Article
Why Mars Kept Its Krypton and Lost Its Carbon
Mars has lost most of its air. Its krypton, though, is essentially where it started — a heavy noble gas still sitting in what is left of an atmosphere that a young Sun's wind spent hundreds of…
Exoplanets
ArticleA Full Exoplanet Chemistry Report From a Single JWST Setting
WASP-39 b is one of the most-studied planets outside our solar system, a puffy hot Jupiter roughly 700 light-years away that became a showcase target for JWST early in the telescope's life. So it…
ArticleWebb Found Signs of Water Ice in All Five Debris Disks It Surveyed
Point a telescope at a nearby star and, mostly, the star is all you get. The ring of rock, boulders and collision dust around it — the leftover scaffolding of planet building, the same kind of belt…
NewsGiant Exoplanets Are Late to Make Methane, JWST Spectra Show
Thirteen transiting giant exoplanets observed by JWST fall on the same color-magnitude sequence as free-floating brown dwarfs at similar temperatures, and the methane expected in the planets'…
NewsJWST Survey Catches Planet-Forming Disks Changing How They Lose Gas
Astronomers have mapped the jets and winds streaming away from 72 planet-forming disks and report that the outflows shift from molecular to atomic as the star draws in less material. The survey,…
NewsA Candidate Planet, Weighed by Its Reflected Light Alone
Astronomers have measured the mass and the size of a candidate planet that never passes in front of its star, working from the light it reflects. The result was published Aug. 25 in Astronomy &…
ArticleOne Cosmic Shoreline Becomes Two, and an Airless Valley Opens Between Them
Draw every known rocky planet on one chart, how hard its star bakes it, against how firmly its gravity holds on, and a line appears. Below the line, worlds keep an atmosphere. Above it, they are…
ArticleComets May Be Evaporating Around a Star Still Building Its Planets
The spectra had been sitting in a public archive for years, taken for someone else's project, a planet hunt at the European Southern Observatory in Chile. On night after night in the spring of 2018…
ArticleA Lava Planet Is Reflecting Three-Quarters of Its Starlight
Stand on the daylit side of TOI-561 b and there would be nothing underfoot but rock hot enough to run like water. It is a rocky planet a little larger than Earth, orbiting so close to its star that a…
ArticleThe Wobble-Hunters' Method That Found the First Exoplanet Is Now Chasing Moons
In 1995, two Swiss astronomers watched a star named 51 Pegasi lurch toward and away from Earth on a four-day beat, and read in that tiny rhythm the presence of an unseen planet. The wobble was the…
ArticleThe Planet That Is Leaking Its Air Into Space
For years, the search for atmospheres on rocky exoplanets has mostly returned bad news. The small worlds that orbit red dwarfs sit close to stars that flare hard and blast them with radiation, and…
NewsJWST's First Look at TRAPPIST-1 F Rules out a Hydrogen-Rich Atmosphere
The first JWST transit spectra of TRAPPIST-1 f rule out hydrogen- and helium-dominated atmospheres with surface pressures higher than about 20 millibars, at 95% confidence, a team led by Olivia Lim…