exoplanets Archives

October 3, 2021October 3, 2021 by Matt Williams

Astronomers Look at Super-Earths That had Their Atmospheres Stripped Away by Their Stars

Figure 1: Artist’s conceptual image showing the sizes of the planets observed in this study. The radius of TOI-1634 is 1.5 times larger than Earth’s radius and TOI-1685 is 1.8 times larger. The planets would appear red, due to the light from the red dwarf stars they orbit. (Credit: Astrobiology Center, NINS)

As the planets of our Solar System demonstrate, understanding the solar dynamics of a system is a crucial aspect of determining habitability. Because of its protective magnetic field, Earth has maintained a fluffy atmosphere for billions of years, ensuring a stable climate for life to evolve. In contrast, other rocky planets that orbit our Sun are either airless, have super-dense (Venus), or have very thin atmospheres (Mars) due to their interactions with the Sun.

In recent years, astronomers have been on the lookout for this same process when studying extrasolar planets. For instance, an international team of astronomers led by the National Astronomical Observatory of Japan (NAOJ) recently conducted follow-up observations of two Super-Earths that orbit very closely to their respective stars. These planets, which have no thick primordial atmospheres, represent a chance to investigate the evolution of atmospheres on hot rocky planets.

September 26, 2021September 26, 2021 by Matt Williams

Astronomers Detect Clouds on an Exoplanet, and Even Measure Their Altitude

The search for planets beyond our Solar System has grown immensely during the past few decades. To date, 4,521 extrasolar planets have been confirmed in 3,353 systems, with an additional 7,761 candidates awaiting confirmation. With so many distant worlds available for study (and improved instruments and methods), the process of exoplanet studies has been slowly transitioning away from discovery towards characterization.

For example, a team of international scientists recently showed how combining data from multiple observatories allowed them to reveal the structure and composition of an exoplanet’s upper atmosphere. The exoplanet in question is WASP-127b, a “hot Saturn” that orbits a Sun-like star located about 525 light-years away. These findings preview how astronomers will characterize exoplanet atmospheres and determine if they are conducive to life as we know it.

September 13, 2021September 13, 2021 by Evan Gough

A New Way to Search for Exomoons

Artist's impression of the view from a hypothetical moon around a exoplanet orbiting a triple star system. Credit: NASA

We’d love to find another planet like Earth. Not exactly like Earth; that’s kind of ridiculous and probably a little more science fiction than science. But what if we could find one similar enough to Earth to make us wonder?

How could we find it? We progress from one planet-finding mission to the next, compiling a list of planets that may be “Earth-like” or “potentially habitable.” Soon, we’ll have the James Webb Space Telescope and its ability to study exoplanet atmospheres for signs of life and habitability.

But one new study is focusing on exomoons and the role they play in a planet’s habitability. If we find a Moon-like exomoon in a stable orbit around its planet, could it be evidence that the planet itself is more Earth-like? Maybe, but we’re not there yet.

September 8, 2021September 7, 2021 by Paul M. Sutter

Ground-Based Observatories Could use Starshades to see Planets too

Artist's concept of the prototype starshade, a giant structure designed to block the glare of stars so that future space telescopes can take pictures of planets. Credit: NASA/JPL

All hail the occulter: an orbiting starshade for ground-based telescopes.

September 4, 2021September 4, 2021 by Matt Williams

Ocean Worlds With Hydrogen-Rich Atmospheres Could be the Perfect Spots for Life

Artist's impression of the surface of a hycean world. Hycean worlds are still hypothetical, and have large oceans and thick hydrogen-rich atmospheres that trap heat. They could be habitable even if they're outside the traditional habitable zone. Credit: University of Cambridge

The search for planets beyond our Solar System (extrasolar planets) has grown by leaps and bounds in the past decade. A total of 4,514 exoplanets have been confirmed in 3,346 planetary systems, with another 7,721 candidates awaiting confirmation. At present, astrobiologists are largely focused on the “low hanging fruit” approach of looking for exoplanets that are similar in size, mass, and atmospheric composition to Earth (aka. “Earth-like.”)

However, astrobiologists are also interested in finding examples of “exotic life,” the kind that emerged under conditions that are not “Earth-like.” For example, a team of astronomers from the University of Cambridge recently conducted a study that showed how life could emerge on ocean-covered planets with hydrogen-rich atmospheres (aka. “Hycean” planets). These findings could have significant implications for exoplanet studies and the field of astrobiology.

August 12, 2021August 12, 2021 by Andy Tomaswick

Rocky Planet Found With Only Half the Mass of Venus

When it comes to finding exoplanets, size matters, but so does weight. The larger and heavier the planet, the more likely they will be discovered by the current crop of telescopes. Both the techniques to find exoplanets and the telescopes using those techniques are biased toward larger, heavier planets. So when even the current crop of telescopes manages to find one that is about half the mass of Venus, it is cause for celebration. That is precisely the size of the planet a team from the European Southern Observatory’s Very Large Telescope has found orbiting a star called L98-59.

August 4, 2021August 4, 2021 by Andy Tomaswick

Astronomers Find a Huge Planet Orbiting its Star at 6,000 Times the Earth-Sun Distance

Tracking exoplanets is hard – especially when that exoplanet is so far away from its parent star that the normally used “transit” method of watching it dim the light of the star itself is ineffectual. But it really helps if the planet is huge, and has its own infrared glow, no matter how far away from its star it might be. At least those properties allowed a team of scientists from the University of Hawai’i to track a particular exoplanet called (and we’re not kidding) Coconuts-2b.

July 28, 2021July 28, 2021 by Andy Tomaswick

This is how you get Tatooines. Binary Star Planet Formation

One of the less appreciated aspects of George Lucas’ vision for Star Wars was that he predicted the existence of planets in binary star systems years before we saw even the first exoplanet. Now a team from the University of Cambridge and the Max Planck Institute for Extra-terrestrial Physics have found how exactly those planets can form without being torn apart by their accompanying suns.

July 25, 2021July 25, 2021 by Andy Tomaswick

Incredible! Astronomers see a Moon-Forming Disk Around a Newly Forming Planet

Planetary formation is a complicated, multilayered process. Even with the influx of data on exoplanets, there are still only two known planets that are not yet fully formed. Known as PDS 70b and PDS 70c, the two planets, which were originally found by the Very Large Telescope, are some of the best objects we have to flesh out our planetary formation models. And now, one of them has been confirmed to have a moon-forming disk around it.

July 8, 2021July 8, 2021 by Matt Williams

There are Probably Many More Earth-Sized Worlds Than Previously Believed

This illustration depicts a planet partially hidden in the glare of its host star and a nearby companion star. After examining a number of binary stars, astronomers have concluded that Earth-sized planets in many two-star systems might be going unnoticed by transit searches, which look for changes in the light from a star when a planet passes in front of it. The light from the second star makes it more difficult to detect the changes in the host star’s light when the planet passes in front of it. Credit: International Gemini Observatory/NOIRLab/NSF/AURA/J. da Silva (Spaceengine)

In the past decade, the discovery of extrasolar planets has accelerated immensely. To date, 4,424 exoplanets have been confirmed in 3,280 star systems, with another 7,453 awaiting confirmation. So far, most of these planets have been gas giants, with about 66% being similar to Jupiter or Neptune, while another 30% have been giant rocky planets (aka. “Super-Earths). Only a small fraction of confirmed exoplanets (less than 4%) have been similar in size to Earth.

However, according to new research by astronomers working at NASA Ames Research Center, it is possible that Earth-sized exoplanets are more common than previously thought. As they indicated in a recent study, there could be twice as many rocky exoplanets in binary systems that are obscured by the glare of their parent stars. These findings could have drastic implications in the search for potentially habitable worlds since roughly half of all stars are binary systems.