supernova light curves

In a quiet back alley of a galaxy, where stars are rare and old, a light suddenly flares up, brighter than an entire galaxy. This is a Type Ia supernova: a thermonuclear explosion of a white dwarf that astronomers use as a standard candle to measure cosmic distances.

After a supernova explosion, a dense ball the size of a city remains at the center — a newborn neutron star. It is hot, compressed, and rings like a bell after being struck. These tremors, the star's oscillations, emit gravitational ripples that sensitive detectors on Earth can catch.

At the end of a massive star's life, its core collapses in a fraction of a second, giving birth to a supernova flash. This cataclysm shakes spacetime itself, emitting gravitational waves — ripples that race across the Universe.

17 supernovae from the ZTF DR2 sample lit up ahead of schedule. In the first hours and days after the explosion, they emitted more light than standard models predict. Astronomers compare this to a Bickford fuse: before the blinding flash tears across the sky, a precursor spark runs through the outer layers.

For centuries, astronomers gazed at the night sky, catching the slightest changes in stellar brightness. These uneven sequences, light curves, are like musical staves: each star performs its own unique melody.

A massive star ends its life in a spectacular collapse: the core compresses into a neutron star or a black hole, while the outer layers fly off in a dazzling supernova.

In the constellation Scorpius, 3,000 light-years from Earth, a dead star steals matter from a living one. A white dwarf in the system IGR J17014-4306 — a superdense carbon-oxygen ball with the mass of the Sun but the size of Earth — siphons hydrogen from a normal companion star.

In April 2021, in a galaxy 35 megaparsecs away, supernova SN 2021foa erupted. It immediately puzzled astronomers: its spectrum feverishly switched between hydrogen and helium lines — as if the star, in agony, was frantically shedding its outer layers.

A pot of boiling porridge, where instead of grains there are layers of oxygen and silicon, and the fire beneath is about to go out, and the star will collapse in on itself. Until now, astrophysicist cooks have used a simplified recipe: they assumed that bubbles and eddies in the porridge obey one and the same average temperature throughout the depth.

A flashlight doesn't cast a uniform circle of light; it has a bright spot in the center and a blurred halo at the edges. If you switch it off quickly, the edges are the last to fade, and by how the light dies, you can guess the shape of the reflector.

A match flares from both ends. First the head ignites, and a moment later the flame engulfs the wooden stick. Something similar may happen in some Type Ia supernovae — except the match is a white dwarf (a star the size of Earth), and the flame is a thermonuclear explosion.

Two lamps in a shop window: one glows with a cool, bluish light, the other a bit warmer and yellower. That's roughly how the two types of supernovae, Ib and Ic, look when astronomers view them through a telescope.

A supernova explosion is the death of a massive star, leaving behind a gas cloud. If there's plenty of hydrogen around, the shock wave spreads like an echo from a distant gunshot.

A sunspot, a dark island on the scorching surface, breathes. Every three minutes, a wave spreads from it, runs along an invisible magnetic arch, and makes the plasma above a neighboring spot flare with a radio signal. Radio telescopes caught seven such flares in a row on February 14, 2024.

A gamma-ray burst is like a shot from a cosmic cannon. First a brief flash of light, then a fading afterglow. But inside that flash, things aren't so simple: its color and brightness don't change at the same time.

Deep beneath Japan's Mount Ikeno sits a tank holding 50,000 tons of the purest water. Inside, it catches neutrinos — ghostly particles that zip through Earth as if it weren't there. When a star explodes in our galaxy, neutrinos arrive first, hours before the light.

A distant lamp shines through uneven glass. The glass bends the rays, and instead of one flame on the wall, several appear — some brighter, some fainter. In much the same way, a massive galaxy bends the light of an exploded star. There was one explosion, but the images show four glowing points.

A massive star's explosion is bright but brief. The flash itself lasts weeks, but the dust it heats around it glows in infrared for years. It's like a camera flash illuminating a room, then hot dust particles lingering in the air — only on a cosmic scale.

When two neutron stars collide, a kilonova is born — a cosmic explosion that shines not only from heat but also from the decay of freshly created heavy elements. Among them is neodymium, a rare-earth metal that hides in minerals deep within the Earth, but in space, for a brief time, becomes the main conductor of light.

When a massive star runs out of fuel, it sheds its hydrogen envelope and explodes, like a final, desperate exhale. That’s exactly the kind of supernova (type Ib) astronomers observed. 62 days after the blast, in the cooling debris, they caught a faint infrared glow: it turned out to be the signature of carbon monoxide (CO).

A shock wave in the Sun's corona is like the sonic boom from an airplane, except instead of air there is scorching plasma, and instead of sound there is a jump in density and magnetic field. On March 10, 2024, such a wave swept across the western part of the solar disk.

Light from distant stars, as it travels through cosmic dust, loses some of its energy. Dust grains absorb and scatter light, and the way they do so at different wavelengths reveals their composition and size. Astronomers call this the dust extinction curve.

When a massive star explodes, it hurls giant clouds of gas into space. These clouds, known as supernova remnants, can stretch across hundreds of trillions of kilometers. Two such clouds — G107.7-5.1 and G150.3+4.5—were recently studied by astronomers using a telescope in Turkey.

When two lead nuclei collide at tremendous speed, a cloud of scorching matter is born for an instant — denser and hotter than the center of the Sun. Through this cloud fly jets of particles: narrow, laser-like beams knocked out by the impact. The CMS detector captures their tracks and shows how the jets change as they fight through the hot 'fog'.

Neutrinos are tiny particles that barely interact with matter. They pass straight through a star like bullets through fog. When a massive star is gearing up to explode, its core contracts, temperatures soar, and neutrinos start streaming out.

Twenty-eight seconds: that's how long it took for an automated camera to lock onto a flash in a constellation whose light had traveled for more than nine billion years.

On December 31, 2023, the Sun unleashed a flare of the highest class — one that releases the energy of billions of atomic bombs in just a few minutes. Along with it, a huge prominence, a cloud of superheated gas, tore away from the surface and shot outward at nearly 3000 kilometers per second.

Deep inside a dying star eight times heavier than the Sun, a quiet fever begins a few days before the final explosion. The star's core contracts and heats up, releasing neutrinos — tiny particles that barely interact with matter. This stream is like a faint whisper before a loud cry: the supernova hasn't flashed yet, but it's already sending a signal of its imminent demise.

The neutron star 1E 161348-5055 in the supernova remnant RCW 103 pulses with a period of 6.67 hours. That's very slow for such a compact object, and astronomers long puzzled over what was going on.

A total solar eclipse offers rare minutes when the Moon blocks the Sun's bright disk, revealing its outer atmosphere — the corona. In white light, the corona extends tens of solar radii, and images show fine structures: vortex rings, waves like ripples on water, and huge plasma ejections.

In October 2022, the space-based detector GECAM-C caught the most powerful gamma-ray burst ever seen, GRB 221009A — an explosion that briefly became the brightest source of gamma rays in the sky. But the most interesting part came after: the instrument detected a series of additional flares, and one of them was record-breaking.

Cosmic neutrinos are ghost particles, passing freely through the Earth. The IceCube telescope in the ice of Antarctica once caught such a neutrino, and it matched an infrared flare. That flare turned out to be the moment a black hole tore a star apart in a distant galaxy.

Some superluminous supernovae show a bright oxygen imprint in their light and expand rapidly, while others do not. It seemed like different phenomena. But supernova PTF12dam broke the rules: as its brightness grew, its oxygen signature changed, shifting from one type to another.

Gamma-ray bursts are the most powerful explosions in the Universe: a dying star collapses into a black hole, ejecting streams of energy. Often this happens after a supernova flare. But astronomers caught a strange rhythm — in the emission of 34 such bursts, clear pulsations appeared, like beats of a cosmic heart.

On October 9, 2022, detectors on Earth recorded a gamma-ray burst of unprecedented power. GRB 221009A was so bright that its radiation ionized the upper layers of the ionosphere, and satellite instruments were temporarily blinded.