'Super puff planet': NASA's James Webb Telescope discovers 4th planet in constellation Cygnus

Produced by Tarun Mishra

Discovery of Kepler-51e


Astronomers have identified a fourth exoplanet, Kepler-51e, in the Kepler-51 star system using the James Webb Space Telescope (JWST). The planet joins three previously discovered "super puff" planets orbiting the sun-like star in the constellation Cygnus.

Characteristics

Kepler-51e and its sibling planets are characterised by their extremely low density, resembling cotton candy. These planets are similar in size to Saturn but only a few times the mass of Earth, with large, puffy atmospheres made of hydrogen or helium.

Early Transit


The discovery of Kepler-51e arose when astronomers observed Kepler-51d’s transit two hours earlier than expected, far outside the usual margin of error. This discrepancy prompted a review of the data, revealing the existence of a previously undetected fourth planet.

Transit Timing

Kepler-51e was identified using transit timing variations (TTV), marking the first time JWST has been used for this purpose. This method detects gravitational interactions between planets, causing shifts in their orbits and transit times.

Mass Characteristics

Kepler-51e is estimated to have a circular orbit lasting 264 days, with a mass similar to the other planets in the system. Further research is required to confirm its classification as a super puff planet.

Formation Theories


The presence of a fourth low-density planet in Kepler-51 challenges existing theories about the formation of super puff planets. Researchers are re-evaluating the system’s dynamics to understand how such planets form and retain their atmospheres.

Future Observations

Kepler-51e’s orbit places it near the star's habitable zone, raising questions about potential additional planets further out. Continued observations and transit analyses will help refine the understanding of this unusual system and its formation history. Research findings were published in The Astronomical Journal on December 3.