Tread lightly: ‘Eggshell planets’ possible around other stars

Strange ‘eggshell planets’ are among the rich variety of exoplanets possible, according to a study from Washington University in St. Louis. These rocky worlds have an ultra-thin outer brittle layer and little to no topography. Such worlds are unlikely to have plate tectonics, raising questions as to their habitability.

Mars habitability limited by its small size, isotope study suggests

Researchers measured the potassium isotope compositions of Martian meteorites in order to estimate the presence, distribution and abundance of volatile elements and compounds, including water, on Mars, finding that Mars has lost more potassium than Earth but retained more potassium than the Moon or the asteroid 4-Vesta; the results suggest that rocky planets with larger mass retain more volatile elements during planetary formation and that Mars and Mars-sized exoplanets fall below a size threshold necessary to retain enough water to enable habitability and plate tectonics.

Superflares may be less harmful to exoplanets than previously thought, study shows

Astronomers have long suspected that superflares, extreme radiation bursts from stars, can cause lasting damage to the atmospheres — and thus habitability — of exoplanets. A new study published in the Monthly Notices of the Royal Astronomical Society reports that they pose only a limited danger to planetary systems.

Are we alone in the universe? UAH’s Dr. Gary Zank doesn’t think so

Are we alone in the universe? Research by Dr. Gary Zank at The University of Alabama in Huntsville (UAH), a part of the University of Alabama System, and collaborators from UAH and other institutions has helped to inform the search for planets that could harbor life.

Hubble Pins Down Weird Exoplanet with Far-Flung Orbit

Astronomers analyzing Hubble images of the double star, HD 106906, have discovered a planet in a huge 15,000-year-long orbit that sweeps it as far from its stellar duo as Planet Nine would be from our Sun. This is observational evidence that similarly far-flung worlds may exist around other stars. Researchers hypothesize that the planet wound up there in a game of planetary pinball where the gravitational pull of a passing star modified the orbit’s shape.

Astronomers develop model for the distribution of inner planetary systems

Data from the Kepler space telescope, launched more than a decade ago, is still helping astronomers who study planets outside of our own solar system — exoplanets — and unravel the mysteries of planetary systems. Initially, astronomers were surprised that Kepler found so many exoplanets, including hundreds of planetary systems with multiple planets orbiting close to their host star. As astronomers developed models to explain the abundance of inner exoplanets, they encountered a new mystery: “Why did Kepler detect just one planet around so many stars, instead of planetary systems with multiple planets?”

ALMA Discovers Misaligned Rings in Planet-Forming Disk Around Triple Stars

Using the Atacama Large Millimeter/submillimeter Array (ALMA), two teams of astronomers have for the first time discovered a planet-forming disk with misaligned rings around a triple star system, called GW Orionis. The astronomers give two possible scenarios for the misalignment: either…

The Strange Orbits of ‘Tatooine’ Planetary Disks

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have found striking orbital geometries in protoplanetary disks around binary stars. While disks orbiting the most compact binary star systems share very nearly the same plane, disks encircling wide binaries have orbital planes that are severely tilted. These systems can teach us about planet formation in complex environments.