NGC 3239 is anirregular galaxy in the constellation ofLeo.[2] The galaxy was discovered in 1784 byWilliam Herschel[3] and is part of theNew General Catalogue. It harbors a large and relatively bright H II region in its southeastern section that was first cataloged by Russian astronomerBoris Vorontsov-Velyaminov as VV95b.[4] It's believed that NGC 3239 is the result of a galactic merger with a low-mass galaxy.[5]
Onesupernova has been observed in NGC 3239.SN 2012A (Type II-P, mag. 14.6) was discovered by Bob Moore,Jack Newton, andTim Puckett on 7 January 2012.[6][7] It reached a peak visual magnitude of +13.6.[8][9] Later analysis concluded that the progenitor was ared supergiant with 10 to 15 times the mass of the sun.[10]
^Tomasella, L.; Cappellaro, E.; Fraser, M.; Pumo, M. L.; Pastorello, A.; Pignata, G.; Benetti, S.; Bufano, F.; Dennefeld, M.; Harutyunyan, A.; Iijima, T.; Jerkstrand, A.; Kankare, E.; Kotak, R.; Magill, L.; Nascimbeni, V.; Ochner, P.; Siviero, A.; Smartt, S.; Sollerman, J.; Stanishev, V.; Taddia, F.; Taubenberger, S.; Turatto, M.; Valenti, S.; Wright, D. E.; Zampieri, L. (2013)."Comparison of progenitor mass estimates for the Type IIP SN 2012A".Monthly Notices of the Royal Astronomical Society.434 (2):1636–1657.arXiv:1305.5789.doi:10.1093/mnras/stt1130.
Media related toNGC 3239 at Wikimedia Commons