![ZTF J1230-2655 b: A Year In 5.7 Hours](https://cdn.slatesource.com/6/7/b/67bd8d58-e02e-4f04-af7d-c47726f2c3d9.webp)

# ZTF J1230-2655 b: A Year In 5.7 Hours

- [Made in Slatesource](https://slatesource.com/@steph/ztf-j1230-2655-b-a-year-in-5-7-hours)
- By [Steph](https://slatesource.com/@steph)
- Created on Sep 19, 2026

## Gas giant around ZTF J1230-2655

It is 1.23 times Jupiter's radius, closest in size to Jupiter, and 7024.0 times Earth's mass. A year there lasts 5.7 hours. The host star ZTF J1230-2655 runs at 10000 K with 0.65 times the Sun's mass.

**5.7** hours: one full year, start to finish

Radius

13.79 Earth radii

Mass

7024.0 Earth masses

One year

5.7 hours

Host star

ZTF J1230-2655 at 10000 K

Distance

609 light-years

Starlight blocked

10536.672% at each transit

Known and unknown, as the archive has it

0%

A size. Yes.

A measured mass. Yes.

A density, the one clue to composition. No.

How far out it orbits. No.

A measured temperature rather than a derived one. No.

An eccentricity, so we know if the orbit is a circle. No.

What a crossing measures

The depth of the dip is the ratio of the two discs, so the radius follows.

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.

Found by Zwicky Transient Facility in 2025.

[NASA Exoplanet Archive: the full record for ZTF J1230-2655 b](https://exoplanetarchive.ipac.caltech.edu/overview/ZTF%20J1230-2655%20b?utm_source=slatesource)