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 below. 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 have 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.
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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.
By 1998 a debris disk had been located around the nearby star 55 Cancri, a system that is also known to contain five planets.[6] Structures in the debris disk around Epsilon Eridani also suggest perturbations by a planetary body in orbit around that star, which may be used to constrain the mass and orbit of the planet.[7]
Origin
Typical debris disks contain small grains 1–100 μm in size. Radiation from the host star can cause these particles to spiral inward because of the Poynting-Robertson effect, so the lifetime of the disk will be on the order of 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. This can occur on a continual basis as collisions grind objects down into ever smaller bodies.[8]
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.[8]
Known belts
Belts of dust or debris have also been detected around stars other than the Sun, including the following:
| Star | Spectral class[9] |
Distance (ly) |
Orbit (AU) |
|---|---|---|---|
| Epsilon Eridani[7] | K2V | 10.5 | 35–75 |
| Tau Ceti[10] | G8V | 11.9 | 35–50 |
| Vega[5][11] | A0V | 25 | 86–200 |
| Fomalhaut[5] | A3V | 25 | 133-158 |
| 51 Ophiuchi[12] | B9 | 131 | 0.5-1200 |
| AU Microscopii[13] | M1Ve | 33 | 50–150 |
| HD 69830[14] | K0V | 41 | <1 |
| 55 Cancri A[6] | G8V | 41 | 27–50 |
| Pi1 Ursae Majoris[15] | G1.5Vb | 46.5 | ? |
| HD 139664[16] | F5IV-V | 57 | 60–109 |
| Eta Corvi[17] | F2V | 59 | 100–150 |
| HD 53143[16] | K1V | 60 | ? |
| Beta Pictoris[11] | A6V | 63 | 25–550 |
| Zeta Leporis[18] | A2Vann | 70 | 2–8 |
| HD 92945[19] | K1V | 72 | 45–175 |
| HD 107146[20] | G2V | 88 | 130 |
| HR 8799[21] | A5V | 129 | 75 |
| HD 12039[22] | G3-5V | 137 | 5 |
| HD 98800[23] | unknown | 150 | 1 |
| HD 15115[24] | F2V | 150 | 315–550 |
| HR 4796 A[25][26] | A0V | 220 | 200 |
| HD 141569[26] | B9.5e | 320 | 400 |
| HD 113766 A[27] | 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
- ^ Wang, Z.; Chakrabarty, D.; Kaplan, D. L. (2006). "A debris disk around an isolated young neutron star". Nature 440 (7085): 772–775. doi:. http://adsabs.harvard.edu/abs/2006astro.ph..4076W.
- ^ "Spitzer Team Says Debris Disk Could Be Forming Infant Terrestrial Planets". NASA. 2005-12-14. http://www.spitzer.caltech.edu/Media/happenings/20051214/. Retrieved 2007-01-03.
- ^ "Spitzer Sees Dusty Aftermath of Pluto-Sized Collision". NASA. 2005-01-10. http://www.spitzer.caltech.edu/Media/happenings/20051214/. Retrieved 2007-01-03.
- ^ "Debris Disk Database". Royal Observatory Edinburgh. http://www.roe.ac.uk/ukatc/research/topics/dust/identification.html. Retrieved 2007-01-03.
- ^ a b c Joint Astronomy Centre (1998-04-21). "Astronomers discover possible new Solar Systems in formation around the nearby stars Vega and Fomalhaut". Press release. http://outreach.jach.hawaii.edu/pressroom/1998_vega/. Retrieved 2006-04-24.
- ^ a b "University Of Arizona Scientists Are First To Discover Debris Disk Around Star Orbited By Planet". ScienceDaily. 1998-10-03. http://www.sciencedaily.com/releases/1998/10/981023073211.htm. Retrieved 2006-05-24.
- ^ 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:.
- ^ a b Kenyon, Scott; Bromley, Benjamin (2007). "Stellar Flybys & Planetary Debris Disks". Smithsonian Astrophysical Observatory. http://www.cfa.harvard.edu/~kenyon/pf/dd/flyby.html. Retrieved 2007-07-23.
- ^ "SIMBAD: Query by identifiers". Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-fid. Retrieved 2007-07-17.
- ^ 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:. http://adsabs.harvard.edu/abs/2004MNRAS.351L..54G. Retrieved 2007-08-14.
- ^ a b Backman, D. E. (1996). "Dust in beta PIC / VEGA Main Sequence Systems". Bulletin of the American Astronomical Society 28: 1056. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1996DPS....28.0122B. Retrieved 2007-06-17.
- ^ Stark, C. et al. (2009). "51 Ophiuchus: A Possible Beta Pictoris Analog Measured with the Keck Interferometer Nuller". Astrophysical Journal 703: 1188–1197. http://adsabs.harvard.edu/abs/2009ApJ...703.1188S.
- ^ Sanders, Robert (2007-01-08). "Dust around nearby star like powder snow". UC Berkeley News. http://www.berkeley.edu/news/media/releases/2007/01/08_dust.shtml. Retrieved 2007-01-11.
- ^ 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:. http://adsabs.harvard.edu/abs/2007ApJ...658..584L. Retrieved 2007-05-25.
- ^ Beichman, C. A.; Tanner, A.; Bryden, G.; Stapelfeldt, K. R.; Werner, M. W.; Rieke, G. H.; Trilling, D. E.; Lawler, S.; Gautier, T. N. (2006). "IRS Spectra of Solar-Type Stars: A Search for Asteroid Belt Analogs". The Astrophysical Journal 639: 1166–1176. doi:.
- ^ 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:. http://adsabs.harvard.edu/abs/2006ApJ...637L..57K. Retrieved 2007-05-25.
- ^ 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:.
- ^ 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. http://arxiv.org/abs/astro-ph/0612550.
- ^ Golimowski, D. et al. (2007). "Observations and Models of the Debris Disk around K Dwarf HD 92945" (PDF). University of California, Berkeley Astronomy Department. http://astro.berkeley.edu/~kalas/lyot2007/Presentations/Golimowski_David_poster.pdf. Retrieved 2007-07-17.
- ^ Williams, Jonathan P. et al. (2004). "Detection of cool dust around the G2V star HD 107146". Astrophysical Journal 604: 414–419. doi:. http://arxiv.org/abs/astro-ph/0311583. Retrieved 2007-06-17.
- ^ Marois, Christian; et al. (November 2008). "Direct Imaging of Multiple Planets Orbiting the Star HR 8799". Science Forthcoming: 1348. doi:. (Preprint at exoplanet.eu)
- ^ 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:. http://adsabs.harvard.edu/abs/2006ApJ...638.1070H. Retrieved 2007-07-17.
- ^ Furlan, Elise (2007-05-02). "HD 98800: A 10-Myr-Old Transition Disk". Cornell University. arXiv. http://arxiv.org/abs/0705.0380. Retrieved 2008-06-20.
- ^ 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:. http://adsabs.harvard.edu/abs/2007ApJ...661L..85K. Retrieved 2007-07-23.
- ^ 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:. http://adsabs.harvard.edu/abs/1998ApJ...503L..83K. Retrieved 2007-06-17.
- ^ a b Villard, Ray; Weinberger, Alycia; Smith, Brad (1999-01-08). "Hubble Views of Dust Disks and Rings Surrounding Young Stars Yield Clues". HubbleSite. http://hubblesite.org/newscenter/archive/releases/1999/03/text/. Retrieved 2007-06-17.
- ^ 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. http://sse.jpl.nasa.gov/news/display.cfm?News_ID=2830. Retrieved 2007-07-17.
External links
- McCabe, Caer (2007-05-30). "Catalog of Resolved Circumstellar Disks". NASA JPL. http://www.circumstellardisks.org/. Retrieved 2007-07-17.
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