Supernova 1994aj: a probe for pre-supernova evolution and mass-loss from the progenitor |
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| Authors: | S Benetti E Cappellaro I J Danziger M Turatto F Patat & M Della Valle |
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| Institution: | European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001 Santiago 19, Chile,;Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, I-35122 Padova, Italy,;European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-8046 Garching bei Müunchen, Germany,;Osservatorio Astronomico di Trieste, via G.B. Tiepolo 11, I-34131 Trieste, Italy,;Dipartimento di Astronomia, Universitàdi Padova, vicolo dell'Osservatorio 5, I-35122 Padova, Italy |
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| Abstract: | Extensive photometric and spectroscopic observations of SN 1994aj until 540 d after maximum light have been obtained. The photometry around maximum suggests that the SN belongs to the Type II Linear class, with a peak absolute magnitude of M V～?17.8 (assuming H 0=75 km s?1 Mpc?1). The spectra of SN 1994aj were unusual, with the presence of a narrow line with a P Cygni profile on top of the broad Balmer line emission. This narrow feature is attributed to the presence of a dense superwind surrounding the SN. At 100–120 d after maximum light the SN ejecta start to interact with this circumstellar material. The SN luminosity decline rates slowed down γ R =0.46 mag (100 d)?1], becoming less steep than the average late luminosity decline of normal SN II ～1 mag (100 d)?1]. This dense ( ˙M / u W～1015 g cm?1) wind was confined to a short distance from the progenitor ( R out=～5×1016 cm), and results from a very strong mass-loss episode ( ˙M =10?3 M⊙ yr?1), which terminated shortly before explosion (～5–10 yr). |
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| Keywords: | supernovae: general supernovae: individual: SN 1994aj supernova remnants |
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