A Possible Massive Asteroid Belt Around zeta Leporis

Asteroidal Objects: 456 km (Ceres) down to micron sized grains
Grain Temperature: 180 K (-135 F)
Grain Distance: 2.1 - 3.3 AU
Objects: 1.6 micron dust grains up to ?
Grain Temperature: 340 K (150 F)
Grain Distance: 2.5 - 6.0 AU

Zone of Terrestrial Planet Formation

zeta Lep is at Most Marginally Resolved from Keck

The solid line is the point spread function for the standard star Capella, normalized to the observations of zeta Lep, while the diamonds show the azimuthally averaged data for zeta Lep. The colored lines are models for the spatial extent of the dust convolved with the point spread function of Capella. The red, green and blue models assume a central point source with an angular radius of 0.2", 0.3" and 0.4" (4 AU, 6 AU and 8 AU) respectively. In each model, the power is divided equally between the pont source and the ring, consistent with the SED.

at 11.7 micron:
FWHM(Capella) = 0.47"
FWHM(zetaLep) = 0.46"
at 17.9 micron:
FWHM(Capella) = 0.49"
FWHM(zetaLep) = 0.57"

Grain Lifetime

Mass of Parent Bodies (Asteroids?)

We can estimate the mass in parent bodies assuming that the grains are in steady state.

MPB= 3.0 × 1026 grams

For comparison,

Mmoon = 7.4 × 1025 grams
Mmain asteroid belt in our solar system = 1.8 × 1024 grams

Last Updated June 7, 2001