TY - JOUR
T1 - Nebular phase observations of the type Ib supernova 2008D/X-Ray transient 080109
T2 - Side-viewed bipolar explosion
AU - Tanaka, Masaomi
AU - Yamanaka, Masayuki
AU - Maeda, Keiichi
AU - Kawabata, Koji S.
AU - Hattori, Takashi
AU - Minezaki, Takeo
AU - Valenti, Stefano
AU - Valle, Massimo Della
AU - Sahu, D. K.
AU - Anupama, G. C.
AU - Tominaga, Nozomu
AU - Nomoto, Ken'Ichi
AU - Mazzali, Paolo A.
AU - Pian, Elena
PY - 2009
Y1 - 2009
N2 - We present optical spectroscopic and photometric observations of supernova (SN) 2008D, associated with the luminous X-ray transient 080109, at >300 days after the explosion (nebular phases). We also give flux measurements of emission lines from the H II region at the site of the SN, and estimates of the local metallicity. The brightness of the SN at nebular phases is consistent with the prediction of the explosion models with an ejected 56Ni mass of 0.07M, which explains the light curve at early phases. The [O I] line in the nebular spectrum shows a double-peaked profile while the [Ca II] line does not. The double-peaked [O I] profile strongly indicates that SN 2008D is an aspherical explosion. The profile can be explained by a torus-like distribution of oxygen viewed from near the plane of the torus. We suggest that SN 2008D is a side-viewed, bipolar explosion with a viewing angle of >50° from the polar direction.
AB - We present optical spectroscopic and photometric observations of supernova (SN) 2008D, associated with the luminous X-ray transient 080109, at >300 days after the explosion (nebular phases). We also give flux measurements of emission lines from the H II region at the site of the SN, and estimates of the local metallicity. The brightness of the SN at nebular phases is consistent with the prediction of the explosion models with an ejected 56Ni mass of 0.07M, which explains the light curve at early phases. The [O I] line in the nebular spectrum shows a double-peaked profile while the [Ca II] line does not. The double-peaked [O I] profile strongly indicates that SN 2008D is an aspherical explosion. The profile can be explained by a torus-like distribution of oxygen viewed from near the plane of the torus. We suggest that SN 2008D is a side-viewed, bipolar explosion with a viewing angle of >50° from the polar direction.
KW - Line: profiles
KW - Nuclear reactions, nucleosynthesis, abundances
KW - Supernovae: general
KW - Supernovae: individual (SN 2008D)
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U2 - 10.1088/0004-637X/700/2/1680
DO - 10.1088/0004-637X/700/2/1680
M3 - Article
AN - SCOPUS:70549113671
SN - 0004-637X
VL - 700
SP - 1680
EP - 1685
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
ER -