Tag: Exoplanets

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Climate analysis checks for most livable exoplanets

TRAPPIST-1 planets
This illustration shows the seven Earth-size planets of TRAPPIST-1, an exoplanet system about 39 light-years away. The image shows the relative sizes of planets b through h, from left to right, but does not represent their orbits to scale. (NASA / JPL-Caltech Illustration)

If you had to pick a place to set up shop amid the seven planets in the TRAPPIST-1 star system, 39 light-years from Earth, the fourth rock from that alien sun is the best place to start.

That Earth-sized world, known as TRAPPIST-1 e, came out on top in a recent round of exoplanetary climate modeling, detailed in a paper published Nov. 1 by the Astrophysical Journal.

Not that anyone’s planning on setting up shop there soon: Unless there’s a breakthrough that allows us to travel at a significant fraction of the speed of light, it would take hundreds of thousands of years to get to TRAPPIST-1. But the climate modeling methods developed for the TRAPPIST-1 system could help scientists decide which planets to target first with telescopes capable of analyzing alien atmospheres.

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Scientists report super-Earth at Barnard’s Star

Barnard's Star b
An artist’s conception shows what the surface of the reported planet known as Barnard’s Star b might look like. (ESO Illustration / M. Kornmesser)

The astronomical team that found the nearest exoplanet at Proxima Centauri has done it again with the reported detection of a super-Earth orbiting Barnard’s Star, the second-closest star system to our own.

The discoverers acknowledge, however, that they’re not completely sure yet.

“After a very careful analysis, we are 99 percent confident that the planet is there,” Spanish astronomer Ignasi Ribas, lead author of a study about the detection published today by the journal Nature, said in a news release. “However, we’ll continue to observe this fast-moving star to exclude possible, but improbable, natural variations of the stellar brightness which could masquerade as a planet.”

Assuming it exists, Barnard’s Star b would be at least 3.2 times as massive as Earth, tracing a 233-Earth-day orbit. It would be as close to its parent star as Mercury is to our own sun — but because Barnard’s Star is a dim red dwarf, surface conditions would be far too chilly for life as we know it. The surface temperature would be about 275 degrees below zero Fahrenheit (-170 degrees Celsius).

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Planet-hunting Kepler telescope runs out of gas

Kepler space telescope
Stylized artwork shows NASA’s Kepler space telescope among planetary systems. (NASA Illustration / Wendy Stenzel / Daniel Rutter)

NASA’s Kepler planet-hunting telescope now belongs to the ages, with its fuel completely spent and its instruments shut down — but the planet quest continues, thanks to a treasure trove of downloaded data as well as a new generation of robotic planet-hunters.

Space agency officials declared the end of spacecraft operations today, nine and a half years after the car-sized probe was launched. The hydrazine fuel ran out about two weeks ago, signaled by a sharp drop in pressure readings for the propulsion system.

“In the end, we didn’t have a drop of fuel left over for anything else,” Charlie Sobeck, project system engineer at NASA’s Ames Research Center, said during a teleconference.

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Hubble boosts evidence for first exomoon

Kepler-1625b and moon transiting star
An artist’s impression shows the Jupiter-sized exoplanet Kepler-1625b transiting its parent star with the Neptune-sized candidate exomoon in tow. (Dan Durda Illustration)

With a lot of help from the Hubble Space Telescope, astronomers now feel confident enough to publish their evidence for the first moon detected in orbit around a planet beyond our solar system.

But they’re still not completely confident.

“At this point, it’s up to us to report what we’re seeing, hand it over to the community and let the community probe it,” said Columbia University astronomer Alex Teachey, one of the authors of a study about the find published in the open-access journal Science Advances. “If they see what we see, I expect some people will be convinced and other people will be skeptical. And that’s all part of the process.”

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TESS probe finds its first potential planets

TESS spacecraft
An artist’s conception shows NASA’s Transiting Exoplanet Survey Satellite, or TESS, with an alien sun and planet in the background. (NASA / GSFC Illustration)

Astronomers on the team for NASA’s Transiting Exoplanet Survey Satellite mission, or TESS, are reporting their first potential planet discoveries, just days after the spacecraft’s first science image was unveiled.

The first reported candidate planet was detected orbiting a star known as Pi Mensae, a sunlike yellow dwarf star nearly 60 light-years from Earth that was already known to harbor a world that’s more than 10 times as massive as Jupiter.

The newly detected prospect is closer to its parent star in the southern constellation Mensa, making a complete orbit every 6.3 Earth days.

In a paper published on the ArXiv pre-print website and submitted to the journal Astronomy & Astrophysics, the team’s scientists say Pi Mensae c appears to be about twice as wide as Earth and 4.5 times as massive.

Its density is estimated as roughly equal to water’s density, which suggests the planet is a super-Earth that “may have held on to a significant atmosphere,” the scientists say.

The second candidate planet orbits a red dwarf star known as LHS 3844, 49 light-years away in the constellation Indus. LHS 3844 b is thought to be a “hot Earth,” with a diameter about a third wider than Earth’s. It swings around its sun every 11 hours.

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Scientists spot planet orbiting Spock’s home star

Planet at HD 26965
An artist’s conception shows a super-Earth in orbit around HD 26965, which is Mr. Spock’s home star in “Star Trek” lore. (University of Florida Illustration)

Has the planet Vulcan been found? Vulcan’s most famous fictional inhabitant, Mr. Spock of “Star Trek” fame, would certainly raise an eyebrow if he heard that astronomers have detected a potentially habitable super-Earth orbiting the star that’s associated with him.

The world orbits a sunlike star that’s a mere 16 light-years away, known as HD 26965 or 40 Eridani A, according to the team behind the Dharma Planet Survey.

In the current Star Trek canon, 40 Eridani A is the star that harbors Spock’s home planet. Some early references pointed to a different star, known as Epsilon Eridani(which is also thought to host at least one exoplanet). But in a 1991 essay, Star Trek creator Gene Roddenberry and a group of astronomers argued that 40 Eridani A, the brightest star in a triple-star system, was a better fit because its 4 billion years of existence provided a wider window for pointy-eared intelligent life to evolve.

The latest findings suggest Roddenberry made the right choice: The planet found at 40 Eridani A is roughly twice Earth’s size, completes an orbit around its parent star every 42 Earth days, and lies just inside the star’s optimal habitable zone, said University of Florida astronomer Jian Ge.

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NASA unveils first science images from TESS probe

TESS images
NASA’s Transiting Exoplanet Survey Satellite, or TESS, captured this snapshot of the Large Magellanic Cloud (right) and the star R Doradus (left) with a single detector on one of its four wide-field cameras on Aug. 7. (NASA / MIT / TESS Photo)

The first science images from NASA’s Transiting Exoplanet Survey Satellite focus on a strip of southern sky that includes the two nearest dwarf galaxies and plenty of potential targets in the probe’s planet search.

“In a sea of stars brimming with new worlds, TESS is casting a wide net and will haul in a bounty of promising planets for further study,” Paul Hertz, astrophysics division director at NASA Headquarters, said today in a news release. “This ‘first light’ science image shows the capabilities of TESS’ cameras, and shows that the mission will realize its incredible potential in our search for another Earth.”

TESS was launched from Florida in April by a SpaceX Falcon 9 rocket, and the mission team has been spending the past few months getting the spacecraft ready for what’s expected to be a two-year mission.

The newly released imagery was captured by TESS’ four wide-field cameras during a 30-minute session on Aug. 7. The mosaic shows parts of a dozen constellations in the southern hemisphere, from Capricornus to Pictor.

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Planet-hunting space telescope wins vote of support

Telescope with starshade
An artist’s conception shows a planet-hunting space telescope accompanied by an umbrella-like starshade that blocks the glare of the planet’s parent star. (NASA / JPL Illustration)

NASA should add a large, technologically advanced space telescope to its lineup to capture direct images of Earthlike planets beyond our solar system, astronomers say in a congressionally mandated report issued today.

The report, published under the aegis of the National Academies of Sciences, Engineering and Medicine, also calls on the National Science Foundation to invest in the next-generation Giant Magellan Telescope and the Thirty Meter Telescope.

The GMT is being built in Chile, with completion set for 2025. The TMT is also due to go into service in the mid-2020s, although the current plan to build it on the top of Hawaii’s Mauna Kea volcano has run into controversy.

Authors of the report, led by Harvard’s David Charbonneau and Ohio State University’s B. Scott Gaudi, voiced support for two space telescopes already in the works — NASA’s James Webb Space Telescope and the Wide-Field Infrared Survey Telescope, or WFIRST. They also said NASA’s recently launched Transiting Exoplanet Survey Satellite, or TESS, would provide valuable information about Earth-size exoplanets as well.

But the report makes clear that the search for alien planets will have to focus down on direct images of planets, as well as detailed analysis of exoplanet atmospheres, in order to address questions about the existence of life beyond our solar system.

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Kepler probe suspends planet hunt to send data

Kepler space telescope
An artist’s conception shows NASA’s Kepler space telescope. (NASA / JPL-Caltech / STScI Illustration)

NASA has hit the pause button on observations by its most prolific planet-hunting probe, the Kepler space telescope, so that it can download 51 days’ worth science data without interruption. The reason? Kepler’s fuel tanks are close to empty. After the download, Kepler will resume data gathering — that is, assuming there’s any fuel left.

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NASA’s planet-hunting probe sends first test image

TESS test image
This test image from one of the four cameras aboard the Transiting Exoplanet Survey Satellite, or TESS, captures a swath of the southern sky along the plane of our galaxy. (NASA / MIT / TESS Photo)

One month after its launch, NASA’s Transiting Exoplanet Survey Satellite has sent back an initial test image that shows more than 200,000 stars in the southern sky.

TESS’ image was taken by one of its cameras with a two-second exposure. The picture is centered on the constellation Centaurus, with the edge of the dark Coalsack Nebula at upper right and the star Beta Centauri prominent along the lower edge.

The picture provides only a hint of what TESS will be seeing once it starts delivering science-quality images next month. When all four wide-field cameras are in operation, TESS’ images should cover more than 400 times as much of the sky.

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