Exoplanet atmospheres Archives

September 13, 2023September 13, 2023 by Brian Koberlein

Has the First Biosignature Been Found on an Exoplanet?

Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity. Credit: Oleg Kuznetsov — Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity, and distant exoplanets might begin similarly. Credit: Oleg Kuznetsov

Recently I wrote about the discovery of a hycean world. A potentially habitable exoplanet with a deep warm ocean and thick, hydrogen-rich atmosphere. Such planets are thought to be somewhat common orbiting red dwarf stars, and they are an excellent candidate for life. While it’s an exciting discovery, buried in the research article was something even more exciting. Tentative evidence of a biosignature, hinting at the presence of life. You can guess which discovery started making headlines. But have astronomers really found life on another planet?

September 1, 2023September 1, 2023 by Brian Koberlein

If Earth Was an Exoplanet, JWST Would Know There's an Intelligent Civilization Here

Sunrise over the Gulf of Saint Lawrence. Credit: NASA's Earth Observatory

Yesterday I presented a rather pessimistic view about our chances of finding evidence of alien civilizations. That work focused on detecting physical structures on an alien planet, which would take an optical telescope array the size of Saturn’s orbit. Today I’ll talk about a more optimistic view, one which focuses not on physical structures, but the fingerprint of molecules in an alien atmosphere. It’s a task that is not only much easier, it’s something we could do now using the James Webb Space Telescope (JWST).

August 31, 2023September 1, 2023 by Laurence Tognetti

Astronomers Confirm First Exoplanet “Thermometer Molecule” that is Typically Used to Study Brown Dwarfs

Artist impression of "hot Jupiter" exoplanet, WASP-31 b. (Credit: ESA/Hubble & NASA)

A recent study published in The Astrophysical Journal Letters examines a rare alloy molecule known as chromium hydride (CrH) and its first-time confirmation on an exoplanet, in this case, WASP-31 b. Traditionally, CrH is only found in large quantities between 1,200 to 2,000 degrees Kelvin (926.85 to 1,726.85 degrees Celsius/1700 to 3,140 degrees Fahrenheit) and used to ascertain the temperature of cool stars and brown dwarfs. Therefore, astronomers like Dr. Laura Flagg in the Department of Astronomy and Carl Sagan Institute at Cornell University refer to CrH as a “thermometer for stars”.

July 28, 2023July 28, 2023 by Alan Boyle

How Will We the Find First Signs of Alien Life — and When?

Astronomers have detected thousands of planets, including dozens that are potentially habitable. To winnow them down, they need to understand their atmospheres and other factors. (NASA Illustration)

When will we find evidence for life beyond Earth? And where will that evidence be found? University of Arizona astronomer Chris Impey, the author of a book called “Worlds Without End,” is betting that the first evidence will come to light within the next decade or so.

But don’t expect to see little green men or pointy-eared Vulcans. And don’t expect to get radio signals from a far-off planetary system, as depicted in the 1992 movie “Contact.”

Instead, Impey expects that NASA’s James Webb Space Telescope — or one of the giant Earth-based telescopes that’s gearing up for observations — will detect the spectroscopic signature of biological activity in the atmosphere of a planet that’s light-years away from us.

“Spectroscopic data is not as appealing to the general public,” Impey admits in the latest episode of the Fiction Science podcast. “People like pictures, and so spectroscopy never gets its fair due in the general talk about astronomy or science, because it’s slightly more esoteric. But it is the tool of choice here.”

https://radiopublic.com/fiction-science-GAxyzK

June 16, 2023June 17, 2023 by Laurence Tognetti

This Hot Jupiter is Leaving a Swirling Tail of Helium in its Wake

Image from the computer simulation of HAT-P-32 b (bright dot left of star) leaving a trail of helium during its 2.2-day, clockwise orbit (dashed line). (Credit: M. MacLeod (Harvard-Smithsonian Center for Astrophysics) and A. Oklopčić (Anton Pannekoek Institute for Astronomy, University of Amsterdam)

In a recent study published in Science Advances, a team of researchers commissioned the Hobby-Eberly Telescope (HET), which is designed to study exoplanetary atmospheres, to examine how a “hot Jupiter” exoplanet is losing its helium atmosphere as it orbits its parent star, leaving tails of helium that extend approximately 25 times the diameter of the planet itself.

June 1, 2023June 1, 2023 by Evan Gough

JWST Scans an Ultra-Hot Jupiter’s Atmosphere

This artist's illustration shows WASP 18 b, a hot Super-Jupiter that orbits its star in less than one day. Image Credit: NASA, ESA, and G. Bacon (STScI).

When astronomers discovered WASP-18b in 2009, they uncovered one of the most unusual planets ever found. It’s ten times as massive as Jupiter is, it’s tidally locked to its Sun-like star, and it completes an orbit in less than one Earth day, about 23 hours.

Now astronomers have pointed the JWST and its powerful NIRSS instrument at the ultra-Hot Jupiter and mapped its extraordinary atmosphere.

May 12, 2023May 12, 2023 by Evan Gough

JWST Looks at the Atmosphere of a Stormy, Steamy Mini-Neptune

This artist’s concept depicts the planet GJ 1214 b, a “mini-Neptune” with what is likely a steamy, hazy atmosphere. A new study based on observations by NASA’s Webb telescope provides insight into this type of planet, the most common in the galaxy. Credit: NASA/JPL-Caltech/R. Hurt (IPAC)

Just because there’s no Mini-Neptune in our Solar System doesn’t mean they’re not common. They appear to be widespread throughout the Milky Way, and according to NASA, are the most common exoplanet type. GJ 1214 b is one of them.

May 3, 2023May 3, 2023 by Matt Williams

JWST Tries to Untangle the Signals of Water. Is it Coming From the Planet or the Star?

This artist concept represents the rocky exoplanet GJ 486 b. Credits: NASA, ESA, CSA, Joseph Olmsted (STScI)

The number of known extrasolar planets has exploded in the past few decades, with 5,338 confirmed planets in 4,001 systems (and another 9,443 awaiting confirmation). When it comes to “Earth-like” planets (aka. rocky), the most likely place to find them is in orbit around M-type red dwarf stars. These account for between 75 and 80% of all stars in the known Universe, are several times smaller than the Sun and are quite cool and dim by comparison. They are also prone to flare activity and have very tight Habitable Zones (HZs), meaning that planets must orbit very closely to get enough heat and radiation.

In addition, red dwarfs are highly-active when they are young, exposing planets in their HZs to lots of ultraviolet and X-ray radiation. As such, whether planets orbiting these stars can maintain or reestablish their atmospheres over time is an open question. Using the James Webb Space Telescope (JWST), researchers from the Space Telescope Science Institute (STScI) observed an exoplanet known as GJ 486 b. As they stated in a recent study, the team detected traces of water vapor, though it is unclear if the signal was coming from the planet or its parent star.

March 27, 2023March 27, 2023 by Nancy Atkinson

Finally, JWST's Data on the First TRAPPIST-1 Planet. Survey Says? It Sucks

This illustration shows what the hot rocky exoplanet TRAPPIST-1 b could look like. A new method can help determine what rocky exoplanets might have large reservoirs of subsurface water. Credits: NASA, ESA, CSA, J. Olmsted (STScI)

With the James Webb Space Telescope’s ability to detect and study the atmospheres of distant planets orbiting other stars, exoplanet enthusiasts have been anticipating JWST’s first data on some of the worlds in the famous TRAPPIST-1 system. This is the system where seven Earth-sized worlds are orbiting a red dwarf star, with several in the habitable zone.

Today, a new study was released on the innermost planet in the system, TRAPPIST-1 b. The authors of the study were quite frank: this world very likely has no atmosphere at all. Additionally, the conditions there for possible life as we know it only get worse from there.

February 8, 2023February 9, 2023 by Laurence Tognetti

Astronomers still scratching their heads over population of ocean-world exoplanets

Artist rendition of a potential water-world exoplanet that might support advanced civilizations. Such life could advertise its existence via technosignatures from industrial or other activities. (Credit: ESA / Hubble / M. Kornmesser) — Artist rendition of a potential water-world exoplanet that might support life. Scientists could determine whether to explore this world based on its planetary entropy production. (Credit: ESA / Hubble / M. Kornmesser)

In a recent study submitted to The Astrophysical Journal Letters, an international team of researchers led by the University of California, Los Angeles (UCLA) examine the potential for water-worlds around M-dwarf stars. Water-worlds, also known as ocean worlds, are planets that possess bodies of liquid water either directly on its surface, such as Earth, or somewhere beneath it, such as Jupiter’s moon, Europa and Saturn’s moon, Enceladus.