exoplanets Archives

December 11, 2024December 11, 2024 by Matt Williams

Could the ESA’s PLATO Mission Find Earth 2.0?

Artist's impression of the ESA's PLATO mission. Credit: ESA/ATG medialab

Currently, 5,788 exoplanets have been confirmed in 4,326 star systems, while thousands more candidates await confirmation. So far, the vast majority of these planets have been gas giants (3,826) or Super-Earths (1,735), while only 210 have been “Earth-like” – meaning rocky planets similar in size and mass to Earth. What’s more, the majority of these planets have been discovered orbiting within M-type (red dwarf) star systems, while only a few have been found orbiting Sun-like stars. Nevertheless, no Earth-like planets orbiting within a Sun-like star’s habitable zone (HZ) have been discovered so far.

This is largely due to the limitations of existing observatories, which have been unable to resolve Earth-sized planets with longer orbital periods (200 to 500 days). This is where next-generation instruments like the ESA’s PLAnetary Transits and Oscillations of stars (PLATO) mission come into play. This mission, scheduled to launch in 2026, will spend four years surveying up to one million stars for signs of planetary transits caused by rocky exoplanets. In a recent study, an international team of scientists considered what PLATO would likely see based on what it would see if observing the Solar System itself.

December 5, 2024December 10, 2024 by Matt Williams

MAUVE: An Ultraviolet Astrophysics Probe Mission Concept

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

For the past thirty years, NASA’s Great Observatories – the Hubble, Spitzer, Compton, and Chandra space telescopes – have revealed some amazing things about the Universe. In addition to some of the deepest views of the Universe provided by the Hubble Deep Fields campaign, these telescopes have provided insight into the unseen parts of the cosmos – i.e., in the infrared, gamma-ray, and ultraviolet spectrums. With the success of these observatories and the James Webb Space Telescope (JWST), NASA is contemplating future missions that would reveal even more of the “unseen Universe.”

This includes the UltraViolet Explorer (UVEX), a space telescope NASA plans to launch in 2030 as its next Astrophysics Medium-Class Explorer mission. In a recent study, a team comprised of graduate students and postdocs from institutions across the US detailed a concept mission known as the Mission to Analyze the UltraViolet universE (MAUVE). This telescope and its sophisticated instruments were conceived during the inaugural NASA Astrophysics Mission Design School. According to the team’s paper, this mission would hypothetically be ready for launch by 2031.

November 13, 2024December 12, 2024 by Matt Williams

New Study Examines How Extraterrestrial Civilizations Could Become “Stellivores.”

Artist's impression of accretion in a binary system. Credit: ESO/L. Calçada

One of the most challenging aspects of astrobiology and the Search for Extraterrestrial Intelligence (SETI) is anticipating what life and extraterrestrial civilizations will look like. Invariably, we have only one example of a planet that supports life (Earth) and one example of a technologically advanced civilization (humanity) upon which to base our theories. As for more advanced civilizations, which statistically seems more likely, scientists are limited to projections of our own development. However, these same projections offer constraints on what SETI researchers should search for and provide hints about our future development.

In a series of papers led by the Blue Marble Space Institute of Science (BMSIS), a team of researchers examines what Earth’s level of technological development (aka. “technosphere”) will look like in the future. In the most recent installment, they offer a reinterpretation of the Kardashev Scale, which suggests that civilizations expand to harness greater levels of energy (planet, host star, and galaxy). Instead, they suggest that the Kardashev Scale establishes upper limits on the amount of stellar energy a civilization can harness (a “luminosity limit”) and that civilizations might circumvent this by harnessing stellar mass directly.

November 11, 2024November 12, 2024 by Matt Williams

Project Hyperion is Seeking Ideas for Building Humanity’s First Generation Ship

Project Hyperion is the first design competition for a generation ship. Credit: Maciej Rebisz/Michel Lamontagne

The dream of traversing the depths of space and planting the seed of human civilization on another planet has existed for generations. For long as we’ve known that most stars in the Universe are likely to have their own system of planets, there have been those who advocated that we explore them (and even settle on them). With the dawn of the Space Age, this idea was no longer just the stuff of science fiction and became a matter of scientific study. Unfortunately, the challenges of venturing beyond Earth and reaching another star system are myriad.

When it comes down to it, there are only two ways to send crewed missions to exoplanets. The first is to develop advanced propulsion systems that can achieve relativistic speeds (a fraction of the speed of light). The second involves building spacecraft that can sustain crews for generations – aka. a Generation Ship (or Worldship). On November 1st, 2024, Project Hyperion launched a design competition for crewed interstellar travel via generation ships that would rely on current and near-future technologies. The competition is open to the public and will award a total of $10,000 (USD) for innovative concepts.

October 17, 2024October 19, 2024 by Matt Williams

Establishing a New Habitability Metric for Future Astrobiology Surveys

The search for exoplanets has grown immensely in recent decades thanks to next-generation observatories and instruments. The current census is 5,766 confirmed exoplanets in 4,310 systems, with thousands more awaiting confirmation. With so many planets available for study, exoplanet studies and astrobiology are transitioning from the discovery process to characterization. Essentially, this means that astronomers are reaching the point where they can directly image exoplanets and determine the chemical composition of their atmospheres.

As always, the ultimate goal is to find terrestrial (rocky) exoplanets that are “habitable,” meaning they could support life. However, our notions of habitability have been primarily focused on comparisons to modern-day Earth (i.e., “Earth-like“), which has come to be challenged in recent years. In a recent study, a team of astrobiologists considered how Earth has changed over time, giving rise to different biosignatures. Their findings could inform future exoplanet searches using next-generation telescopes like the Habitable Worlds Observatory (HWO), destined for space by the 2040s.

October 17, 2024October 17, 2024 by Matt Williams

Astronomers Solve the Mystery of the Famed Brown Dwarf That is Too Bright: It’s Twins!

This artwork highlights a pair of recently uncovered brown dwarf twins, named Gliese 229 Ba and Gliese 229 Bb. Credit: K. Miller/R. Hurt (Caltech/IPAC)

In 1995, Caltech researchers at the Institute’s Palomar Observatory first observed what appeared to be a brown dwarf orbiting Gliese 229 – a red dwarf star located about 19 light-years from Earth. Since then, this brown dwarf (Gliese 229 B) has mystified astronomers because it appeared too dim for its mass. With 70 times the mass of Jupiter, it should have been brighter than what telescopes had observed. However, a Caltech-led international team of astronomers recently solved the mystery by determining that the brown dwarf is a pair of closely orbiting twins!

October 12, 2024October 14, 2024 by Matt Williams

A Possible Exomoon Could be Volcanic, like Jupiter’s Moon Io

New NASA-led research suggests a sodium cloud seen around the exoplanet WASP-49 b might be created by a volcanic moon, which is depicted in this artist’s concept. Jupiter’s fiery moon Io produces a similar cloud. Credit: NASA/JPL-Caltech

In 2012, astronomers detected a gas giant transiting in front of WASP-49A, a G-type star located about 635 light-years from Earth. The data obtained by the WASP survey indicated that this exoplanet (WASP-49 b) is a gas giant roughly the same size as Jupiter and 37% as massive. In 2017, WASP-49 b was found to have an extensive cloud of sodium, which was confounding to scientists. Further observations in 2019 using the Hubble Space Telescope detected the presence of other minerals, including magnesium and iron, which appeared to be magnetically bound to the gas giant.

WASP-49 b and its star are predominantly composed of hydrogen and helium, with only trace amounts of sodium – not enough to account for this cloud. In addition, there was no indication of how this sodium cloud was ejected into space. In our Solar System, gas emissions from Jupiter’s volcanic moon Io create a similar phenomenon. In a recent study, an international team led by scientists from NASA’s Jet Propulsion Laboratory found potential evidence of a rocky, volcanic moon orbiting WASP-49 b. While not yet confirmed, the presence of a volcanic exomoon around this gas giant could explain the presence of this sodium cloud.

October 10, 2024October 10, 2024 by Matt Williams

Exoplanet Discovered in a Binary System Could Explain Why Red Dwarfs Form Massive Planets

This artist's concept illustrates a red dwarf star surrounded by exoplanets. Credit: NASA/JPL-Caltech

In recent years, the number of known extrasolar planets (aka. exoplanets) has grown exponentially. To date, 5,799 exoplanets have been confirmed in 4,310 star systems, with thousands more candidates awaiting confirmation. What has been particularly interesting to astronomers is how M-type (red dwarf) stars appear to be very good at forming rocky planets. In particular, astronomers have detected many gas giants and planets that are several times the mass of Earth (Super-Earths) orbiting these low-mass, cooler stars.

Consider TOI-6383A, a cool dwarf star less than half the mass of the Sun that orbits with an even smaller, cooler companion – the red dwarf star TOI-6383B. In a recent study, an international team of astronomers with the Searching for Giant Exoplanets around M-dwarf Stars (GEMS) survey detected a giant planet transiting in front of the primary star, designated TOI-6383Ab. This planet is similar in size and mass to the system’s companion star, which raises questions about the formation of giant planets in red dwarf star systems.

October 1, 2024October 1, 2024 by Laurence Tognetti

We Don’t See Many Planets in Old Triple Star Systems

Example of a triple star system. (Credit: Caltech/R. Hurt (Infrared Processing and Analysis Center, or IPAC)

Why is it important to search for exoplanets in triple star systems and how many can we find there? This is what a recent study accepted by Astrophysics & Space Science hopes to address as a pair of researchers from the University of Texas at Arlington investigated the statistical likelihood of triple star systems hosting exoplanets. This study holds the potential to help researchers better understand the formation and evolution of triple star systems and whether they are suitable to find life as we know it.

September 21, 2024September 21, 2024 by Matt Williams

Advanced Civilizations Will Overheat Their Planets Within 1,000 Years

Global temperature increases over the past thirty years, visualized. Credit: NOAA/NCEI

Earth’s average global temperatures have been steadily increasing since the Industrial Revolution. According to the National Oceanic and Atmospheric Agency (NOAA), Earth has been heating up at a rate of 0.06 °C (0.11 °F) per decade since 1850 – or about 1.11 °C (2 °F) in total. Since 1982, the average annual increase has been 0.20 °C (0.36 °F) per decade, more than three times as fast. What’s more, this trend is projected to increase by between 1.5 and 2 °C (2.7 to 3.6 °F) by mid-century, possibly more! This is a direct consequence of burning fossil fuels, which has increased exponentially since the mid-19th century.

Depending on the extent of temperature increases, the impact on Earth’s habitability could be catastrophic. In a recent study, a team of scientists examined how temperature increases are a long-term issue facing advanced civilizations and not just a matter of fossil fuel consumption. As they argue, rising planetary temperatures could be an inevitable result of the exponential growth of energy consumption. Their findings could have serious implications for astrobiology and the Search for Extraterrestrial Intelligence (SETI).