Luminous, rapidly declining supernovae as stripped transitional objects in low-metallicity environments: The case of SN 2022lxg

We present an analysis of the optical and near-infrared properties of SN 2022lxg, a bright ( M g peak = −19.41 mag) and rapidly evolving supernova (SN). It was discovered within a day of explosion, and rose to peak brightness in ∼10 d. Two distinct phases of circumstellar interaction are evident in the data. The first is marked by a steep blue continuum ( T > 15 000 K) with flash-ionisation features due to hydrogen and He II . The second, weaker phase is marked by a change in the colour evolution accompanied by changes in the shapes and velocities of the spectral line profiles. Narrow P-Cygni profiles (∼150 km s −1 ) of He I further indicate the presence of slow-moving, unshocked material and suggest partial stripping of the progenitor. The fast decline of the light-curve from the peak (3.48 ± 0.26 mag (50 d) −1 in g band) implies that the ejecta mass must be low. Spectroscopically, until +35 d there are similarities with some Type IIb SNe but then there is a transition to spectra that are more reminiscent of an interacting SN II. However, metal lines are largely absent in the spectra, even at epochs of ∼80 d. Its remote location (∼4.6 kpc projected offset) from the presumed host galaxy, a dwarf with M B ∼ −14.4 mag, is consistent with our metallicity estimate – close to the values of the Small Magellanic Cloud – obtained from scaling relations. Furthermore, several lines of evidence (including intrinsic polarisation of p ∼ (0.5 − 1.0)%) point to deviations from spherical symmetry. We suggest that a plausible way of uniting the observational clues is to consider a binary system that underwent case C mass transfer. This failed to remove the entire H envelope of the progenitor before it underwent core collapse. In this scenario, the progenitor itself would be more compact and perhaps straddle the boundary between blue and yellow supergiants, which ties in with the early spectroscopic similarity to Type IIb SNe.

Authors

Publication Details

Journal
Astronomy and Astrophysics
Published
2025-07-05
DOI
https://doi.org/10.1051/0004-6361/202554648
Citations
2
Primary Topic
Gamma-ray bursts and supernovae
Type
article
Field-Weighted Citation Impact
2.31

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Luminous, rapidly declining supernovae as stripped transitional objects in low-metallicity environments: The case of SN 2022lxg

E. Kankare, P. J. Pessi, L. Tartaglia, K. Maeda et al.
2 citations
Astronomy and Astrophysics
Gamma-ray bursts and supernovae
2.31
article

Luminous, rapidly declining supernovae as stripped transitional objects in low-metallicity environments: The case of SN 2022lxg

E. Kankare, P. J. Pessi, L. Tartaglia, K. Maeda, Yongzhi Cai, J. Sollerman, C. Fremling, P. Charalampopoulos, Frank J. Masci, M. Pursiainen, S. Mattila, K-Ryan Hinds, A. Reguitti, M. Stritzinger, D.A. Perley, Peter Lundqvist, Thomas L. Killestein, A. Wold, R. Kotak, Tim Reynolds, T. Kangas, H. Kuncarayakti, Jan van Roestel, Steve Schulze, C. P. Gutiérrez, Theophile Jegou du Laz, M. M. Kasliwal
article en
2 citations

Abstract

We present an analysis of the optical and near-infrared properties of SN 2022lxg, a bright ( M g peak = −19.41 mag) and rapidly evolving supernova (SN). It was discovered within a day of explosion, and rose to peak brightness in ∼10 d. Two distinct phases of circumstellar interaction are evident in the data. The first is marked by a steep blue continuum ( T > 15 000 K) with flash-ionisation features due to hydrogen and He II . The second, weaker phase is marked by a change in the colour evolution accompanied by changes in the shapes and velocities of the spectral line profiles. Narrow P-Cygni profiles (∼150 km s −1 ) of He I further indicate the presence of slow-moving, unshocked material and suggest partial stripping of the progenitor. The fast decline of the light-curve from the peak (3.48 ± 0.26 mag (50 d) −1 in g band) implies that the ejecta mass must be low. Spectroscopically, until +35 d there are similarities with some Type IIb SNe but then there is a transition to spectra that are more reminiscent of an interacting SN II. However, metal lines are largely absent in the spectra, even at epochs of ∼80 d. Its remote location (∼4.6 kpc projected offset) from the presumed host galaxy, a dwarf with M B ∼ −14.4 mag, is consistent with our metallicity estimate – close to the values of the Small Magellanic Cloud – obtained from scaling relations. Furthermore, several lines of evidence (including intrinsic polarisation of p ∼ (0.5 − 1.0)%) point to deviations from spherical symmetry. We suggest that a plausible way of uniting the observational clues is to consider a binary system that underwent case C mass transfer. This failed to remove the entire H envelope of the progenitor before it underwent core collapse. In this scenario, the progenitor itself would be more compact and perhaps straddle the boundary between blue and yellow supergiants, which ties in with the early spectroscopic similarity to Type IIb SNe.

Astronomy and AstrophysicsVol. 700
National Science Foundation, Gordon and Betty Moore Foundation, California Institute of Technology, Northwestern University, Aarhus Universitet, University of Washington, University of Warwick, European Commission, National Research Foundation, Trinity College Dublin, Danmarks Grundforskningsfond, Weizmann Institute of Science, National Natural Science Foundation of China, Aarhus Universitets Forskningsfond, Generalitat de Catalunya, Ministerio de Ciencia e Innovación, Universitetet i Oslo, Háskóli Íslands, Turun Yliopisto, Stockholms Universitet, Turun Yliopistosäätiö, Deutsches Elektronen-Synchrotron, Japan Society for the Promotion of Science, Agencia Estatal de Investigación, National Key Research and Development Program of China, Institut National de Physique Nucléaire et de Physique des Particules, Lawrence Berkeley National Laboratory
Openalex Percentile: Top 11%
Gamma-ray bursts and supernovae
2.31
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.