INTERPLANETARY MATTER

ON THE MOON

V.V.Shevchenko Sternberg Astronomical Institute, Moscow

University

THE SECOND MOSCOW SOLAR SYSTEM SYMPOSIUMMOONS OF PLANETS

MOSCOW 2011IKI RAS

Neutron flux measurements of the Moon’s south polar region from the Lunar Exploration Neutron Detector (LEND) on the Lunar Reconnaissance

Orbiter (LRO) spacecraft were used for hydrogen mapping of the south pole area.

LRO/LEND

The final value corresponds to a water (as ice) content of ~4% by weight (Mitrofanov et al.,

2010), which is in good agreement with independent estimates of the water content

associated with the LCROSS Centaur impact site.

The maximum total water vapor and water ice within the LCROSS instrument field of view was 155 kilograms. Given

the estimated total excavated mass of regolith that reached sunlight, and hence was observable, the concentration of

water ice in the regolith at the LCROSS impact site is estimated to be 5.6 % by mass.

In addition to water, spectral bands of a number of other volatile compounds were observed,

including light hydrocarbons, sulfur-bearing species, and carbon dioxide

(H2S/H2O, NH3/H2O, SO2/H2O, and CO/H2O). Of interest is the indication from this preliminary

analyses that some volatiles other than water are considerably more abundant (some by orders

of magnitude) than the ratios found in comets, in the interstellar medium, or predicted from gas-gas reactions in the protoplanetary disk

(Colaprete et al., 2011).

LRO/LCROSS IMPACT MISSION: crater with diameter ~ 28 mhas total water abundance about 155 kg (A. Colaprete et al., 2011)

COLD TRAPS IN CRATER

CABEUS (T < 110 K)Sternberg dataon the base of

LRO/LOLA measurements

H, km

.

Total area ofthe cold trap incrater Cabeusis ~ 530 km2

So, we can assume

that total water abundance in

crater Cabeus is~ 18х103 t

SWIRLS IN MARE INGENII AS RESULT OF COMET IMPACT

“CLOSE LOOPS”

MARE INGENII MARE MARGINIS

“OPEN LOOPS”

MARE INGENII

MARE MARGINIS

Calculations show, that in case of falling on the Moon

such comet as a comet Hale-Bopp, in the lunar environment should remain about 0.1 % of its mass.

Taking into account a share of presumably

remaining substance on everyone 1 км2

of lunar surfaces should have about

0.5 × 105 t of material.

It’s real model

(Shevcnenko, 1993 – 1999) COMET HALE-BOPP: 1997NUCLEUS SIZES: 40 – 80 KMNUCLEUS MASS: ~ 3х1015 KG

Huge comets of

Hale-Bopp type usually

come from Oort Cloud

Comet Hale-Bopp has drifted beyond the orbit of Neptune, over 30,7 AU from the Sun.

It continues its outward journey on an epic 2,500 year orbit

(Szabo et al., 2011)

KUIPER BELT

European Southern Observatory's 2.2 meter telescope

at La Silla Paranal Observatory in Chile

IN SCIENCE BY LEVINSON ET AL. (2010) presented numerical simulations show

that the Sun captured comets from other stars while it was in its birth cluster. The results imply that a

substantial fraction of the Oort Cloud comets, perhaps exceeding 90%, are from the protoplanetary disks of other

stars (!!!)

So, it may be that LRO/LEND is seeing interstellar substance on the Moon !?

LEND