Extrasolar Planets Archives

February 7, 2023February 7, 2023 by Evan Gough

This Exoplanet Orbits Around its Star’s Poles

Astronomers have found another hot Jupiter in a polar orbit around its star. This illustration shows the exoplanet WASP-79 b following a polar orbit around its star. Image Credit: NASA/GSFC

In 1992, humanity’s effort to understand the Universe took a significant step forward. That’s when astronomers discovered the first exoplanets. They’re named Poltergeist (Noisy Ghost) and Phobetor (Frightener), and they orbit a pulsar about 2300 light-years away.

Even though we thought there must be other planets around other stars, and entire science fiction franchises were built on the idea, we didn’t know for sure and couldn’t just assume it to be true. A quick glance at human history shows how wrong our assumptions about nature can be.

January 14, 2023January 14, 2023 by Matt Williams

NASA’s Exoplanet Watch Wants Your Help Studying Planets Around Other Stars

NASA's Exoplanet Watch allows citizen scientists to participate in exoplanet research. Credit: NASA

It’s no secret that the study of extrasolar planets has exploded since the turn of the century. Whereas astronomers knew less than a dozen exoplanets twenty years ago, thousands of candidates are available for study today. In fact, as of January 13th, 2023, a total of 5,241 planets have been confirmed in 3,916 star systems, with another 9,169 candidates awaiting confirmation. While opportunities for exoplanet research have grown exponentially, so too has the arduous task of sorting through the massive amounts of data involved.

Hence why astronomers, universities, research institutes, and space agencies have come to rely on citizen scientists in recent years. With the help of online resources, data-sharing, and networking, skilled amateurs can lend their time, energy, and resources to the hunt for planets beyond our Solar System. In recognition of their importance, NASA has launched Exoplanet Watch, a citizen science project sponsored by NASA’s Universe of Learning. This project lets regular people learn about exoplanets and get involved in the discovery and characterization process.

December 21, 2022December 23, 2022 by Matt Williams

Astronomers Scanned 12 Planets for Alien Signals While They Were in Front of Their Stars

TOI 1338 b is a circumbinary planet orbiting its two stars. It was discovered by TESS. Image Credit: NASA's Goddard Space Flight Center/Chris Smith

The Robert C. Byrd Green Bank Telescope (GBT), part of the Green Bank Observatory in West Virginia, is the world’s premiere single-dish radio telescope. Between its 100-meter dish (328-foot), unblocked aperture, and excellent surface accuracy, the GBT provides unprecedented sensitivity in the millimeter to meter wavelengths – very high to extremely high frequency (VHF to EHF). Since 2017, it also became one of the main instruments used by Breakthrough Listen and other institutes engaged in the Search for Extraterrestrial Intelligence (SETI).

Recently, an international team of researchers from the SETI Institute, Breakthrough Listen, and multiple universities scanned twelve exoplanets for signs of technological activity (aka. “technosignatures”). Their observations were timed to coincide with the planets passing in front of their sun relative to the observer (i.e., making a transit). While the survey did not detect any definitive evidence of technosignatures, they did identify two radio signals of interest that warrant follow-up observation. This new technique could vastly expand the field of SETI and create all kinds of opportunities for future research.

December 19, 2022January 28, 2023 by Matt Williams

Hubble and Spitzer Team up to Find a Pair of Waterworld Exoplanets

Artist’s impression of a water world, where half of its mass consists of water. Just like our Moon, the planet is bound to its star by tidal forces and always shows the same face to its host star. Credit: Pilar Montañés

As of December 19th, 2022, 5,227 extrasolar planets have been confirmed in 3,908 systems, with over 9,000 more awaiting confirmation. While most of these planets are Jupiter- or Neptune-sized gas giants or rocky planets many times the size of Earth (Super-Earths), a statistically significant number have been planets where water makes up a significant part of their mass fraction – aka. “water worlds.” These planets are unlike anything we’ve seen in the Solar System and raise several questions about planet formation in our galaxy.

In a recent study, an international team led by researchers from the University of Montreal’s Institute for Research on Exoplanets (iREx) found evidence of two water worlds in a single planetary system located about 218 light-years away in the constellation Lyra. Based on their densities, the team determined that these exoplanets (Kepler-138c and Kepler-138d) are lighter than rocky “Earth-like” ones but heavier than gas-dominated ones. The discovery was made using data from NASA’s now-retired Spitzer Space Telescope and the venerable Hubble Space Telescope.

November 9, 2022November 9, 2022 by Matt Williams

The Case of the “Missing Exoplanets”

An illustration of the variations among the more than 5,000 known exoplanets discovered since the 1990s. Could their stars' metallicity play a role in making them habitable to life? Credit: NASA/JPL-Caltech

Today, the number of confirmed exoplanets stands at 5,197 in 3,888 planetary systems, with another 8,992 candidates awaiting confirmation. The majority have been particularly massive planets, ranging from Jupiter and Neptune-sized gas giants, which have radii about 2.5 times that of Earth. Another statistically significant population has been rocky planets that measure about 1.4 Earth radii (aka. “Super-Earths”). This presents a mystery to astronomers, especially where the exoplanets discovered by the venerable Kepler Space Telescope are concerned.

Of the more than 2,600 planets Kepler discovered, there’s an apparent rarity of exoplanets with a radius of about 1.8 times that of Earth – which they refer to as the “radius valley.” A second mystery, known as “peas in a pod,” refers to neighboring planets of similar size found in hundreds of planetary systems with harmonious orbits. In a study led by the Cycles of Life-Essential Volatile Elements in Rocky Planets (CLEVER) project at Rice University, an international team of astrophysicists provide a new model that accounts for the interplay of forces acting on newborn planets that could explain these two mysteries.

November 4, 2022November 4, 2022 by Matt Williams

What Happens to Hot Jupiters when their Star Becomes a Red Giant?

exoplanet hot jupiter transiting its star — This artist’s impression shows an ultra-hot exoplanet as it is about to transit in front of its host star. Credit: ESO

The study of extrasolar planets has led to some astounding discoveries, many of which have defied the expectations of astronomers and challenged our notions about the forms planetary systems can take. For example, the discovery of Jupiter-sized planets that orbit closely to their stars (“Hot Jupiters”) defied what astronomers suspected about gas giants. Previously, the general consensus was that gas giants form beyond the “Frost Line” – the boundary beyond which volatile elements (like water) freeze solid – and remain there for the rest of their lives.

Interestingly, this will happen when our Sun leaves its main sequence phase and enters its Red Giant Branch (RGB) phase. This raises the question of what happens to Hot Jupiters when their parent stars expand to become Red Giants. Using advanced 3D simulations, a team of researchers led by the Compact Object Mergers: Population Astrophysics and Statistics (COMPAS) consortium simulated how red giants will expand to engulf Hot Jupiters. Their findings could answer another mystery confronting astronomers, which is why some binary systems have one rapidly-rotating star with strange chemical compositions.

October 27, 2022October 27, 2022 by Matt Williams

Here are Four Ways JWST Could Detect Alien Life

Artist conception of the James Webb Space Telescope. Credit: NASA GSFC/CIL/Adriana Manrique Gutierrez

Less than a year after it went to space, the James Webb Space Telescope (JWST) has already demonstrated its worth many times over. The images it has acquired of distant galaxies, nebulae, exoplanet atmospheres, and deep fields are the most detailed and sensitive ever taken. And yet, one of the most exciting aspects of its mission is just getting started: the search for evidence of life beyond Earth. This will consist of Webb using its powerful infrared instruments to look for chemical signatures associated with life and biological processes (aka. biosignatures).

The chemical signatures vary, each representing a different pathway toward the potential discovery of life. According to The Conversation’s Joanna Barstow, a planetary scientist and an Ernest Rutherford Fellow at The Open University specializing in the study of exoplanet atmospheres, there are four ways that Webb could do this. These include looking for chemicals that lifeforms depend on, chemical byproducts produced by living organisms, chemicals essential to maintaining a stable climate, and chemicals that shouldn’t coexist.

October 16, 2022October 16, 2022 by Matt Williams

TESS has Resumed Normal Operations

An artist’s rendition of the Transiting Exoplanet Survey Satellite (TESS). Credit: NASA's Goddard Space Flight Center

In April 2018, NASA launched the Transiting Exoplanet Survey Satellite (TESS), the successor to the Kepler Space Telescope that revolutionized the exoplanet studies field. Like its predecessor, TESS has been scanning almost the entire sky for five years for extrasolar planets using the Transit Method. This consists of monitoring thousands of stars for periodic dips in brightness, which may indicate a planet passing in front of the star relative to the observer. To date, TESS has made 243 confirmed discoveries, with another 4562 candidates – or TESS Objects of Interest (TOI) – awaiting confirmation.

On Monday, October 10th, fans of the TESS mission and the research it conducts got a bit of a scare as the observatory experienced a malfunction and had to be put into safe mode. Three days later, at around 06:30 PM EDT (03:30 PM PDT) on October 13th, NASA announced that their engineers had successfully powered up the instrument and brought it back online. While technicians at NASA are still investigating the cause of the malfunction, the spacecraft is now back in its fine-pointing mode and has resumed its second extended mission (EM2).

September 27, 2022September 27, 2022 by Matt Williams

TESS Finds a Super-Earth and two Mini-Neptunes in a Single System

The field of extrasolar planet studies continues to grow by leaps and bounds. Currently, 5,090 exoplanets have been confirmed in 3,816 systems, and another 8,933 candidates are awaiting confirmation. The majority of these have been Neptune-like gas giants (1,779), gas giants comparable to Jupiter or Saturn (1,536), and rocky planets many times the size of Earth (1,582). The most effective means for finding exoplanets has been the Transit Method (aka. Transit Photometry), where periodic dips in a star’s brightness are seen as an indication of a planet passing in front of its star (transiting) relative to the observer.

Using data from NASA’s Transiting Exoplanet Survey Satellite (TESS), an international team of astronomers has discovered a three-planet system orbiting a Sun-like star (HD 22946, or TOI 11) located about 205.5 light-years. Based on size estimates yielded from their transits, the team theorizes that these exoplanets consist of a rocky planet several times the size of Earth (a Super-Earth) and two gas giants smaller than Neptune. Given its proximity, this system could be ideal for follow-up studies and characterization with the James Webb Space Telescope (JWST).

September 14, 2022September 14, 2022 by Matt Williams

There Could be as Many Water Worlds as Earths in the Milky Way

Artist’s impression of the strange landscape of a water world. Credit: Pilar Montañés

On July 12th, 2022, NASA released the first images acquired by the James Webb Space Telescope, which were taken during its first six months of operation. Among its many scientific objectives, Webb will search for smaller, rocky planets that orbit closer to their suns – especially dimmer M-type (red dwarf) stars, the most common in the Universe. This will help astronomers complete the census of exoplanets and gain a better understanding of the types of worlds that exist out there. In particular, astronomers are curious about how many terrestrial planets in our galaxy are actually “water worlds.”

These are rocky planets that are larger than Earth but have a lower density, which suggests that volatiles like water make up a significant amount (up to half) of their mass-fraction. According to a recent study by researchers from the University of Chicago and the Instituto de Astrofísica de Canarias (IAC), water worlds may be just as common as “Earth-like” rocky planets. These findings bolster the case for exoplanets that are similar to icy moons in the Solar System (like Europa) and could have significant implications for future exoplanet studies and the search for life in our Universe.