exoplanets Archives

November 22, 2019November 26, 2019 by Matt Williams

Of the Two Stars in Alpha Centauri, One is Probably More Habitable than the Other

Artist's impression of a hypothetical planet orbiting the star Alpha Centauri B, a member of the triple star system that is the closest to Earth. Credit: ESO

In the past, the number of known exoplanets has exploded, with 4093 confirmed detections so far (and another 4,727 candidates awaiting confirmation). With the discovery of so many planets that are dozens, hundreds, or even thousands of light years away, a great deal of attention has understandably been directed to our nearest stellar neighbors. Could planets be right next door, with the possibility of life being there as well?

While a potentially-habitable planet was recently discovered around Proxima Centauri (Proxima b), Alpha Centauri remains something of a question mark. But thanks to a recent study from the Georgia Institute of Technology (GIT), we might be getting closer to determining if this neighboring system supports life. In a twist, the study revealed that one of the stars in the binary system is more likely to be habitable than the other.

November 18, 2019November 18, 2019 by Brian Koberlein

How Large Can A Planet Be?

How big can a planet be? Credit: NASA/JPL-Caltech

Jupiter is the largest planet in the solar system. In terms of mass, Jupiter towers over the other planets. If you were to gather all the other planets together into a single mass, Jupiter would still be 2.5 times more massive. It is hard to understate just how huge Jupiter is. But as we’ve discovered thousands of exoplanets in recent decades, it raises an interesting question about how Jupiter compares. Put another way, just how large can a planet be? The answer is more subtle than you might think.

November 15, 2019November 15, 2019 by Evan Gough

Tatooines everywhere? Many of the Exoplanets Already Discovered are in Multi-Star Systems

These images show some of the exoplanet host stars with companion stars (B, C) that were found during the project. The images are RGB composite images taken with the Panoramic Survey Telescope and Rapid Response System (PanSTARRS) in the y- (960 nm), i- (760 nm), and g-band (480 nm). The image in the middle shows a hierarchical triple star system. Image: Mugrauer, PanSTARRS

Right now, we know of about 4,000 confirmed exoplanets, mostly thanks to the Kepler mission. TESS, the Transiting Exoplanet Survey Satellite, will likely raise that 4000 by a lot. But what about the stars that all of these planets orbit?

A new study from the Astrophysical Institute and University Observatory of the University of Jena identified over 200 exoplanets that exist in multiple star systems. The study is part of the effort to understand how host stars shape the formation and evolution of planets.

November 8, 2019November 8, 2019 by Matt Williams

TESS Has Now Captured Almost the Entire Southern Sky. Here’s a Mosaic Made of 15,347 Photographs

On April 18th, 2018, NASA’s Transitting Exoplanet Survey Satellite (TESS) took to space for the first time. By August, it began capturing the light curves of distant stars for signs of planetary transits, effectively picking up where the Kepler Space Telescope left off. Now, just a few months away from the end of its primary mission, NASA has put a year’s worth of images of the southern sky together to create the beautiful mosaic you see here.

November 5, 2019November 5, 2019 by Evan Gough

It Seems Impossible, But Somehow This Planet Survived its Star’s Red Giant Phase

An artists's illustration of TESS, the Transiting Exoplanet Survey Satellite. Image Credit: NASA

Astronomers working with TESS (Transiting Exoplanet Survey Satellite) data have found a planet where it shouldn’t be: in the space recently filled by its host star when it was a red giant.

October 28, 2019October 28, 2019 by Evan Gough

Astronomers See the Wreckage from a Collision Between Exoplanets

RArtist’s concept illustrating a catastrophic collision between two rocky exoplanets in the planetary system BD +20 307, turning both into dusty debris. Credits: NASA/SOFIA/Lynette Cook

The history of our Solar System is punctuated with collisions. Collisions helped create the terrestrial planets and end the reign of the dinosaurs. And a massive collision between Earth and an ancient body named Theia likely created the Moon.

Now astronomers have found of evidence of a collision between two exoplanets in a distant solar system.

October 15, 2019October 15, 2019 by Evan Gough

Planet Sizes Matter for Habitability Too.

In order to be considered habitable, a planet needs to have liquid water. Cells, the smallest unit of life, need water to carry out their functions. For liquid water to exist, the temperature of the planet needs to be right. But how about the size of the planet?

Without sufficient mass a planet won’t have enough gravity to hold onto its water. A new study tries to understand how size affects the ability of a planet to hold onto its water, and as a result, its habitability.

October 1, 2019October 1, 2019 by Evan Gough

A Red Dwarf Star Has a Jupiter-Like Planet. So Massive it Shouldn’t Exist, and Yet, There It Is

Artist's illustration of the newfound gas-giant planet GJ 3512b, which circles a red dwarf star. (Image credit: Guillem Anglada-Escude—IEEC/Science-wave, using SpaceEngine.org (CC BY 4.0))

Thanks to the Kepler mission and other efforts to find exoplanets, we’ve learned a lot about the exoplanet population. We know that we’re likely to find super-Earths and Neptune-mass exoplanets orbiting low-mass stars, while larger planets are found around more massive stars. This lines up well with the core accretion theory of planetary formation.

But not all of our observations comply with that theory. The discovery of a Jupiter-like planet orbiting a small red dwarf means our understanding of planetary formation might not be as clear as we thought. A second theory of planetary formation, called the disk instability theory, might explain this surprising discovery.

September 23, 2019September 23, 2019 by Fraser Cain

Better Than Earth? Are There Superhabitable Worlds In The Milky Way?

NASA visualization of ocean currents. Credit: NASA/SVS

I’ve said many times in the past that the Earth is the best planet in the Universe. No matter where we go, we’ll never find a planet that’s a better home to Earth life than Earth. Of course, that’s because we, and all other Earth life evolved in this environment. Evolution adapted us to this planet, and it’s unlikely we could ever find another planet this good for us.

However, is it the best planet? Are there places in the Universe which might have the conditions for more diversity of life?

September 11, 2019September 11, 2019 by Evan Gough

Water Discovered in the Atmosphere of an Exoplanet in the Habitable zone. It Might Be Rain

An artist's concept of K2-18b, a super-Earth exoplanet that could support life. But, not all habitable planets are pale blue dots. Some are dry and yellow. Courtesy STScI

Astronomers using the Hubble space telescope have discovered water in the atmosphere of an exoplanet in its star’s habitable zone. If confirmed, it will be the first time we’ve detected water—a critical ingredient for life as we know it—on an exoplanet. The water was detected as vapour in the atmosphere, but the temperature of the planet means it could sustain liquid water on its surface, if it’s rocky.