Search

A key missing piece in the puzzle of supernovae is the difficulty of identifying and studying progenitor stars; in only a single case (SN 1987A) has a star been detected at the supernova location before the explosion. The proposed progenitor of supernova SN 2005gl has now been confirmed by Gal-Yam and Leonard as indeed the progenitor of that supernova; standard stellar evolution predicts that this very massive luminous blue variable should not have exploded in that state.

Observations of SN 2021yfj reveal that its progenitor is a massive star stripped down to its O/Si/S core, which remarkably continued to expel vast quantities of silicon-, sulfur-, and argon-rich material before the explosion, informing us that current theories for how stars evolve are too narrow.

Multi-epoch spectropolarimetry of a supernova reveals the abrupt appearance of significant polarization when the inner core is first exposed in the thinning ejecta — roughly 90 days after explosion.

The identification of two superluminous supernovae at redshifts of 2.05 and 3.90 extends the present technological redshift limit on supernova detection and presents the possibility of studying the deaths of the first stars to form after the Big Bang.

Multi-instrument detection of a nearby type 1a supernova shows that the exploding star was probably a carbon–oxygen white dwarf star in a binary system with a main-sequence companion.

Type IIn supernovae are luminous core-collapse explosions of massive stars that, unlike other types, are very bright in the ultraviolet and have strong, long-lived emission lines that should enable detection at redshift z ≈ 2. Here, three spectroscopically confirmed type IIn supernovae are reported at redshifts z = 0.808, 2.013 and 2.357, detected in archival data.

The detection of strong emission lines in an early-time spectrum of type IIb supernova SN 2013cu reveals Wolf–Rayet-like wind signatures, suggesting that the supernova’s progenitor may have been a Wolf–Rayet star with a wind dominated by helium and nitrogen, with traces of hydrogen.

Very early observations of a type Ia supernova—from within one hour of explosion—show a red colour that develops and rapidly disappears. These data provide information on the initial explosion mechanism: surface nuclear burning on the white dwarf or extreme mixing of the nuclear burning process.

Observations of optical flares from AT2022tsd (the ‘Tasmanian Devil’) show that they have durations on the timescale of minutes, occur over a period of months, are highly energetic, are probably nonthermal and have supernova luminosities.

Superluminous supernova SN 2017egm has a complex light curve that is well modelled by successive collisions of a shockwave with dense circumstellar shells ejected by its massive progenitor star during the pair-instability pulsation stage. Such a scenario might be responsible for providing a power source for superluminous supernovae in general.

A type Ia supernova shows the presence of helium-rich circumstellar material, as demonstrated by its spectral features, infrared emission and a radio counterpart, that probably originates from a single-degenerate system in which a white dwarf accretes material from a helium donor star.

The tidal disruption event AT2019dsg is probably associated with a high-energy neutrino, suggesting that such events can contribute to the cosmic neutrino flux. The electromagnetic emission is explained in terms of a central engine, a photosphere and an extended synchrotron-emitting outflow.

A stripped-envelope supernova, SN 2022jli, shows 12.4-day periodic undulations during the declining light curve, and narrow Hα emission is detected in late-time spectra with concordant periodic velocity shifts.

Optical observations of γ-ray burst (GRB) 060614 (duration ∼100s) rule out the presence of an associated supernova. This would seem to require a new explosive process: either a massive 'collapsar' that powers a GRB without any associated supernova, or a new type of engine, as long-lived as the collapsar but without a massive star.

Observations of the supernova SN 2019hgp, identified about a day after its explosion, show that it occurred within a nebula of carbon, oxygen and neon, and was probably the explosion of a massive WC/WO star.

Supernovae are thought to arise through one of two processes. Type Ib/c and type II supernovae are produced when the cores of massive, short-lived stars undergo gravitational core collapse and eject a few solar masses. Type Ia supernovae are thought to form by the thermonuclear detonation of a carbon-oxygen white dwarf. Here a faint type Ib supernova, SN 2005E, is reported that seems not to have had a core-collapse origin, but perhaps arose from a low-mass, old progenitor, probably a helium-accreting white dwarf in a binary.

Extremely massive stars with initial masses of more than 140 solar masses end their lives when pressure-supporting photons turn into electron–positron pairs, leading to a violent contraction that triggers a nuclear explosion, unbinding the star in a pair-instability supernova. Here, the mass of the exploding core of supernova SN 2007bi is estimated at around 100 solar masses, in which case theory unambiguously predicts a pair-instability supernova. Further observations are well fitted by models of pair-instability supernovae.

The spectral properties of a short gamma-ray burst indicate that, contrary to expectations, it arose from the collapse of a massive star rather than from a compact binary merger. This discovery also confirms that most collapsars do not produce ultra-relativistic jets.

In this work, more than fifty late-time nebular spectra of stripped-envelope supernovae are studied in order to understand more about the massive-star progenitors of these objects. Type Ib and IIb progenitors are largely indistinguishable; type Ic progenitors likely have more massive carbon–oxygen cores.

Observations of an event (several energetic eruptions leading to a terminal explosion that is surprisingly hydrogen-rich) with the spectrum of a supernova do not match with other observations of supernovae.

Observations of declining ultraviolet emission from a type Ia supernova within four days of the explosion are as expected if material ejected by the supernova collided with a companion star, supporting the single degenerate channel model of supernova progenitors.