Scientists Discover Molten “Liquid Planets” Beyond Solar System

James Webb Telescope Reveals New Class of Magma Ocean Exoplanets

Astronomers have identified a new category of exoplanets that exist in a continuously molten state, based on observations from the James Webb Space Telescope . These worlds are neither conventional rocky planets nor water-rich bodies but are dominated by global oceans of molten rock, expanding current understanding of planetary diversity.

Discovery of a New Planetary Class

The study, published in Nature Astronomy , introduces a third class of small planets— magma-dominated “liquid planets.” Earlier classifications typically included rocky terrestrial planets or ocean worlds.

This new category suggests that under extreme conditions, planets can remain in a semi-fluid or molten state for prolonged periods, challenging traditional models of planetary formation and evolution.

Key Features of L 98-59 d

A prominent example is L 98-59 d , located about 35 light-years from Earth. The planet is approximately 1.6 times larger than Earth and significantly more massive.

Surface temperatures approach 1,900°C , leading to a global ocean of molten silicates. Gravitational interactions with neighbouring planets generate tidal forces that may create large-scale waves across its lava surface.

Extreme Atmosphere and Conditions

The atmosphere of L 98-59 d contains gases such as hydrogen sulphide, producing a harsh and toxic environment.

A strong runaway greenhouse effect traps heat efficiently, preventing the planet from cooling and ensuring that its surface remains molten. These extreme conditions make the possibility of life highly unlikely.

Scientific Significance

The discovery indicates that some exoplanets previously thought to be water-rich may actually be molten worlds. Such planets provide valuable insights into early planetary stages, including conditions similar to those on early Earth when its surface was largely molten.

These findings broaden the scope of exoplanet research and highlight the immense diversity of planetary systems in the universe.

Exam-Focused Points

• L 98-59 d is located ~35 light-years away.

• Observed using the James Webb Space Telescope .

• Surface temperature ~ 1,900°C , leading to a magma ocean .

• Presence of hydrogen sulphide gas in the atmosphere.

• Maintains molten state due to runaway greenhouse effect .