June 22, 2024

Sometimes miniature Neptunes are reduced to super-Earths

Sometimes miniature Neptunes are reduced to super-Earths

© APA / AFP / ESA / Hubble / M. Grain Knife / M.

A team of space researchers led by Michael Zhang of the California Institute of Technology has one New study To produce an explanation for that shrink Certain planets are shown. In space there is a lot of so-called Mini Neptuneand gaseous planets with less mass than Neptune, many of which are called super dust, that is, the rocky planets with a greater mass than the Earth. One can sometimes become the other by shrinking.

A gap between the types of minor planets

Space explorers have always been puzzled about the difference between miniature Neptune and a super-Earth There is a gap. While the super-Earth reaches 1.5 times the radius From our planet, the smallest super Neptune twice the radius of the earth start there nothing in between. But a link has long been suspected. Shrink some super Neptune. By largely losing their gaseous atmosphere, they become smaller rocky planets.

Internal heat or external radiation

been there until now two theoriesHow does this shrinkage process work: either through Heat inside the planet himself or through Radiation pressure from the parent star. For the new study, the contraction of four Super Neptunes was observed. He found that the process proceeds at a speed that cannot be explained by the first theory.

Photoevaporation is the cause

Thus, Super Neptunes are shrinking due to radiation from their parent stars, the so-called Photo evaporation. says study director Zhang to Science Alert: “Our results show that young Neptunes around Sun-like stars have larger atmospheres and that photoevaporation is efficient operation is for this Release the atmosphere and transforming these planets into super-terrestrial planets.”

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