Proplyd

A proplyd, a syllabic abbreviation of an ionized protoplanetary disk, is an externally illuminated photoevaporating disk around a young star. Nearly 180 proplyds have been discovered in the Orion Nebula.[1] Images of proplyds in other star-forming regions are rare, while Orion is the only region with a large known sample due to its relative proximity to the Earth.[2] In the Orion Nebula the proplyds seen are usually one of two types: Proplyds glowing around a bright stars, the disks is close to the star and glows from the stars brightness. The other proplyds are found a distance from the host star and show up as a dark silhouettes due to the cooler dust and gases. Some proplyds show signs of movement from the solar irradiance shock waves pushing the proplyds. The Orion Nebula is approximately 1,500 light-years from the Sun with very active star formation. The Orion Nebula and the Sun are in the same spiral arm of the Milky way Galaxy. [3] [4][5][6]

Proplyd may from new planets and planetesimal systems. Current models show that the metallicity of the star and proplyd along with the correct planetary system temperature and distance from the star are keys to planet and planetesimals formation. To date the solar system with 8 planets and 5 planetesimal systems is the largest solar system found. Most proplyds develop into a system with no planetesimals systems or one very large planetesimals system. [7][8][9][10] [11] [12]

Proplyds in the Orion Nebula.
View of several proplyds within the Orion Nebula taken by the Hubble Space Telescope
Very bright proplyd 181-825 in the Orion Nebula, from Hubble Space Telescope
Dark proplyd 132-1832 in the Orion Nebula, from Hubble Space Telescope
Bright proplyd 170-249 in the Orion Nebula, from Hubble Space Telescope. The upward tail is a jet of dust and gas blowing away from the excited proplyd

See also

References

  1. ↑ Ricci, L.; et al. (2008). "The Hubble Space Telescope/Advanced Camera for Surveys Atlas of Protoplanetary Disks in the Great Orion Nebula". Astronomical Journal. 136 (5): 2136–2151. Bibcode:2008AJ....136.2136R. doi:10.1088/0004-6256/136/5/2136.
  2. ↑ Sharkey, Colleen; Ricci, Luca (Dec 14, 2009). "Born in beauty: proplyds in the Orion Nebula" (Press release). Hubble/ESA, Garching, Germany. NASA/ESA. Retrieved Aug 4, 2015.
  3. ↑ Space Telescope, Born in beauty: proplyds in the Orion Nebula, 14 December 2009
  4. ↑ Space Telescope, Proplyds
  5. ↑ Nemiroff, R.; Bonnell, J., eds. (22 December 2009). "Planetary Systems Now Forming in Orion". Astronomy Picture of the Day. NASA.
  6. ↑ Nemiroff, R.; Bonnell, J., eds. (7 December 1996). "Planetary Systems Now Forming in Orion". Astronomy Picture of the Day. NASA.
  7. ↑ Caltech, Planet-Metallicity Correlation - The Rich Get Richer, by Ji Wang, Planet-Metallicity Correlation
  8. ↑ The Planet-Metallicity Correlation. 2005, April 200, by Debra A. Fischer, Jeff Valenti
  9. ↑ arxiv.org, Revealing A Universal Planet-Metallicity Correlation For Planets of Different Sizes Around Solar-Type Stars, by Ji Wang, Debra A. Fischer, 29 Oct 2013
  10. ↑ Astrobiology Magazine, astrobio.net, When Stellar Metallicity Sparks Planet Formation, By Ray Sanders, 9 April 2012
  11. ↑ From Lithium to Uranium (IAU S228): Elemental Tracers of Early Cosmic Evolution By International Astronomical Union. Symposium, by Vanessa Hill, Patrick Francois, Francesca Primas, page 509-511, "the G star problem"
  12. ↑ Oxford Journals Dynamics and accretion of planetesimals, by Eiichiro Kokubo1 and Shigeru, June 14, 2012
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