Fast and Not-so-Furious: Case Study of the Fast and Faint Type IIb SN 2021bxu

Abstract

We present photometric and spectroscopic observations and analysis of SN 2021bxu (ATLAS21dov), a low-luminosity, fast-evolving Type IIb supernova (SN). SN 2021bxu is unique, showing a large initial decline in brightness followed by a short plateau phase. With $M_r=-15.93\pm 0.16\mathrm{mag}$ during the plateau, it is at the lower end of the luminosity distribution of stripped-envelope supernovae (SE-SNe) and shows a distinct $\sim$10 day plateau not caused by H- or He-recombination. SN 2021bxu shows line velocities which are at least $\sim 1500\mathrm{km}{\mathrm{s}}^{-1}$ slower than typical SE-SNe. It is photometrically and spectroscopically similar to Type IIb SNe during the photospheric phases of evolution, with similarities to Ca-rich IIb SNe. We find that the bolometric light curve is best described by a composite model of shock interaction between the ejecta and an envelope of extended material, combined with a typical SN IIb powered by the radioactive decay of ${}^{56}$Ni. The best-fit parameters for SN 2021bxu include a ${}^{56}$Ni mass of $M_{\mathrm{Ni}}=0.029_{-0.005}^{+0.004}{\mathrm{M}}_{\odot }$, an ejecta mass of $M_{\mathrm{ej}}=0.61_{-0.05}^{+0.06}{\mathrm{M}}_{\odot }$, and an ejecta kinetic energy of $K_{\mathrm{ej}}=8.8_{-1.0}^{+1.1}\times 10^{49}\mathrm{erg}$. From the fits to the properties of the extended material of Ca-rich IIb SNe we find a trend of decreasing envelope radius with increasing envelope mass. SN 2021bxu has $M_{\mathrm{Ni}}$ on the low end compared to SE-SNe and Ca-rich SNe in the literature, demonstrating that SN 2021bxu-like events are rare explosions in extreme areas of parameter space. The progenitor of SN 2021bxu is likely a low mass He star with an extended envelope.

arXiv comment18 pages, 15 figures, accepted to MNRAS

References in corpus (83)

• Stellar population synthesis at the resolution of 2003
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• The Complete Light-curve Sample of Spectroscopically Confirmed Type Ia Supernovae from Pan-STARRS1 and Cosmological Constraints from The Combined Pantheon Sample
• How Massive Single Stars End their Life
• The Zwicky Transient Facility: System Overview, Performance, and First Results
• The Swift Ultra-Violet/Optical Telescope
• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• The u'g'r'i'z' Standard Star Network
• The Zwicky Transient Facility: Data Processing, Products, and Archive
• ATLAS: A High-Cadence All-Sky Survey System
• Explosion Mechanisms of Core-Collapse Supernovae
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• Core-Collapse Supernovae from 9 to 120 Solar Masses Based on Neutrino-powered Explosions
• An ultra-deep near-infrared spectrum of a compact quiescent galaxy at z=2.2
• WISeREP - An Interactive Supernova Data Repository
• The Pan-STARRS1 Database and Data Products
• The Effects of Binary Evolution on the Dynamics of Core Collapse and Neutron-Star Kicks
• On the role of continuum-driven eruptions in the evolution of very massive stars and Population III stars
• Characterizing the V-band light-curves of hydrogen-rich type II supernovae
• PESSTO : survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Objects
• Design and operation of the ATLAS Transient Science Server
• Pan-STARRS Photometric and Astrometric Calibration
• The Supernova Channel of Super-AGB Stars
• The Carnegie Supernova Project: The Low-Redshift Survey
• On the Source of the Dust Extinction in Type Ia Supernovae and the Discovery of Anomalously Strong Na I Absorption
• Formation of contact in massive close binaries
• SOUSA: the Swift Optical/Ultraviolet Supernova Archive
• Detailed Analysis of Early to Late-Time Spectra of Supernova 1993J
• The Type IIb Supernova 2011dh from a Supergiant Progenitor
• Optical Spectroscopy of Type Ib/c Supernovae
• PTF11eon/SN2011dh: Discovery of a Type IIb Supernova From a Compact Progenitor in the Nearby Galaxy M51
• Calcium-rich gap transients in the remote outskirts of galaxies
• Core-collapse explosions of Wolf-Rayet stars and the connection to type IIb/Ib/Ic supernovae
• Hydrodynamical models of Type II-Plateau Supernovae
• The Carnegie Supernova Project I: Third Photometry Data Release of Low-Redshift Type Ia Supernovae and Other White Dwarf Explosions
• The Carnegie Supernova Project I: analysis of stripped-envelope supernova light curves
• What Can We Learn from the Rising Lightcurves of Radioactively-Powered Supernovae?
• Revisiting the Lick Observatory Supernova Search Volume-Limited Sample: Updated Classifications and Revised Stripped-Envelope Supernova Fractions
• An Updated Ultraviolet Calibration for the Swift/UVOT
• The bolometric light curves and physical parameters of stripped-envelope supernovae
• The Pan-STARRS Data Processing System
• Pan-STARRS Pixel Processing: Detrending, Warping, Stacking
• Spectroscopy of Type Ia Supernovae by the Carnegie Supernova Project
• A Sample of Type II-L Supernovae
• Supernovae with Two Peaks in the Optical Light Curve and the Signature of Progenitors with Low-mass Extended Envelopes
• Analyzing the Largest Spectroscopic Dataset of Stripped Supernovae to Improve Their Identifications and Constrain Their Progenitors
• Optical Spectroscopy of Supernova 1993J During Its First 2500 Days
• Investigating the properties of stripped-envelope supernovae, what are the implications for their progenitors?
• Analysis of Late--time Light Curves of Type IIb, Ib and Ic Supernovae
• Characterising the environments of supernovae with MUSE
• PISCO: The Pmas/ppak Integral-field Supernova hosts COmpilation
• A Binary Progenitor for the Type IIb Supernova 2011dh in M51
• Nearby supernova host galaxies from the CALIFA Survey: I. Sample, data analysis, and correlation to star-forming regions
• EC-SNe from super-AGB progenitors: theoretical models vs. observations
• Shock breakout theory
• The AMUSING++ Nearby Galaxy Compilation: I. Full Sample Characterization and Galactic--Scale Outflows Selection
• Inferring supernova IIb/Ib/Ic ejecta properties from light curves and spectra: Correlations from radiative-transfer models
• A massive star origin for an unusual helium-rich supernova in an elliptical galaxy
• Carnegie Supernova Project-II: Extending the Near-Infrared Hubble Diagram for Type Ia Supernovae to $z\sim 0.1$
• SN 2013df, a double-peaked IIb supernova from a compact progenitor and an extended H envelope
• The Subluminous and Peculiar Type Ia Supernova PTF09dav
• Shock Cooling Emission from Extended Material Revisited
• A Catalog of Near Infrared Spectra from Type Ia Supernovae
• SN2019dge: a Helium-rich Ultra-Stripped Envelope Supernova
• A physically motivated classification of stripped-envelope supernovae
• SN 2011fu: A type IIb Supernova with a luminous double-peaked light curve
• The Carnegie Supernova Project I: photometry data release of low-redshift stripped-envelope supernovae
• Radiation-driven winds of hot luminous stars. XVI. Expanding atmospheres of massive and very massive stars and the evolution of dense stellar clusters
• Early Time Light Curves of Type Ia Supernovae Observed with TESS
• Observations of SN 2017ein Reveal Shock Breakout Emission and A Massive Progenitor Star for a Type Ic Supernova
• The Progenitors of Calcium-Strong Transients
• The old environment of the faint calcium-rich supernova SN 2005cz
• iPTF 16hgs: A double-peaked Ca-rich gap transient in a metal poor, star forming dwarf galaxy
• Comparison of the optical light curves of hydrogen-rich and hydrogen-poor type II supernovae
• High-Cadence, Early-Time Observations of Core-Collapse Supernovae From the TESS Prime Mission
• Type II supernovae from the Carnegie Supernova Project-I. I. Bolometric light curves of 74 SNe II using uBgVriYJH photometry
• A Speed Bump: SN 2021aefx Shows that Doppler Shift Alone can Explain Early-Excess Blue Flux in Some Type Ia Supernovae
• Studying Type II supernovae as cosmological standard candles using the Dark Energy Survey
• SN 2018gjx reveals that some SNe Ibn are SNe IIb exploding in dense circumstellar material
• Photometric and polarimetric observations of fast declining Type II supernovae 2013hj and 2014G
• Calcium-rich Transient SN 2019ehk in A Star-Forming Environment: Yet Another Candidate for An Ultra-Stripped Envelope Supernova
• Swift-XRT Follow-up of Gravitational Wave Triggers in the Second Advanced LIGO/Virgo Observing Run
• Supernova SN1987A Revisited as a Major Production Site for r-Process Elements

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