Sub – Neptunes

• Astronomers have identified six sub-Neptune planets orbiting in a rare synchronised dance around a distant star.
• The star, known as HD110067, is located approximately 100 light-years away in the constellation Coma Berenices and is about 20% less massive than our Sun.
• The six planets were detected by observing minute dimming of the star’s brightness as each planet transited, or passed in front of, the star from our perspective on Earth.
• The newly discovered sub-Neptunes range from 1.9 to 2.9 times Earth’s diameter and all seem to have substantial atmospheres.
  • None of the six planets lie within the traditional habitable zone—the region around a star where conditions might be right for liquid water and potentially life.

• However they do possess atmospheres that could modify their surface temperatures, expanding the potentially habitable zone for such planets.

• The orbital resonance of these planets is intriguing, meaning their orbits are synchronised in such a way that they have remained stable for about 4 billion years.
  • This suggests that no major disruptions, like colossal impacts, have disturbed their paths since their formation.

ABOUT SUB-NEPTUNES

• Planets with radii between that of Earth and Neptune are called ‘Sub-Neptunes’.
• Sub-Neptunes are the most commonly observed type of planet in our galaxy, yet their fundamental nature remains a puzzle.
• They could be rocky worlds with thick atmospheres of hydrogen and helium gas, or perhaps composed of rock and ice with warm, water-rich atmospheres.