SN 2016iog: A fast-declining Type II-L supernova with an ultra-faint tail persistently interacting with circumstellar material
We present optical photometric and spectroscopic observations of the rapidly declining Type IIL supernova (SN) 2016iog. SN 2016iog reached its peak ∼14 days after explosion, with an absolute magnitude in the V band of −18.64 ± 0.15 mag, followed by a steep decline of 8.85 ± 0.15 mag (100 d) −1 post-peak. Such a high decline rate makes SN 2016iog one of the fastest-declining Type IIL SNe observed to date. The rapid rise in the light curve, combined with the nearly featureless continuum observed in the spectrum at +9.3 days, suggests the presence of interaction. In the recombination phase, we observed broad H α lines that persist at all epochs. In addition, the prominent double-peaked H α feature observed in the late-time spectrum (+190.8 days) is likely attributable either to significant dust formation within a cool dense shell or to asymmetric circumstellar material. These features suggest the presence of a sustained interaction around SN 2016iog. We propose that the observed characteristics of SN 2016iog can be qualitatively explained by assuming a low-mass H-rich envelope surrounding a red supergiant progenitor star with low-density circumstellar material.
Authors
- L. Tomasella (ORCID: https://orcid.org/0000-0002-3697-2616)
- Songpeng Pei (ORCID: https://orcid.org/0000-0002-0851-8045)
- Qi Fang (ORCID: https://orcid.org/0000-0002-9762-2687)
- Xiaofang Wang (ORCID: https://orcid.org/0000-0003-3246-3205)
- G. Valerin
- Zhongmin Peng (ORCID: https://orcid.org/0000-0003-3035-1672)
- Yongzhi Cai (ORCID: https://orcid.org/0000-0002-7714-493X)
- A. Fiore (ORCID: https://orcid.org/0000-0002-0403-3331)
- S. Benetti (ORCID: https://orcid.org/0000-0002-3256-0016)
- M. Berton (ORCID: https://orcid.org/0000-0002-1058-9109)
- A. Reguitti (ORCID: https://orcid.org/0000-0003-4254-2724)
- M. Turatto (ORCID: https://orcid.org/0000-0002-9719-3157)
- A. Pastorello
- G. La Mura (ORCID: https://orcid.org/0000-0001-8553-499X)
- Enrico Congiu (ORCID: https://orcid.org/0000-0002-8549-4083)
- Shengyu Yan (ORCID: https://orcid.org/0009-0004-4256-1209)
- E. Cappellaro (ORCID: https://orcid.org/0000-0001-5008-8619)
- Bo Wang (ORCID: https://orcid.org/0000-0002-3231-1167)
- R. Raddi
- V. Granata (ORCID: https://orcid.org/0000-0002-1425-4541)
- G. Terreran (ORCID: https://orcid.org/0000-0003-0794-5982)
- Shuai Zha (ORCID: https://orcid.org/0000-0003-3636-1177)
- P. Ochner
- N. Elias–Rosa (ORCID: https://orcid.org/0000-0002-1381-9125)
- J. Isern (ORCID: https://orcid.org/0000-0002-0819-9574)
- Pan Yu (ORCID: https://orcid.org/0000-0002-3333-9719)
- Chao Wu (ORCID: https://orcid.org/0000-0002-1331-2746)
- L. Borsato
- Zhenru Wang (ORCID: https://orcid.org/0000-0003-1697-6414)
Institutions
- Chongqing University of Posts and Telecommunications (CN)
- Adler Planetarium (US)
- University of Padua (IT)
- Yunnan University (CN)
- Chinese Academy of Sciences (CN)
- National Institutes of Natural Sciences (JP)
- LIP - Laboratory of Instrumentation and Experimental Particle Physics (PT)
- Yunnan Observatories (CN)
- Brera Astronomical Observatory (IT)
- Purple Mountain Observatory (CN)
- Institut d'Estudis Espacials de Catalunya (ES)
- Institute of Space Sciences (ES)
- Reial Acadèmia de Ciències i Arts de Barcelona (ES)
- Collurania Teramo Observatory (IT)
- European Southern Observatory (CL)
- Liupanshui Normal University (CN)
- Astronomy and Space (AU)
- Osservatorio Astronomico di Cagliari (IT)
- Osservatorio Astronomico di Padova (IT)
- National Astronomical Observatory of Japan (JP)
- National Astronomical Observatories (CN)
- University of Chinese Academy of Sciences (CN)
- Universitat Politècnica de Catalunya (ES)
- Tsinghua University (CN)
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2025-11-28
- DOI
- https://doi.org/10.1051/0004-6361/202556330
- Primary Topic
- Gamma-ray bursts and supernovae
- Type
- article
- Field-Weighted Citation Impact
- 0.00