• 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.

An orbital resonance occurs when two satellites have orbital periods that are related by integer relationships, allowing them to exert a gravitational influence over each other and affecting the eccentricity of their orbits.

• 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.