ZTF J1828+2308 b: A Year In 2.7 Hours
Gas giant around ZTF J1828+2308
It is 0.99 times Jupiter's radius, closest in size to Jupiter, and 6356.6 times Earth's mass. A year there lasts 2.7 hours. The host star ZTF J1828+2308 runs at 15900 K with 0.61 times the Sun's mass.
2.7hours: one full year, start to finish
Radius
11.13 Earth radii
Mass
6356.6 Earth masses
One year
2.7 hours
Host star
ZTF J1828+2308 at 15900 K
Distance
658 light-years
Starlight blocked
6054.236% at each transit
What has been measured here and what has not
A size. Yes.
A mass. Yes.
A density, which decides rock or gas. No.
How far out it orbits. No.
A measured temperature rather than a derived one. No.
The shape of the orbit. No.
What the transit gives
Block a known fraction of a known star and you have measured a width.
Found by Zwicky Transient Facility in 2025.
The size came from a crossing, the mass did not. That pairing is uncommon and it is what lets anyone say whether this is rock or gas.
