Extrasolar Planets Archives

June 30, 2022June 30, 2022 by Matt Williams

Tidal Heating Could Make Exomoons Much More Habitable (and Detectable)

An artist's illustration of the Kepler 1625 system. The star in the distance is called Kepler 1625. The gas giant is Kepler 1625B, and the exomoon orbiting it is unnamed. The moon is about as big as Neptune, but is a gas moon. Image: NASA, ESA, and L. Hustak (STScI)

Within the Solar System, most of our astrobiological research is aimed at Mars, which is considered to be the next-most habitable body beyond Earth. However, future efforts are aimed at exploring icy satellites in the outer Solar System that could also be habitable (like Europa, Enceladus, Titan, and more). This dichotomy between terrestrial (rocky) planets that orbit within their a system’s Habitable Zones (HZ) and icy moons that orbit farther from their parent stars is expected to inform future extrasolar planet surveys and astrobiology research.

In fact, some believe that exomoons may play a vital role in the habitability of exoplanets and could also be a good place to look for life beyond the Solar System. In a new study, a team of researchers investigated how the orbit of exomoons around their parent bodies could lead to (and place limits on) tidal heating – where gravitational interaction leads to geological activity and heating in the interior. This, in turn, could help exoplanet-hunters and astrobiologists determine which exomoons are more likely to be habitable.

June 15, 2022June 15, 2022 by Matt Williams

There Could Be Four Hostile Civilizations in the Milky Way

This artists’s cartoon view gives an impression of how common planets are around the stars in the Milky Way. The planets, their orbits and their host stars are all vastly magnified compared to their real separations. A six-year search that surveyed millions of stars using the microlensing technique concluded that planets around stars are the rule rather than the exception. The average number of planets per star is greater than one.

In 1977, the Big Ear Radio Telescope at Ohio State University picked up a strong narrowband signal from space. The signal was a continuous radio wave that was very strong in intensity and frequency and had many expected characteristics of an extraterrestrial transmission. This event would come to be known as the Wow! Signal, and it remains the strongest candidate for a message sent by an extraterrestrial civilization. Unfortunately, all attempts to pinpoint the source of the signal (or detect it again) have failed.

This led many astronomers and theorists to speculate as to the origin of the signal and what type of civilization may have sent it. In a recent series of papers, amateur astronomer and science communicator Alberto Caballero offered some fresh insights into the Wow! Signal and extraterrestrial intelligence in our cosmic neighborhood. In the first paper, he surveyed nearby Sun-like stars to identify a possible source for the signal. In the second, he estimates the prevalence of hostile extraterrestrial civilizations in the Milky Way Galaxy and the likelihood that they’ll invade us.

May 27, 2022February 17, 2023 by Matt Williams

A new Quantum Technique Could Enable Telescopes the Size of Planet Earth

These annotated images, obtained with the GRAVITY instrument on ESO’s Very Large Telescope Interferometer (VLTI) between March and July 2021, show stars orbiting very close to Sgr A*, the supermassive black hole at the heart of the Milky Way. One of these stars, named S29, was observed as it was making its closest approach to the black hole at 13 billion kilometres, just 90 times the distance between the Sun and Earth. Another star, named S300, was detected for the first time in the new VLTI observations. To obtain the new images, the astronomers used a machine-learning technique, called Information Field Theory. They made a model of how the real sources may look, simulated how GRAVITY would see them, and compared this simulation with GRAVITY observations. This allowed them to find and track stars around Sagittarius A* with unparalleled depth and accuracy.

There’s a revolution underway in astronomy. In fact, you might say there are several. In the past ten years, exoplanet studies have advanced considerably, gravitational wave astronomy has emerged as a new field, and the first images of supermassive black holes (SMBHs) have been captured. A related field, interferometry, has also advanced incredibly thanks to highly-sensitive instruments and the ability to share and combine data from observatories worldwide. In particular, the science of very-long baseline interferometry (VLBI) is opening entirely new realms of possibility.

According to a recent study by researchers from Australia and Singapore, a new quantum technique could enhance optical VLBI. It’s known as Stimulated Raman Adiabatic Passage (STIRAP), which – in combination with pre-distributed entanglement – allows quantum information to be transferred without losses. When imprinted into a quantum error correction code, this technique could allow for VLBI observations into previously inaccessible wavelengths. Once integrated with next-generation instruments, this technique could allow for more detailed studies of black holes, exoplanets, the Solar System, and the surfaces of distant stars.

May 21, 2022May 21, 2022 by Matt Williams

The Closeby Habitable Exoplanet Survey (CHES) Could Detect Exoplanets Within a few Dozen Light-Years of Earth Using Astrometry

Artist's concept of Earth-like exoplanets, which (according to new research) need to strike the careful balance between water and landmass. Credit: NASA

As of this article’s writing, NASA has indicated that 5,030 extrasolar planets have been confirmed in 3,772 systems, with another 8,974 candidates awaiting confirmation. With next-generation instruments like the James Webb Space Telescope (JWST) coming online, the number and diversity of confirmed exoplanets are expected to grow exponentially. In particular, astronomers anticipate that the number of known terrestrial planets and Super-Earths will drastically increase.

In the coming years, the opportunities for exoplanet studies will increase considerably as thousands more are discovered using various methods. In a recent study, a team led by the Chinese Academy of Sciences (CAS) described a new space-telescope concept known as the Closeby Habitable Exoplanet Survey (CHES). This proposed observatory will search for Earth-like planets in the habitable zones (HZs) of Sun-like stars within approximately 33 light-years (10 parsecs) using a method known as micro-arcsecond relative astrometry.

March 20, 2022March 20, 2022 by Matt Williams

Why Would an Alien Civilization Send Out Von Neumann Probes? Lots of Reasons, says a new Study

Artist's concept of the New Horizons spacecraft encountering a Kuiper Belt object, part of an extended mission after the spacecraft’s July 2015 Pluto flyby. Credits: NASA/JHUAPL/SwRI

In 1948-49, mathematician, physicist, computer scientist, and engineer John von Neumann introduced the world to his idea of “Universal Assemblers,” a species of self-replicating robots. Von Neumann’s ideas and notes were later compiled in a book titled “Theory of self-reproducing automata,” published in 1966 (after his death). In time, this theory would have implications for the Search for Extraterrestrial Intelligence (SETI), with theorists stating that advanced intelligence must have deployed such probes already.

The reasons and technical challenges of taking the self-replicating probe route are explored in a recent paper by Gregory L. Matloff, an associate professor at the New York City College of Technology (NYCCT). In addition to exploring why an advanced species would opt to explore the galaxy using Von Neumann probes (which could include us someday), he explored possible methods for interstellar travel, strategies for exploration, and where these probes might be found.

March 19, 2022March 19, 2022 by Matt Williams

Machine Learning Will be one of the Best Ways to Identify Habitable Exoplanets

Illustration of Kepler-186f, a recently-discovered, possibly Earthlike exoplanet that could be a host to life. Scientists could use this one or one like it to measure planetary entropy production as a prelude to exploration. (NASA Ames, SETI Institute, JPL-Caltech, T. Pyle)

The field of extrasolar planet studies is undergoing a seismic shift. To date, 4,940 exoplanets have been confirmed in 3,711 planetary systems, with another 8,709 candidates awaiting confirmation. With so many planets available for study and improvements in telescope sensitivity and data analysis, the focus is transitioning from discovery to characterization. Instead of simply looking for more planets, astrobiologists will examine “potentially-habitable” worlds for potential “biosignatures.”

This refers to the chemical signatures associated with life and biological processes, one of the most important of which is water. As the only known solvent that life (as we know it) cannot exist, water is considered the divining rod for finding life. In a recent study, astrophysicists Dang Pham and Lisa Kaltenegger explain how future surveys (when combined with machine learning) could discern the presence of water, snow, and clouds on distant exoplanets.

March 4, 2022March 4, 2022 by Evan Gough

Astronomers Scan 800 Pulsars to See If Any of Them Have Planets

Lich (PSR B1257+12) is a pulsar 2,300 ly away in the constellation of Virgo - 20 km in diameter, formed 2 billion years ago by two white dwarfs merging with each other - Has three known planets, named Draugr, Poltergeist and Phobetor - Both the first extrasolar planets and the first pulsar planets to be discovered - Draugr is the lowest-mass planet yet discovered by any observational technique (twice the mass of Earth's moon.) Image Credit: By Pablo Carlos Budassi - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=94333766

Astronomers discovered the first exoplanets in 1992. They found a pair of them orbiting the pulsar PSR B1257+12 about 2300 light-years from the Sun. Two years later they discovered the third planet in the system.

Now a team of astronomers are trying to duplicate that feat by searching 800 known pulsars for exoplanets.

March 3, 2022March 3, 2022 by Matt Williams

How to Search for Life as we Don’t Know it

The fields of extrasolar planet studies and astrobiology have come a long way in recent years. To date, astronomers have confirmed the existence of 4,935 exoplanets in 3,706 star systems, with another 8,709 candidates awaiting confirmation. With so many planets to study, next-generation instruments, and improved data analysis, the focus is transitioning from discovery to characterization. With the James Webb Space Telescope now deployed, these fields are about to advance much farther!

In particular, scientists anticipate that the characterization of planetary atmospheres may lead to the discovery of “biosignatures” – signs we associate with life and biological processes. The challenge will be how to recognize signatures that don’t conform to “life as we know it.” In a recent study, researchers from the School of Earth and Space Exploration (SESE) at Arizona State University (ASU) investigate possible tools for searching for life “as we don’t know it.”

February 25, 2022February 25, 2022 by Matt Williams

An Exoplanet is Definitely Orbiting Two Stars

Artist's impression of Kepler-16b, the first planet known to definitively orbit two stars - what's called a circumbinary planet. The planet, which can be seen in the foreground, was discovered by NASA's Kepler mission. Credit: NASA/JPL-Caltech/T. Pyle

Remember that iconic scene in Star Wars, where a young Skywalker steps out onto the surface of Tatooine and watches the setting of two suns? As it turns out, this may be what it is like for lifeforms on the exoplanet known as Kepler-16, a rocky planet that orbits in a binary star system. Originally discovered by NASA’s Kepler mission, an international team of astronomers recently confirmed that this planet orbits two stars at once – what is known as a circumbinary planet.

February 12, 2022February 12, 2022 by Matt Williams

A THIRD Planet Found Orbiting Nearby Proxima Centauri

This artist’s impression shows Proxima d, a planet candidate recently found orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The planet is believed to be rocky and to have a mass about a quarter that of Earth. Two other planets known to orbit Proxima Centauri are visible in the image too: Proxima b, a planet with about the same mass as Earth that orbits the star every 11 days and is within the habitable zone, and candidate Proxima c, which is on a longer five-year orbit around the star.

In August of 2016, astronomers with the European Southern Observatory (ESO) announced that they had discovered an exoplanet orbiting in neighboring Proxima Centauri. Based on Radial Velocity measurements (aka. Doppler Photometry), the discovery team estimated that the planet was roughly the same size and mass as Earth and orbited with Proxima Centauri’s Circumsolar Habitable Zone (HZ). In 2020, this planet was confirmed by follow-up observations.

In that same year, a second exoplanet (Proxima c) roughly seven times the mass of Earth (a Super-Earth or mini-Neptune) was confirmed. As if that wasn’t enough, an international team of astronomers with the ESO recently announced that they detected a third exoplanet around Proxima Centauri – Proxima d! This Mars-sized planet orbits about halfway between its host star and Proxima b and is one of the lightest exoplanets ever discovered.