A future observational plan of dust particles around the Moon by LDM (Lunar Dust Monitor) onboard the orbiter of the next Japanese lunar mission

Earth, Planets and Space

Table 1. Properties of dust particles around the Moon.

Dust	Origin	Kinetic property in heliocentric coordinates
Dust	Origin	Velocity (mass)	Direction of arrival
Interstellar dust	Local interstellar cloud	25 km/s* (<10⁻⁸ g*)	Ecliptic longitude of 252° & ecliptic latitude of 5°*
Interplanetary dust	Cometary and asteroidal materials	<42 km/s (<10⁻⁵ g)	Anti-apex of the Earth or higher eccentricities and various inclinations
β meteoroids	Interplanetary dust swept by solar radiation	>42 km/s* (<10⁻¹² g**)	Solar direction
Lunar dust	Materials on the lunar surface, regolith	>0 km/s***** (unknown)	Lunar direction

* Refer to Kimura et al. (2003a, b).
** Refer to Fechtig (1982) and Grün et al. (1985).
*** Escape velocity at the Earth/Moon location with respect to the Sun's gravity.
**** The mass of which a spherical particle with a density of 2 g/cm³ has a high β factor greater than 0.5. Such dust particles can be accelerated by radiation pressure to above the escape velocity at 1 AU (Zook and Berg, 1975).
***** Selenocentric velocity measured in an orbit of 100-km altitude.