Interpretation of Photo-polarimetric Observations of Comet 17P/Holmes During Outburst in 2007

Details Interpretation of Photo-polarimetric Observations of Comet 17P/Holmes During Outburst in 2007 Interpretation of Photo-polarimetric Observations of Comet 17P/Holmes During Outburst in 2007

Sep 2009

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009dps....41.2303z&link_type=abstract

American Astronomical Society, DPS meeting #41, #23.03

Astronomy and Astrophysics

Astronomy

1

Scientific paper

The outstanding outburst of comet 17P/Holmes on October 24, 2007 has attracted attention of many observers. Furusho (2008) was able to perform spectral photo-polarimetric observations of the comet already on October 25 (phase angle α=16.7°) later, she repeated the observations on October 27 (α=16.2°) and November 3 (α=14.4°). On October 25, the degree of linear polarization P revealed quite unusual dependence on wavelength λ: an increasing of λ from 0.48 to 0.9 μm decreases the negative polarization from -0.7% to almost 0. On the next observation, this dependence was already less pronounced; whereas, on the last observation, P was about -1% through all λ.
We could interpret Furusho's observations as follows. Negative polarization depends significantly on size parameter x of particles (x=2πr/λ, here r - is radius of particle). For instance, in the case of agglomerated debris particles, the effect appears only at x>4 whereas, the deepest negative polarization occurs at x=8-10. Practically, it means that cometary particles with radius of 0.6 μm produce noticeable negative polarization at λ=0.48 (x=7.85) but, simultaneously, they do not produce negative polarization at λ=0.9 (x=4.19). Our numerical simulation showed: if agglomerated debris particles have a power law size distribution with index of -3.5, we can reproduce quite well the wavelength dependence of polarization of comet 17P/Holmes found by Furusho on October 25, 2007. Furthermore, alteration of the power index from -3.5 to -1.5 reproduces the evolution of wavelength dependence of negative polarization between October 25 and November 3, 2007. Such an alteration of power index means a decreasing of a relative contribution of small particles with time. This conclusion seems to be a completely reasonable because the smaller particles should have a higher velocity and, thus, they have to leave an inner coma of comet 17P/Holmes sooner than larger ones.

Affiliated with

Also associated with

No associations

Rating

Interpretation of Photo-polarimetric Observations of Comet 17P/Holmes During Outburst in 2007 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Interpretation of Photo-polarimetric Observations of Comet 17P/Holmes During Outburst in 2007, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Interpretation of Photo-polarimetric Observations of Comet 17P/Holmes During Outburst in 2007 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1332510