Optical Signatures of Circumstellar Interaction in Type Iip Supernovae
نویسندگان
چکیده
We propose new diagnostics for circumstellar interaction in Type IIP supernovae (SNe IIP) by the detection of high velocity (HV) absorption features in Hα and He I 10830 Å lines during the photospheric stage. To demonstrate the method, we compute the ionization and excitation of H and He in supernova ejecta taking into account time-dependent effects and X-ray irradiation. We find that the interaction with a typical red supergiant wind should result in the enhanced excitation of the outer layers of unshocked ejecta and the emergence of corresponding HV absorption, i.e. a depression in the blue absorption wing of Hα and a pronounced absorption of He I 10830 Å at a radial velocity of about −10 km s. We identify HV absorption in Hα and He I 10830 Å lines of SN 1999em and in Hα of SN 2004dj as being due to this effect. The derived mass loss rate is close to 10 M⊙ yr −1 for both supernovae, assuming a wind velocity 10 km s. We argue that, in addition to the HV absorption formed in the unshocked ejecta, spectra of SN 2004dj and SN 1999em show a HV notch feature that is formed in the cool dense shell (CDS) modified by the Rayleigh-Taylor instability. The CDS results from both shock breakout and radiative cooling of gas that has passed through the reverse shock wave. The notch becomes dominant in the HV absorption during the late photospheric phase, & 60 d. The wind density deduced from the velocity of the CDS is consistent with the wind density found from the HV absorption produced by unshocked ejecta. Subject headings: stars: mass loss — supernovae: general — supernovae: individual (SN 1999em, SN 2004dj) Institute of Astronomy, RAS, Pyatnitskaya 48, 109017 Moscow, Russia; [email protected] Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904; [email protected] Institute of Theoretical and Experimental Physics, 117218 Moscow, Russia; [email protected]
منابع مشابه
Circumstellar Interaction Around Supernovae
Circumstellar interaction has been observed around all types of massive star supernovae, especially at radio and X-ray wavelengths. The interaction shells in Type Ib/c supernovae appear to be moving rapidly, although SN 1998bw remains the only case for which the evidence points to relativistic expansion. Type IIP supernovae have relatively low mass loss rates, consistent with moderate mass sing...
متن کاملCIRCUMSTELLAR Na I AND Ca II LINES IN TYPE IIP SUPERNOVAE AND SN 1998S
We study a possibility of detection of circumstellar absorption lines of Na I D1,2 and Ca II H,K in spectra of type IIP supernovae at the photospheric epoch. The modelling shows that the circumstellar lines of Na I doublet will not be seen in type IIP supernovae for moderate wind density, e.g., characteristic of SN 1999em, whereas rather pronounced Ca II lines with P Cygni profile should be det...
متن کاملEjecta and progenitor of the low-luminosity Type IIP supernova 2003Z
Context. The origin of low-luminosity Type IIP supernovae is unclear: they have been proposed to originate either from massive (∼ 25 M⊙) or low-mass (∼ 9 M⊙) stars. Aims. We wish to determine parameters of the low-luminosity Type IIP supernova 2003Z, to estimate a mass-loss rate of the presupernova, and to recover a progenitor mass. Methods. We compute the hydrodynamic models of the supernova t...
متن کاملPolarized Line Profiles as Diagnostics of Circumstellar Geometry in Type Iin Supernovae
Supernovae of type IIn possess spectral signatures that indicate an intense interaction between the supernova ejecta and surrounding dense circumstellar material cast off by the star in pre-explosion mass-loss episodes. Studying this interaction can yield clues to the nature of Type IIn progenitors and their mass loss history. In particular, polarization spectra of Type IIn’s show complex line ...
متن کاملThe Rise of the Remarkable Type IIn Supernova SN 2009ip
Recent observations by Mauerhan et al. have shown the unprecedented transition of the previously identified luminous blue variable (LBV) and supernova impostor SN 2009ip to a real Type IIn supernova (SN) explosion. We present high-cadence optical imaging of SN 2009ip obtained between 2012 UT Sep. 23.6 and Oct. 9.6, using 0.3 − 0.4 meter aperture telescopes from the Coral Towers Observatory in C...
متن کامل