THE SUBLUMINOUS AND PECULIAR TYPE Ia SUPERNOVA PTF 09dav

Journal Article · Tue May 10 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/732/2/118· OSTI ID:21576835

Sullivan, M; Ofek, E O; Blake, S; Podsiadlowski, P ^[1]; Kasliwal, M M; Cooke, J; Quimby, R; Kulkarni, S R ^[2]; Nugent, P E; Thomas, R C; Poznanski, D ^[3]; Howell, D A ^[4]; Arcavi, I; Gal-Yam, A ^[5]; Hook, I M ^[6]; Mazzali, P ^[7]; Bildsten, L ^[8]; Bloom, J S; Cenko, S B ^[9]; Law, N ^[10]

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1. Department of Physics (Astrophysics), University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom)
2. Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)
3. Computational Cosmology Center, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)
4. Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States)
5. Department of Particle Physics and Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100 (Israel)
6. INAF-Osservatorio di Roma, via Frascati 33, I-00040 Monteporzio Catone (Roma) (Italy)
7. Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching (Germany)
8. Department of Physics, University of California Santa Barbara, Santa Barbara, CA 93106 (United States)
9. Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)
10. Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto M5S 3H4, Ontario (Canada)

PTF 09dav is a peculiar subluminous Type Ia supernova (SN) discovered by the Palomar Transient Factory (PTF). Spectroscopically, it appears superficially similar to the class of subluminous SN1991bg-like SNe, but it has several unusual features which make it stand out from this population. Its peak luminosity is fainter than any previously discovered SN1991bg-like SN Ia (M{sub B} {approx} -15.5), but without the unusually red optical colors expected if the faint luminosity were due to extinction. The photospheric optical spectra have very unusual strong lines of Sc II and Mg I, with possible Sr II, together with stronger than average Ti II and low velocities of {approx}6000 km s{sup -1}. The host galaxy of PTF09dav is ambiguous. The SN lies either on the extreme outskirts ({approx}41 kpc) of a spiral galaxy or in an very faint (M{sub R} {>=} -12.8) dwarf galaxy, unlike other 1991bg-like SNe which are invariably associated with massive, old stellar populations. PTF 09dav is also an outlier on the light-curve-width-luminosity and color-luminosity relations derived for other subluminous SNe Ia. The inferred {sup 56}Ni mass is small (0.019 {+-} 0.003 M{sub sun}), as is the estimated ejecta mass of 0.36 M{sub sun}. Taken together, these properties make PTF 09dav a remarkable event. We discuss various physical models that could explain PTF 09dav. Helium shell detonation or deflagration on the surface of a CO white dwarf can explain some of the features of PTF 09dav, including the presence of Sc and the low photospheric velocities, but the observed Si and Mg are not predicted to be very abundant in these models. We conclude that no single model is currently capable of explaining all of the observed signatures of PTF 09dav.

• OSTI ID: 21576835
• Journal Information: Astrophysical Journal, Vol. 732, Issue 2; Other Information: DOI: 10.1088/0004-637X/732/2/118; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
GALAXIES
LUMINOSITY
MASS
SUPERNOVAE
BINARY STARS
ERUPTIVE VARIABLE STARS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
STARS
VARIABLE STARS