Size-dependent modification of asteroid family Yarkovsky V-shapes

Abstract

Context. The thermal properties of the surfaces of asteroids determine the magnitude of the drift rate cause by the Yarkovsky force. In the general case of Main Belt asteroids, the Yarkovsky force is indirectly proportional to the thermal inertia, Γ. Aims. Following the proposed relationship between Γ and asteroid diameter D, we find that asteroids' Yarkovsky drift rates might have a more complex size dependence than previous thought, leading to a curved family V-shape boundary in semi-major axis, a, vs. 1/D space. This implies that asteroids are drifting faster at larger sizes than previously considered decreasing on average the known ages of asteroid families. Methods. The V-Shape curvature is determined for >25 families located throughout the Main Belt to quantify the Yarkovsky sizedependent drift rate. Results. We find that there is no correlation between family age and V-shape curvature. In addition, the V-shape curvature decreases for asteroid families with larger heliocentric distances suggesting that the relationship between Γ and D is weaker in the outer MB possibly due to homogenous surface roughness among family members. B. T. Bolin et al.: Size-dependent modification of asteroid family Yarkovsky V-shapesThe Yarkovsky force has diurnal and seasonal components, but the seasonal component has a much smaller effect on a than the diurnal component, so we assume the following form for the orbit-averaged da dt from (Rubincam 1995;Farinella et al. 1998;Vokrouhlický 1999).

Characterization of Temporarily Captured Minimoon 2020 CD3 by Keck Time-resolved Spectrophotometry

“…However, the role of the 3:1 resonance in transporting 2020 CD 3 into Earth-crossing space from the Main Belt seems unlikely due to its ∼5% source probability. In addition, the Yarkovsky effect is able to transport meter-scale objects like 2020 CD 3 into the proximity of the n 6 resonance, the most likely source of 2020 CD 3 , in <1 Myr if it were to have originated as a fragment at 2.3 au (Bottke et al 2006;Vokrouhlický et al 2015), where most V-type asteroids are found, even if possesses significantly different thermal inertia properties compared to larger, kilometer-scale asteroids (Delbo et al 2007;Bolin et al 2018a). In addition, is apparent from the wide distribution of the 1 km Vesta family fragments covering the entirety of the inner Main Belt (Bolin et al 2017) that the size-dependent velocity distribution of family fragments originating from Vesta could have placed 2020 CD 3 -sized objects anywhere between the nu 6 resonance at ∼2.2 au and the 3:1 resonance at 3.5 au (Carruba & Nesvorný 2016;Bolin et al 2018b).…”

Efficiency characterization of the V-shape asteroid family detection method

“…As anticipated in the previous section, edge effect is mostly a result of having a small number of objects outside the V related to those inside the V (where → 0 would lead to 2 ∕ → ∞). Therefore, edge effect could result as a strong signal in a K vs diagram (commonly used in many previous works as a tool to find family signals; Bolin et al, 2017Bolin et al, , 2018aDelbó et al, 2017Delbó et al, , 2019, even if no family was present. However, we have to point out that: 1) The edge effect is highly dependent on the searching method applied, i.e., whether both-sides or left/right-side are used.…”

“…( ) as function of C; both-and one-(right/left) side scoring in the ( )-ℎ Now we turn our attention to the ( )-ℎ (recall that as and are a function of each other, both or methods are equivalent and based in small changes in the nominal slope). The ℎ was pioneered by Bolin et al (2017Bolin et al ( , 2018a and makes direct use of the characteristic value (Vokrouhlický et al, 2006;Walsh et al, 2013) while the ℎ was applied by Delbó et al (2019). Here we will focus on the ℎ (Bolin et al, 2017(Bolin et al, , 2018a, while a translation for the ℎ should be straightforward.…”

“…The evolution of asteroid's semimajor axis as a function of their size creates the identifiable "V" shape (see Figure 1) when plotted in or 1∕ . This effect is simply showing the 1/D dependence in asteroid drift rates (see Bolin et al (2018a) for variations on the simplistic 1/D dependence based on thermal inertia effects). Walsh et al (2013) used the formulations of Vokrouhlický et al (2006) where the distance in semimajor axis of two asteroids was normalized by their size to determine the Yarkovsky drift distance of all neighboring asteroids.…”

Characterization of Temporarily-Captured Minimoon 2020 CD$_3$ by Keck Time-resolved Spectrophotometry

“…However, the role of the 3:1 resonance in transporting 2020 CD 3 into Earth-crossing space from the Main Belt seems unlikely due to its ∼5% source probability. In addition, the Yarkovsky effect is able to transport meter-scale objects like 2020 CD 3 into the proximity of the ν 6 resonance, the most likely source of 2020 CD 3 , in <1 Myrs if it were to have originated as a fragment at 2.3 au (Bottke et al 2006;Vokrouhlický et al 2015) where most V-type asteroids are found even if possesses significantly different thermal inertia properties compared to larger, km-scale asteroids (Delbo et al 2007;Bolin et al 2018a). In addition, is apparent from the wide distribution of 1 km Vesta family fragments covering the entirety of the inner Main Belt (Bolin et al 2017) that the size-dependent velocity distribution of family fragments originating from Vesta could have placed 2020 CD 3 -sized objects anywhere between the nu 6 resonance at ∼2.2 au and the 3:1 resonance at 3.5 au (Carruba & Nesvorný 2016;Bolin et al 2018b).…”