Exoplanets Archives

October 10, 2024October 10, 2024 by Mark Thompson

A New Way to Detect Rocky Exoplanet Atmospheres

University of Chicago astronomers have tested a simpler, and more accurate way to determine whether or not exoplanets have atmospheres, a leap in learning more about the potential habitability of far-away planets. Above, an artist’s rendering of what terrestrial exoplanet GJ 1132 b may look like.

The total number of exoplanets discovered to date totals 5,288. Among them are a host of rocky, Earth-like exoplanets but none of them seem to have atmospheres. It’s a fairly challenging observation to make but a team of researchers think they’ve come up with a new, simpler technique. It involves measuring the combined temperature of a star and the exoplanet just before the planet passes behind. If it’s lower than expected, the planet is likely to have an atmosphere regulating its temperature!

October 2, 2024October 2, 2024 by Brian Koberlein

Bernard's Star Has a Planet (Again)!

This artist’s impression shows Barnard b, a sub-Earth-mass planet that was discovered orbiting Barnard’s star. Credit: ESO/M. Kornmesser

The thing about exoplanets is that astronomers don’t see them the way most people think they do. Part of the reason for that is the way we announce them. Whenever an interesting exoplanet is discovered, the press release usually has colorful artwork showing oceans, mountains, and clouds. Something visually captivating like the image above. But the reality is that we have only imaged a few exoplanets directly, and even then, they appear only as small fuzzy blobs. Most of the known exoplanets were discovered by the transit method, where the star dims slightly as the planet passes in front of it. So what astronomers actually see is a periodic flickering of starlight.

October 1, 2024October 2, 2024 by Matt Williams

An Earth-like Planet Around a Dead Sun Provides Some Reassurance About the Future of Earth

Astronomers have discovered a distant white dwarf with an Earth-like planet in an orbit just beyond where Mars is in our solar system. Earth could end up in such an orbit circling a white dwarf in about 8 billion years, if, like this exoplanet, it can survive the sun's red giant phase on its way to becoming a white dwarf. Credit: Adam Makarenko

In about five billion years, our Sun will exit its main sequence phase and transition to its red giant phase. At this point, the Sun will expand and consume the planets of the inner Solar System, including Mercury and Venus. What will become of Earth when this happens has been the subject of debate for many decades. But with the recent explosion in exoplanet discoveries, 5,759 confirmed in 4,305 systems so far, astronomers hope to learn more about how planets fare as their stars near the end of their life cycle.

Using the 10-meter telescope at the Keck Observatory in Hawaii, an international team of astronomers discovered an Earth-like planet orbiting a white dwarf star 4,000 light-years from Earth. This planet orbits its star, about half the mass of our Sun, at a distance roughly twice that of the Earth today. The system resembles what is expected to become of our system once the Sun has exhausted the last of its fuel and sheds its outer layers. It also offers some assurances that Earth will survive the Sun becoming a red giant and exploding in a supernova.

October 1, 2024October 1, 2024 by Laurence Tognetti

We Don’t See Many Planets in Old Triple Star Systems

Example of a triple star system. (Credit: Caltech/R. Hurt (Infrared Processing and Analysis Center, or IPAC)

Why is it important to search for exoplanets in triple star systems and how many can we find there? This is what a recent study accepted by Astrophysics & Space Science hopes to address as a pair of researchers from the University of Texas at Arlington investigated the statistical likelihood of triple star systems hosting exoplanets. This study holds the potential to help researchers better understand the formation and evolution of triple star systems and whether they are suitable to find life as we know it.

September 27, 2024September 27, 2024 by Mark Thompson

Astronomers Find a Strange Lopsided Planet

Artist's illustration of the exoplanet WASP-107 b based on transit observations from NASA's James Webb Space Telescope as well as other space- and ground-based telescopes, led by Matthew Murphy of the University of Arizona and a team of researchers around the world.

I’ve often stated that planets come in a wide range of sizes but rarely do I find myself stating they come in a wide range of shapes too! The discovery of WASP-107b is a case in point since this planet is the size of Jupiter but only a tenth of its mass. But there’s more… Using the James Webb Space Telescope a team of astronomers have accurately identified that the planet has an east-west asymmetry in its atmosphere, in other words, it’s lopsided. It is tidally locked to the star and on one side, the atmosphere seems to be inflated compared to the other.

September 25, 2024September 25, 2024 by Brian Koberlein

Biosignatures Can be Made in the Lab. No Life Needed.

The most likely way we will discover life on a distant exoplanet is by discovering a biosignature. This can be done by looking at the atmospheric spectra of a world to discover the spectral pattern of a molecule that can only be created through biological processes. While it sounds straightforward it isn’t. The presence of simple molecules such as water and oxygen don’t prove life exists on a planet. It’s true that Earth’s atmosphere is oxygen rich thanks to life, but geological activity can also produce large quantities of oxygen. And as a new study shows, some molecules we’ve long thought to be biological in origin may not be.

September 20, 2024September 20, 2024 by Brian Koberlein

Could Stars Hotter Than the Sun Still Support Life?

A comparison of typical sizes of main sequence stellar classes. Credit: NASA’s Goddard Space Flight Center

Although most potentially habitable worlds orbit red dwarf stars, we know larger and brighter stars can harbor life. One yellow dwarf star, for example is known to have a planet teaming with life, perhaps even intelligent life. But how large and bright can a star be and still have an inhabited world? That is the question addressed in a recent article in the Astrophysical Journal.

September 19, 2024September 19, 2024 by Brian Koberlein

Exoplanets Could be Hiding Their Atmospheres

Illustration of the tidally locked world TRAPPIST-1f. Credit: NASA/JPL-Caltech

Most of the exoplanets we’ve discovered orbit red dwarf stars. This isn’t because red dwarfs are somehow special, simply that they are common. About 75% of the stars in the Milky Way are red dwarfs, so you would expect red dwarf planets to be the most abundant. This also means that most habitable worlds are going to orbit these small, cool stars, and that has some significant consequences for our search for life.

September 9, 2024September 9, 2024 by Mark Thompson

Iron Winds are Blowing on WASP-76 b

WASP-76 b has been the subject of numerous studies since its discovery in 2013. The temperature there reaches 2,400 degrees Celsius. © Tania Cunha (Planetário do Porto - Centro Ciência Viva/Instituto de Astrofísica e Ciências do Espaço)

Exoplanets have been discovered with a wide range of environmental conditions. WASP-76b is one of the most extreme with a dayside temperature of over 2,000 degrees. A team of researchers have found that it’s even more bizarre than first thought! It’s tidally locked to its host star so intense winds encircle the planet. They contain high quantities of iron atoms that stream from the lower to upper layers around the atmosphere.

September 7, 2024September 7, 2024 by Carolyn Collins Petersen

There’s More Water Inside Planets Than We Thought

Planets with magma oceans like this one, GJ 1214b, could have most of their water beneath the surface, deep in their interiors. Image: NASA/JPL-Caltech/R. Hurt

When you walk across your lawn or down the street, you move on the surface of a surprisingly layered world. Some of those layers are rock, others are molten. A surprising amount of water is mixed into those layers, as well. It turns out that most planets have more of it “deep down” than we imagined.