What Role do Radioactive Elements Play in a Planet’s Habitability?

To date, astronomers have confirmed the existence of 4,301 extrasolar planets in 3,192 star systems, with another 5,650 candidates awaiting confirmation. In the coming years, next-generation telescopes will allow astronomers to directly observe many of these exoplanets and place tighter constraints on their potential habitability. In time, this could lead to the discovery of life beyond our Solar System!

The only problem is, finding evidence of life requires that we know what to look for. According to a new study by an interdisciplinary team of scientists from the University of California Santa Cruz (UCSC), radioactive elements might play a role in planetary habitability. Future studies of rocky exoplanets, they argue, should therefore look for specific isotopes that indicate the presence of long-lived elements like thorium and uranium.

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Based on Kepler Data, There’s a 95% Chance of an Earth-Like Planet Within 20 Light-Years

In the past few decades, the study of exoplanets has grown by leaps and bounds, with 4296 confirmed discoveries in 3,188 systems and an additional 5,634 candidates awaiting confirmation. Because of this, scientists have been able to get a better idea about the number of potentially-habitable planets that could be out there. A popular target is stars like our own, which are known as G-type yellow dwarfs.

Recently, an international team of scientists (led by researchers from the NASA Ames Research Center) combined data from by the now-defunct Kepler Space Telescope and the European Space Agency’s (ESA) Gaia Observatory. What this revealed is that half of the Sun-like stars in our Universe could have rocky, potentially-habitable planets, the closest of which could be in our cosmic backyard!

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Those are Exoplanets. You’re Looking at Actual Exoplanets 63 Light-Years Away!

Located 63.4 light-years from Earth in the constellation Pictor is the young and bright blue star, Beta Pictoris. In 2008, observations conducted from the ESO’s Paranal Observatory in Chile confirmed the presence of an extrasolar planet. This planet was Beta Pictoris b, a Super-Jupiter with an orbital period of up between 6890 and 8890 days (~19 to 24 years) that was confirmed by directly imaging it as it passed behind the star.

In August of 2019, a second planet was detected (another Super-Jupiter) orbiting closer to Beta Pictoris. However, due to its proximity to its parent star, it could only be studied through indirect means (radial velocity measurements). After conducting a reanalysis of data obtained by the VLT, astronomers with the GRAVITY collaboration were able to confirm the existence of Beta Pictoris c through direct imaging.

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Machine Learning Algorithm Scoops up 50 New Exoplanets

Advances in technology are having a profound impact on astronomy and astrophysics. At one end, we have advanced hardware like adaptive optics, coronographs, and spectrometers that allow for more light to be gathered from the cosmos. At the other end, we have improved software and machine learning algorithms that are allowing for the data to be analyzed and mined for valuable nuggets of information.

One area of research where this is proving to be invaluable is in the hunt for exoplanets and the search for life. At the University of Warwick, technicians recently developed an algorithm that was able to confirm the existence of 50 new exoplanets. When used to sort through archival data, this algorithm was able to sort through a sample of candidates and determine which were actual planets and which were false positives.

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There are Natural Starshades Out There, Which Would Help Astronomers Image Exoplanets

In the past few decades, the study of extrasolar planets has grown by leaps and bounds, with the confirmation of over 4000 exoplanets. With so many planets available for study, the focus of exoplanet-researchers is shifting from discovery to characterization. In the coming years, new technologies and next-generation telescopes will also enable Direct Imaging studies, which will vastly improve our understanding of exoplanet atmospheres.

To facilitate this process, astronomers will rely on costly technologies like coronagraphs and starshades, which block out the light of a star so any planets orbiting it will become more visible. However, according to a new study by an international team of astronomers and cosmologists, eclipsing binary stars could provide all the shading that’s needed to directly image planets orbiting them.

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Do the TRAPPIST-1 Planets Have Atmospheres?

Most exoplanets orbit red dwarf stars because they're the most plentiful stars. This is an artist's illustration of what the TRAPPIST-1 system might look like from a vantage point near planet TRAPPIST-1f (at right). Credits: NASA/JPL-Caltech

In February of 2017, the scientific community rejoiced as NASA announced that a nearby star (TRAPPIST-1) had a system of no less than seven rocky planets! Since that time, astronomers have conducted all kinds of follow-up observations and studies in the hopes of learning more about these exoplanets. In particular, they have been attempting to learn if any of the planets located in the stars Habitable Zone (HZ) could actually be habitable.

Many of these studies have been concerned with whether or not the TRAPPIST-1 planets have sufficient water on their surfaces. But just as important is the question of whether or not any have viable atmospheres. In a recent study that provides an overview of all observations to date on TRAPPIST-1 planets, a team found that depending on the planet in question, they are likely to have good atmospheres, if any at all.

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Do Hot Jupiters Form Close in, or Do They Migrate? A Newly-Discovered Planet Might Help Answer This

The discovery of over 4000 planets (4,171 confirmed and counting!) beyond our Solar System has revolutionized the field of astronomy. Unfortunately, one of the downsides of all these discoveries is how it has shaken up theories about how our Solar System formed. In the past, astronomers thought that the eight planets (or nine, or over one hundred, depending on your point of view) formed where they are currently located.

However, the discovery of gas giants that orbit close to their stars (aka. “Hot Jupiters”) has confounded this thinking. But according to a recent NASA-supported study, the recent discovery of a young gas giant could offer clues as to how Jupiter-like planets form and whether or not they migrate. This discovery was made possible thanks to the Spitzer Space Telescope, which continues to reveal things about our Universe even in retirement.

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Tiny Cubesat Detects an Exoplanet

In the past decade and a half, a total of 4,164 thousand planets have been discovered beyond our Solar System, while another 5220 await confirmation. The majority of these were detected by the venerable Kepler Space Telescope, while the remainder have been observed by the Transitting Exoplanet Survey Satellite (TESS) and a combination of other satellites and ground-based telescopes.

But in what is a new record, a known super-Earth was recently observed by the Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA) small satellite – making it the smallest observatory to spot an exoplanet. Led by a team from the Massachusetts Institute of Technology (MIT), this mission has demonstrated that small satellites can perform complex tasks in space normally carried out by large observatories.

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What Are Some Clues to the Climates of Exoplanets?

In the past few decades, the number of planets discovered beyond our Solar System has grown exponentially. To date, a total of 4,158 exoplanets have been confirmed in 3,081 systems, with an additional 5,144 candidates awaiting confirmation. Thanks to the abundance of discoveries, astronomers have been transitioning in recent years from the process of discovery to the process of characterization.

In particular, astronomers are developing tools to assess which of these planets could harbor life. Recently, a team of astronomers from the Carl Sagan Institute (CSI) at Cornell University designed an environmental “decoder” based on the color of exoplanet surfaces and their hosts stars. In the future, this tool could be used by astronomers to determine which exoplanets are potentially-habitable and worthy of follow-up studies.

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Fomalhaut’s Planet Has Gone Missing, But it Might Have Been Something Even More Interesting

Planets don’t simply disappear. And yet, that appears to be what happened to Fomalhaut b (aka. Dagon), an exoplanet candidate located 25 light-years from Earth. Observed for the first time by the Hubble Space Telescope in 2004, then confirmed by follow-up observations in 2008 and 2012, this exoplanet candidate was the first to be detected in visible wavelengths (i.e. the Direct Imaging Method.)

Over time, this candidate got fainter and wider until it disappeared from sight altogether. This led to all kinds of speculation, which included the possibility of a collision that reduced the planet to debris. Recently, a team of astronomers from the University of Arizona has suggested another possibility – Fomalhaut b was never a planet at all, but an expanding cloud of dust from two planetesimals that smashed together.

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