Planets?

• ionize and excite the gas in a circumstellar disk Fig. 20-5
  • Bright end of disk pointing toward Trapezium
  • Spectral analysis indicates gas densities in disk

• Will planets form in these dusty/gaseous disks?

  • They seem very similar to our picture of the early Solar Nebula
    • Theories indicate planets should form

• Planets are very difficult to detect directly

  • The surface area of a planet is 1013 times smaller than the same material in micron-sized dust grains
    • Jupiter at 4 ly would be about 22 mag
      • detectable, except for the fact that
    • the Sun at 4 ly, about 0 mag, i.e. 22 mag or 109 times brighter
      • planet’s light completely swamped
      • like trying to see a fire-fly near a very bright spotlight
    • The planet:star contrast is much better in the infrared

Previous slide

Next slide

Back to first slide

View graphic version