What are sub-Neptune planets?

Key findings:

• 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 orbital resonance of these planets, i.e., their orbits, is synchronised in such a way that they have remained stable for about 4 billion years.

About sub-Neptune planets:

• These are the most commonly observed types of planets in our galaxy.
• 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.
• These planets have radii between those of the Earth and Neptune.

Key points about Neptune

• It's the last of the planets in our solar system.
• It's more than 30 times as far from the sun as Earth is.
• Neptune is very similar to Uranus. It's made of a thick fog of water, ammonia, and methane over an earth-sized solid centre.
• Its atmosphere is made of hydrogen, helium, and methane.
• Structure and Surface
  • Neptune is encircled by six rings and is an ice giant.
  • It is made of a thick soup of water, ammonia, and methane flowing over a solid core about the size of Earth.
  • It has a thick, windy atmosphere.
• Time on Neptune
  • One day on Neptune goes by in 16 hours.
  • Neptune has such a long journey around the sun that it takes 165 Earth years to go around once.