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Debris disk

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Hubble Space Telescope observation of the debris ring around Fomalhaut. The inner edge of the disk may have been shaped by the orbit of Fomalhaut b, at lower right.

A debris disk is a circumstellar disk of dust and debris in orbit around a star. Sometimes these disks contain prominent rings, as seen in the image of Fomalhaut above. Debris disks have been found around both evolved and young stars, as well as at least one debris disk in orbit around a neutron star.[1] They can constitute a phase in the formation of a planetary system following the protoplanetary disk phase.[2] They can also be produced and maintained as the remnants of collisions between planetismals.[3]

By 2001, over 900 candidate stars had been found to possess a debris disk. They are usually located by examining the star system in infrared light and looking for an excess of radiation beyond that emitted by the star. This excess is inferred to be radiation from the star that has been absorbed by the disk, then radiated away as infrared energy.[4]

Debris disks are often described as massive analogs to the debris in the solar system. Most known debris disks have radii of 10-100 astronomical units (AU); they resemble the Kuiper Belt in the solar system, but with much more dust. Some debris disks contain a component of warmer dust located within 10 AU from the central star. This dust is sometimes called exozodiacal dust by analogy to zodiacal dust in the solar system.

Observation history

In 1984 a debris disk was detected around the star Vega using the IRAS satellite. Initially this was believed to be a protoplanetary disk, but it is now thought to be a debris disk due to the lack of gas in the disk and the age of the star. Subsequently irregularities have been found in the disk, which may be indicative of the presence of planetary bodies.[5] Similar discoveries of debris disks were made around the stars Fomalhaut and Beta Pictoris.

The nearby star 55 Cancri, a system that is also known to contain five planets, was reported to also have a debris disk.[6], but that detection could not be confirmed.[7] Structures in the debris disk around Epsilon Eridani suggest perturbations by a planetary body in orbit around that star, which may be used to constrain the mass and orbit of the planet.[8]

Origin

Typical debris disks contain small grains 1–100 μm in size. Collisions will grind down these grains to sub-micron sizes, which will be removed from the system by radiation pressure from the host star. In very tenuous disks like the ones in our solar system, the Poynting-Robertson effect can cause particles to spiral inward instead. Both processes limit the lifetime of the disk to 10 Myr or less. Thus, for a disk to remain intact, a process is needed to continually replenish the disk. This can occur, for example, by means of collisions between larger bodies, followed by a cascade that grinds down the objects to the observed small grains.[9]

For collisions to occur in a debris disk, the bodies must be gravitationally perturbed sufficiently to create relatively large collisional velocities. A planetary system around the star can cause such perturbations, as can a binary star companion or the close approach of another star.[9]

Known belts

Belts of dust or debris have also been detected around stars other than the Sun, including the following:

Star Spectral
class[10] 		Distance
(ly) 		Orbit
(AU)
Epsilon Eridani[8] K2V 10.5 35–75
Tau Ceti[11] G8V 11.9 35–50
Vega[5][12] A0V 25 86–200
Fomalhaut[5] A3V 25 133–158
51 Ophiuchi[13] B9 131 0.5–1200
AU Microscopii[14] M1Ve 33 50–150
HD 69830[15] K0V 41 <1
55 Cancri A[6] G8V 41 27–50
Pi1 Ursae Majoris[16] G1.5Vb 46.5 ?
HD 207129[17] G0V 52 148–178
HD 139664[18] F5IV-V 57 60–109
Eta Corvi[19] F2V 59 100–150
HD 53143[18] K1V 60 ?
Beta Pictoris[12] A6V 63 25–550
Zeta Leporis[20] A2Vann 70 2–8
HD 92945[21] K1V 72 45–175
HD 107146[22] G2V 88 130
HR 8799[23] A5V 129 75
HD 12039[24] G3-5V 137 5
HD 98800[25] K5e (?) 150 1
HD 15115[26] F2V 150 315–550
HR 4796 A[27][28] A0V 220 200
HD 141569[28] B9.5e 320 400
HD 113766 A[29] F4V 430 0.35–5.8

The orbital distance of the belt is an estimated mean distance or range, based either on direct measurement from imaging or derived from the temperature of the belt. The Earth has an average distance from the Sun of 1 AU.

See also

References

  1. ^ Wang, Z.; Chakrabarty, D.; Kaplan, D. L. (2006). "A debris disk around an isolated young neutron star". Nature. 440 (7085): 772–775. doi:10.1038/nature04669. PMID 16598251.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. ^ "Spitzer Team Says Debris Disk Could Be Forming Infant Terrestrial Planets". NASA. 2005-12-14. Archived from the original on 2006-09-08. Retrieved 2007-01-03.
  3. ^ "Spitzer Sees Dusty Aftermath of Pluto-Sized Collision". NASA. 2005-01-10. Archived from the original on 2006-09-08. Retrieved 2007-01-03.
  4. ^ "Debris Disk Database". Royal Observatory Edinburgh. Retrieved 2007-01-03.
  5. ^ a b c "Astronomers discover possible new Solar Systems in formation around the nearby stars Vega and Fomalhaut" (Press release). Joint Astronomy Centre. 1998-04-21. Retrieved 2006-04-24.
  6. ^ a b "University Of Arizona Scientists Are First To Discover Debris Disk Around Star Orbited By Planet". ScienceDaily. 1998-10-03. Retrieved 2006-05-24.
  7. ^ Schneider, G.; Becklin, E. E.; Smith, B. A.; Weinberger, A. J.; Silverstone, M.; Hines, D. C. (2001). "NICMOS Coronagraphic Observations of 55 Cancri". The Astronomical Journal. 121: 525. doi:10.1086/318050.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ a b Greaves, J. S.; Holland, W. S.; Wyatt, M. C.; Dent, W. R. F.; Robson, E. I.; Coulson, I. M.; Jenness, T.; Moriarty-Schieven, G. H.; Davis, G. R.; Butner, H. M.; Gear, W. K.; Dominik, C.; Walker, H. J. (2005). "Structure in the Epsilon Eridani Debris Disk". The Astrophysical Journal. 619: L187–L190. doi:10.1086/428348.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ a b Kenyon, Scott; Bromley, Benjamin (2007). "Stellar Flybys & Planetary Debris Disks". Smithsonian Astrophysical Observatory. Retrieved 2007-07-23.{{cite web}}: CS1 maint: multiple names: authors list (link)
  10. ^ "SIMBAD: Query by identifiers". Centre de Données astronomiques de Strasbourg. Retrieved 2007-07-17.
  11. ^ Greaves, J. S.; Wyatt, M. C.; Holland, W. S.; Dent, W. R. F. (2004). "The debris disc around tau Ceti: a massive analogue to the Kuiper Belt". Monthly Notices of the Royal Astronomical Society. 351 (3): L54–L58. doi:10.1111/j.1365-2966.2004.07957.x. Retrieved 2007-08-14.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. ^ a b Backman, D. E. (1996). "Dust in beta PIC / VEGA Main Sequence Systems". Bulletin of the American Astronomical Society. 28: 1056. Retrieved 2007-06-17.
  13. ^ Stark, C.; et al. (2009). "51 Ophiuchus: A Possible Beta Pictoris Analog Measured with the Keck Interferometer Nuller". Astrophysical Journal. 703: 1188–1197. doi:10.1088/0004-637X/703/2/1188. {{cite journal}}: Explicit use of et al. in: |author= (help)
  14. ^ Sanders, Robert (2007-01-08). "Dust around nearby star like powder snow". UC Berkeley News. Retrieved 2007-01-11.
  15. ^ Lisse, C. M.; Beichman, C. A.; Bryden, G.; Wyatt, M. C. (1999). "On the Nature of the Dust in the Debris Disk around HD 69830". The Astrophysical Journal. 658 (1): 584–592. doi:10.1086/511001. Retrieved 2007-05-25.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  16. ^ Beichman, C. A. (2006). "IRS Spectra of Solar-Type Stars: A Search for Asteroid Belt Analogs". The Astrophysical Journal. 639: 1166–1176. doi:10.1086/499424. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  17. ^ Krist, John E. (2010). "HST and Spitzer Observations of the HD 207129 Debris Ring". The Astronomical Journal. 140 (4): 1051–1061. Bibcode:2010AJ....140.1051K. doi:10.1088/0004-6256/140/4/1051. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  18. ^ a b Kalas, Paul; Graham, James R.; Clampin, Mark C.; Fitzgerald, Michael P. (2006). "First Scattered Light Images of Debris Disks around HD 53143 and HD 139664". The Astrophysical Journal. 637 (1): L57–L60. doi:10.1086/500305. Retrieved 2007-05-25.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  19. ^ Wyatt, M. C.; Greaves, J. S.; Dent, W. R. F.; Coulson, I. M. (2005). "Submillimeter Images of a Dusty Kuiper Belt around Corvi". The Astrophysical Journal. 620: 492–500. doi:10.1086/426929. {{cite journal}}: |access-date= requires |url= (help)CS1 maint: multiple names: authors list (link)
  20. ^ Moerchen, M. M.; Telesco, C. M.; Packham, C.; Kehoe, T. J. J. (2006). "Mid-infrared resolution of a 3 AU-radius debris disk around Zeta Leporis". Astrophysical Journal Letters.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  21. ^ Golimowski, D.; et al. (2007). "Observations and Models of the Debris Disk around K Dwarf HD 92945" (PDF). University of California, Berkeley Astronomy Department. Retrieved 2007-07-17. {{cite web}}: Explicit use of et al. in: |author= (help)
  22. ^ Williams, Jonathan P.; et al. (2004). "Detection of cool dust around the G2V star HD 107146". Astrophysical Journal. 604: 414–419. doi:10.1086/381721. Retrieved 2007-06-17. {{cite journal}}: Explicit use of et al. in: |author= (help)
  23. ^ Marois, Christian (2008). "Direct Imaging of Multiple Planets Orbiting the Star HR 8799". Science. Forthcoming (5906): 1348. doi:10.1126/science.1166585. PMID 19008415. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help) (Preprint at exoplanet.eu)
  24. ^ Hines, Dean C.; et al. (2006). "The Formation and Evolution of Planetary Systems (FEPS): Discovery of an Unusual Debris System Associated with HD 12039". The Astrophysical Journal. 638 (2): 1070–1079. doi:10.1086/498929. Retrieved 2007-07-17. {{cite journal}}: Explicit use of et al. in: |author= (help)
  25. ^ Furlan, Elise (2007-05-02). "HD 98800: A 10-Myr-Old Transition Disk". Cornell University. arXiv. Retrieved 2008-06-20.
  26. ^ Kalas, Paul; Fitzgerald, Michael P.; Graham, James R. (2007). "Discovery of Extreme Asymmetry in the Debris Disk Surrounding HD 15115". The Astrophysical Journal. 661 (1): L85–L88. doi:10.1086/518652. Retrieved 2007-07-23.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  27. ^ Koerner, D. W.; Ressler, M. E.; Werner, M. W.; Backman, D. E. (1998). "Mid-Infrared Imaging of a Circumstellar Disk around HR 4796: Mapping the Debris of Planetary Formation". Astrophysical Journal Letters. 503: L83. doi:10.1086/311525. Retrieved 2007-06-17.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  28. ^ a b Villard, Ray; Weinberger, Alycia; Smith, Brad (1999-01-08). "Hubble Views of Dust Disks and Rings Surrounding Young Stars Yield Clues". HubbleSite. Retrieved 2007-06-17.{{cite web}}: CS1 maint: multiple names: authors list (link)
  29. ^ Meyer, M. R.; Backman, D. (2002-01-08). "Belt of Material Around Star May Be First Step in Terrestrial Planet Formation". University of Arizona, NASA. Retrieved 2007-07-17.{{cite news}}: CS1 maint: multiple names: authors list (link)

External links

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