exoplanets Archives

July 2, 2023July 2, 2023 by Brian Koberlein

A Planet Was Swallowed by a Red Giant, But it Survived

Artist view of Halla as two stars merge to become the star Baekdu. Credit: W. M. Keck Observatory/Adam Makarenko

The Sun is going to kill us. Not anytime soon, but it will kill us. At the moment the Sun keeps itself going by fusing hydrogen into helium and other heavier elements, but in five or so billion years it is going to run out of hydrogen. When that happens, the Sun will make a desperate attempt to keep going by fusing helium. During this period it will swell to a red giant, likely so large that it engulfs the Earth, baking it to a crisp in its diffuse hot atmosphere.

June 29, 2023June 29, 2023 by Laurence Tognetti

A Direct Image of a Planet That’s Just Like Jupiter, Only Younger

Direct images of the extrasolar planet, AF Lep b (white spot around 10 o’clock), orbiting its host star (center) taken in Dec. 2021 and Feb. 2023 using the W. M. Keck Observatory’s 10-meter telescope in Hawai?i. (Credit: Kyle Franson, University of Texas at Austin/W. M. Keck Observatory)

In a recent study published in The Astrophysical Journal Letters, a team of astronomers used the W. M. Keck Observatory on Maunakea, Hawai?i Island to identify exoplanet, AF Lep b, which is three times the mass of Jupiter orbiting a Sun-sized star located approximately 87.5 light-years from Earth. What makes this discovery unique is AF Lep b is the first exoplanet discovered using a method called astrometry, which involves measuring unexpected, miniscule changes in the position of a star relative to nearby stars, which could indicate another object, an exoplanet, is causing gravitational tugs on its parent star.

June 24, 2023June 24, 2023 by Brian Koberlein

There Could Be Captured Planets in the Oort Cloud

An icy planet distantly orbiting its star. Credit: NASA/JPL-Caltech

Our solar system has had a chaotic past. Earth and the other planets are now in stable orbits, but while they were forming they experienced drastic location shifts. Jupiter was likely much closer to the Sun than it is now, and its shift not only shifted other planets but also cleared the solar system of debris, tossing much of it to the Oort Cloud.

June 19, 2023June 19, 2023 by Andy Tomaswick

Can We Predict if a System Will Have Giant Planets?

Prediction is one of the hallmarks of scientific endeavors. Scientists pride themselves on being able to predict physical realities based on inputs. So it should come as no surprise that a team of scientists at Notre Dame has developed a theory that can be used to predict the existence of giant planets on the fringes of an exoplanetary system.

June 17, 2023June 17, 2023 by Scott Alan Johnston

We Could See the Glint off Giant Cities on Alien Worlds

How large would an extraterrestrial city have to be for current telescopes to see it? Would it need to be a planet-sized metropolis like Star Wars’ Coruscant? Or could we see an alien equivalent of Earth’s own largest urban areas, like New York City or Tokyo?

A recent preprint by Bhavesh Jaiswal of the Indian Institute of Science suggests that, in fact, we could see cities a mere fraction of that size, using a feature of light known as specular reflection.

June 16, 2023June 17, 2023 by Laurence Tognetti

This Hot Jupiter is Leaving a Swirling Tail of Helium in its Wake

Image from the computer simulation of HAT-P-32 b (bright dot left of star) leaving a trail of helium during its 2.2-day, clockwise orbit (dashed line). (Credit: M. MacLeod (Harvard-Smithsonian Center for Astrophysics) and A. Oklopčić (Anton Pannekoek Institute for Astronomy, University of Amsterdam)

In a recent study published in Science Advances, a team of researchers commissioned the Hobby-Eberly Telescope (HET), which is designed to study exoplanetary atmospheres, to examine how a “hot Jupiter” exoplanet is losing its helium atmosphere as it orbits its parent star, leaving tails of helium that extend approximately 25 times the diameter of the planet itself.

June 15, 2023June 15, 2023 by Evan Gough

Did Life Need Plate Tectonics to Emerge?

New research indicates that mobile plate tectonics—thought to be necessary for the creation of a habitable planet—was not occurring on Earth 3.9 billion years ago. Image Credit: University of Rochester illustration / Michael Osadciw

It’s widely accepted that Earth’s plate tectonics are a key factor in life’s emergence. Plate tectonics allows heat to move from the mantle to the crust and plays a critical role in cycling nutrients. They’re also a key part of the carbon cycle that moderates Earth’s temperature.

But new research suggests that there was no plate tectonic activity when life appeared sometime around 3.9 billion years ago. Does this have implications for our search for habitable worlds?

June 7, 2023June 7, 2023 by Evan Gough

Is it Time for a New Definition of “Habitable?”

This artist’s impression shows the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The double star Alpha Centauri AB also appears in the image between the planet and Proxima itself. Proxima b is a little more massive than the Earth and orbits in the habitable zone around Proxima Centauri, where the temperature is suitable for liquid water to exist on its surface. Credit: ESO/M. Kornmesser

Things tend to move from the simple to the complex when you’re trying to understand something new. This is the situation exoplanet scientists find themselves in when it comes to the term ‘habitable.’ When they were discovering the first tranche of exoplanets, the term was useful. It basically meant that the planet could have liquid water on its surface.

But now that we know of over 5,000 confirmed exoplanets, the current definition of habitable is showing its age.

June 1, 2023June 1, 2023 by Evan Gough

JWST Scans an Ultra-Hot Jupiter’s Atmosphere

This artist's illustration shows WASP 18 b, a hot Super-Jupiter that orbits its star in less than one day. Image Credit: NASA, ESA, and G. Bacon (STScI).

When astronomers discovered WASP-18b in 2009, they uncovered one of the most unusual planets ever found. It’s ten times as massive as Jupiter is, it’s tidally locked to its Sun-like star, and it completes an orbit in less than one Earth day, about 23 hours.

Now astronomers have pointed the JWST and its powerful NIRSS instrument at the ultra-Hot Jupiter and mapped its extraordinary atmosphere.

May 31, 2023May 31, 2023 by Laurence Tognetti

A Third of Planets Orbiting Red Dwarf Stars Could be in the Habitable Zone

A recent study published in the Proceedings of the National Academy of Sciences, a pair of researchers from the University of Florida (UF) examine orbital eccentricities for exoplanets orbiting red dwarf (M dwarf) stars and determined that one-third of them—which encompass hundreds of millions throughout the Milky Way—could exist within their star’s habitable zone (HZ), which is that approximate distance from their star where liquid water can exist on the surface. The researchers determined the remaining two-thirds of exoplanets orbiting red dwarfs are too hot for liquid water to exist on their surfaces due to tidal extremes, resulting in a sterilization of the planetary surface.