exoplanets Archives

March 31, 2022March 31, 2022 by Evan Gough

It’s Not Conclusive, But Methane is Probably the Best Sign of Life on Exoplanets

Illustration of Kepler-186f, a recently-discovered, possibly Earthlike exoplanet that could be a host to life. Scientists could use this one or one like it to measure planetary entropy production as a prelude to exploration. (NASA Ames, SETI Institute, JPL-Caltech, T. Pyle)

When the James Webb Space Telescope aims at exoplanet atmospheres, it’ll use spectroscopy to identify chemical elements. One of the things it’s looking for is methane, a chemical compound that can indicate the presence of life.

Methane is a compelling biosignature. Finding a large amount of methane in an exoplanet’s atmosphere might be our most reliable indication that life’s at work there. There are abiotic sources of methane, but for the most part, methane comes from life.

But to understand methane as a potential biosignature, we need to understand it in a planetary context. A new research letter aims to do that.

March 21, 2022March 21, 2022 by Evan Gough

Dust Might Reveal the Presence of Habitable Planets

Artist's conceptualization of the dusty TYC 8241 2652 system as it might have appeared several years ago when it was emitting large amounts of excess infrared radiation. Credit: Gemini Observatory/AURA artwork by Lynette Cook. https://www.gemini.edu/node/11836

NASA’s next great space telescope should launch no later than 2027. The Nancy Grace Roman Space Telescope is a powerful wide-field infrared telescope that will create panoramic fields of view 100 times greater than Hubble’s. The Roman Telescope has a variety of scientific objectives, and one of its jobs is to complete a census of exoplanets to answer questions around habitability.

A new study shows how the Roman Space Telescope can measure the dust in distant solar systems to help find habitable planets.

March 15, 2022March 15, 2022 by Evan Gough

Smaller, Ground-Based Telescopes can Study Exoplanet Atmospheres too

An artist's illustration of exoplanet Kelt-9b. Image Credit: NASA/JPL-Caltech

The next step to understanding exoplanets is to understand their atmospheres better. Astronomers can determine a planet’s mass, density, and other physical characteristics fairly routinely. But characterizing their atmospheres is more complicated.

Astronomers have had some success studying exoplanet atmospheres, and spacecraft like the James Webb Space Telescope and the ESA’s ARIEL mission will help a lot. But there are thousands of confirmed exoplanets with many more to come, and the Webb has many demands on its time.

Can smaller, ground-based telescopes play a role in understanding exoplanet atmospheres?

March 14, 2022March 14, 2022 by Evan Gough

Planets Have Just Started to Form in This Binary System

Binary stars are common and imaging their planets will be a challenge. How can astronomers block all that light so they can see the planets? This artist's illustration shows the eclipsing binary star Kepler 16, as seen from the surface of an exoplanet in the system. Image Credit: NASA

Astronomers have watched the young binary star system SVS 13 for decades. Astronomers don’t know much about how planets form around proto-binary stars like SVS 13, and the earliest stages are especially mysterious. A new study based on three decades of research reveals three potentially planet-forming disks around the binary star.

March 4, 2022March 4, 2022 by Evan Gough

Astronomers Scan 800 Pulsars to See If Any of Them Have Planets

Lich (PSR B1257+12) is a pulsar 2,300 ly away in the constellation of Virgo - 20 km in diameter, formed 2 billion years ago by two white dwarfs merging with each other - Has three known planets, named Draugr, Poltergeist and Phobetor - Both the first extrasolar planets and the first pulsar planets to be discovered - Draugr is the lowest-mass planet yet discovered by any observational technique (twice the mass of Earth's moon.) Image Credit: By Pablo Carlos Budassi - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=94333766

Astronomers discovered the first exoplanets in 1992. They found a pair of them orbiting the pulsar PSR B1257+12 about 2300 light-years from the Sun. Two years later they discovered the third planet in the system.

Now a team of astronomers are trying to duplicate that feat by searching 800 known pulsars for exoplanets.

February 24, 2022February 24, 2022 by Evan Gough

Mini-Neptunes can Lose gas and Turn Into Super-Earths

An artist's illustration of the mini-Neptune TOI 560.01 losing its atmosphere and transitioning to a super-Earth. Image Credit: Image Credit: Adam Makarenko (Keck Observatory)

Can one type of planet become another? Can a mini-Neptune lose its atmosphere and become a super-Earth? Astronomers have found two examples of mini-Neptunes transitioning to super-Earths, and the discovery might help explain a noted “gap” in the size distribution of exoplanets.

February 15, 2022 by Evan Gough

Planet Found in the Habitable Zone of a White Dwarf

An artist’s impression of the white dwarf star WD1054–226 orbited by clouds of planetary debris and a major planet in the habitable zone. Credit Mark A. Garlick / markgarlick.com Licence type Attribution (CC BY 4.0)

Most stars will end their lives as white dwarfs. White dwarfs are the remnant cores of once-luminous stars like our Sun, but they’ve left their lives of fusion behind and no longer generate heat. They’re destined to glow with only their residual energy for billions of years before they eventually fade to black.

Could life eke out an existence on a planet huddled up to one of these fading spectres?

February 14, 2022February 14, 2022 by Brian Koberlein

Astronomers see Dead Planets Crashing Into Dead Stars

Artist’s impression of a white dwarf accreting planetary material from a circumstellar debris disk. Credit: University of Warwick/Mark Garlick

When our Sun dies, the Earth will die with it. As a star of middling mass, the Sun will end its life by swelling into a red giant star. After a last cosmic moment of brilliance, the remnant core of the Sun will collapse into a white dwarf. This won’t occur for billions of years, but the mass and composition of the Sun means a white dwarf is its inevitable fate.

February 12, 2022February 12, 2022 by Matt Williams

A THIRD Planet Found Orbiting Nearby Proxima Centauri

This artist’s impression shows Proxima d, a planet candidate recently found orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The planet is believed to be rocky and to have a mass about a quarter that of Earth. Two other planets known to orbit Proxima Centauri are visible in the image too: Proxima b, a planet with about the same mass as Earth that orbits the star every 11 days and is within the habitable zone, and candidate Proxima c, which is on a longer five-year orbit around the star.

In August of 2016, astronomers with the European Southern Observatory (ESO) announced that they had discovered an exoplanet orbiting in neighboring Proxima Centauri. Based on Radial Velocity measurements (aka. Doppler Photometry), the discovery team estimated that the planet was roughly the same size and mass as Earth and orbited with Proxima Centauri’s Circumsolar Habitable Zone (HZ). In 2020, this planet was confirmed by follow-up observations.

In that same year, a second exoplanet (Proxima c) roughly seven times the mass of Earth (a Super-Earth or mini-Neptune) was confirmed. As if that wasn’t enough, an international team of astronomers with the ESO recently announced that they detected a third exoplanet around Proxima Centauri – Proxima d! This Mars-sized planet orbits about halfway between its host star and Proxima b and is one of the lightest exoplanets ever discovered.

February 11, 2022February 11, 2022 by Matt Williams

Astronomers Measure the Layers of an Exoplanet's Atmosphere

An artist's conception of the hot Jupiter WASP-79b. (Image credit: NASA)

The number of planets discovered beyond our Solar System has grown exponentially in the past twenty years, with 4,919 confirmed exoplanets (and another 8,493 awaiting confirmation)! Combined with improved instruments and data analysis, the field of study is entering into an exciting new phase. In short, the focus is shifting from discovery to characterization, where astronomers can place greater constraints on potential habitability.

In particular, the characterization of exoplanet atmospheres will allow astronomers to determine their chemical makeup and whether they have the right characteristics to support life. In a new study led by the University of Lund, an international team of researchers characterized the atmosphere of one of the most extreme exoplanets yet discovered. This included discerning what could be several distinct layers that have particular characteristics.