MESSENGER MASCS

M1 Flyby Preliminary Results

MASCS Flyby Trajectories

Courtesy Killen et al. 2008 LPSC Abstract

TailsweepH, Na

spacecraft (S/C)time shown

~1 min

S, Na

H,O,O,Ca,K,Na

S, Ca, K, Na

MASCS at M1

Courtesy Killen et al. 2008 LPSC Abstract

Preliminary Results

• H, Na, and Ca observed• S and K not observed• First high spatial resolution observations of the Na tail

emission• First detection of the H tail emission• First time H and Na observed in the tail simultaneously• Ca detected in near-Mercury atmosphere• Spatial asymmetries seen in the Na and H emission –

confirms ground-based measurements of asymmetry• Killen et al. collected ground-based observations of the Na

emission from Kitt Peak’s McMath-Pierce Solar telescope during the flyby

Color Scale: 0 – 40 KRayleighs

Color Scale: 100 – 400 Rayleighs