SN2019yvq Does Not Conform to SN Ia Explosion Models

Abstract

We present new photometric and spectroscopic observations of SN 2019yvq, a Type Ia supernova (SN Ia) exhibiting several peculiar properties including an excess of UV/optical flux within days of explosion, a high SiII velocity, and a low peak luminosity. Photometry near the time of first light places new constraints on the rapid rise of the UV/optical flux excess. A near-infrared spectrum at $+173$ days after maximum light places strict limits on the presence of H or He emission, effectively excluding the presence of a nearby non-degenerate star at the time of explosion. New optical spectra, acquired at +128 and +150 days after maximum light, confirm the presence of CaII$\lambda 7300$Å and persistent CaII NIR triplet emission as SN 2019yvq transitions into the nebular phase. The lack of [OI]$\lambda 6300$Å emission disfavors the violent merger of two C/O white dwarfs (WDs) but the merger of a C/O WD with a He WD cannot be excluded. We compare our findings with several models in the literature postulated to explain the early flux excess including double-detonation explosions, ${}^{56}$Ni mixing into the outer ejecta during ignition, and interaction with H- and He-deficient circumstellar material. Each model may be able to explain both the early flux excess and the nebular [CaII] emission, but none of the models can reconcile the high photospheric velocities with the low peak luminosity without introducing new discrepancies.

19 pages, 10 figures, and 2 tables. Accepted by ApJ

References in corpus (42)

• The Transiting Exoplanet Survey Satellite
• The Zwicky Transient Facility: System Overview, Performance, and First Results
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• Double-detonation sub-Chandrasekhar supernovae: can minimum helium shell masses detonate the core?
• Faint Thermonuclear Supernovae from AM Canum Venaticorum Binaries
• Double-detonation sub-Chandrasekhar supernovae: synthetic observables for minimum helium shell mass models
• Cosmological parameters from the comparison of peculiar velocities with predictions from the 2M++ density field
• Secondary Maximum in the Near-Infrared Lightcurves of Type Ia Supernovae
• Double-detonation supernovae of sub-Chandrasekhar mass white dwarfs
• The Carnegie Supernova Project: Intrinsic Colors of Type Ia Supernovae
• Galaxy Groups within 3500 km s${}^{-1}$
• Constraining the Type Ia Supernova Progenitor: The Search for Hydrogen in Nebular Spectra
• The Carnegie Supernova Project I: Third Photometry Data Release of Low-Redshift Type Ia Supernovae and Other White Dwarf Explosions
• The Initiation and Propagation of Helium Detonations in White Dwarf Envelopes
• A hybrid type Ia supernova with an early flash triggered by helium-shell detonation
• No X-rays from the very nearby Type Ia SN2014J: constraints on its environment
• ZTF Early Observations of Type Ia Supernovae I: Properties of the 2018 Sample
• Exploring the spectral diversity of low-redshift Type Ia supernovae using the Palomar Transient Factory
• Evidence for sub-Chandrasekhar-mass progenitors of Type Ia supernovae at the faint end of the width-luminosity relation
• Cosmicflows-3: Two Distance$-$Velocity Calculators
• Nebular spectra and abundance tomography of the type Ia supernova SN 2011fe: a normal SN Ia with a stable Fe core
• Double Detonations with Thin, Modestly Enriched Helium Layers Can Make Normal Type Ia Supernovae
• Optical and IR observations of SN 2002dj: some possible common properties of fast expanding SNe Ia
• Light and color curve properties of type Ia supernovae: Theory vs. Observations
• The peculiar velocity field up to $z\sim 0.05$ by forward-modeling Cosmicflows-3 data
• SNe Ia from double detonations: Impact of core-shell mixing on the carbon ignition mechanism
• Signatures of A Companion Star in Type Ia Supernovae
• The Spectacular Ultraviolet Flash From the Peculiar Type Ia Supernova 2019yvq
• Investigating the Diversity of Type Ia Supernova Spectra with the Open-Source Relational Database Kaepora
• Strong Calcium Emission Indicates that the Ultraviolet-Flashing Type Ia SN 2019yvq was the Result of a Sub-Chandrasekhar Mass Double-Detonation Explosion
• An investigation of ${}^{56}$Ni shells as the source of early light curve bumps in type Ia supernovae
• One-dimensional non-LTE time-dependent radiative transfer of an He-detonation model and the connection to faint and fast-decaying supernovae
• Predicting polarization signatures for double-detonation and delayed-detonation models of Type Ia supernovae
• Comparative Direct Analysis of Type Ia Supernova Spectra. IV. Postmaximum
• Late-time near-infrared observations of SN 2005df
• Helium in Double-Detonation Models of Type Ia Supernovae
• Carnegie Supernova Project-II: A new method to photometrically identify sub-types of extreme Type Ia Supernovae
• Defining Photometric Peculiar Type Ia Supernovae
• Spectral signatures of H-rich material stripped from a non-degenerate companion by a Type Ia supernova
• Identification of the feature that causes the I-band secondary maximum of a type Ia supernova
• Nebular H$\alpha$ Limits for Fast Declining Type Ia Supernovae
• The HI content of the advanced merger NGC 4441

Cited by in corpus (12)

• A Bright Ultraviolet Excess in the Transitional 02es-like Type Ia Supernova 2019yvq
• Constraining the Progenitor System of the Type Ia Supernova 2021aefx
• A Speed Bump: SN 2021aefx Shows that Doppler Shift Alone can Explain Early-Excess Blue Flux in Some Type Ia Supernovae
• SN 2021zny: an early flux excess combined with late-time oxygen emission suggests a double white dwarf merger event
• From Out of the Blue: Swift Links 2002es-like, 2003fg-like, and Early-Time Bump Type Ia Supernovae
• The origin and evolution of the normal Type Ia SN 2018aoz with infant-phase reddening and excess emission
• A Rapid Ionization Change in the Nebular-Phase Spectra of the Type Ia SN 2011fe
• SN 2016dsg: A Thermonuclear Explosion Involving A Thick Helium Shell
• The Early Light Curve of SN 2023bee: Constraining Type Ia Supernova Progenitors the Apian Way
• Early excess emission in Type Ia supernovae from the interaction between supernova ejecta and their circumstellar wind
• The New Status Qvo? SN 2021qvo is Another 2003fg-like Type Ia Supernova with a Rising Light-Curve Bump
• Circumstellar Medium Constraints on the Environment of Two Nearby Type Ia Supernovae: SN 2017cbv and SN 2020nlb