| Name: Divyanshu Janghel |
| Affiliation: Aryabhatta Research Institute of Observational Sciences (ARIES) |
| Conference ID: ASI2026_354 |
| Title: A Slow-Declining Type IIb: Photometric and Spectroscopic Insights into SN 2019tua. |
| Abstract Type: Poster |
| Abstract Category: High Energy Phenomena, Fundamental Physics and Astronomy |
| Author(s) and Co-Author(s) with Affiliation: Divyanshu Janghel(Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital-263001, Uttarakhand, India.), Kuntal Misra(Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital-263001, Uttarakhand, India.), Anjasha Gangopadhyay(Department of Astronomy, Oskar Klein Center, Stockholm University, SE-106 91 Stockholm, Sweden.) |
| Abstract: A subgroup of core-collapse supernovae (CCSNe) exhibits an early, broad Hα absorption that later fades, while strong He I lines emerge, a distinctive characteristic of Type IIb SNe. These Type IIb events are relatively rare, making up roughly 7% of all SN explosions. We present a detailed photometric and spectroscopic study of the Type IIb SN 2019tua hosted in the galaxy UGC 11860, covering about 2 to 380 days after explosion. Unlike many Type IIb SNe, which exhibit an early, rapidly evolving cooling peak, SN 2019tua does not show this feature, which may be attributed either to its late discovery or the intrinsic absence of such a peak. Photometric analysis reveals a bright main peak (Mv = −17.88 ± 0.15 mag) and a slower post-peak decline compared to other SNe in our sample. The spectral evolution reveals a weakening of Hα features and the emergence of He I lines over time, confirming its classification as a Type IIb SNe. Light-curve and spectral modeling indicate a massive progenitor that retained only a thin hydrogen envelope at explosion, with MOSFiT light-curve fits giving Mej≈1.3M⊙, MNi≈0.3M⊙ and vej≈8000 km s−1. |
