Planets beyond our solar system
Astronomers used decades of archival data and new radial velocity measurements to search for exoplanets around a neaby binary star, 70 Oph AB. They didn't find any, which can seem like a failure. But in this case, their work only ruled out large, Jupiter-mass planets at certain distances. There could still be Earth-sized planets there, and their precise findings will only fuel a deeper search with more powerful telescopes.
Brown dwarfs are the black (or brown?) sheep of astronomy. Theyâre too big to be considered a traditional gas planet, but they are too small to have started nuclear fusion and made the full transition to star-hood. They also change dramatically over time, cooling, shrinking, and spinning faster as they age. Or at least we think they do - our models of the atmospheres of these celestial objects arenât the best, according to a new paper in The Astrophysical Journal Letters by a team led by Zafar Rustamkulov at Caltech and NASAâs Jet Propulsion Laboratory.
Potential âSecond generationâ planet detection around a dying stellar white dwarf opens a whole new chapter of exoplanetary science.
Exoplanets continue to challenge our understanding of planetary formation, evolution, and whether they might be able to support life as we know it. Scientists often use planets in our solar system as analogs for exoplanets, studying exoplanets with extremely short orbital periods forces scientists to constantly rethink our understanding of what planets can withstand during their lifetimes. One such type of exoplanet that has entered the foray in recent years are âlava worldâ exoplanets, and especially lava exoplanets that orbit dangerously close to their stars. But while it has been long known that lava worlds on with higher temperatures have atmospheres, âcolderâ lava worlds have been found to lack atmospheres.
Since their first discovery in 1995, hot Jupiter exoplanets (hot Jupiters, for short) quickly challenged our understanding of exoplanet formation and evolution, including exoplanetary system architecture. This is because, as their name implies, they orbit at extremely close distances to their host stars, ranging from a few days to a few hours. Some of their orbits are even oval-shaped, called eccentric in the scientific community, meaning their orbit is oval-shaped. But could such an orbit cause a hot Jupiter to completely vanish from view, preventing astronomers from studying it?
In our own solar system, all eight planets orbit our Sun in a nice, orderly fashion. None are more than 7° or so out of alignment with the equator, and all of them rotate in the same direction as the Sun itself. But thatâs not the case for all solar systems, and a new paper published in Astronomy & Astrophysics from a team of researchers led by Yann Carteret, a PhD student at the University of Geneva (UNIGE), describes the first time weâve ever found an exoplanet orbiting the opposite direction of its red dwarf parent star - and it has major implications for our understanding of planet formation theory.
Most exoplanets we find have been around a long time. Theyâve cleared out their orbital path (one of the requirements of planethood, as fans of Pluto well know), have their own gravitational pull, and in many cases shine with their own infrared light. But it takes a long time to get to that point - finding âyoungâ planets is much harder. But a new paper available in The Astrophysical Journal Letters by a research team led by Andrea Bernardi of Diego Portales University in Chile describes a new paper that definitely takes the prize as the youngest exoplanet weâve yet found.
Studying exoplanets has provided astronomers with a plethora of insights regarding what characteristics need to be searched to find life beyond Earth. For the longest time, astronomers merely thought an exoplanet in a starâs habitable zone was a sufficient criterion for an Earth-like world. However, astronomers have learned that certain stars are more active than our Sun, resulting in exoplanets orbiting in the habitable zone being blasted with far more radiation than Earth could handle. In recent years, astronomers have recognized that a planetâs magnetic field, which shields the Earth from harmful radiation, could be a prime characteristic for identifying Earth-like worlds.
Weâve found over 5,500 exoplanets so far. Dozens of them have been in the habitable zone of their parent stars, where, at least in theory, they could host an ocean. But weâve never definitively found a liquid ocean on another planet. A new paper from researchers Eleanor Cornish and Tyler Robinson of the University of Arizona, available in pre-print on arXiv and submitted to the Astrophysical Journal, looks at a unique way we might be able to find one - by looking for its âglintâ.
The James Webb Space Telescope (JWST) has opened up many wonders of the cosmos to scientists since it began its science operations a few years ago. But one thing that it hasnât done is find an âexomoonâ. These, as yet still theoretical, moons orbit exoplanets in other star systems, and JWST was supposed to find a plethora of them. However, so far it has found precisely none. It seems the cause is noise in the telescopeâs instrumentation or noise from the star itself. But a new paper, available in pre-print form on arXiv from David Kipping, an astronomer at Columbia and also the host of the Cool Worlds YouTube Channel, shows how JWST can, in fact, find an exomoon. It likely just has to look for one in the same place repeatedly.
The discovery of lava worlds with atmospheres is challenging our theories of how atmospheres escape, and calling into question the idea of the cosmic shoreline. Stanford researchers have developed a model that explains how lava-covered worlds close to their stars can retain their atmospheres. The new theory could inform the search for life beyond our Solar System.
A new study warns that astronomers measuring the rotation of distant exoplanets may often be measuring atmospheric winds instead, since the clouds of Venus circle the planet roughly 60 times faster than Venus itself actually spins. Kane proposes using multi-wavelength observations to correct for this, work that will matter enormously once the European Space Agency's PLATO mission launches in 2027 and, researchers predict, discovers several hundred Venus like exoplanets.
Astronomers found evidence that a giant stream of gas flowing into the GW Orionis young triple-star system may have tilted its planet-forming disk, offering a new explanation for why some planetary systems are misaligned. The next step is to search for shock fronts in the system, and to search for more of these massive streams of gas in other systems.
Reading the atmosphere of another world means catching starlight as it filters through that planet's air during a transit. The signal is about one part in a million and a true Earth twin transits only once a year, so you cannot simply repeat the measurement until the noise averages away. Each attempt has to work on its own. A team led from Shanghai has proposed the alternative to building an impossibly large mirror in space - nine hundred, one metre telescopes, flying together, watching the same transit and analysing the light together.
Most exoplanetary systems have a plane of dust similar to the zodiacal dust of our solar system. This dust absorbs some of the very light we use to find biosignatures in exoplanet atmospheres, and could make our search for life more challenging.
When astronomers talk about directly imaging an exoplanet that is orbiting a far away star, the analogy they most commonly go with is trying to spot a fireflight next to a massive search light. An Earth-like exoplanet is incredibly dim - usually between 100 million and 10 billion times fainter than its host star. Understandably, that makes them very difficult to see. But a new paper from Hyunsoo Choi of Hanyang University in South Korea and his co-authors, which is available in pre-print on arXiv, describes a theoretical solution - use a mix of smart computer algorithms and quantum physics.
Jupiterâs moon, Io, is the most volcanically active planetary body in the solar system, boasting hundreds of active volcanoes spewing molten lava into space. This occurs from a process called tidal heating where Jupiterâs massive gravity constantly stretches and compresses the much smaller moon during the latterâs non-circular orbit. However, a lesser-known fact is that Ioâs volcanic gases fuel Jupiterâs aurorae by traveling along Jupiterâs magnetic field lines, resulting in Jupiterâs bright aurorae observed by spacecraft and Earth-based telescopes. But what if this same phenomenon could be used to detect Io-like exomoons, also called exo-Ios, orbiting Jupiter-like exoplanets?
Scientists at ASU's School of Earth and Space Exploration have demonstrated how clouds in a sub-Neptune's atmosphere shape the interior structure of the planet.
Through the Photonics-Enabled Exoplanet Spectroscopic System (PEEPSS) program, researchers are developing a technology that will assist NASA's planned Habitable World's Observatory (HWO).
Sub-Neptune exoplanets, exoplanets that are slightly smaller than Neptune, have been designated as the most common type of planet in the Milky Way Galaxy based on their vast discovery numbers, totaling almost 3,300 out of the more than 6,300 confirmed exoplanets to date. Despite these numbers, the characteristics of sub-Neptunes remain relatively unknown. This is primarily due to our own solar system not having its own sub-Neptune to use as an analog, along with their atmospheres being thick and hazy. As a result, this makes telescopic observations, even from powerful instruments like NASAâs James Webb Space Telescope, extremely difficult.
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