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.

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

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

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.”

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Astronomers Measure the Layers of an Exoplanet's Atmosphere

The NASA/ESA Hubble Space Telescope’s data was used to analyze the atmosphere of the super-hot exoplanet WASP-79b, located 780 light-years away in the constellation Eridanus. Among exoplanets, WASP-79b is among the largest ever observed. The planet is larger than Jupiter, and its very deep, hazy atmosphere sizzles at 1,650 degrees Celsius – the temperature of molten glass. The Hubble Space Telescope and other observatories measured how starlight is filtered through the planet's atmosphere, allowing for its chemical composition to be analyzed. Hubble has detected the presence of water vapor. The surprise in recently published results, is that the planet's sky doesn't have any evidence for an atmospheric phenomenon called Rayleigh scattering, where certain colors of light are dispersed by very fine dust particles in the upper atmosphere. Rayleigh scattering is what makes Earth's skies blue by scattering the shorter (bluer) wavelengths of sunlight. Because WASP-79b doesn't seem to have this phenomenon, the daytime sky would likely be yellowish, researchers say. Link: NASA Press Release

The number of planets discovered beyond our Solar System has grown exponentially in the past twenty years, with 4,919 confirmed exoplanets (and another 8,493 awaiting confirmation)! Combined with improved instruments and data analysis, the field of study is entering into an exciting new phase. In short, the focus is shifting from discovery to characterization, where astronomers can place greater constraints on potential habitability.

In particular, the characterization of exoplanet atmospheres will allow astronomers to determine their chemical makeup and whether they have the right characteristics to support life. In a new study led by the University of Lund, an international team of researchers characterized the atmosphere of one of the most extreme exoplanets yet discovered. This included discerning what could be several distinct layers that have particular characteristics.

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A Moon Might Have Been Found Orbiting an Exoplanet

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)
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)

In the past three decades, the field of extrasolar planet studies has advanced by leaps and bounds. To date, 4,903 extrasolar planets have been confirmed in 3,677 planetary systems, with another 8,414 candidates awaiting confirmation. The diverse nature of these planets, ranging from Super-Jupiters and Super-Earths to Mini-Neptunes and Water Worlds, has raised many questions about the nature of planet formation and evolution. A rather important question is the role and commonality of natural satellites, aka. “exomoons.”

Given the number of moons in the Solar System, it is entirely reasonable to assume that moons are ubiquitous in our galaxy. Unfortunately, despite thousands of know exoplanets, there are still no confirmed exomoons available for study. But thanks to Columbia University’s Professor David Kipping and an international team of astronomers, that may have changed. In a recent NASA-supported study, Kipping and his colleagues report on the possible discovery of an exomoon they found while examining data from the Kepler Space Telescope.

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Astronomers Find 70 Planets Without Stars Floating Free in the Milky Way

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.

The field of extrasolar planet studies continues to reveal some truly amazing things about our Universe. After decades of having just a handful of exoplanets available for study, astronomers are now working with a total of 4,884 confirmed exoplanets and another 8,288 awaiting confirmation. This number is expected to increase exponentially in the coming years as next-generation missions like the James Webb Space Telescope (JWST), Euclid, PLATO, and the Nancy Grace Roman Space Telescope (RST) reveal tens of thousands more.

In addition to learning a great deal about the types of exoplanets that are out there and what kind of stars are known to give rise to them, astronomers have also made another startling discovery. There is no shortage of exoplanets in our galaxy that don’t have a parent star. Using telescopes from around the world, a team of astronomers recently discovered 70 additional free-floating planets (FFPs), the largest sample of “Rogue Planets” discovered to date, and nearly doubling the number of FFPs available for study.

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Would Mars be More Habitable if it Orbited a Red Dwarf?

Artist’s rendering of an exoplanet system experiencing atmospheric escape in connection with its host star. Credit: MACH Center / Aurore Simonnet

Thanks to the explosion in discoveries made in the last decade, the study of extrasolar planets have entered a new phase. With 4,884 confirmed discoveries in 3,659 systems (and another 7,958 candidates awaiting confirmation), scientists are shifting their focus from discovery to characterization. This means examining known exoplanets more closely to determine if they possess the necessary conditions for life, as well as “biomarkers” that could indicate the presence of life.

A key consideration is how the type of star may impact a planet’s chances of developing the right conditions for habitability. Consider red dwarf stars, the most common stellar class in the Universe and a great place to find “Earth-like,” rocky planets. According to a new study by an international team of scientists, a lifeless planet in our own backyard (Mars) might have evolved differently had it orbited a red dwarf instead of the Sun.

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A Space Telescope With one job: Find Habitable Planets at Alpha Centauri

Artist's impression of a hypothetical planet orbiting the star Alpha Centauri B, a member of the triple star system that is the closest to Earth. Credit: ESO

Alpha Centauri, the nearest star system to our Sun, is like a treasure trove with many scientific discoveries just waiting to be found. Part of what makes it so compelling is that our efforts to detect extrasolar planets there have failed to yield any concrete results to date. While the study of exoplanets has progressed exponentially in recent years, with 4,575 confirmed planets in 3,392 systems in the Milky Way (and even neighboring galaxies), astronomers are still having difficulty determining if anyone is next door.

In the coming decades, Breakthrough Initiatives plans to send a mission there known as Starshot, a lightsail craft that could make the journey in 20 years. On Nov. 16th, Breakthrough Initiatives announced another project for detecting exoplanets next door. It’s called the Telescope for Orbit Locus Interferometric Monitoring of our Astronomical Neighbourhood (TOLIMAN), a space telescope dedicated to finding rocky planets orbiting in Alpha Centauri’s circumsolar habitable zone (aka. “Goldilocks Zone”).

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Astronomers Measure the Atmosphere on a Planet Hundreds of Light-Years Away

The NASA/ESA Hubble Space Telescope’s data was used to analyze the atmosphere of the super-hot exoplanet WASP-79b, located 780 light-years away in the constellation Eridanus. Among exoplanets, WASP-79b is among the largest ever observed. The planet is larger than Jupiter, and its very deep, hazy atmosphere sizzles at 1,650 degrees Celsius – the temperature of molten glass. The Hubble Space Telescope and other observatories measured how starlight is filtered through the planet's atmosphere, allowing for its chemical composition to be analyzed. Hubble has detected the presence of water vapor. The surprise in recently published results, is that the planet's sky doesn't have any evidence for an atmospheric phenomenon called Rayleigh scattering, where certain colors of light are dispersed by very fine dust particles in the upper atmosphere. Rayleigh scattering is what makes Earth's skies blue by scattering the shorter (bluer) wavelengths of sunlight. Because WASP-79b doesn't seem to have this phenomenon, the daytime sky would likely be yellowish, researchers say. Link: NASA Press Release

The field of extrasolar planet research has advanced by leaps and bounds over the past fifteen years. To date, astronomers have relied on space-based and ground-based telescopes to confirm the existence of 4,566 exoplanets in 3,385 systems, with another 7,913 candidates awaiting confirmation. More importantly, in the past few years, the focus of exoplanet studies has slowly shifted from the process of discovery towards characterization.

In particular, astronomers are making great strides when it comes to the characterization of exoplanet atmospheres. Using the Gemini South Telescope (GST) in Chile, an international team led by Arizona State University (ASU) was able to characterize the atmosphere of a “hot Jupiter” located 340 light-years away. This makes them the first team to directly measure the chemical composition of a distant exoplanet’s atmosphere, a significant milestone in the hunt for habitable planets beyond our Solar System.

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Rocky Planets Might Need to be the Right age to Support Life

This artist’s impression shows the planet orbiting the Sun-like star HD 85512 in the southern constellation of Vela (The Sail). This planet is one of sixteen super-Earths discovered by the HARPS instrument on the 3.6-metre telescope at ESO’s La Silla Observatory. This planet is about 3.6 times as massive as the Earth lis at the edge of the habitable zone around the star, where liquid water, and perhaps even life, could potentially exist. Credit: ESO

Extrasolar planets are being discovered at a rapid rate, with 4,531 planets in 3,363 systems (with another 7,798 candidates awaiting confirmation). Of these, 166 have been identified as rocky planets (aka. “Earth-like”), while another 1,389 have been rocky planets that are several times the size of Earth (“Super-Earths). As more and more discoveries are made, the focus is shifting from the discovery process towards characterization.

In order to place tighter constraints on whether any of these exoplanets are habitable, astronomers and astrobiologists are looking for ways to detect biomarkers and other signs of biological processes. According to a new study, astronomers and astrobiologists should look for indications of a carbon-silicate cycle. On Earth, this cycle ensures that our climate remains stable for eons and could be the key to finding life on other planets.

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A Technique to Find Oceans on Other Worlds

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

You could say that the study of extrasolar planets is in a phase of transition of late. To date, 4,525 exoplanets have been confirmed in 3,357 systems, with another 7,761 candidates awaiting confirmation. As a result, exoplanet studies have been moving away from the discovery process and towards characterization, where follow-up observations of exoplanets are conducted to learn more about their atmospheres and environments.

In the process, exoplanet researchers hope to see if any of these planets possess the necessary ingredients for life as we know it. Recently, a pair of researchers from Northern Arizona University, with support from the NASA Astrobiology Institute’s Virtual Planetary Laboratory (VPL), developed a technique for finding oceans on exoplanets. The ability to find water on other planets, a key ingredient in life on Earth, will go a long way towards finding extraterrestrial life.

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