Discovery of two new candidates for “oceanic planets” covered in vast oceans Expectations for observations by the Web Space Telescope | sorae Portal site to space

[▲ An illustration of an exoplanet orbiting the red dwarf Kepler 138 (Credit: NASA, ESA, L. Hustak (STScI))]

A research team headed by Caroline Piaulet of the University of Montreal’s Institute for Exoplanets (iREx) has discovered new information regarding extrasolar planets orbiting the red dwarf Kepler-138, regarding 218 light-years away in the constellation Lyra. Published research results.

In 2014, Kepler 138 reported the discovery of three exoplanets “Kepler 138b”, “Kepler 138c” and “Kepler 138d”. This time, the research team analyzed the observation data of the “Hubble” Space Telescope and the “Kepler” Space Telescope, and found that both Kepler-138c and Kepler-138d have a radius of regarding 1.51 times that of the Earth, and the mass of Kepler-138c is regarding 2.3 that of the Earth. It is said that Kepler-138d was regarding 2.1 times the size of the Earth, and that it was a very similar planet, almost like a twin.

In addition, it was shown that Kepler-138c and Kepler-138d may have up to half of the volume of materials that are ‘heavy than hydrogen and helium and lighter than rocks’. The research team believes that the two planets are likely to be oceanic planets with deep and vast oceans covering the surface, as the most common candidate for the substance that meets this condition is ‘water’. The temperature of the atmosphere is likely to be above the boiling point of water even on Kepler-138d, which is far from the main star. ) are believed to exist.

[▲ Cross-section of Earth (left) and Kepler-138d (right). Kepler-138d may be covered by oceans at a depth of regarding 2000 km (Credit: Benoit Gougeon (University of Montreal))]

Study participant Jose-Manuel Almenara of the University of Grenoble-Alpes commented that the results underscore the great diversity of exoplanets that might be the result of different formation and evolutionary processes. I’m here. The research team also points out that there may be another undiscovered exoplanet revolving around Kepler 138.

As for extrasolar oceanic planets, another research team at the University of Montreal has also reported the discovery of ‘TOI-1452 b’ as a promising candidate. However, the observations of Kepler-138c, Kepler-138d, and TOI-1452 b have so far failed to actually detect water, and expectations are high for additional observations by the James Webb Space Telescope.

connection:Discovery of a promising candidate for an ‘oceanic planet’ 100 light-years away, expected to be observed by the Webb Space Telescope

Source

• Image Credit: NASA, ESA, L. Hustak (STScI), Benoit Gougeon (University of Montreal)
• University of Montreal – Université de Montréal astronomers find that two exoplanets may be mostly water
• STScI – Two Exoplanets May Be Mostly Water, NASA’s Hubble and Spitzer Find
• ESA/Hubble – Hubble Helps Discover a New Type of Planet Largely Composed of Water
• Piaulet et al. – Evidence for the volatile-rich composition of a 1.5-Earth-radius planet

Text / Takehiro Matsumura