IAS Gyan

Daily News Analysis


13th May, 2024 Science and Technology

Source: Hindu

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  • Astronomers have located a rocky exoplanet with an atmosphere, marking a significant discovery in the search for habitable worlds beyond our solar system.
  • This rocky planet, known as 55 Cancri e or Janssen, orbits a star in the constellation Cancer, approximately 41 light-years away from Earth.


Characteristics of 55 Cancri e

  • Classified as a "super-Earth," 55 Cancri e is larger than Earth but smaller than Neptune.
  • It orbits its host star at a close distance, completing an orbit every 18 hours.
  • The planet's surface is estimated to be molten rock, with temperatures reaching 3,140 degrees Fahrenheit (1,725 degrees Celsius/2,000 degrees Kelvin).
  • 55 Cancri e is likely tidally locked, meaning one side of the planet always faces its host star.
  • With scorching surface temperatures and inhospitable conditions, 55 Cancri e is one of the hottest rocky exoplanets known.

Atmosphere Composition:

  • Infrared observations using instruments aboard the James Webb Space Telescope revealed the presence of a substantial atmosphere around 55 Cancri e.
  • The atmosphere is likely rich in carbon dioxide or carbon monoxide, with the possibility of other gases such as water vapor and sulfur dioxide.
  • The exact thickness of the atmosphere remains uncertain, but it could be comparable to Earth's or even thicker than Venus' dense atmosphere.
  • Due to its extreme temperatures and lack of liquid water, 55 Cancri e is deemed uninhabitable for life as we know it.

About Super-Earth Exoplanets

  • Super-Earths are a class of exoplanets that are larger than Earth but smaller than Neptune, with masses typically ranging from 1 to 10 times that of Earth. 

Characteristics of Super-Earths:

  • Super-Earths have masses and radii larger than Earth's but smaller than gas giants like Neptune.
  • While some super-Earths may have rocky compositions similar to Earth, others may contain significant amounts of water, ice, or gases.
  • Some super-Earths may possess atmospheres, which can vary in composition and thickness, impacting their potential habitability.

Detection Methods:

  • Transit Method: Super-Earths are often detected using the transit method, which observes the slight dimming of a star's light as a planet passes in front of it.
  • Radial Velocity Method: Variations in a star's radial velocity caused by the gravitational pull of an orbiting super-Earth can also indicate the presence of these exoplanets.
  • Direct Imaging: Advanced telescopes may directly image super-Earths, although this method is challenging due to the planets' small size and proximity to their host stars.

Notable Examples of Super-Earths:

  • Kepler-452b: Dubbed "Earth's cousin," Kepler-452b is located in the habitable zone of its star and shares similarities with Earth in terms of size and orbital period.
  • Gliese 581d: Gliese 581d is a potentially habitable super-Earth orbiting within the habitable zone of its red dwarf star, although its exact composition and atmosphere remain uncertain.




Q.  Exoplanets, especially 'super-Earths,' have garnered significant attention in recent astronomical research. Discuss the significance of super-Earth exoplanets in expanding our understanding of planetary systems beyond our solar system. (150 words)