Giant planets live in the suburbs (earthsky.org)

[eppur_se_muova]

Posted by
Kelly Kizer Whitt
June 4, 2021

Our solar system is normal

In late May 2021, astronomers released new results in a 30-year census of planetary systems beyond our own. The results show that most are arranged much like our solar system. That is, most giant exoplanets aren’t close to their parent stars, but instead live in the suburbs of their systems. That’s contrary to what astronomers thought when first discovering giant exoplanets in the 1990s. For awhile, they thought hot Jupiters – giant planets close to their stars – might be the norm. Now the California Legacy Survey, which began in the 1990s, has proven otherwise. The newly released census results describe our solar system as “normal.” Or, as astronomer Andrew Howard of Caltech said in a statement:

We’re starting to see patterns in other planetary systems that make our solar system look a bit more familiar.

The results were published on May 25, 2021, in two studies (here and here) in the peer-reviewed Astrophysical Journal Supplement.

Our solar system is arranged with the rocky, terrestrial planets closest to our sun and the gas giant planets farther out. Astronomers typically speak of distances in planetary systems in astronomical units (AU). One AU is the same as Earth’s distance from the sun, or 93 million miles (150 million km). Jupiter lies 5 AU from our sun. Saturn lies 9 AU from our sun. The survey showed that giant exoplanets mostly live within 1 and 10 AU from their parent stars.

Giant planets have a big impact on the formation of their planetary systems. Astronomer Lauren Weiss of the University of Hawaii Institute for Astronomy commented:

Dynamically speaking, Jupiter and Saturn are the VIPs – Very Important Planets – of the solar system. They are thought to have shaped the assembly of the terrestrial planets, potentially stunting the growth of Mars and slingshotting water-bearing comets toward Earth.

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https://earthsky.org/space/giant-planets-live-suburbs-exoplanets/?utm_source=EarthSky+News

[brush]

1. And the close in planets are most likely not to have moons as the more powerful...

Last edited Sat Jun 5, 2021, 03:31 AM - Edit history (2)

gravitational pull of the parent star outweighs the gravitational pull of smaller, close in planets to hold onto any moon, like in our solar system. Earth, father away than Mercury and Venus has only one moon while even Mars, smaller than Earth but farther from the Sun, has two. And of course the big gas giants farther out and with powerful gravity to hold onto moons, all have many moons.