JWST spectra of SN 2022acko reveal CO masses of 1.55e-4 and 2.47e-4 solar masses, IME velocities ~300 km/s vs ~100 km/s for H/He/IGEs suggesting bipolar outflow, and substantially less molecule formation than higher-mass Type II SNe.
The early detection and follow-up of the highly obscured Type II supernova 2016ija/DLT16am
2 Pith papers cite this work. Polarity classification is still indexing.
abstract
We present our analysis of the Type II supernova DLT16am (SN~2016ija). The object was discovered during the ongoing $\rm{D}<40\,\rm{Mpc}$ (DLT40) one day cadence supernova search at $r\sim20.1\,\rm{mag}$ in the `edge-on' nearby ($D=20.0\pm1.9\,\rm{Mpc}$) galaxy NGC~1532. The subsequent prompt and high-cadenced spectroscopic and photometric follow-up revealed a highly extincted transient, with $E(B-V)=1.95\pm0.15\,\rm{mag}$, consistent with a standard extinction law with $R_V=3.1$ and a bright ($M_V=-18.49\pm0.65\,\rm{mag}$) absolute peak-magnitude. The comparison of the photometric features with those of large samples of Type II supernovae reveals a fast rise for the derived luminosity and a relatively short plateau phase, with a slope of $S_{50V}=0.84\pm0.04\,\rm{mag}/50\,\rm{d}$ consistent with the photometric properties typical of those of fast declining Type II supernovae. Despite the large uncertainties on the distance and the extinction in the direction of DLT16am, the measured photospheric expansion velocity and the derived absolute $V$-band magnitude at $\sim50\,\rm{d}$ after the explosion match the existing luminosity-velocity relation for Type II supernovae.
fields
astro-ph.HE 2years
2026 2verdicts
UNVERDICTED 2representative citing papers
SN 2023rve exhibits absent [O I] nebular lines with inferred 14-18 solar mass progenitor, 0.27e51 erg explosion energy, and 0.0064 solar mass nickel, possibly indicating partial fallback.
citing papers explorer
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JWST Medium-Resolution Infrared Spectroscopy of SN 2022acko: Tracing Molecule Formation in the Nebular Phase
JWST spectra of SN 2022acko reveal CO masses of 1.55e-4 and 2.47e-4 solar masses, IME velocities ~300 km/s vs ~100 km/s for H/He/IGEs suggesting bipolar outflow, and substantially less molecule formation than higher-mass Type II SNe.
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SN 2023rve: A Type II Supernova with No Nebular Oxygen
SN 2023rve exhibits absent [O I] nebular lines with inferred 14-18 solar mass progenitor, 0.27e51 erg explosion energy, and 0.0064 solar mass nickel, possibly indicating partial fallback.