Circumstellar Medium Interaction in SN 2018lab, A Low-Luminosity II-P Supernova observed with TESS

TL;DR

SN 2018lab is a low-luminosity Type IIP supernova with early-time data revealing circumstellar interaction, providing insights into progenitor characteristics and explosion mechanisms.

Contribution

This study presents the first densely sampled early light curve and spectra of a low-luminosity Type IIP supernova, emphasizing the role of circumstellar medium interaction.

Findings

Early light curve shows rapid rise likely due to CSM interaction.

Spectra exhibit blue-shifted, broadened flash features indicating ejecta-CSM interaction.

Models suggest a red supergiant progenitor with extended envelope and nearby CSM.

Abstract

We present photometric and spectroscopic data of SN 2018lab, a low luminosity type IIP supernova (LLSN) with a V-band peak luminosity of $-15.1\pm0.1$ mag. SN 2018lab was discovered by the Distance Less Than 40 Mpc (DLT40) SNe survey only 0.73 days post-explosion, as determined by observations from the Transiting Exoplanet Survey Satellite (TESS). TESS observations of SN 2018lab yield a densely sampled, fast-rising, early time light curve likely powered by circumstellar medium (CSM) interaction. The blue-shifted, broadened flash feature in the earliest spectra ($<$2 days) of SN 2018lab provide further evidence for ejecta-CSM interaction. The early emission features in the spectra of SN 2018lab are well described by models of a red supergiant progenitor with an extended envelope and close-in CSM. As one of the few LLSNe with observed flash features, SN 2018lab highlights the need for more early spectra to explain the diversity of flash feature morphology in type II SNe.