=http://links.jstor.org/sici?sici=0021-1753(197709)68%3A3%3C443%3AITSOA1%3E2.0.CO%3B2-H | accessdate=2006-09-24 | doi=10.1086/351822 ] The gaseous shell RCW 86 is suspected as being the remnant of this event, and recent X-ray studies show a good match for the expected age. [cite news
title=New evidence links stellar remains to oldest recorded supernova
publisher=ESA News | date=September 18, 2006
url=http://www.esa.int/esaCP/SEMGE58LURE_index_0.html
accessdate=2006-05-24 ]

In 393 CE, the Chinese recorded the appearance of another "guest star", SN 393, in the modern constellation of Scorpius. [cite conference
first=Z.-R. | last=Wang | coauthors=Qu, Q. Y.; Chen, Y.
title = The AD 393 Guest Star; the SNR RX 51713.7-3946
booktitle = Proceedings of IAU Symposium #188
pages = 262 | publisher = Dordrecht: Kluwer Academic
year = 1998
url = http://adsabs.harvard.edu/abs/1998IAUS..188..262W
accessdate = 2006-09-24 ] Additional unconfirmed supernovae events may have been observed in 369 CE, 386 CE,437 CE, 827 CE and 902 CE. However these have not yet been associated with a supernova remnant, and so they remain only candidates. Over a span of about 2,000 years, Chinese astronomers recorded a total of twenty such candidate events, including later explosions noted by Islamic, European and possibly Indian and other observers. [cite web
author=Hartmut Frommert, Christine Kronberg
url = http://www.seds.org/messier/more/mw_sn.html
title = Supernovae observed in the Milky Way: Historical Supernovae
publisher = SEDS | accessdate = 2007-01-03 ]

The supernova SN 1006 appeared in the southern constellation of Lupus during the year 1006 CE. This was the brightest recorded star ever to appear in the night sky, and its presence was noted in China, Egypt, Iraq, Italy, Japan and Switzerland. It may also have been noted in France, Syria and North America. Egyptian physician, astronomer and astrologer Ali ibn Ridwan gave the brightness of this star as one-quarter the brightness of the Moon. Modern astronomers have discovered the faint remnant of this explosion and determined that it was only 7,100 light-years from the Earth. [cite web
date = March 5, 2003
url = http://www.noao.edu/outreach/press/pr03/pr0304.html
title = Astronomers Peg Brightness of History’s Brightest Star
publisher = NAOA News | accessdate = 2006-06-08 ]

Supernova SN 1054 was another widely-observed event, with Arab, Chinese and Japanese astronomers recording the star's appearance in 1054 CE. It may also have been recorded by the Anasazi as a petroglyph. [cite web
last = Greening | first = Dan | year = 1995
url = http://www.astronomy.pomona.edu/archeo/outside/chaco/nebula.html | title = 1054 Supernova Petrograph
publisher = Pomona College Astronomy Program
accessdate = 2006-09-25 ] This explosion appeared in the constellation of Taurus, where it produced the Crab Nebula remnant. At its peak, the luminosity of SN 1054 may have been four times as bright as Venus, and it remained visible in daylight for 23 days and was visible in the night sky for 653 days. [cite journal
first=G. W. | last=Collins II
coauthors=Claspy, W. P.; Martin, J. C.
title=A Reinterpretation of Historical References to the Supernova of A.D. 1054
journal=Publications of the Astronomical Society of the Pacific
year=1999 | volume=111 | issue=761 | pages=871–880
url=http://www.journals.uchicago.edu/doi/abs/10.1086/316401
accessdate=2008-06-04
doi=10.1086/316401 ] [ cite journal
last = Brecher | first = K. | coauthors = "et al."
year = 1983 | pages = 106–113
title = Ancient records and the Crab Nebula supernova
journal = The Observatory | volume = 103
url=http://adsabs.harvard.edu/abs/1983Obs...103..106B
accessdate =2008-06-04 ]

There are fewer records of supernova SN 1181, which occurred in the constellation Cassiopeia just over a century after SN 1054. It was noted by Chinese and Japanese astronomers, however. The pulsar 3C58 may be the stellar relic from this event. [cite web
date = December 14, 2004
url = http://chandra.harvard.edu/photo/2004/3c58/
title = 3C58: Pulsar Gives Insight on Ultra Dense Matter and Magnetic Fields
publisher = Harvard-Smithsonian Center for Astrophysics
accessdate = 2006-09-26 ]

The Danish astronomer Tycho Brahe was noted for his careful observations of the night sky from his observatory on the island of Hven. In 1572 he noted the appearance of a new star, also in the constellation Cassiopeia. Later called SN 1572, thissupernova was associated with a remnant during the 1960s. [cite news
first=R. | last=Villard | coauthors=Sanders, R.
title=Stellar survivor from 1572 CE explosion supports supernova theory
publisher=UCBerkeley News | date=July 24, 1991
url=http://www.berkeley.edu/news/media/releases/2004/10/27_Tycho.shtml
accessdate=2006-09-25 ]

A common belief in Europe during this period was the Aristotelian idea that the world beyond the Moon and planets was immutable. So observers argued that the phenomenon was something in the Earth's atmosphere. However Tycho noted that the object remained stationary from night to night—never changing its parallax—so it must lie far away. [cite journal
first=R. | last=Cowen
title=Danish astronomer argues for a changing cosmos
journal=Science News | year=1999 | volume=156
issue=25 & 26
accessdate = 2006-09-25 – ^{[http://scholar.google.co.uk/scholar?hl=en&lr=&q=author%3A+intitle%3ADanish+astronomer+argues+for+a+changing+cosmos&as_publication=Science+News&as_ylo=1999&as_yhi=1999&btnG=Search Scholar search]} ] [cite book
first=Don | last=Nardo | year=2007
title=Tycho Brahe: Pioneer of Astronomy
publisher=Compass Point Books | isbn=0756533090 ] He published his observations in the small book "De Stella Nova" (Latin for "concerning the new star") in 1573. It is from the title of this book that the modern word "nova" for cataclysmic variable stars is derived. [cite web
last = Stacey | first = Blake
url = http://snews.bnl.gov/popsci/tycho-kepler.html
title = Supernovas: Making Astronomical History
publisher = SNEWS: Supernova Early Warning System
accessdate = 2006-09-25 ]

The last supernova to be seen in the Milky Way galaxy was SN 1604, which was observed October 9, 1604. Several people noted the sudden appearance of this star, but it was Johannes Kepler who became noted for his systematic study of the object. He published his observations in the work "De Stella nova in pede Serpentarii". [cite web
url = http://www.nysoclib.org/collections/kepler_johannes.html
title = Johannes Kepler: De Stella Nova
publisher = New York Society Library
accessdate = 2007-01-03 ]

Galileo, like Tycho before him, tried in vain to measure the parallax of this new star, and then argued against the Aristotelian view of an immutable heavens. [cite web
last = Wilson | first = Fred L.
date = July 7, 1996
url = http://www.rit.edu/~flwstv/galileo.html
title = History of Science: Galileo and the Rise of Mechanism
publisher = Rochester Institute of Technology
accessdate = 2006-09-25 ] The remnant of this supernova was identified in 1941 at the Mt. Wilson observatory. [cite web
last = Blair | first = Bill
url = http://fuse.pha.jhu.edu/~wpb/Kepler/kepler.html
title = Bill Blair's Kepler's Supernova Remnant Page
publisher = NASA and Johns Hopkins University
accessdate = 2006-09-20 ]

Telescope observation

The true nature of the supernova remained obscure for some time. Observers slowly came to recognize a class of stars that undergo long-term periodic fluctuations in luminosity. Both John Russell Hind in 1848 and Norman Pogson in 1863 had charted stars that underwent sudden changes in brightness. However these received little attention from the astronomical community. In 1866, however, William Higgins made the first spectroscopic observations of a nova, discovering lines of hydrogen in the unusual spectrum of the recurrent nova T Coronae Borealis. [cite journal
last = Higgins | first = William | title=On a New Star
journal=Monthly Notices of the Royal Astronomical Society
year=1866 | volume=26 | pages=275
url=http://adsabs.harvard.edu/abs/1866MNRAS..26..275H
accessdate=2008-06-04 ] Higgins proposed a cataclysmic explosion as the underlying mechanism, and his efforts drew interest from other astronomers. [cite web
last = Becker | first = Barbara J. | year = 1993
url = http://eee.uci.edu/clients/bjbecker/huggins/ch3.html
title = Eclecticism, Opportunism, and the Evolution of a New Research Agenda: William and Margaret Huggins and the Origins of Astrophysics
publisher = University of California—Irvine
accessdate = 2006-09-27 ]

In 1885, a nova-like outburst was observed in the direction of the Andromeda galaxy by Ernst Hartwig in Estonia. S Andromedae increased to 6th magnitude, outshining the entire nucleus of the galaxy, then faded in a manner much like a nova. However, in 1917, George W. Ritchey measured the distance to the Andromeda galaxy and discovered it lay much further than had previously been thought. This meant that S Andromedae, which did not just lie along the line of sight to the galaxy but had actually resided in the nucleus, released a much greater amount of energy than was typical for a nova. [cite web
last =van Zyl | first = Jan Eben | year = 2003
url = http://www.aqua.co.za/assa_jhb/new/canopus/can2003/c039litu.htm
title = VARIABLE STARS VI
publisher = Astronomical Society of Southern Africa
accessdate = 2006-09-27 ]

Early work on this new category of nova was performed during the 1930s by Walter Baade and Fritz Zwicky at Mount Wilson Observatory. [cite conference
first=W. | last=Baade | coauthors=Zwicky, F.
title=On Super-Novae
booktitle=Proceedings of the National Academy of Sciences of the United States of America
year=1934 | volume=20 | issue=5 | pages=254–259
url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1076395
accessdate=2008-06-04 ] They identified S Andromedae, what they considered a typical supernova, as an explosive event that released radiation approximately equal to the Sun's total energy output for 10⁷ years. They decided to call this new class of cataclysmic variables super-novae, and postulated that the energy was generated by the gravitational collapse of ordinary stars into neutron stars. [cite journal
first=D. E. | last=Osterbrock
title=Who Really Coined the Word Supernova? Who First Predicted Neutron Stars?
journal=Bulletin of the American Astronomical Society
year=1999 | volume=33 | pages=1330
url=http://adsabs.harvard.edu/abs/2001AAS...199.1501O
accessdate=2008-06-04 ]

Although supernova are relatively rare events, occurring on average about once a century in the Milky Way, observations of distant galaxies allowed supernovae to be discovered and examined more frequently. The first spectral classification of these distant supernova was performed by Rudolph Minkowski in 1941. He categorized them into two types, based on whether or not lines of the element hydrogen appeared in the supernova spectrum. [cite journal
last = Rudolph | first = Minkowski
title=Spectra of Supernovae
journal=Publications of the Astronomical Society of the Pacific
year=1941 | volume=53 | issue=314 | pages=224
url=http://adsabs.harvard.edu/abs/1941PASP...53..224M
accessdate=2008-06-04
doi=10.1086/125315 ] Zwicky later proposed additional types III, IV and V, although these are no longer used and now appear to be associated with single peculiar supernova types. Further sub-division of the spectra categories resulted in the modern supernova classification scheme. [cite journal
first=L. A. L. | last=da Silva
title=The Classification of Supernovae
journal=Astrophysics and Space Science | year=1993
volume=202 | issue=2 | pages=215–236
url=http://adsabs.harvard.edu/abs/1993Ap&SS.202..215D
accessdate=2008-06-04
doi=10.1007/BF00626878 ]

In the aftermath of the Second World War, Fred Hoyle worked on the problem of how the various observed elements in the universe were produced. In 1946 he proposed that a massive star could generate the necessary thermonuclear reactions, and the nuclear reactions of heavy elements were responsible for the removal of energy necessary for a gravitational collapse to occur. The collapsing star became rotationally unstable, and produced an explosive expulsion of elements that were distributed into interstellar space. [cite journal
last = Hoyle | first = Fred | authorlink = Fred Hoyle
title=The Synthesis of the Elements from Hydrogen
journal=Monthly Notices of the Royal Astronomical Society
year=1946 | volume=106 | pages=343–383
url=http://adsabs.harvard.edu/abs/1946MNRAS.106..343H
accessdate=2008-06-04 ] The concept that rapid nuclear fusion was the source of energy for a supernova explosion was developed by Hoyle and William Fowler during the 1960s. [cite journal
first=S. E. | last=Woosley
title=Hoyle & Fowler's Nucleosynthesis in Supernovae
journal=Astrophysical Journal | year=1999
volume=525C | pages=924
url=http://adsabs.harvard.edu/abs/1946MNRAS.106..343H
accessdate=2008-06-04 ]

Recent results

The modern standard model for Type Ia supernovae explosions is founded on a proposal by Whelan and Iben in 1973, and is based upon a mass-transfer scenario to a degenerate companion star. [cite journal
first=J. | last=Whelan | coauthors=Iben Jr., I.
title=Binaries and Supernovae of Type I
journal=Astrophysical Journal | year=1973 | volume=186
pages=1007–1014
url=http://adsabs.harvard.edu/abs/1973ApJ...186.1007W
accessdate=2008-06-04
doi=10.1086/152565 ] In particular, the light curve of SN 1972e in NGC 5253, which was observed for more than a year, was followed long enough to discover that after its broad "hump" in brightness, the supernova faded at a nearly constant rate of about 0.01 magnitudes per day. Translated to another system of units, this is nearly the same as the decay rate of cobalt-56 (⁵⁶Co), whose half-life is 77 days. The degenerate explosion model predicts the production of about a solar mass of nickel-56 (⁵⁶Ni) by the exploding star. The ⁵⁶Ni decays with a half-life of 6.8 days to ⁵⁶Co, and the decay of the nickel and cobalt provides the energy radiated away by the supernova late in its history. The agreement in both total energy production and the fade rate between the theoretical models and the observations of 1972e led to rapid acceptance of the degenerate-explosion model. [cite journal
first=V. | last=Trimble
title=Supernovae. Part I: the events
journal=Reviews of Modern Physics | year=1982
volume=54 | pages=1183–1224
url=http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1982RvMP...54.1183T
accessdate=2008-06-04
doi=10.1103/RevModPhys.54.1183 ]

Through observation of the light curves of many Type Ia supernovae, it was discovered that they appear to have a common peak luminosity. [cite journal
first=C. T. | last=Kowal
title=Absolute magnitudes of supernovae
journal=Astronomical Journal | year=1968
volume=73 | pages=1021–1024
url=http://adsabs.harvard.edu/cgi-bin/bib_query?1968AJ.....73.1021K
accessdate=2008-06-04
doi=10.1086/110763 ] By measuring the luminosity of these events, the distance to their host galaxy can be estimated with good accuracy. Thus this category of supernovae has become highly useful as a standard candle for measuring cosmic distances. In 1998, the High-Z Supernova Search and the Supernova Cosmology Project discovered that the most distant Type Ia supernovae appeared dimmer than expected. This has provided evidence that the expansion of the universe may be accelerating.cite journal
first=B. | last=Leibundgut | coauthors=Sollerman, J.
title=A cosmological surprise: the universe accelerates
journal=Europhysics News | year=2001 | volume=32 | issue=4
url=http://www.eso.org/~bleibund/papers/EPN/epn.html
accessdate=2008-06-04 ] cite news
title=Confirmation of the accelerated expansion of the Universe
publisher=Centre National de la Recherche Scientifique
date=September 19, 2003
url=http://www2.cnrs.fr/en/45.htm?&debut=160xt/
accessdate=2006-11-03 ]

Although no supernova has been observed in the Milky Way since 1604, it appears that a supernova exploded in the constellation Cassiopeia about 300 years ago, around the year 1667 or 1680. The remnant of this explosion, Cassiopeia A - is heavily obscured by interstellar dust, which is possibly why it did not make a notable appearance. However it can be observed in other parts of the spectrum, and it is the currently the brightest radio source beyond our solar system. [cite web
url = http://coolcosmos.ipac.caltech.edu//cosmic_classroom/multiwavelength_astronomy/multiwavelength_museum/casA.html
title = Cassiopeia A - SNR
publisher = CalTech/NASA Infrared Processing and Analysis Center
accessdate = 2006-10-02 ]

In 1987, Supernova 1987A in the Large Magellanic Cloud was observed within hours of its start. The relative proximity of this supernovae has allowed detailed observation, and it provided the first opportunity for modern theories of supernova formation to be tested against observations.

The "Champagne Supernova" was discovered in a forming galaxy in 2003. The appearance of this supernova was studied in "real-time", and it has posed several major physical questions as it seems more massive than the Chandrasekhar limit would allow. [cite conference
first=D. A. | last=Howell
coauthors="et al"
title=Snls-03d3bb: An Overluminous, Low Velocity Type Ia Supernova Discovered At Z=0.244
booktitle=American Astronomical Society Meeting 208
year=2006
url=http://adsabs.harvard.edu/abs/2006AAS...208.0203H
accessdate=2008-06-04 ]

First observed in September 2006, the supernova SN 2006gy, which occurred in a galaxy called NGC 1260 (240 million light-years away), is the largest and, until confirmation of luminosity of SN 2005ap in October 2007, the most luminous supernova ever observed. The explosion was at least 100 times more luminous than any previously observed supernova, [cite news
url=http://sciencenow.sciencemag.org/cgi/content/full/2007/507/2
title=Star Goes Out Big Time | accessdate=2008-06-04
first=Phil | last=Berardelli | date=May 7, 2007
publisher=Science Magazine ScienceNOW Daily News] [cite news
url=http://www.nasa.gov/centers/marshall/news/news/releases/2007/07-052.html
title=NASA's Chandra Sees Brightest Supernova Ever
author=Grey Hautaluoma, Grey Hautaluoma and Megan Watzke
date=May 7, 2007
publisher=NASA | accessdate=2008-06-04 ] with the progenitor star being estimated 150 times more massive than our Sun. [cite news
url=http://abc.net.au/science/news/stories/2007/1917458.htm?space
title=Brightest supernova ever seen
first=Will | last=Dunham | date=May 8, 2007
publisher=News in Science, Space and Astronomy] Although this had some characteristics of a Type Ia supernova, Hydrogen was found in the spectrum. [cite news
first = David | last = Shiga
title=Brightest supernova discovery hints at stellar collision
publisher=New Scientist | date=January 3, 2007
url=http://space.newscientist.com/article/dn10883-brightest-supernova-discovery-hints-at-stellar-collision.html
accessdate=2006-05-24 ] Currently it is thought that SN 2006gy is a likely candidate for a pair-instability supernova. SN 2005ap, which was discovered by Robert Quimby who also discovered SN 2006gy, was about twice as bright as SN 2006gy and about 300 times as bright as a normal type II supernova. [cite web
last=Than | first=Ker | date=October 11, 2007
url=http://www.msnbc.msn.com/id/21259692/
title=Supernova blazed like 100 billion suns
publisher=MSNBC | accessdate=2007-10-17 ]

On May 21, 2008, astronomers announced that they had for the first time caught a supernova on camera just as it was exploding. By chance, a burst of X-rays was noticed while looking at galaxy NGC 2770, 88 million light-years from Earth, and a variety of telescopes were aimed in that direction just in time to capture what has been named SN 2008D. "This eventually confirmed that the big X-ray blast marked the birth of a supernova," said Alicia Soderberg of Princeton University. [cite news
author=Anonymous | date=May 21, 2008
title=Supernova caught exploding on camera
publisher=Yahoo! news
url=http://news.yahoo.com/s/nm/20080521/sc_nm/supernova_dc
accessdate=2008-05-22 ]

Future

The estimated rate of supernova production in a galaxy the size of the Milky Way is about one every 50 years. This is much higher than the actual observed rate, implying that a portion of these events have been obscured from the Earth by interstellar dust. However new instruments that can observe across a wide range of the spectrum, as well as the deployment of neutrino detectors, mean that the next such event will almost certainly be detected. [cite journal
last = Türler | first = Marc
title=INTEGRAL reveals Milky Ways' supernova rate
journal=CERN Courier | year=2006 | volume=46 | issue=1
url=http://cerncourier.com/main/article/46/1/14
accessdate=2008-06-04 ]

Some historical supernovae

ee also

* History of astronomy

References

External links

* cite news
last=Hecht
first=Jeff
title=Enigmatic object baffles supernova team
publisher=NewScientist.com
date=June 19, 2006
url=http://www.newscientist.com/article.ns?id=dn9360&feedId=online-news_rss20
accessdate=2006-12-01