FYFD

Tag: exoplanets

  • Inside an Alien Atmosphere

    Inside an Alien Atmosphere

    Studying the physics of planetary atmospheres is challenging, not least because we only have a handful of examples to work from in our own solar system. So it’s exciting that researchers have unveiled our first look at the 3D structure of an exoplanet‘s atmosphere.

    Using ground-based observations, researchers studied WASP-121b, also known as Tylos, an ultra-hot Jupiter that circles its star in only 30 Earth hours. One face of the planet always faces its star while the other faces into space. The team found that the exoplanet has a flow deep in the atmosphere that carries iron from the hot daytime side to the colder night side. Higher up, the atmosphere boasts a super-fast jet-stream that doubles in speed (from an estimated 13 kilometers per second to 26 kilometers per second) as it crosses from the morning terminator to the evening. As one researcher observed, the planet’s everyday winds make Earth’s worst hurricanes look tame. (Image credit: ESO/M. Kornmesser; research credit: J. Seidel et al.; via Gizmodo)

    Fediverse Reactions
  • An Exoplanet’s Supersonic Jet Stream

    An Exoplanet’s Supersonic Jet Stream

    WASP-127b is a hot Jupiter-type exoplanet located about 520 light-years from us. A new study of the planet’s atmosphere reveals a supersonic jet stream whipping around its equatorial region at 9 kilometers per second. For comparison, our Solar System’s fastest winds, on Neptune, are a comparatively paltry 0.5 kilometers per second. The team estimates the speed of sound — which depends on temperature and the atmosphere’s chemical make-up — on WASP-127b as about 3 kilometers per second, far below the measured wind speed. The planet’s poles, in contrast, are much colder and have far lower wind speeds.

    Of course, these measurements can only give us a snapshot of what the exoplanet’s atmosphere is like; we don’t have altitude data, for example, to see how the wind speed varies with height. Nevertheless, it shows that exoplanets beyond our planetary system can have some unimaginably wild weather. (Video and image credit: ESO/L. Calçada; research credit: L. Nortmann et al.; via Gizmodo)

    Fediverse Reactions
  • An Exoplanet With Earth-Like Temperatures

    An Exoplanet With Earth-Like Temperatures

    Although researchers have identified thousands of exoplanets in the last 25 years, most of them are far larger and far hotter than Earth. But a team recently announced the discovery of a temperate neighbor, Gliese 12 b, some 40 light years away. Gliese 12 b is a rocky Venus-sized planet orbiting the cool red dwarf star Gliese 12. Based on the star’s energy output and the planet’s characteristics, the team estimate its equilibrium temperature — about how hot it would be without an atmosphere — as 42 degrees Celsius. (For comparison, Earth’s average surface temperature is 15 degrees Celsius and rising.) The next goal will be to determine whether Gliese 12 b has an atmosphere and, if so, what it’s made up of. (Image credit: NASA/JPL-Caltech/R. Hurt; research credit: S. Dholakia et al.; via Gizmodo)

  • Rocky Exoplanet With an Atmosphere

    Rocky Exoplanet With an Atmosphere

    In the past few decades, the number of exoplanets we’ve found has ballooned to over 5,000, but most of these worlds are gas giants closer to Jupiter than our rocky Earth. But a recent study has turned up evidence of a rocky exoplanet that, like Earth, has an atmosphere made up of more than hydrogen.

    By combining observations from the JWST with those from other telescopes, the team found that 55 Cancri e — an exoplanet nearly 9 times more massive than Earth in a system about 41 light years from us — probably has an atmosphere made up of carbon dioxide or carbon monoxide. 55 Cancri e is still a planet extremely unlike our own, though; it’s tidally locked to its star so that one side always faces the star, and its equilibrium temperature is an estimated 2000 Kelvin. That’s actually a lower temperature than expected, indicating that an atmosphere is helping distribute heat around the planet. Based on the JWST measurements, the researchers suggest that the planet’s volatile atmosphere could be supported by outgassing from a magma ocean. (Image credit: NASA/ESA/CSA/R. Crawford; research credit: R. Hu et al.; via Gizmodo)

  • Exoplanet Heating

    Exoplanet Heating

    WASP-96B is a tidally-locked exoplanet between the size of Saturn and Jupiter. This hot, massive planet lies close to its star, orbiting in less than three-and-a-half Earth days. A recent study shows that planets like these can have very different weather, depending on what depth their atmosphere absorbs heat at.

    Using numerical simulations, researchers took a detailed look at the possible atmospheric dynamics on this planet. When the atmosphere absorbed heat at a shallow depth — near the outer layers of the planet — a coupled vortex pair formed (left, below). These vortices promenaded westward and completed a circuit around the planet every 11-15 days.

    Shallow heating on a hot Jupiter produces a pair of coupled vortices (left), but deeper heating in the atmosphere generates four more-chaotic vortices (right).
    Shallow heating on a hot Jupiter produces a pair of coupled vortices (left), but deeper heating in the atmosphere generates four more-chaotic vortices (right).

    In contrast, deeper heating produced a more-chaotic pattern of four vortices (right, above) that each lasted 3 to 15 days before disappearing, replaced by a new vortex. This atmosphere, they found, was very turbulent, with smaller-scale vortices as well.

    Since each weather pattern is visually distinct and carries its own brightness signature, the authors predict that additional observations of WASP-96b with the current generation of telescopes will show which type of heating dominates on the exoplanet. (Image and research credit: J. Skinner et al.; via APS Physics)

    Snapshots from a simulation of a deep-heated hot Jupiter. Each image shows the planet on a different day.
    Snapshots from a simulation of a deep-heated hot Jupiter. Each image shows the planet on a different consecutive day.
  • Extreme Weather

    Extreme Weather

    Many of the exoplanets we’ve observed so far are extreme environments. WASP-121b is known as a hot Jupiter, a gas giant so close to its star that it orbits in just 30 hours. The exoplanet is tidally-locked to its star, meaning that one side always faces toward the star and the other faces away. This constant sunlight makes the daytime side of the planet hot enough to vaporize metals. A recent study combined observations of the exoplanet with numerical simulations to model both the daytime and nighttime atmosphere of the exoplanet. The results are pretty wild. The authors found evidence of 18,000 km/h winds that blow hot gases from the dayside to the nightside, where temperatures cool enough for some metals — primarily corundum — to rain out of the atmosphere. Given the trace amounts of other elements available in the atmosphere, the authors posit that the nightside of the planet may have rainfall of liquid rubies and sapphires. (Image credit: NASA/ESA; research credit: T. Mikal-Evans et al.; via Physics World)

  • Inside a Super-Earth

    Inside a Super-Earth

    When studying exoplanets, scientists often judge habitability by the possibility of liquid water on the planet’s surface. But there is more to Earth’s habitability than water. The liquid iron dynamo within our planet is critical for life here because it generates magnetic fields that protect the planet from harmful solar radiation. It’s been difficult to predict what the interiors of a bigger and more massive planet like a super-Earth would look like, but a recent study changes that.

    Researchers at the National Ignition Facility used its high-powered lasers to subject liquid iron to conditions similar to those expected in a super-Earth’s core, including pressures as high as ~1000 GPa. That’s more than 3 times higher than pressures at the boundary where Earth’s liquid iron meets its solid core. Based on their findings, the team concluded that super-Earths likely have a similar interior structure to our planet, with a solid iron-heavy core surrounded by churning liquid iron capable of generating a protective magnetosphere. (Image credit: NASA; research credit: R. Kraus et al.; via Science)

  • Reader Question: Exoplanetary Life

    Reader orbiculator asks:

    I’ve been having this thought regarding biological adaptations to viscous mediums. In a hypothetical exoplanet where the ocean is this thick, aqueous gel – could we assume that the native macroscopic species would have morphologies similar to Earth’s plankton despite their large sizes? That is, instead of being propelled by fins like our fish and whales, they’d go around using large ciliar or flagella?

    Propulsion-wise, that’s a reasonable theory. If the ambient environment were viscous enough that macroscopic creatures would still be limited to laminar flow, then, yes, you could expect them to use something like cilia or flagella to move. They’d be restricted by the same reversibility that microscopic species are here on Earth.

    But there are other factors that could come into play. Many microscopic species rely on diffusion for survival, whether that’s chemical diffusion across their exterior or diffusion within their body. As a species gets larger, the distance diffusion has to occur across grows, and diffusion becomes harder and harder to sustain. 

    So while hydrodynamic constraints might result in an exoplanet’s fauna having features similar to Earth’s microscopic life, it probably wouldn’t be as simple as merely enlarging the species we see here on Earth. Some of the key biophysics that goes on inside cellular life as we know it just doesn’t hold at larger scales.

  • A Real Tatooine

    A Real Tatooine

    Since at least the release of “Star Wars”, we have wondered what life would be like on a circumbinary planet – a planet orbiting two stars. In the past few decades, we have discovered several such planets, but we are still in the early days of modeling the climate of these worlds. One recent study uses the stars of the Kepler 35 system, which are only slightly less luminous than our sun, to explore the climate of an Earth-like water planet.

    According to the study, this fictional planet would maintain Earth-like habitability at a distance of 1.165–1.195 astronomical units from its suns’ center of gravity – just a little further out than our own orbital distance. Variables like the planet’s mean global surface temperature and precipitation vary with two distinct periods – the time required for the stars to orbit one another and the time it takes for the planet to orbit its stars. Both factors affect how much sunlight the planet receives. The planet’s climate response to these changes is complex and varies depending on location, but the overall variations observed in the climate are small. It does show, however, that places like Tatooine don’t have to be desert planets! (Image credit: Tatooine – Star Wars; Kepler 35 system – L. Cook; research credit: M. Popp and S. Eggl)