Nav: Home

Exoplanet interiors have Earth-like geochemistry

October 17, 2019

The interiors of some exoplanets have Earth-like geochemistry, according to a new study, which finds that extrasolar rocks share similar levels of oxidation, or oxygen fugacity, to those in the Solar System. The results suggest that some of the rocky exoplanets orbiting distant stars have similar internal properties to Earth and Mars. Alexandra Doyle and colleagues were able to probe the geochemistry of distant rocks by evaluating their elemental remains, imprinted in the atmospheres of white dwarfs after rocky bodies crashed into them. Most rocky materials in the Solar System have a high degree of oxidation, known as oxygen fugacity (fO2), which reflects conditions during the earliest stages of protoplanetary rock formation around the Sun. fO2 influences a planet's overall geochemical and geophysical properties - including the composition of any atmosphere it produces. However, determining these properties in exoplanets is both difficult and often unreliable, so it has been uncertain whether the same processes which oxidized planet-forming material in our Solar System occurred elsewhere, in solar systems around other stars. A white dwarf (WD) is the dense, exhausted core of a dead star; due to its strong gravitational pull, WD surface atmospheres should be composed almost entirely of the lightest elements, hydrogen and helium. However, some WDs have been identified with atmospheres "polluted" by heavier elements, including magnesium, iron and oxygen, introduced by rocky exoplanets and asteroids that have crashed into the WD. Spectroscopic observations of six polluted WDs allowed Doyle et al. to measure the constituent elements of these extrasolar rocks and to determine the abundance of oxidized iron within the rocks. The results probe the bulk composition of the former exoplanets, including their interiors. They find that rocky bodies that once orbited these long-dead stars had high fO2, similar to Earth, Mars and the asteroids in our Solar System, but unlike Mercury.
-end-


American Association for the Advancement of Science

Related Solar System Articles:

Pressure runs high at edge of solar system
Out at the boundary of our solar system, pressure runs high.
What a dying star's ashes tell us about the birth of our solar system
A UA-led team of researchers discovered a dust grain forged in a stellar explosion before our solar system was born.
What scientists found after sifting through dust in the solar system
Two recent studies report discoveries of dust rings in the inner solar system: a dust ring at Mercury's orbit, and a group of never-before-detected asteroids co-orbiting with Venus, supplying the dust in Venus' orbit.
Discovered: The most-distant solar system object ever observed
A team of astronomers has discovered the most-distant body ever observed in our solar system.
Discovery of the first body in the Solar System with an extrasolar origin
Asteroid 2015 BZ509 is the very first object in the Solar System shown to have an extrasolar origin.
First interstellar immigrant discovered in the solar system
A new study has discovered the first known permanent immigrant to our solar system.
A star disturbed the comets of the solar system in prehistory
About 70,000 years ago, when the human species was already on Earth, a small reddish star approached our solar system and gravitationally disturbed comets and asteroids.
Scientists detect comets outside our solar system
Scientists from MIT and other institutions, working closely with amateur astronomers, have spotted the dusty tails of six exocomets -- comets outside our solar system -- orbiting a faint star 800 light years from Earth.
Does the organic material of comets predate our solar system?
The Rosetta space probe discovered a large amount of organic material in the nucleus of comet 'Chury.' In an article published by MNRAS on Aug.
Tracking a solar eruption through the solar system
Ten spacecraft, from ESA's Venus Express to NASA's Voyager-2, felt the effect of a solar eruption as it washed through the solar system while three other satellites watched, providing a unique perspective on this space weather event.
More Solar System News and Solar System Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.