Skip to main content

Advertisement

We’d like to understand how you use our websites in order to improve them. Register your interest.

Optical properties of dust aggregates in the disk of Beta Pictoris

Abstract

Dust particles in the disk of Beta Pictoris (β Pic) is modeled by fluffy aggregates consisting of slightly modified interstellar grains. We calculate the optical properties by Discrete Dipole Approximation with a1-term method. It is found that the characteristic size of an aggregate is defined by the radius of volume-equivalent sphere. The wavelength dependence of the scattering efficiency in visible becomes flat when the volume-equivalent sphere exceeds 1 μm irrespective of the monomer size, while the infrared silicate feature is present even for aggregates larger than 10 μm. Therefore, our model can account for the coexistence of the neutral scattering and silicate feature in the β Pic disk without detailed tuning of the dust size distribution. Due to the enhancement of geometrical cross section, aggregates generally show higher scattering and absorption efficiencies in visible compared with the volume-equivalent sphere. In contrast, the absorption efficiency for an aggregate is comparable to that for the volume-equivalent sphere when the size is smaller than wavelength. These properties are also consistent with the observed superheat and high albedo of the dust particles in the β Pic disk.

References

  1. Aitken, D. K., T. J. T. Moore, P. F. Roche, C. H. Smith, and C. M. Wright, Mid infrared spectroscopy of beta pictoris—constrains on the dust grain size—, Mon. Not. Astron. Roy. Soc., 265, L41–45, 1993.

    Article  Google Scholar 

  2. Artymowicz, P., Radiation pressure forces on particles in the Beta Pictoris system, Astrophys. J., 335, L79–82, 1988.

    Article  Google Scholar 

  3. Artymowicz, P., Beta Pictoris: An early solar system?, Annu. Rev. Earth Planet. Sci., 25, 175, 1997.

    Article  Google Scholar 

  4. Artymowicz, P., C. Burrows, and F. Paresce, The structure of the Beta Pictoris disk and the properties of its particles, Astrophys. J., 337, 494–513, 1989.

    Article  Google Scholar 

  5. Backman, D. E., F. C. Whittebprn, and F. C. Gillet, Infrared observations and thermal models of the Beta Pictoris disk, Astrophys. J., 385, 670–679, 1992.

    Article  Google Scholar 

  6. Draine, B. T., The discrete-dipole approximation and its application to interstellar graphite grains, Astrophys. J., 333, 848–872, 1988.

    Article  Google Scholar 

  7. Draine, B. T. and H. M. Lee, Optical properties of interstellar graphite and silicate grains, Astrophys. J., 285, 89–108, 1984.

    Article  Google Scholar 

  8. Greenberg, J. M. and A. Li, What are the true astronomical silicates?, Astron. Astrophys., 309, 258–266, 1996.

    Google Scholar 

  9. Kalas, P. and D. Jewitt, The detectability of Beta Pic-like circumstellar disks around nearby main sequence stars, Astron. J., 111, 1347–1355, 1996.

    Article  Google Scholar 

  10. Knacke, R. F., S. B. Fajardo-acosta, C. M. Telesco, J. A. Hackwell, D. K. Lynch, and R. W. Russell, The silicates in the disk of beta Pictoris, Astrophys. J., 418, 440–454, 1993.

    Article  Google Scholar 

  11. Lagage, P. O. and E. Pantin, Dust depletion in the inner disk of beta-pictoris as a possible indicator of planets, Nature, 369, 628–630, 1994.

    Article  Google Scholar 

  12. Lecavelier des Etangs, A., G. Perrin, R. Ferlet, A. Vidal-Madjar, J. Lecacheux, M. Deleuil, and C. Gry, Observation of the central part of the beta-pictoris disk with an anti-blooming CCD, Astron. Astrophys., 274, 877–882, 1993.

    Google Scholar 

  13. Lecavelier des Etangs, A., A. Vidal-Madjar, and R. Ferelet, Dust distribution in disks supplied by small bodies: is the beta Pictoris disk a gigantic multi-cometary tail?, Astron. Astrophys., 307, 542–550, 1996.

    Google Scholar 

  14. Mathis, J. S., W. Rumpl, and K. H. Nordsieck, The size distribution of interstellar grains, Astrophys. J., 217, 425–433, 1977.

    Article  Google Scholar 

  15. Matsuura, S., T. Matsumoto, H. Matsuhara, and M. Noda, Rocket-borne observations of the zodiacal light in the near-infrared wavelengths, Icarus, 115, 199–208, 1995.

    Article  Google Scholar 

  16. Mouillet, D., A. M. Lagrange, J. L. Beuzit, and N. Renaud, A stellar coronograph for the COME-ON-PLUS adaptive opticssystem. II. First astronomical results, Astron. Astrophys., 324, 1083–1090, 1997.

    Google Scholar 

  17. Mukai, T. and C. Koike, Optical constants of olivine particles between wavelengths of 7 and 200 microns, Icarus, 87, 180–187, 1990.

    Article  Google Scholar 

  18. Mukai, T., H. Ishimoto, T. Kozasa, J. Blum, and J. M. Greenberg, Radiation pressure forces of fluffy porous grains, Astron. Astrophys., 262, 315–320, 1992.

    Google Scholar 

  19. Nakano, T., Formation of planets around stars of various masses. III — Massive and small-mass stars and the regions of planet formation, Mon. Not. Astron. Roy. Soc., 235, 193–201, 1988.

    Article  Google Scholar 

  20. Okamoto, H., Light scattering by clusters; the a1 term method, Opt. Rev., 2, 407–412, 1995.

    Article  Google Scholar 

  21. Okamoto, H. and Y. Xu, Light scattering by irregular interplanetary dust particles, Earth Planets Space, 50, this issue, 577–585, 1998.

    Article  Google Scholar 

  22. Ootsubo, T., T. Onaka, I. Yamamura, T. Tanabé, T. L. Roellig, K.-W. Chan, and T. Matsumoto, IRTS observation of the mid-infrared spectrum of the zodiacal emission, Earth Planets Space, 50, this issue, 507–511, 1998.

    Article  Google Scholar 

  23. Paresce, F. and C. Burrows, Broad-band imaging of the Beta Pictoris circumstellar disk, Astrophys. J., 319, L23–25, 1987.

    Article  Google Scholar 

  24. Reach, W. T., A. Abergel, F. Boulanger, F. Desert, M. Perault, J. P. Bernerd, J. Blommaert, C. Cesarsky, D. Cesarsky, L. Metcalfe, J. L. Puget, F. Sibille, and L. Vigroux, Mid-Infrared spectrum of the zodiacal light, Astron. Astrophys., 315, L381–384, 1996.

    Google Scholar 

  25. Sandford, S. A. and R. M. Walker, Laboratory infrared transmission spectra of individual interplanetary dust particles from 2.5 to 25 microns, Astrophys. J., 291, 838–851, 1985.

    Article  Google Scholar 

  26. Telesco, C. M., R. Decher, E. E. Becklin, and R. D. Wolstencroft, Resolution of the circumstellar disk of Beta Pictoris at 10 and 20 microns, Nature, 335, 51–54, 1988.

    Article  Google Scholar 

  27. Whitmire, D. P., J. Matese, and P. Whitman, Velocity streaming of IRAS main-sequence disk stars and the episodic enhancement of particulate disks by interstellar clouds, Astrophys. J., 388, 190–195, 1992.

    Article  Google Scholar 

  28. Xing, Z. and M. S. Hanner, Light scattering by aggregate particles, Astron. Astrophys., 324, 805–820, 1997.

    Google Scholar 

  29. Yamamoto, S. and T. Mukai, Dust production by impacts of interstellar dust on Edgeworth-Kuiper Belt objects, Astron. Astrophys., 329, 785–791, 1998.

    Google Scholar 

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to R. Nakamura.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Nakamura, R. Optical properties of dust aggregates in the disk of Beta Pictoris. Earth Planet Sp 50, 587–593 (1998). https://doi.org/10.1186/BF03352152

Download citation

Keywords

  • Dust Particle
  • Interstellar Dust
  • Infrared Observation
  • Geometrical Cross Section
  • Radiation Pressure Force