Posted on by Matt Williams

Astronomers Have Found a Star with a Hot Jupiter and a Cold Super Jupiter in Orbit

Artist's vision of a cold super-Jupiter in the HD 118203 system. It is an extremely massive gas planet orbiting its star in an orbit six times that of Earth. Credit: NCU/ Maciejewski, G. et al (2024)

Located in the constellation Ursa Major, roughly 300 light-years from Earth, is the Sun-like star HD 118203 (Liesma). In 2006, astronomers detected an exoplanet (HD 118203 b) similar in size and twice as massive as Jupiter that orbits very closely to Liesma (7% of the distance between Earth and the Sun), making it a “Hot Jupiter.” In a recent study, an international team of astronomers announced the detection of a second exoplanet in this system: a Super Jupiter with a wide orbit around its star. In short, they discovered a “Cold Super-Jupiter” in the outskirts of this system.

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Posted on by Brian Koberlein

Old Stars Don't Have Hot Jupiters

Hot Jupiters may not last long near Sun-like stars. Credit: NASA/JPL-Caltech

As we began to discover hundreds, then thousands of exoplanets, we found that there were two types of worlds unlike anything in our solar system. The first are super-Earths. These worlds straddle the line between large rocky worlds like Earth and small gas planets like Neptune. The second are hot Jupiters. Large gas giants that orbit their star in a matter of days. While there may be a super-Earth lurking at the outer edge of our solar system, we know our Sun has no hot Jupiters. This is a little surprising since close-orbiting gas giants seem to be fairly common. But a new study could explain why our solar system has no planet Vulcan.

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