The Early Phases of Supernova 2020pni: Shock-Ionization of the Nitrogen-Enriched Circumstellar Material

Abstract

We present multiwavelength observations of the Type II SN 2020pni. Classified at $\sim 1.3$ days after explosion, the object showed narrow (FWHM $<250\text{km}{\text{s}}^{-1}$) recombination lines of ionized helium, nitrogen, and carbon, as typically seen in flash-spectroscopy events. Using the non-LTE radiative transfer code CMFGEN to model our first high resolution spectrum, we infer a progenitor mass-loss rate of $\dot{M}=(3.5-5.3)\times 10^{-3}$ M${}_{\odot }$ yr${}^{-1}$ (assuming a wind velocity of $v_w=200\text{km}{\text{s}}^{-1}$), estimated at a radius of $R_{\mathrm{in}}=2.5\times 10^{14}\mathrm{cm}$. In addition, we find that the progenitor of SN 2020pni was enriched in helium and nitrogen (relative abundances in mass fractions of 0.30$-$0.40, and $8.2\times 10^{-3}$, respectively). Radio upper limits are also consistent with a dense CSM, and a mass-loss rate of $\dot{M}>5\times 10^{-4}{\mathrm{M}}_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$. During the first 4 days after first light, we also observe an increase in velocity of the hydrogen lines (from $\sim 250\text{km}{\text{s}}^{-1}$ to $\sim 1000\text{km}{\text{s}}^{-1}$), which suggests a complex CSM. The presence of dense and confined CSM, as well as its inhomogeneous structure, suggest a phase of enhanced mass loss of the progenitor of SN 2020pni during the last year before explosion. Finally, we compare SN 2020pni to a sample of other shock-photoionization events. We find no evidence of correlations among the physical parameters of the explosions and the characteristics of the CSM surrounding the progenitors of these events. This favors the idea that the mass-loss experienced by massive stars during their final years could be governed by stochastic phenomena, and that, at the same time, the physical mechanisms responsible for this mass-loss must be common to a variety of different progenitors.

arXiv comment19 pages, 14 figures

References in corpus (83)

• Astropy: A Community Python Package for Astronomy
• Stellar population synthesis at the resolution of 2003
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• The Dust Content and Opacity of Actively Star-Forming Galaxies
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• The Swift X-ray Telescope
• The Zwicky Transient Facility: System Overview, Performance, and First Results
• The Swift Ultra-Violet/Optical Telescope
• The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
• Mass-loss predictions for O and B stars as a function of metallicity
• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• Las Cumbres Observatory Global Telescope Network
• A Method of Correcting Near-Infrared Spectra for Telluric Absorption
• Mass Loss: Its Effect on the Evolution and Fate of High-Mass Stars
• An ultra-deep near-infrared spectrum of a compact quiescent galaxy at z=2.2
• 2MASS Extended Source Catalog: Overview and Algorithms
• The Zwicky Transient Facility: Science Objectives
• WISeREP - An Interactive Supernova Data Repository
• An Empirical Relation between Sodium Absorption and Dust Extinction
• Shock Breakout in Dense Mass Loss: Luminous Supernovae
• An Open Catalog for Supernova Data
• ESI, a new Keck Observatory echellette spectrograph and imager
• Confined Dense Circumstellar Material Surrounding a Regular Type II Supernova: The Unique Flash-Spectroscopy Event of SN 2013fs
• Wave-Driven Mass Loss in the Last Year of Stellar Evolution: Setting the Stage for the Most Luminous Core-Collapse Supernovae
• A Wolf-Rayet-like progenitor of supernova SN 2013cu from spectral observations of a wind
• Circumstellar Emission from Type Ib and Ic Supernovae
• SN 2006jc: A Wolf-Rayet Star Exploding in a Dense He-Rich Circumstellar Medium
• The Remarkable Deaths of 9 - 11 Solar Mass Stars
• Evidence for Asphericity in the Type IIn Supernova 1998S
• The Distance to SN 1999em from the Expanding Photosphere Method
• The Structure of the Homunculus: I. Shape and Latitude Dependence from H2 and [Fe II] Velocity Maps of Eta Carinae
• Evolution of massive stars with pulsation-driven superwinds during the RSG phase
• SOUSA: the Swift Optical/Ultraviolet Supernova Archive
• A panchromatic view of the restless SN2009ip reveals the explosive ejection of a massive star envelope
• Flash Spectroscopy: Emission Lines from the Ionized Circumstellar Material around $<10$-Day-Old Type II Supernovae
• The SED Machine: a robotic spectrograph for fast transient classification
• The mass-loss rates of red supergiants and the de Jager prescription
• Pre-Supernova Outbursts via Wave Heating in Massive Stars I: Red Supergiants
• An outburst from a massive star 40 days before a supernova explosion
• Relativistic Shocks: Particle Acceleration and Magnetization
• Setting the Stage for Circumstellar Interaction in Core-Collapse Supernovae II: Wave-Driven Mass Loss in Supernova Progenitors
• Characterizing Supernova Progenitors via the Metallicities of their Host Galaxies, from Poor Dwarfs to Rich Spirals
• Unifying Type II Supernova Light Curves with Dense Circumstellar Material
• Testing LMC Microlensing Scenarios: The Discrimination Power of the SuperMACHO Microlensing Survey
• Type II-Plateau supernova radiation: dependencies on progenitor and explosion properties
• Optical and Infrared Spectroscopy of the type IIn SN 1998S : Days 3-127
• Ultraviolet Light Curves of Supernovae with Swift Uvot
• The first month of evolution of the slow rising type II-P SN 2013ej in M74
• Core-Collapse Supernovae and Host Galaxy Stellar Populations
• Measuring the Progenitor Masses and Dense Circumstellar Material of Type II Supernovae
• A large fraction of hydrogen-rich supernova progenitors experience elevated mass loss shortly prior to explosion
• Supernovae from Red Supergiants with Extensive Mass Loss
• Fundamental properties of core-collapse Supernova and GRB progenitors: predicting the look of massive stars before death
• Variety in Supernovae
• A Fully Automated Integral Field Spectrograph Pipeline for the SEDMachine: pysedm
• Explosion of red-supergiant stars: influence of the atmospheric structure on shock breakout and the early-time supernova radiation
• The Absolute Magnitudes of Type Ia Supernovae in the Ultraviolet
• The Young Supernova Experiment: Survey Goals, Overview, and Operations
• Early-time spectra of supernovae and their precursor winds: the luminous blue variable/yellow hypergiant progenitor of SN 2013cu
• Shock breakout theory
• Early Emission from the Type IIn Supernova 1998S at High Resolution
• Short-Lived Circumstellar Interaction in the Low-Luminosity Type IIP SN 2016bkv
• The Type IIP SN 2007od in UGC 12846: from a bright maximum to dust formation in the nebular phase
• A Diversity of Wave-driven Pre-supernova Outbursts
• The multi-faceted Type II-L supernova 2014G from pre-maximum to nebular phase
• The diverse lives of progenitors of hydrogen-rich core-collapse supernovae: the role of binary interaction
• Models of interacting supernovae and their spectral diversity
• The Berkeley sample of Type II supernovae: BVRI light curves and spectroscopy of 55 SNe II
• Type II supernova spectral diversity II: Spectroscopic and photometric correlations
• SN 2018zd: An Unusual Stellar Explosion as Part of the Diverse Type II Supernova Landscape
• Supernova 1998S at 14 years Postmortem: Continuing Circumstellar Interaction and Dust Formation
• The Unusual Temporal and Spectral Evolution of the Type IIn Supernova 2011ht
• The early discovery of SN 2017ahn: signatures of persistent interaction in a fast declining Type II supernova
• Low-luminosity Type IIP Supernova 2016bkv with early-phase circumstellar interaction
• Shock-heating of stellar envelopes: A possible common mechanism at the origin of explosions and eruptions in massive stars
• Progenitors of early-time interacting supernovae
• Catching a star before explosion: the luminous blue variable progenitor of SN 2015bh
• SN 2016coi (ASASSN-16fp): an energetic H-stripped core-collapse supernova from a massive stellar progenitor with large mass loss
• Flash ionization signatures in the type Ibn supernova SN 2019uo
• The diversity of supernovae and impostors shortly after explosion
• Partial Stellar Explosions -- Ejected Mass and Minimal Energy
• A pre-explosion extended effervescent zone around core collapse supernova progenitors

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