Multiple Peaks and a Long Precursor in the Type IIn Supernova 2021qqp: An Energetic Explosion in a Complex Circumstellar Environment

Journal Article · 28 March 2024 · The Astrophysical Journal

DOI: https://doi.org/10.3847/1538-4357/ad2854 · OSTI ID:2583046

Hiramatsu, Daichi ; Matsumoto, Tatsuya ; Berger, Edo ; Ransome, Conor ; Villar, V. ; Gomez, Sebastian ; Cendes, Yvette ; De, Kishalay ; Bostroem, K. ; Farah, Joseph ; Howell, D. ; McCully, Curtis ; Newsome, Megan ; Padilla Gonzalez, Estefania ; Pellegrino, Craig ; Suzuki, Akihiro ; Terreran, Giacomo

Abstract We present optical photometry and spectroscopy of the Type IIn supernova (SN) 2021qqp. Its unusual light curve is marked by a long precursor for ≈300 days, a rapid increase in brightness for ≈60 days, and then a sharp increase of ≈1.6 mag in only a few days to a first peak ofM_r≈ −19.5 mag. The light curve then declines rapidly until it rebrightens to a second distinct peak ofM_r≈ −17.3 mag centered at ≈335 days after the first peak. The spectra are dominated by Balmer lines with a complex morphology, including a narrow component with a width of ≈1300 km s⁻¹(first peak) and ≈2500 km s⁻¹(second peak) that we associate with the circumstellar medium (CSM) and a P Cygni component with an absorption velocity of ≈8500 km s⁻¹(first peak) and ≈5600 km s⁻¹(second peak) that we associate with the SN–CSM interaction shell. Using the luminosity and velocity evolution, we construct a flexible analytical model, finding two significant mass-loss episodes with peak mass loss rates of ≈10 and ≈5M_⊙yr⁻¹about 0.8 and 2 yr before explosion, respectively, with a total CSM mass of ≈2–4M_⊙. We show that the most recent mass-loss episode could explain the precursor for the year preceding the explosion. The SN ejecta mass is constrained to be ≈5–30M_⊙for an explosion energy of ≈(3–10) × 10⁵¹erg. We discuss eruptive massive stars (luminous blue variable, pulsational pair instability) and an extreme stellar merger with a compact object as possible progenitor channels.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 2583046
• Journal Information: The Astrophysical Journal, Journal Name: The Astrophysical Journal Journal Issue: 2 Vol. 964; ISSN 0004-637X
• Publisher: IOP PublishingCopyright Statement
• Country of Publication: United States
• Language: English