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We investigate the relationships among the angular orbital elements --- thelongitude of the ascending node, Omega, the inclination, i, and the argument ofperihelion, omega --- of the Kreutz system's faint, dwarf sungrazers observedonly with the SOHO/STEREO coronagraphs; their published orbits were derivedusing a parabolic, purely gravitational approximation. In a plot of i againstOmega the bright Kreutz sungrazers (such as C/1843 D1, C/1882 R1, C/1963 R1,etc.) fit a curve of fixed apsidal orientation, whereas the dwarf members aredistributed along a curve that makes with the apsidal curve an angle of 15 deg.The dwarf sungrazers' perihelion longitude is statistically invariable, buttheir perihelion latitude increases systematically with Omega. We find thatthis trend can be explained by a strong erosion-driven nongravitationalacceleration normal to the orbit plane, confirmed for several test dwarf Kreutzsungrazers by orbital solutions with nongravitational terms incorporateddirectly in the equations of motion on a condition of fixed apsidalorientation. Proceeding in three steps, we first apply Marsden et al.'sstandard formalism, solving for the normal acceleration only, and eventuallyrelax additional constraints on the nongravitational law and the acceleration'sradial and transverse components. The resulting nongravitational accelerationson the dwarf sungrazers exceed the maximum for catalogued comets innearly-parabolic orbits by up to three orders of magnitude, topping inexceptional cases the Sun's gravitational acceleration! A mass-loss modelsuggests that the dwarf sungrazers' nuclei fragment copiously and theirdimensions diminish rapidly near the Sun, implying the objects' imminent demiseshortly before they reach perihelion.

Strong Erosion-Driven Nongravitational Effects in Orbital Motions of the Kreutz Sungrazing System's Dwarf Comets