Latest astronomy nouvelles

Researchers have modeled the atmospheric and surface conditions of five rocky exoplanets that orbit their stars very closely. These ultra-short-period planets, including TOI-431 b, likely host permanent magma oceans due to extreme temperatures. By simulating their internal and atmospheric evolution, the study provides predictions for future observations of how these worlds maintain or lose their atmospheres....

Data from the TESS space telescope reveals a sub-Earth-sized planet candidate orbiting within the Gliese 774 binary star system. Located 12.86 parsecs away, the signal likely originates from the primary star, Gliese 774 A. If confirmed, this world would be one of the smallest planets identified in a nearby system, offering a valuable opportunity for future studies of terrestrial planet atmospheres....

TOI-3686 hosts a hot Jupiter and a smaller sub-Neptune that orbit in a 2:1 resonance: the outer planet takes almost exactly twice as long to orbit as the inner one. Both planets show large shifts in their transit timings, and TOI-3686 is the only known hot Jupiter system in a truly resonant configuration....

Simulations show that ammonia and hydrogen can separate into distinct layers under some planetary conditions. The boundary between mixing and separation crosses expected temperature profiles inside Uranus and Neptune, suggesting ammonia may be raining out there. In warmer sub-Neptune TOI-270 d, the two substances are likely to remain mixed....

The star PDS 70 is significantly older than previously estimated, according to new kinematic measurements. By tracking the motion of surrounding stars, researchers determined PDS 70 is between 12 and 16 million years old. This adjustment challenges existing theories on how its two protoplanets formed, suggesting that at least one of these giant worlds may have developed long after the central star itself....

Observations from the Transiting Exoplanet Survey Satellite have revealed a candidate sub-Neptune planet orbiting the nearby orange dwarf star TIC 402710280. The planet completes one orbit every 36.34 days and maintains an equilibrium temperature of approximately 498 Kelvin. Detailed analysis of light curves confirms the transit signal originates from the target star rather than background interference....

Researchers used the JWST to observe the granulation on the surfaces of stars LTT 9779 and WASP 121. Granulation is the visible pattern of energy rising and falling on a star's surface. By studying how this light flickers across different wavelengths, they measured the amplitude and duration of these convective cycles, providing new insight into the small-scale stellar activity that can interfere with exoplanet observations....

The massive pulsating star HD 112485 is part of an eclipsing binary, where the two stars pass in front of each other from our viewpoint. Analysis of 65 such systems found tentative signs that HD 112485’s interior rotates at different rates. Across the sample, pulsation amplitude decreased as pulsation frequency increased, while neither frequency nor amplitude showed a significant link to the binary’s orbital period....

Observations from the ALMA telescope reveal the chemical composition of gas and ice in the planet-forming disks surrounding the stars HD 100546 and IRS 48. By measuring the ratios of water, methanol, and methyl formate, researchers have gained new insights into how these building blocks of planets evolve during the intermediate stages of star formation....