Extrasolar Planets Archives

September 17, 2024September 17, 2024 by Matt Williams

Astronomers Have Found a Star with a Hot Jupiter and a Cold Super Jupiter in Orbit

Artist's vision of a cold super-Jupiter in the HD 118203 system. It is an extremely massive gas planet orbiting its star in an orbit six times that of Earth. Credit: NCU/ Maciejewski, G. et al (2024)

Located in the constellation Ursa Major, roughly 300 light-years from Earth, is the Sun-like star HD 118203 (Liesma). In 2006, astronomers detected an exoplanet (HD 118203 b) similar in size and twice as massive as Jupiter that orbits very closely to Liesma (7% of the distance between Earth and the Sun), making it a “Hot Jupiter.” In a recent study, an international team of astronomers announced the detection of a second exoplanet in this system: a Super Jupiter with a wide orbit around its star. In short, they discovered a “Cold Super-Jupiter” in the outskirts of this system.

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 23, 2024April 23, 2024 by Nancy Atkinson

Purple Bacteria — Not Green Plants — Might Be the Strongest Indication of Life

Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity. Credit: Oleg Kuznetsov — Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity, and distant exoplanets might begin similarly. Credit: Oleg Kuznetsov

Astrobiologists continue to work towards determining which biosignatures might be best to look for when searching for life on other worlds. The most common idea has been to search for evidence of plants that use the green pigment chlorophyll, like we have on Earth. However, a new paper suggests that bacteria with purple pigments could flourish under a broader range of environments than their green cousins. That means current and next-generation telescopes should be looking for the emissions of purple lifeforms.

“Purple bacteria can thrive under a wide range of conditions, making it one of the primary contenders for life that could dominate a variety of worlds,” said Lígia Fonseca Coelho, a postdoctoral associate at the Carl Sagan Institute (CSI) and first author of “Purple is the New Green: Biopigments and Spectra of Earth-like Purple Worlds,” published in the Monthly Notices of the Royal Astronomical Society: Letters.

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.

January 31, 2024January 31, 2024 by Matt Williams

Six Planets Found Orbiting an Extremely Young Star

Artist rendering of the TOI-1136 system and its young star flaring. Credit: Rae Holcomb/Paul Robertson/UCI

The field of exoplanet study continues to grow by leaps and bounds. As of the penning of this article, 5,572 extrasolar planets have been confirmed in 4,150 systems (with another 10,065 candidates awaiting confirmation. Well, buckle up because six more exoplanets have been confirmed around TOI-1136, a Sun-like star located roughly 276 light-years from Earth. This star is less than 700 million years old, making it relatively young compared to our own (4.6 billion years). This system will allow astronomers to observe how systems like our own have evolved with time.

September 28, 2023September 28, 2023 by Matt Williams

If Earth is Average, We Should Find Extraterrestrial Life Within 60 Light-Years

Astronomers have detected thousands of planets, including dozens that are potentially habitable. To winnow them down, they need to understand their atmospheres and other factors. (NASA Illustration)

In 1960, while preparing for the first meeting on the Search for Extraterrestrial Intelligence (SETI), legendary astronomer and SETI pioneer Dr. Frank Drake unveiled his probabilistic equation for estimating the number of possible civilizations in our galaxy – aka. The Drake Equation. A key parameter in this equation was n_e, the number of planets in our galaxy capable of supporting life – aka. “habitable.” At the time, astronomers were not yet certain other stars had systems of planets. But thanks to missions like Kepler, 5523 exoplanets have been confirmed, and another 9,867 await confirmation!

Based on this data, astronomers have produced various estimates for the number of habitable planets in our galaxy – at least 100 billion, according to one estimate! In a recent study, Professor Piero Madau introduced a mathematical framework for calculating the population of habitable planets within 100 parsecs (326 light-years) of our Sun. Assuming Earth and the Solar System are representative of the norm, Madau calculated that this volume of space could contain as much as 11,000 Earth-sized terrestrial (aka. rocky) exoplanets that orbit within their stars’ habitable zones (HZs).

July 28, 2023July 28, 2023 by Matt Williams

If Rogue Planets are Everywhere, How Could We Explore Them?

This artist’s impression shows an example of a rogue planet with the Rho Ophiuchi cloud complex visible in the background. Rogue planets have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. Image Credit: ESO/M. Kornmesser/S. Guisard

At one time, astronomers believed that the planets formed in their current orbits, which remained stable over time. But more recent observations, theory, and calculations have shown that planetary systems are subject to shake-ups and change. Periodically, planets are kicked out of their star systems to become “rogue planets,” bodies that are no longer gravitationally bound to any star and are adrift in the interstellar medium (ISM). Some of these planets may be gas giants with tightly bound icy moons orbiting them, which they could bring with them into the ISM.

Like Jupiter, Saturn, Uranus, and Neptune, these satellites could have warm water interiors that might support life. Other research has indicated that rocky planets with plenty of water on their surfaces could also support life through a combination of geological activity and the decay of radionuclides. According to a recent paper by an international team of astronomers, there could be hundreds of rogue planets in our cosmic neighborhood. Based on their first-ever feasibility analysis, they also indicate that deep space missions could explore these unbound objects more easily than planets still bound to their stars.

May 3, 2023May 3, 2023 by Matt Williams

JWST Tries to Untangle the Signals of Water. Is it Coming From the Planet or the Star?

This artist concept represents the rocky exoplanet GJ 486 b. Credits: NASA, ESA, CSA, Joseph Olmsted (STScI)

The number of known extrasolar planets has exploded in the past few decades, with 5,338 confirmed planets in 4,001 systems (and another 9,443 awaiting confirmation). When it comes to “Earth-like” planets (aka. rocky), the most likely place to find them is in orbit around M-type red dwarf stars. These account for between 75 and 80% of all stars in the known Universe, are several times smaller than the Sun and are quite cool and dim by comparison. They are also prone to flare activity and have very tight Habitable Zones (HZs), meaning that planets must orbit very closely to get enough heat and radiation.

In addition, red dwarfs are highly-active when they are young, exposing planets in their HZs to lots of ultraviolet and X-ray radiation. As such, whether planets orbiting these stars can maintain or reestablish their atmospheres over time is an open question. Using the James Webb Space Telescope (JWST), researchers from the Space Telescope Science Institute (STScI) observed an exoplanet known as GJ 486 b. As they stated in a recent study, the team detected traces of water vapor, though it is unclear if the signal was coming from the planet or its parent star.

April 26, 2023April 26, 2023 by Matt Williams

The Next Generation of Telescopes Will Tell Us About the Weather on Other Worlds

This artist’s rendering shows the Extremely Large Telescope in operation on Cerro Armazones in northern Chile. The telescope is shown using lasers to create artificial stars high in the atmosphere. Image: ESO/E-ELT

The field of astronomy is about to be revolutionized, thanks to the introduction of Extremely Large Telescopes that rely on primary mirrors measuring 30 meters (or more) in diameter, adaptive optics (AO), coronographs, and advanced spectrometers. This will include the eponymously-named Extremely Large Telescope (ELT), the Giant Magellan Telescope (GMT), and the Thirty Meter Telescope (TMT). These telescopes will enable astronomers to study exoplanets using the Direct Imaging (DI) method, which will yield valuable data on the composition of their atmospheres.

According to a new study by a team of researchers from Ohio State University (OSU), these telescopes will also allow astronomers to study “ultracool objects,” like very low-mass stars (VLMs), brown dwarfs, and exoplanets. In addition to being able to visualize magnetic starspots and determine the chemical compositions of these objects, ELTs will be able to reveal details about atmospheric dynamics and cloud systems. These types of studies could reveal a wealth of information about some of the least-studied objects in our Universe and significantly aid in the search for life beyond our Solar System.

March 28, 2023March 28, 2023 by Matt Williams

Moons Orbiting Rogue Planets Could be Habitable

An artist's conception of a potentially-habitable exomoon. It seems reasonable that exoplanets have exomoons, and now we're going to look for them. Credit: NASA

When looking for signs of life beyond the Solar System, astrobiologists are confined to looking for life as we understand it. For the most part, that means looking for rocky planets that orbit within their star’s circumsolar habitable zone (HZ), the distance at which liquid water can exist on its surface. In the coming years, next-generation telescopes and instruments will allow astronomers to characterize exoplanet atmospheres like never before. When that happens, they will look for the chemical signatures we associate with life, like nitrogen, oxygen, carbon dioxide, methane, and ammonia.

However, astrobiologists have theorized that life could exist in the outer Solar System beneath the surfaces of icy moons like Europa, Callisto, Titan, and other “Ocean Worlds.” Because of this, there is no shortage of astrobiologists who think that the search for extraterrestrial life should include exomoons, including those that orbit free-floating planets (FFPs). In a recent study, researchers led by the Max Planck Institute for Extraterrestrial Physics (MPE) determined the necessary properties that allow moons orbiting FFPs to retain enough liquid water to support life.