Extrasolar Planets Archives

July 25, 2024July 25, 2024 by Matt Williams

Planetary Habitability Depends on its Star’s Magnetic Field

Earth's magnetosphere is the region defined by our planet's magnetic field. Image Credit: NASA

The extrasolar planet census recently passed a major milestone, with 5500 confirmed candidates in 4,243 solar systems. With so many exoplanets available for study, astronomers have learned a great deal about the types of planets that exist in our galaxy and have been rethinking several preconceived notions. These include the notion of “habitability” and whether Earth is the standard by which this should be measured – i.e., could there be “super habitable” exoplanets out there? – and the very concept of the circumsolar habitable zone (CHZ).

Traditionally, astronomers have defined habitable zones based on the type of star and the orbital distance where a planet would be warm enough to maintain liquid water on its surface. But in recent years, other factors have been considered, including the presence of planetary magnetic fields and whether they get enough ultraviolet light. In a recent study, a team from Rice University extended the definition of a CHZ to include a star’s magnetic field. Their findings could have significant implications in the search for life on other planets (aka. astrobiology).

July 23, 2024July 23, 2024 by Matt Williams

The Ultraviolet Habitable Zone Sets a Time Limit on the Formation of Life

Artist's impression of the range of habitable zones for different types of stars. Credit: NASA/Kepler Mission/Dana Berry

The field of extrasolar planet studies has grown exponentially in the past twenty years. Thanks to missions like Kepler, the Transiting Exoplanet Survey Satellite (TESS), and other dedicated observatories, astronomers have confirmed 5,690 exoplanets in 4,243 star systems. With so many planets and systems available for study, scientists have been forced to reconsider many previously-held notions about planet formation and evolution and what conditions are necessary for life. In the latter case, scientists have been rethinking the concept of the Circumsolar Habitable Zone (CHZ).

By definition, a CHZ is the region around a star where an orbiting planet would be warm enough to maintain liquid water on its surface. As stars evolve with time, their radiance and heat will increase or decrease depending on their mass, altering the boundaries of the CHZ. In a recent study, a team of astronomers from the Italian National Institute of Astrophysics (INAF) considered how the evolution of stars affects their ultraviolet emissions. Since UV light seems important for the emergence of life as we know it, they considered how the evolution of a star’s Ultraviolet Habitable Zone (UHZ) and its CHZ could be intertwined.

July 9, 2024July 9, 2024 by Mark Thompson

Do Planets Have the Raw Ingredients for Life? The Answer is in their Stars

Finding planets that already have, or have the ingredients for intelligent life is a real challenge. It is exciting that new telescopes and spacecraft are in development that will start to identify candidate planets. Undertaking these observations will take significant amounts of telescope time so we need to find some way to prioritise which ones to look at first. A new paper has been published that suggests we can study the host stars first for the necessary raw elements giving a more efficient way to hunt for similar worlds to Earth.

June 28, 2024June 28, 2024 by Evan Gough

Take a Look at These Stunning New Exoplanet Infographics

"Icy and Rocky Worlds" is a new exoplanet infographic from Martin Vargic, an artist and space enthusiast from Slovakia. It's available as a wall poster on his website. Image Credit and Copyright: Martin Vargic.

Martin Vargic is a space enthusiast, author, and graphic artist from Slovakia. He created two new infographic posters that show almost 1600 exoplanets of different types and sizes. One is called Icy and Rocky Worlds, and the other is called The Exoplanet Zoo.

June 9, 2024June 9, 2024 by Matt Williams

Instead of Losing its Atmosphere, an Exoplanet Puffed Up and Held Onto it

Artist's impression of the "hot Neptune" Phoenix orbiting its red giant star. Credit: Credit: Roberto Molar Candanosa/JHU

To date, astronomers have confirmed the existence of 5638 extrasolar planets in 4,199 star systems. In the process, scientists have found many worlds that have defied expectations. This is certainly the case regarding “hot Neptunes,” planets that are similar to the “ice giants” of the outer Solar System but orbit much closer to their stars. But when a Johns Hopkins University-led team of astronomers discovered TIC365102760 b (aka. Pheonix), they observed something entirely unexpected: a Neptune-sized planet that retained its atmosphere by puffing up.

May 18, 2024May 18, 2024 by Matt Williams

Astronomers Discover the Second-Lightest “Cotton Candy” Exoplanet to Date.

A NASA illustration of the giant planet WASP-193b and its star. Credit: NASA/ESA/CSA)

The hunt for extrasolar planets has revealed some truly interesting candidates, not the least of which are planets known as “Hot Jupiters.” This refers to a particular class of gas giants comparable in size to Jupiter but which orbit very closely to their suns. Strangely, there are some gas giants out there that have very low densities, raising questions about their formation and evolution. This is certainly true of the Kepler 51 system, which contains no less than three “super puff” planets similar in size to Jupiter but is about one hundred times less dense.

These planets also go by the moniker “cotton candy” giants because their density is comparable to this staple confection. In a recent study, an international team of astronomers spotted another massive planet, WASP-193b, a fluffy gas giant orbiting a Sun-like star 1,232 light-years away. While this planet is roughly one and a half times the size of Jupiter, it is only about 14% as massive. This makes WASP-193b the second-lightest exoplanet observed to date. Studying this and other “cotton candy” exoplanets could provide valuable insight into how these mysterious giants form.

April 15, 2024April 15, 2024 by Matt Williams

You Can't Know the True Size of an Exoplanet Without Knowing its Star's Magnetic Field

Artist's impression of a "hot Jupiter" orbiting close to a Sun-like star. Credit: NASA

In 2011, astronomers with the Wide Angle Search for Planets (WASP) consortium detected a gas giant orbiting very close to a Sun-like (G-type) star about 700 light-years away. This planet is known as WASP-39b (aka. “Bocaprins”), one of many “hot Jupiters” discovered in recent decades that orbits its star at a distance of less than 5% the distance between the Earth and the Sun (0.05 AU). In 2022, shortly after the James Webb Space Telescope (JWST) it became the first exoplanet to have carbon dioxide and sulfur dioxide detected in its atmosphere.

Alas, researchers have not constrained all of WASP-39b’s crucial details (particularly its size) based on the planet’s light curves, as observed by Webb. which is holding up more precise data analyses. In a new study led by the Max Planck Institute for Solar System Research (MPS), an international team has shown a way to overcome this obstacle. They argue that considering a parent star’s magnetic field, the true size of an exoplanet in orbit can be determined. These findings are likely to significantly impact the rapidly expanding field of exoplanet study and characterization.

March 18, 2024March 21, 2024 by Matt Williams

Webb Finds Hints of a Third Planet at PDS 70

An artist's illustration of the PDS 70 system, not to scale. The two planets are clearing a gap in the circumstellar disk as they form. As they accrete in-falling material, the heat makes them glow. Image Credit: W. M. Keck Observatory/Adam Makarenko

The exoplanet census now stands at 5,599 confirmed discoveries in 4,163 star systems, with another 10,157 candidates awaiting confirmation. So far, the vast majority of these have been detected using indirect methods, including Transit Photometry (74.4%) and Radial Velocity measurements (19.4%). Only nineteen (or 1.2%) were detected via Direct Imaging, a method where light emitted or reflected from an exoplanet’s atmosphere or surface is used to detect and characterize it. Thanks to the latest generation of high-contrast and high-angular resolution instruments, this is starting to change.

This includes the James Webb Space Telescope and its sophisticated mirrors and advanced infrared imaging suite. Using data obtained by Webb‘s Near-Infrared Camera (NIRCam), astronomers within the MIRI mid-INfrared Disk Survey (MINDS) survey recently studied a very young variable star (PDS 70) about 370 light-years away with two confirmed protoplanets. After examining the system and its extended protoplanetary disk, they found evidence of a third possible protoplanet orbiting the star. These observations could help advance our understanding of planetary systems that are still in the process of formation.

March 9, 2024March 17, 2024 by Matt Williams

This Hot Jupiter is Doomed to Crash Into its Star in Just Three Million Years

Artist's impression of the searing-hot gas planet WASP-12b and its star. A Princeton-led team of astrophysicists has shown that this exoplanet is spiraling in toward its host star, heading toward certain destruction in about 3 million years. Credit: NASA/JPL-Caltech

In 2008, astronomers with the SuperWASP survey spotted WASP-12b as it transited in front of its star. At the time, it was part of a new class of exoplanets (“Hot Jupiters”) discovered a little more than a decade before. However, subsequent observations revealed that WASP-12b was the first Hot Jupiter observed that orbits so closely to its parent star that it has become deformed. While several plausible scenarios have been suggested to explain these observations, a widely accepted theory is that the planet is being pulled apart as it slowly falls into its star.

Based on the observed rate of “tidal decay,” astronomers estimate that WASP-12b will fall into its parent star in about ten million years. In a recent study, astronomers with The Asiago Search for Transit Timing Variations of Exoplanets (TASTE) project presented an analysis that combines new spectral data from the Telescopio Nazionale Galileo (TNG) in La Palma with 12 years worth of unpublished transit light curves and archival data. Their results are consistent with previous observations that suggest WASP-12b is rapidly undergoing tidal dissipation and will be consumed by its star.

March 8, 2024March 8, 2024 by Matt Williams

Science Fiction is Learning About Exoplanets From Science

Artist’s impression of a sunset seen from the surface of an Earth-like exoplanet. Credit: ESO/L. Calçada

As long as it has existed as a genre, there has been a notable relationship between science fiction and science fact. Since our awareness of the Universe and everything in it has changed with time, so have depictions and representations in popular culture. This includes everything from space exploration and extraterrestrial life to extraterrestrial environments. As scientists keep pushing the boundaries of what is known about the cosmos, their discoveries are being related to the public in film, television, print, and other media.

In the field of science communication, however, there is a certain hesitancy to use science fiction materials as an educational tool. In a recent paper that appeared in the Journal of Science Communication (JCOM), a team from the St Andrews Centre for Exoplanet Science and the Space Research Institute (IWF) of the Austrian Academy of Sciences focused on a specific area of scientific study – extrasolar planets. After analyzing a multimedia body of science fiction works produced since the first confirmed exoplanet discovery, they found that depictions have become more realistic over time.