Interpretation of spectro-polarimetry of comet
17P/Holmes during outburst in 2007
E. Zubko*,1,2, R. Furusho3, K. S. Kawabata4, T. Yamamoto5, K. Muinonen1,6 and G. Videen7
- 1 Department of Physics, University of Helsinki, P.O. box 64, FI-00014 Finland.
- 2 Institute of Astronomy, Kharkov National University, 35 Sumskaya St., Kharkov, 61022, Ukraine.
- 3 National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588, Japan.
- 4 Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi- Hiroshima, 739-8526, Japan.
- 5 Institute of Low Temperature Science, Hokkaido University, Kita-ku North 19 West 8, Sapporo 060-0819, Japan.
- 6 Finnish Geodetic Institute, P.O. box 15, FI-02431 Masala, Finland.
- 7 Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 USA.
Spectro-polarimetry of comet 17P/Holmes carried out a day after its outburst in October 24, 2007 shows a strong dependence of negative polarization on wavelength λ: while λ increases from 0.5 to 0.9 μm the polarization falls from –0.6% to almost 0. Ten days after the outburst, polarization was found to be approximately -1% for all λ. We found such behavior to be consistent with highly absorbing (e.g., m = 1.5 + 0.1i) agglomerated debris particles that obey a power-law size distribution and have a small-size limit near 0.6 μm.
- * Corresponding author