Near Earth Asteroids with measurable Yarkovsky effect
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...We then scale the numerically computed da/dt with ω, following Farnocchia et al. (2013), and with cos( ) for the diurnal component and with sin2( ) for the seasonal one....
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...This concentration around 90o might favor the seasonal Yarkovsky (which is not included in these runs) over the diurnal one even if the semi–major axis drift is expected to be slower due to the slower rotation rates of the bodies (Farnocchia et al. 2013)....
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...Following Farnocchia et al.[3], the coefficient A2 is expressed as A2 = 4(1−A) 9 Φ(1au) f (Θ)cosγ , f (Θ) = 0....
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...Following Farnocchia et al.[3], the coefficient A2 is expressed as A2 = 4(1−A) 9 Φ(1au) f (Θ)cosγ , f (Θ) = 0.5Θ 1+Θ +0.5Θ 2 , (15) where Φ(1au) is the standard radiation force factor at 1 astronomical unit, A is the Bond albedo, Θ is the thermal parameter, and γ is the obliquity....
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...The latter is assumed to be a purely transverse acceleration A2/r(2), where r is the heliocentric distance and A2 is a function of the asteroid physical quantities[3]....
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...Farnocchia et al.[3] related the thermal parameter Θ to the thermal inertia Γ :...
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...Farnocchia et al.[3] related the thermal parameter Θ to the thermal inertia Γ : Θ = Γ εσT 3ss √ 2π Prot , (17) where ε is the emissivity coefficient, σ is the Stefan-Boltzmann constant, Prot is the rotation period, and Tss is the subsolar temperature[2] Tss = [ (1−A)L0 ηεσr2 ]1/4 , (18) where r is the heliocentric distance of the body and η is the so-called beaming parameter, which is equal to one in the case that each point of the surface is in instantaneous thermal equilibrium with solar radiation....
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"Near Earth Asteroids with measurabl..." refers background or methods in this paper
...This excess of retrograde rotators can be explained by the nature of resonance feeding into the inner Solar System (Bottke et al., 2002). Most of the primary NEA source regions (e.g., the 3:1 resonance, JFCs, Outer Belt, etc.) allow main belt asteroids to enter by drifting either inwards or outwards, but the m6 resonance is at the inner edge of the main belt and so asteroids can generally enter only by inwards drift, i.e., with retrograde rotation. Bottke et al. (2002) report that 37% of NEAs with absolute magnitude H < 22 arrive via m6 resonance. La Spina et al. (2004) point out that this implies 37% of NEAs have retrograde spin (via m6), plus half of the complement (via other pathways). Thus, the retrograde fraction should be 0.37 + 0.5 0.63 = 0.69, while La Spina et al. (2004) report 67% retrograde for their sample, which is dominated by large NEAs. Table 2 contains 81% retrograde rotators, which is larger than 69% and thus, at face value, appears to be inconsistent with the theory. The sample of asteroids shown in Table 2, however, is based on measured Yarkovsky mobility and is not a representative sample of the debiased NEA population as described by Bottke et al. (2002). For example, the sample is dominated by small PHAs (MOID < 0.05 AU) on fairly deep Earth-crossing orbits. We find that 9 of the 21 objects are Aten asteroids (43%), compared to the 6% fraction predicted for the debiased NEA population. Bottke et al. (2002) suggest that the majority of Atens ( 79%) should come from the innermost region of the main belt where the m6 resonance is located....
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...This excess of retrograde rotators can be explained by the nature of resonance feeding into the inner Solar System (Bottke et al., 2002)....
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...This excess of retrograde rotators can be explained by the nature of resonance feeding into the inner Solar System (Bottke et al., 2002). Most of the primary NEA source regions (e.g., the 3:1 resonance, JFCs, Outer Belt, etc.) allow main belt asteroids to enter by drifting either inwards or outwards, but the m6 resonance is at the inner edge of the main belt and so asteroids can generally enter only by inwards drift, i.e., with retrograde rotation. Bottke et al. (2002) report that 37% of NEAs with absolute magnitude H < 22 arrive via m6 resonance....
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...This excess of retrograde rotators can be explained by the nature of resonance feeding into the inner Solar System (Bottke et al., 2002). Most of the primary NEA source regions (e.g., the 3:1 resonance, JFCs, Outer Belt, etc.) allow main belt asteroids to enter by drifting either inwards or outwards, but the m6 resonance is at the inner edge of the main belt and so asteroids can generally enter only by inwards drift, i.e., with retrograde rotation. Bottke et al. (2002) report that 37% of NEAs with absolute magnitude H < 22 arrive via m6 resonance. La Spina et al. (2004) point out that this implies 37% of NEAs have retrograde spin (via m6), plus half of the complement (via other pathways). Thus, the retrograde fraction should be 0.37 + 0.5 0.63 = 0.69, while La Spina et al. (2004) report 67% retrograde for their sample, which is dominated by large NEAs. Table 2 contains 81% retrograde rotators, which is larger than 69% and thus, at face value, appears to be inconsistent with the theory. The sample of asteroids shown in Table 2, however, is based on measured Yarkovsky mobility and is not a representative sample of the debiased NEA population as described by Bottke et al. (2002). For example, the sample is dominated by small PHAs (MOID < 0....
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...Bottke et al. (2002) report that 37% of NEAs arrive via ν6 resonance....
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"Near Earth Asteroids with measurabl..." refers background in this paper
...It is well known that nongravitational forces should be considered as important as collisions and gravitational perturbations for the overall understanding of asteroid evolution (Bottke et al., 2006)....
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