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.

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Astronomers See the Wreckage from a Collision Between Exoplanets

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.

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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.

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

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.

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

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.

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One Year, Almost 1,000 Planetary Candidates. An Update On TESS

NASA’s Transiting Exoplanet Survey Telescope launched back in April, 2018. After a few months of testing, it was ready to begin mapping the southern sky, searching for planets orbiting stars relatively nearby.

We’re just over a year into the mission now, and on July 18th, TESS has shifted its attention to the Northern Hemisphere, continuing the hunt for planets in the northern skies.

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Snowball Exoplanets Might Be Better for Life Than We Thought

When astronomers discover a new exoplanet, one of the first considerations is if the planet is in the habitable zone, or outside of it. That label largely depends on whether or not the temperature of the planet allows liquid water. But of course it’s not that simple. A new study suggests that frozen, icy worlds with completely frozen oceans could actually have livable land areas that remain habitable.

The new study was published in the AGU’s Journal of Geophysical Research: Planets. It focuses on how CO2 cycles through a planet and how it affects the planet’s temperature. The title is “Habitable Snowballs: Temperate Land Conditions, Liquid Water, and Implications for CO2 Weathering.”

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NASA Promised More Smaller, Earth-size Exoplanets. TESS is Delivering.

When NASA launched TESS (Transiting Exoplanet Survey Satellite) in 2018, it had a specific goal. While its predecessor, the Kepler spacecraft, found thousands of exoplanets, many of them were massive gas giants. TESS was sent into space with a promise: to find smaller planets similar in size to Earth and Neptune, orbiting stable stars without much flaring. Those constraints, astronomers hoped, would identify more exoplanets that are potentially habitable.

With this discovery of three new exoplanets, TESS is fulfilling its promise.

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Here’s a First. Astronomers See a Moon Forming Around a Baby Exoplanet

Astronomers have discovered, for the first time, moons forming in the disk of debris around a large exoplanet. Astronomers have suspected for a long time that this is how larger planets—like Jupiter in our own Solar System—get their moons. It’s all happening around a very young star named PDS 70, about 370 light years away in the constellation Centaurus.

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