We Finally Know How Planets Like Jupiter and Saturn Become Giants

Wednesday, 29 November 2017 - 1:57PM
Wednesday, 29 November 2017 - 1:57PM
We Finally Know How Planets Like Jupiter and Saturn Become Giants
Image credit: NASA
We just solved one of the greatest mysteries in the universe. We finally know how planets like Jupiter and Saturn become giants.

In a landmark discovery, a group of University of Hawaii Institute for Astronomy researchers has learned that extrasolar planets are big and puffy because their home stars may be giving them boosts.
If you follow the continuing search by scientists for new planets outside our Solar System, you may have noticed that since the first subjects were discovered in the 1990s, many are reported to be super-large gas giants, which are sometimes referred to as "Jupiters," after our system's biggest planetary resident—and those that travel close to their stars are known as "hot Jupiters."

Similar in mass to Jupiter and Saturn, the hot Jupiters tend to be much larger than their Sun-orbiting namesakes, with some puffing up to almost star-size.
Heat is believed to be the culprit behind this expansion, but science is still working out exactly how this all goes down. However, the Hawaii U researchers have proposed a theory that explains everything.

Using data from NASA's K2 exoplanet detection mission, focusing on hot Jupiters orbiting red giant stars, the researchers believe these red giants are expanding themselves, due to their upper age and decreasing years.

Inspired by a theory put forth by NASA researcher Eric Lopez that hot Jupiters orbiting red giant stars are probably inflating from direct energy garnered from the host stars, the University of Hawaii team has zeroed in on two such cases, with the planets orbiting approximately every nine days.
Observations indicate that these worlds, despite being having about half the mass of Jupiter, are actually 30 percent larger than Jupiter. "This suggests that the current sizes of these planets are directly correlated to their current irradiation," said lead researcher Samuel Grunblatt. "Further studies of planets around evolved stars are essential to confirm the planet re-inflation hypothesis."

Science has also found things work the other way around, as red giants may devour their orbiting planets instead.

We Finally Know How Planets Like Jupiter and Saturn Become Giants