SN 1994I is a Type Ic supernova discovered on April 2, 1994 in the Whirlpool Galaxy by amateur astronomers Tim Puckett and Jerry Armstrong of the Atlanta Astronomy Club. Type Ic supernova are a rare type of supernova that result from the explosion of a very massive star that has shed its outer layers of hydrogen and helium. The explosion results in a highly luminous burst of radiation that then dims over the course of weeks or months. SN 1994I was a relatively nearby supernova, and provided an important addition to the then small collection of known Type Ic supernova. Very early images were captured of SN 1994I, as two high school students in Oil City, Pennsylvania serendipitously took images of the Whirlpool Galaxy using the 30-inch telescope at Leuschner Observatory on March 31, 1994, which included SN 1994I just after it began to brighten.
SN 1994I was independently discovered by multiple observers, with the first reports from amateur astronomers Tim Puckett and Jerry Armstrong, followed within the hour by reports by amateurs Wayne Johnson and Doug Millar, Richard Berry, and Reiki Kushida. It was confirmed quickly by Michael Richmond and Alex Filippenko using the Berkeley Automated Imaging Telescope at Leuschner Observatory, who noted that SN 1994I was particularly blue.[1] Initial reports disagreed on the nature of the supernova, with different teams claiming that it was a Type Ia supernova, a Type II supernova, and a Type Ic supernova. Supernova types are observationally distinguished by the presence or absence of spectral lines, with hydrogen being the most important diagnostic. After a week of more data being collected, consensus grew among observers that SN 1994I was a Type Ic.[2]
By chance, observations of SN 1994I were obtained before its discovery was reported. High school students Heather Tartara and Melody Spence requested observations of the Whirlpool Galaxy on March 29 and 31, 1994.[3][4] Their request was made through the Hands-On Universe program, which allows elementary and high school students to request observations on automated telescopes.[5] Their images captured the Whirlpool Galaxy just before and after SN 1994I began to brighten, and are some of the earliest data recorded for a supernova.[6]
CharacteristicsEdit
The progenitors of Type Ib, Ic, and II supernovae are commonly called core-collapse supernovae, as they result from massive stars that cannot produce enough pressure to balance the inward force of self-gravity. Yet all Type I supernova are distinguished by their lack of hydrogen absorption lines, and Type Ic also lack helium lines. Initial failure to detect hydrogen or helium led to SN 1994I being classified as a Type Ic. Follow-up observations showed very weak helium absorption features, and thus SN 1994I seems to bridge the two classes, though it is still considered one of the best examples of a Type Ic supernova.[7][8] There are two proposed mechanisms for removing the hydrogen. One suggests that the progenitors of Type Ib and Ic may be Wolf-Rayet stars, as they produce stellar winds that could blow away the hydrogen. The other possibility is mass transfer to a companion star. The proximity of SN 1994I allowed for detailed comparison of models to the observations. These comparisons showed that SN 1994I was consistent with having lost its outer layers to a companion.[9]
ReferencesEdit
^ abcPuckett, T.; et al. (1994). Marsden, B. G. (ed.). "Supernova 1994I in NGC 5194". IAU Circ. 5961: 1. Bibcode:1994IAUC.5961....1P.
^ abcRichmond, M. W.; van Dyk, S. D.; Ho, W.; Peng, C. Y.; et al. (1996). "UBVRI Photometry of the Type IC SN 1994I in M51". Astronomical Journal. 111: 327–339. Bibcode:1996AJ....111..327R. doi:10.1086/117785.
^"Oil City students stumble across supernova". Allegheny Times. May 6, 1994. Retrieved 2010-03-08.
^Pennypacker, C.; Deustua, S.; Perlmutter, S.; Goldhaber, G.; et al. (December 1994). Successful Operation of Remote Telescopes for Education and Research. American Astronomical Society, 185th AAS Meeting, #69.05. Vol. 26. Bulletin of the American Astronomical Society. p. 1423. Bibcode:1994AAS...185.6905P.
^Smith, Heather (May 30, 2007). . Archived from the original on 2007-08-23. Retrieved 2010-03-08.
^Filippenko, Alexei V.; Barth, Aaron J.; Matheson, Thomas; Armus, Lee; et al. (1995). "The Type IC Supernova 1994I in M51: Detection of Helium and Spectral Evolution". Astrophysical Journal Letters. 450 (1): L11–15. Bibcode:1995ApJ...450L..11F. doi:10.1086/309659.
^Sauer, D. N.; Mazzali, P. A.; Deng, J.; Valenti, S.; et al. (2006). "The properties of the 'standard' Type Ic supernova 1994I from spectral models". Monthly Notices of the Royal Astronomical Society. 369 (4): 1939–1948. arXiv:astro-ph/0604293. Bibcode:2006MNRAS.369.1939S. doi:10.1111/j.1365-2966.2006.10438.x. S2CID 119510845.
^Nomoto, K.; Yamaoka, H.; Pols, O. R.; van den Heuvel, E. P. J.; et al. (1994). "A carbon–oxygen star as progenitor of the type Ic supernova 1994I". Nature. 371 (6494): 227–229. Bibcode:1994Natur.371..227N. doi:10.1038/371227a0. S2CID 4349341.
External linksEdit
Light curves and spectra on the Open Supernova Catalog
August 27, 2023
1994i, type, supernova, discovered, april, 1994, whirlpool, galaxy, amateur, astronomers, puckett, jerry, armstrong, atlanta, astronomy, club, type, supernova, rare, type, supernova, that, result, from, explosion, very, massive, star, that, shed, outer, layers. SN 1994I is a Type Ic supernova discovered on April 2 1994 in the Whirlpool Galaxy by amateur astronomers Tim Puckett and Jerry Armstrong of the Atlanta Astronomy Club Type Ic supernova are a rare type of supernova that result from the explosion of a very massive star that has shed its outer layers of hydrogen and helium The explosion results in a highly luminous burst of radiation that then dims over the course of weeks or months SN 1994I was a relatively nearby supernova and provided an important addition to the then small collection of known Type Ic supernova Very early images were captured of SN 1994I as two high school students in Oil City Pennsylvania serendipitously took images of the Whirlpool Galaxy using the 30 inch telescope at Leuschner Observatory on March 31 1994 which included SN 1994I just after it began to brighten SN 1994IEvent typeSupernova IcDateApril 2 1994ConstellationCanes VenaticiRight ascension13h 27m 47 62s 1 Declination47 26 59 1 1 Epoch1950Distance8 32 Mpc 27 1 Mly RemnantN AHostWhirlpool GalaxyColour B V 0 86 2 Peak apparent magnitude12 91 2 Other designationsSN 1994I AAVSO 1325 47 edit on Wikidata Contents 1 Discovery and observations 2 Characteristics 3 References 4 External linksDiscovery and observations EditSN 1994I was independently discovered by multiple observers with the first reports from amateur astronomers Tim Puckett and Jerry Armstrong followed within the hour by reports by amateurs Wayne Johnson and Doug Millar Richard Berry and Reiki Kushida It was confirmed quickly by Michael Richmond and Alex Filippenko using the Berkeley Automated Imaging Telescope at Leuschner Observatory who noted that SN 1994I was particularly blue 1 Initial reports disagreed on the nature of the supernova with different teams claiming that it was a Type Ia supernova a Type II supernova and a Type Ic supernova Supernova types are observationally distinguished by the presence or absence of spectral lines with hydrogen being the most important diagnostic After a week of more data being collected consensus grew among observers that SN 1994I was a Type Ic 2 By chance observations of SN 1994I were obtained before its discovery was reported High school students Heather Tartara and Melody Spence requested observations of the Whirlpool Galaxy on March 29 and 31 1994 3 4 Their request was made through the Hands On Universe program which allows elementary and high school students to request observations on automated telescopes 5 Their images captured the Whirlpool Galaxy just before and after SN 1994I began to brighten and are some of the earliest data recorded for a supernova 6 Characteristics EditThe progenitors of Type Ib Ic and II supernovae are commonly called core collapse supernovae as they result from massive stars that cannot produce enough pressure to balance the inward force of self gravity Yet all Type I supernova are distinguished by their lack of hydrogen absorption lines and Type Ic also lack helium lines Initial failure to detect hydrogen or helium led to SN 1994I being classified as a Type Ic Follow up observations showed very weak helium absorption features and thus SN 1994I seems to bridge the two classes though it is still considered one of the best examples of a Type Ic supernova 7 8 There are two proposed mechanisms for removing the hydrogen One suggests that the progenitors of Type Ib and Ic may be Wolf Rayet stars as they produce stellar winds that could blow away the hydrogen The other possibility is mass transfer to a companion star The proximity of SN 1994I allowed for detailed comparison of models to the observations These comparisons showed that SN 1994I was consistent with having lost its outer layers to a companion 9 References Edit a b c Puckett T et al 1994 Marsden B G ed Supernova 1994I in NGC 5194 IAU Circ 5961 1 Bibcode 1994IAUC 5961 1P a b c Richmond M W van Dyk S D Ho W Peng C Y et al 1996 UBVRI Photometry of the Type IC SN 1994I in M51 Astronomical Journal 111 327 339 Bibcode 1996AJ 111 327R doi 10 1086 117785 Oil City students stumble across supernova Allegheny Times May 6 1994 Retrieved 2010 03 08 Pennypacker C Deustua S Perlmutter S Goldhaber G et al December 1994 Successful Operation of Remote Telescopes for Education and Research American Astronomical Society 185th AAS Meeting 69 05 Vol 26 Bulletin of the American Astronomical Society p 1423 Bibcode 1994AAS 185 6905P Hands On Universe Retrieved 2010 03 10 Smith Heather May 30 2007 NASA Student Discoveries Archived from the original on 2007 08 23 Retrieved 2010 03 08 Filippenko Alexei V Barth Aaron J Matheson Thomas Armus Lee et al 1995 The Type IC Supernova 1994I in M51 Detection of Helium and Spectral Evolution Astrophysical Journal Letters 450 1 L11 15 Bibcode 1995ApJ 450L 11F doi 10 1086 309659 Sauer D N Mazzali P A Deng J Valenti S et al 2006 The properties of the standard Type Ic supernova 1994I from spectral models Monthly Notices of the Royal Astronomical Society 369 4 1939 1948 arXiv astro ph 0604293 Bibcode 2006MNRAS 369 1939S doi 10 1111 j 1365 2966 2006 10438 x S2CID 119510845 Nomoto K Yamaoka H Pols O R van den Heuvel E P J et al 1994 A carbon oxygen star as progenitor of the type Ic supernova 1994I Nature 371 6494 227 229 Bibcode 1994Natur 371 227N doi 10 1038 371227a0 S2CID 4349341 External links EditLight curves and spectra on the Open Supernova Catalog Retrieved from https en wikipedia org w index php title SN 1994I amp oldid 1013378825, wikipedia, wiki, book, books, library,
