SUNSET: 
Mapping a Supernova's Radioactive Glow
A radioactive element produced near the heart of collapsing stars hints at the mechanism behind Cassiopeia A’s supernova explosion.
The Purest Star Tells an Ancient Tale
Astronomers have discovered the purest star to date. Composed almost exclusively of hydrogen and helium — with 15 million times less iron than our Sun — it illuminates what happened among the first supernovae in the early universe.
Red Sky for Brown Dwarf
Astronomers have discovered a new “failed star” with unusually red, dusty skies. The dust makes the object look much younger than it actually is, complicating studies of this type of brown dwarf.
New Cutoff for Star Sizes
Astronomers have found a size gap between stars that fuse hydrogen in their cores and so-called failed stars, which never muster the ability to sustain fusion. This boundary could help observers precisely identify the smallest stellar citizens.
Watch a Mesmerizing Light Show
The gossamer veil of reflective dust surrounding the star RS Puppis reflects its flickering light in a fantastic display.
The Crab's Surprise Molecule
Astronomers have identified a molecule containing the noble gas argon in the Crab Nebula. It's the first such molecule detected in space and confirms predictions of where a certain argon isotope is created in the cosmos.
Triple Collision in Infant Galaxy
A complex of three bright, star-forming clumps called Himiko is merging in the early universe. With its light reaching us from when the universe was only 800 million years old, this primordial galaxy could yield insight into the elusive process of early galaxy formation.
Downsizing a Black Hole
Astronomers have revealed a supposedly monster black hole to be rather ordinary in size.
Oddball Pulsar Origin?
A few whirling neutron stars might get their start as very different objects, at least if a new analysis is correct.
Monster Burst Challenges Theories
Observations of one of the most powerful supernovas ever recorded suggest that the standard model for gamma-ray bursts might be missing a piece of the puzzle.
Cassiopeia A in 3D
Explore a supernova remnant with this fun interactive simulation, created from detailed space- and ground-based observations in multiple wavelengths.
Warm Glow from an Orphaned Planet
Observers have found an object floating in Capricornus, far from any star, that appears to be a free-floating planet with six times the mass of Jupiter.
Fomalhaut Star System Actually a Triple
Turns out “the lonely star of autumn” has not just one, but two distant companions, making it one of the most widely separated systems known.
Pulsar on the Fence
Astronomers have discovered a neutron star that switches between X-ray and radio emission within a few days. The find is fabulous news for theorists, who have long predicted that the two pulsar types were connected.
Glimpse Into Sun Befuddles Theorists
Scientists sneaked a peek into the Sun’s interior, but what they saw contradicts the assumptions made by models predicting solar activity.
Skinny Stars or Fat Planets?
New studies of the coolest brown dwarfs are helping astronomers explore the mysterious objects that bridge the gap between stars and planets.
Sun Loses Lithium with Age
Observations of two solar twins — one old and one young — confirm that the Sun has probably destroyed the fragile element as the star has grown older.
Old, Fat Stars Flicker
Observing the pattern of flickers in a star’s light offers a new way for astronomers to measure one of the basic properties of stars — and any exoplanets they might host.
Dead Stars Caught Colliding
Astronomers have detected a signal that looks like it's from two neutron stars crashing together. The observations could be solid evidence for the hypothesized culprits of short gamma-ray bursts.
The Weakest Solar Cycle in 100 Years
Scientists are struggling to explain the Sun’s bizarre recent behavior. Is it a fluke, or a sign of a deeper trend?
