Extremely Hot Exoplanets Can Have Extreme Weather, Like Clouds of Aluminum Oxide and Titanium Rain

Thanks to the success of the Kepler mission, we know that there are multitudes of exoplanets of a type called “Hot Jupiters.” These are gas giants that orbit so close to their stars that they reach extremely high temperatures. They also have exotic atmospheres, and those atmospheres contain a lot of strangeness, like clouds made of aluminum oxide, and titanium rain.

A team of astronomers has created a cloud atlas for Hot Jupiters, detailing which type of clouds and atmospheres we’ll see when we observe different Hot Jupiters.

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What Are Some Clues to the Climates of Exoplanets?

In the past few decades, the number of planets discovered beyond our Solar System has grown exponentially. To date, a total of 4,158 exoplanets have been confirmed in 3,081 systems, with an additional 5,144 candidates awaiting confirmation. Thanks to the abundance of discoveries, astronomers have been transitioning in recent years from the process of discovery to the process of characterization.

In particular, astronomers are developing tools to assess which of these planets could harbor life. Recently, a team of astronomers from the Carl Sagan Institute (CSI) at Cornell University designed an environmental “decoder” based on the color of exoplanet surfaces and their hosts stars. In the future, this tool could be used by astronomers to determine which exoplanets are potentially-habitable and worthy of follow-up studies.

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This is an Actual Image of a Planet-Forming Disc in a Distant Star System

In 2017, astronomers used ALMA (Atacama Large Millimeter/sub-millimeter Array) to look at the star AB Aurigae. It’s a type of young star called a Herbig Ae star, and it’s less then 10 million years old. At that time, they found a dusty protoplanetary disk there, with tell-tale gaps indicating spiral arms.

Now they’ve taken another look, and found a very young planet forming there.

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Ocean Circulation Might Be the Key to Finding Habitable Exoplanets

Artist's depiction of a waterworld. A new study suggests that Earth is in a minority when it comes to planets, and that most habitable planets may be greater than 90% ocean. Credit: David A. Aguilar (CfA)

We’ve found thousands and thousands of exoplanets now. And spacecraft like TESS will likely find thousands and thousands more of them. But most exoplanets are gassy giants, molten hell-holes, or frozen wastes. How can we find those needles-in-the-haystack habitable worlds that may be out there? How can we narrow our search?

Well, first of all, we need to find water. Oceans, preferably, since that’s where life began on Earth. And according to a new study, those oceans need to circulate in particular ways to support life.

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Astronomers Are Sure These Are Two Newborn Planets Orbiting a Distant Star

Planet formation is a notoriously difficult thing to observe. Nascent planets are ensconced inside dusty wombs that resist our best observation efforts. But recently, astronomers have made progress in imaging these planetary newborns.

A new study presents the first-ever direct images of twin baby planets forming around their star.

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Worlds With Hydrogen in Their Atmospheres Could Be the Perfect Place to Search for Life

We’re waiting patiently for telescopes like the James Webb Space Telescope to see first light, and one of the reasons is its ability to study the atmospheres of exoplanets. The idea is to look for biosignatures: things like oxygen and methane. But a new study says that exoplanets with hydrogen in their atmospheres are a good place to seek out alien life.

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Rocky Planets Orbiting White Dwarf Stars Could be the Perfect Places to Search for Life

Some very powerful telescopes will see first light in the near future. One of them is the long-awaited James Webb Space Telescope (JWST.) One of JWST’s roles—and the role of the other upcoming ‘scopes as well—is to look for biosignatures in the atmospheres of exoplanets. Now a new study is showing that finding those biosignatures on exoplanets that orbit white dwarf stars might give us our best chance to find them.

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Astronomers Find a Six-Planet System Which Orbit in Lockstep With Each Other

Artist's concept of the TRAPPIST-1 star system, an ultra-cool dwarf that has seven Earth-size planets orbiting it. We're going to keep finding more and more solar systemsl like this, but we need observatories like WFIRST, with starshades, to understand the planets better. Credits: NASA/JPL-Caltech

To date, astronomers have confirmed the existence of 4,152 extrasolar planets in 3,077 star systems. While the majority of these discoveries involved a single planet, several hundred star systems were found to be multi-planetary. Systems that contain six planets or more, however, appear to be rarer, with only a dozen or so cases discovered so far.

This is what astronomers found after observing HD 158259, a Sun-like star located about 88 light-years from Earth, for the past seven years using the SOPHIE spectrograph. Combined with new data from the Transiting Exoplanet Space Satellite (TESS), an international team reported the discovery of a six planet system where all were in near-perfect rhythm with each other.

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How Did the TRAPPIST-1 Planets Get Their Water?

Most exoplanets orbit red dwarf stars because they're the most plentiful stars. This is an artist's illustration of what the TRAPPIST-1 system might look like from a vantage point near planet TRAPPIST-1f (at right). Credits: NASA/JPL-Caltech

In 2017, an international team of astronomers announced a momentous discovery. Based on years of observations, they found that the TRAPPIST-1 system (an M-type red dwarf located 40 light-years from Earth) contained no less than seven rocky planets! Equally exciting was the fact that three of these planets were found within the star’s Habitable Zone (HZ), and that the system itself has had 8 billion years to develop the chemistry for life.

At the same time, the fact that these planets orbit tightly around a red dwarf star has given rise to doubts that these three planets could maintain an atmosphere or liquid water for very long. According to new research by an international team of astronomers, it all comes down to the composition of the debris disk that the planets formed from and whether or not comets were around to distribute water afterward.

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