About the image. Drawn as a banded giant with a glowing night side. The radius and temperature are measured. The iron rain is one interpretation of the data, not an observation of rain.
53×as wide as our Sun looks from Earth
4 100×the light Earth gets
Tidally locked: the star stays putNo ground: the view from the cloud tops
The sky from WASP-76b
WASP-76 would look 53× as wide as the Sun does from Earth, and the planet gets 4 100× as much light as Earth gets.
Its colour comes from its surface temperature of 6 329 K (6 060 °C); the Sun's is about 5 772 K (5 500 °C).
WASP-76b is tidally locked: one side always faces the star.
There are no sunrises. Where you stand decides where the star hangs, overhead on the day side, low at the edge, gone on the night side.
Apparent size = star radius ÷ orbit; light = size² × (temperature ÷ 5 772 K)⁴. Both from the values on this page. The landscape is imagined.
WASP-76b is an ultra-hot Jupiter: nearly twice as wide as Jupiter, a little lighter, and circling its star in under two days. One side always faces the star.
The iron rain story
In March 2020 a team led by David Ehrenreich reported neutral iron in the planet’s atmosphere and an odd asymmetry: iron seemed to be present where the hot dayside turns into night, but not where night turns back into day. Their explanation was dramatic. On the dayside, around 2 700 K (2 430 °C), iron evaporates; winds carry it to the night side, which is about a thousand degrees cooler, where it condenses into droplets. In other words, it rains iron.
The challenge
Two months later, Hubble data showed that the earlier spectrum had been contaminated by light from a nearby companion star. A revised model no longer needed neutral iron at all. By 2021 the debate had shifted again: the asymmetry could also come from temperature differences across the planet, and the existing data cannot cleanly tell the two explanations apart. A 2022 study found no clear sign of large-scale iron condensing on the night side.
So the honest answer is: maybe. It is still one of the best places to study weather on a world that hot. In 2024 researchers also suggested a “glory” effect, a rainbow-like halo of light, might explain a brightening at one edge of the planet. If confirmed, it would be the first one seen outside the Solar System.
Its orbit, to scale
WASP-76b goes around once every 1.8 days, at 0.033 AU from its star. The whole view is tiny on Solar System scale: Mercury orbits the Sun about 12 times farther out than the outermost orbit shown here.
WASP-76b: equilibrium temperature. Logarithmic scale from 100 K to 10 000 K. Reference values: NASA, IAU.
How long to get there?
WASP-76b is about 634 light-years away.
Light299 792 km/s634 years
Breakthrough Starshotplanned light sail, 20% of light speed3 170 years
Parker Solar Probefastest spacecraft so far, 192 km/s989 938 years
Voyager 1leaving the Solar System, 17 km/s11.2 million years
At Voyager 1's speed the trip would take about 139 756 human lifetimes of 80 years. Bars are on a logarithmic scale. Speeds: NASA, Breakthrough Initiatives.
Your weight on WASP-76b
On WASP-76b
Gravity there is about 0.66× Earth's, at the cloud tops; there is no surface. Calculated from the measured mass and radius.
Gallery
Artist's impressions rendered from the same model as the view at the top of this page.
Timeline
2016Discovered by the SuperWASP survey.
2020Iron rain is proposed in March; in May, Hubble shows the spectrum was contaminated by a companion star.
2021Temperature differences are shown to explain the data equally well.
2024A rainbow-like "glory" is suggested at one edge of the planet.
Questions people ask
Does it really rain iron on WASP-76b?
Possibly, but it is not established. The original evidence can also be explained by temperature differences across the planet, and current data cannot tell the two apart.
How hot is WASP-76b?
Its equilibrium temperature is about 2 230 K (1 960 °C), and its dayside has been measured at about 2 500 K (2 230 °C).
How big is WASP-76b?
About 1.85 times as wide as Jupiter but slightly less massive.