Final Moments. I. Precursor Emission, Envelope Inflation, and Enhanced Mass Loss Preceding the Luminous Type II Supernova 2020tlf

W. V. Jacobson-Galán*, L. Dessart, D. O. Jones, R. Margutti, D. L. Coppejans, G. Dimitriadis, R. J. Foley, C. D. Kilpatrick, D. J. Matthews, S. Rest, G. Terreran, P. D. Aleo, K. Auchettl, P. K. Blanchard, D. A. Coulter, K. W. Davis, T. J.L. De Boer, L. Demarchi, M. R. Drout, N. EarlA. Gagliano, C. Gall, J. Hjorth, M. E. Huber, A. L. Ibik, D. Milisavljevic, Y. C. Pan, A. Rest, R. Ridden-Harper, C. Rojas-Bravo, M. R. Siebert, K. W. Smith, K. Taggart, S. Tinyanont, Q. Wang, Y. Zenati

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

68 Scopus citations


We present panchromatic observations and modeling of supernova (SN) 2020tlf, the first normal Type II-P/L SN with confirmed precursor emission, as detected by the Young Supernova Experiment transient survey. Pre-SN activity was detected in riz-bands at -130 days and persisted at relatively constant flux until first light. Soon after discovery, "flash"spectroscopy of SN 2020tlf revealed narrow, symmetric emission lines that resulted from the photoionization of circumstellar material (CSM) shed in progenitor mass-loss episodes before explosion. Surprisingly, this novel display of pre-SN emission and associated mass loss occurred in a red supergiant (RSG) progenitor with zero-age main-sequence mass of only 10-12 M o˙, as inferred from nebular spectra. Modeling of the light curve and multi-epoch spectra with the non-LTE radiative-transfer code CMFGEN and radiation-hydrodynamical code HERACLES suggests a dense CSM limited to r ≈ 1015 cm, and mass-loss rate of 10-2 M o˙ yr-1. The luminous light-curve plateau and persistent blue excess indicates an extended progenitor, compatible with an RSG model with R ∗ = 1100 R o˙. Limits on the shock-powered X-ray and radio luminosity are consistent with model conclusions and suggest a CSM density of ρ < 2 × 10-16 g cm-3 for distances from the progenitor star of r ≈ 5 × 1015 cm, as well as a mass-loss rate of at larger distances. A promising power source for the observed precursor emission is the ejection of stellar material following energy disposition into the stellar envelope as a result of gravity waves emitted during either neon/oxygen burning or a nuclear flash from silicon combustion.

Original languageEnglish (US)
Article number15
JournalAstrophysical Journal
Issue number1
StatePublished - Jan 1 2022

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Final Moments. I. Precursor Emission, Envelope Inflation, and Enhanced Mass Loss Preceding the Luminous Type II Supernova 2020tlf'. Together they form a unique fingerprint.
  • Final moments. I. Type II SN 2020tlf

    Jacobson-Galán, W. V. (Contributor), Dessart, L. (Creator), Jones, D. O. (Creator), Margutti, R. (Creator), Coppejans, D. L. (Creator), Dimitriadis, G. (Creator), Foley, R. J. (Creator), Kilpatrick, C. D. (Creator), Matthews, D. J. (Creator), Rest, S. (Creator), Terreran, G. (Creator), Aleo, P. D. (Creator), Auchettl, K. (Creator), Blanchard, P. K. (Creator), Coulter, D. A. (Creator), Davis, K. W. (Creator), De Boer, B. T. J. L. (Contributor), Demarchi, L. (Contributor), Drout, M. R. (Creator), Earl, N. (Creator), Gagliano, A. (Creator), Gall, C. (Creator), Hjorth, J. (Creator), Huber, M. E. (Creator), Ibik, A. L. (Creator), Milisavljevic, D. (Creator), Pan, Y. (Creator), Rest, A. (Creator), Ridden-Harper, R. (Creator), Rojas-Bravo, C. (Creator), Siebert, M. R. (Creator), Smith, K. W. (Creator), Taggart, K. (Creator), Tinyanont, S. (Creator), Wang, Q. (Creator) & Zenati, Y. (Creator), Centre de Donnees Strasbourg (CDS), 2023


Cite this