In the latest exoplanet news:
● China is now focusing on the search for a planet like Earth:
Most likely, such a planet does exist, but in the relatively nascent field of exoplanet research, no one has yet managed to find it. It’s not for lack of trying. Kepler spent nine years searching for more than 150,000 stars, and although it discovered almost 3,000 new exoplanets, none met the criteria for being Earth-sized in the habitable zone of a Sun-like star. Bad luck may have played a role—the authors of the new paper even calculated that, statistically, Kepler probably should have found at least one Earth-sized planet in the habitable zone.
Andy Thomaswick, ‘Ambitious plan to find Earth 2.0’ in Universe Today (July 21, 2022)
A team led by Jian Ge of the Shanghai Astronomical Institute believes that using their method – the Earth Telescope 2.0 or ET – they can locate at least 17 such planets. In all, they hope to discover 30,000 new exoplanets, including 5,000 rocky ones like Earth. Their ambitious space mission will be located at L2 Lagrange Point, next to the James Webb Space Telescope. Their paper, by the way, is open access.
Earth 2.0?
● A planet’s location on the ground may matter for life, says the Royal Astronomical Society:
A team of researchers from the University of Toronto applied a three-dimensional climate model (ExoPlaSim) to simulated Earth-like planets with two different dayside configurations. The first configuration is a round continent in the middle of the day surrounded by an ocean. The second configuration is the opposite: a round ocean in the middle of the day with land everywhere else. In both cases, the circle size was resized to show how the planet’s climate depends on the portion of the land for each of these continent configurations.
Among other things, the habitability of a planet depends on the temperature of its surface and the amount of moisture in its atmosphere. The study models net precipitation, cloud fraction, and daytime surface temperature on the planet for various ground configurations.
The results show that both the amount of land and its configuration can have a large effect on the planet’s surface conditions. For models with similar daytime land fractions but opposite configurations, the mean surface temperature can change by up to ~20oC. The results show that the amount of water vapor in the planet’s atmosphere strongly depends on the area of ice-free ocean on its surface. Planets with a large fraction of land have hotter and drier daysides with clouds and precipitation mostly confined to small central areas.
Royal Astronomical Society, ‘The puzzle of life: A planet’s land location could affect its habitability’ in Newswise (11 July 2022)
This finding suggests that planets where most of the surface is water without ice are a better bet for life. On Earth, 71% of the surface is (mostly) ice-free water. Also, Earth has the right mass to hold water while getting rid of gases that are toxic to life.
Here’s the ExoPlaSim planet modeling system if you’re interested in installing and trying it out.
● Some exoplanets may have hot sand clouds, if similar brown dwarf stars are anything to go by. (Brown dwarfs are something between a star and a planet.)
With the combined data, astronomers found compelling evidence for sand clouds in brown dwarfs. But brown dwarfs only support sand clouds if they have a temperature lower than 3,100 degrees Fahrenheit (about 1,700 degrees Celsius) and warmer than 1,900 F (1,000 degrees Celsius).
If brown dwarfs are too cool, the silicates cannot evaporate, and if they are too warm, the silicates can condense into clouds.
Some exoplanets are in the same temperature range, and based on this research, astronomers believe that these worlds are likely to contain sand clouds as well.
Paul M. Sutter, “The Earth Has Clouds of Water. Hot exoplanets have clouds of sand’ in Universe Today (July 20, 2022)
The astronomy paper requires a fee or subscription, but here’s NASA’s take: “”Understanding the atmospheres of brown dwarfs and planets where silicate clouds can form can also help us understand what we would see in the atmosphere of a planet that is closer in size and temperature to Earth,” said Stanimir Mechev, professor of exoplanet research at Western University in London, Ontario, and co-author of the study.” – Spitzer Telescope
And the James Webb Space Telescope continues to surprise scientists: About WASP-96b, an exoplanet more than 1,000 light-years away, we learn the following:
With the combined powers of its 270-square-foot mirror, precision spectrographs, and sensitive detectors, Webb revealed—in a single observation—the unmistakable signature of water, indications of haze, and evidence of clouds previously thought not to exist. The transmission spectrum of the hot gas giant WASP-96 b, taken using Webb’s Near Infrared Camera and Spectrograph, provides just a glimpse of the bright future of exoplanet exploration with Webb. [emphasis added]
Breaking news, “Webb: WASP-96b most detailed spectrum of exoplanet atmosphere” at Astronomy Now
First exoplanet spectrum: WASP-96b Artist’s impression of the pulsar-planet system Psr B1257+12 discovered in 1992/NASA/JPL-Caltech
And to think that we only discovered the first exoplanet in 1992… Oddly enough, recent research shows that exoplanets of this type are actually quite rare: “less than 0.5% of all known pulsars could to host Earth-mass planets.”
You may also want to read: Among the 5,000 known exoplanets, there are some really weird ones. Planets so weird they’re making us rethink the ‘planetary rulebook’. To summarize, whatever we see or read about planets in science fiction, something out there is probably even stranger.
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