Exoplanets

• Exoplanets are planets out of the solar system.
• Exoplanets are born by circumstellar disks of gas and dust around young stars.
• Exoplanets are made out of similar elements that make up the planets in the solar system. They may be made of water, ice, carbon, iron, or others.
• The 5 ways astronauts find exoplanets consists of:

  Radial velocity

  Transit

  Direct imaging

  Gravitational microlensing

  Astrometry
• Radial velocity measures the star's wobble as it's pulled down by gravity.
• Transit measures the decrease in a star's brightness when a planet moves in front of it.
• Direct imaging uses the light emitted by the planets to find them.
• Gravitational microlensing depends on the gravitational lens effect. It uses gravity lens. It relies on the bending of light by a massive object.
• Astrometry track and measure the tiny movements of the planet.
• Discovering exoplanets helps us understand the processes and evolutions of planets all around.
• There are more than 5,000 exoplanets discovered.
• 4 types of exoplanets consists of:

  Gas giant

  Neptunian

  Super earth

  Terrestrial
• Planet Psr B1620-26 B is the oldest exoplanet at 12.7 billion years old.
• Gas giant exoplanets are very big and made up of gas. They possess thick atmospheres and extreme weather conditions.
• Neptunian exoplanets have helium and hydrogen atmospheres. They are also called mini-neptunes.
• Mini-neptunes are smaller than neptune but larger than earth.
• Super-earths are made up of gas, rocks, or both. They are rockier and more massive than earth but lighter than neptune. They may or may not have atmospheres.
• Terrestrial exoplanets have rocky surfaces mostly made of rock and metal. Some might have oceans or atmospheres. They might be habitable.