SN 2009kn - the twin of the Type IIn supernova 1994W
Artikel i vetenskaplig tidskrift, 2012

We present an optical and near-infrared photometric and spectroscopic study of supernova (SN) 2009kn spanning ˜1.5 yr from the discovery. The optical spectra are dominated by the narrow (full width at half-maximum ˜1000 km s-1) Balmer lines distinctive of a Type IIn SN with P Cygni profiles. Contrarily, the photometric evolution resembles more that of a Type IIP SN with a large drop in luminosity at the end of the plateau phase. These characteristics are similar to those of SN 1994W, whose nature has been explained with two different models with different approaches. The well-sampled data set on SN 2009kn offers the possibility to test these models, in the case of both SN 2009kn and SN 1994W. We associate the narrow P Cygni lines with a swept-up shell composed of circumstellar matter and SN ejecta. The broad emission line wings, seen during the plateau phase, arise from internal electron scattering in this shell. The slope of the light curve after the post-plateau drop is fairly consistent with that expected from the radioactive decay of 56Co, suggesting an SN origin for SN 2009kn. Assuming radioactivity to be the main source powering the light curve of SN 2009kn in the tail phase, we infer an upper limit for 56Ni mass of 0.023 Msun. This is significantly higher than that estimated for SN 1994W, which also showed a much steeper decline of the light curve after the post-plateau drop. We also observe late-time near-infrared emission which most likely arises from newly formed dust produced by SN 2009kn. As with SN 1994W, no broad lines are observed in the spectra of SN 2009kn, not even in the late-time tail phase.

supernovae: individual: SN 2009kn

supernovae: individual: SN 1994W

supernovae: general


E. Kankare

Nordic Optical Telescope

Tuorla Observatory

M Ergon

Stockholms universitet

F Bufano

Osservatorio Astronomico di Padova

Osservatorio Astrofisico di Catania

J Spyromilio

European Southern Observatory

S. Mattila

Tuorla Observatory

N. N. Chugai

Russian Academy of Sciences

P. Lundqvist

Stockholms universitet

A. Pastorello

Osservatorio Astronomico di Padova

Queen's University Belfast

R Kotak

Queen's University Belfast

S. Benetti

Osservatorio Astronomico di Padova

M.-T. Botticella

Osservatorio Astronomico di Padova

Queen's University Belfast

Robert Cumming

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

C. Fransson

Stockholms universitet

M Fraser

Queen's University Belfast

G. Leloudas

Stockholms universitet

Dark Cosmology Centre

M Miluzio

Osservatorio Astronomico di Padova

J Sollerman

Stockholms universitet

M. Stritzinger

Aarhus Universitet

M. Turatto

Osservatorio Astronomico di Trieste

S Valenti

Osservatorio Astronomico di Padova

Queen's University Belfast

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 424 855-873


Astronomi, astrofysik och kosmologi


Grundläggande vetenskaper


Onsala rymdobservatorium