Zhang, J, Wang, X, Sasdelli, M, Zhang, T, Liu, Z, Mazzali, PA, Meng, X, Maeda, K, Chen, J, Huang, F, Zhao, X, Zhang, K, Zhai, Q, Pian, E, Wang, B, Chang, L, Yi, W, Wang, C-J, Wang, X, Xin, Y et al, Wang, J, Lun, B, Zheng, X, Zhang, X, Fan, Y and Bai, J (2015) A Luminous Peculiar Type Ia Supernova SN 2011hr: More Like SN 1991T or SN 2007if? ASTROPHYSICAL JOURNAL, 817 (2). ISSN 0004-637X

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Abstract

Photometric and spectroscopic observations of a slowly declining, luminous type Ia supernova (SN Ia) 2011hr in the star-burst galaxy NGC 2691 are presented. SN~2011hr is found to peak at $M_{B}=-19.84 \pm 0.40\,\rm{mag}$, with a post-maximum decline rate $\Delta$m$_{15}$(B) = 0.92 $\pm$ 0.03\,$\rm{mag}$. From the maximum-light bolometric luminosity, $L=(2.30 \pm 0.90) \times 10^{43}\,\rm{erg\,s^{-1}}$, we estimate the mass of synthesized \Nifs\ in SN~2011hr to be $M(\rm{^{56}Ni})=1.11 \pm 0.43\,M_{\sun}$. SN 2011hr appears more luminous than SN 1991T at around maximum light, and the absorption features from its intermediate-mass elements (IMEs) are noticeably weaker than the latter at similar phases. Spectral modelling suggests that SN 2011hr has the IMEs of $\sim$\,0.07 M$_{\sun}$ in the outer ejecta, which is much lower than the typical value of normal SNe Ia (i.e., 0.3 -- 0.4 M$_{\sun}$) and is also lower than the value of SN 1991T (i.e., $\sim$\,0.18 M$_{\sun}$). These results indicate that SN~2011hr may arise from a Chandrasekhar-mass white dwarf progenitor that experienced a more efficient burning process in the explosion. Nevertheless, it is still possible that SN~2011hr may serve as a transitional object connecting the SN 1991T-like SNe Ia with the super-luminous subclass like SN 2007if given that the latter also shows very weak IMEs at all phases.

Item Type:	Article
Uncontrolled Keywords:	astro-ph.SR; astro-ph.SR
Subjects:	Q Science > QB Astronomy
Divisions:	Astrophysics Research Institute
Publisher:	American Astronomical Society and IOP Publishing
Related URLs:	http://arxiv.org/abs/1512.03995v1
Date Deposited:	16 Dec 2015 12:51
Last Modified:	04 Sep 2021 13:44
URI:	https://researchonline.ljmu.ac.uk/id/eprint/2483

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