In:
Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP), Vol. 509, No. 2 ( 2021-11-18), p. 2013-2032
Abstract:
We present multiband optical photometric and spectroscopic observations of an unusual Type II supernova, SN 2018hfm, which exploded in the nearby (d ≈ 34.67 Mpc) dwarf galaxy PGC 1297331 with a very low star formation rate (0.0270 M⊙ yr−1) and a subsolar metallicity environment (∼0.5 Z⊙). The V-band light curve of SN 2018hfm reaches a peak with value of −18.69 ± 0.64 mag, followed by a fast decline (4.42 ± 0.13 mag (100 d)−1). After about 50 d, it is found to experience a large flux drop (∼3.0 mag in V), and then enters into an unusually faint tail, which indicates a relatively small amount of 56Ni synthesized during the explosion. From the bolometric light curve, SN 2018hfm is estimated to have low ejecta mass (∼1.3 M⊙) and low explosion energy (∼1050 erg) compared with typical SNe II. The photospheric spectra of SN 2018hfm are similar to those of other SNe II, with P Cygni profiles of the Balmer series and metal lines, while at late phases the spectra are characterized by box-like profiles of H α emission, suggesting significant interaction between the SN ejecta and circumstellar matter. These box-like emission features are found to show increasing asymmetry with time, with the red-side component becoming gradually weaker, indicating that dust is continuously formed in the ejecta. Based on the dust-estimation tool damocles, we find that the dust increases from ∼10−6 M⊙ to 10−4–10−3 M⊙ between +66.7 d and +389.4 d after explosion.
Type of Medium:
Online Resource
ISSN:
0035-8711
,
1365-2966
DOI:
10.1093/mnras/stab3007
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
2021
detail.hit.zdb_id:
2016084-7
SSG:
16,12
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