The Yarkovsky-O'Keefe-Radzievskii-Paddack(YORP) effect is a net torque caused by solar radiation directly reflected and thermally re-emitted from the surface of small asteroids and is considered to be crucial in t...The Yarkovsky-O'Keefe-Radzievskii-Paddack(YORP) effect is a net torque caused by solar radiation directly reflected and thermally re-emitted from the surface of small asteroids and is considered to be crucial in their dynamical evolution. By long-term photometric observations of selected near-Earth asteroids, it is hoped to enlarge asteroid samples with a detected YORP effect to facilitate the development of a theoretical framework. Archived light-curve data are collected and photometric observations are made for(1685) Toro and(85989) 1999 JD6,which enables measurement of their YORP effect by inverting the light curve to fit observations from a convex shape model. For(1685) Toro, a YORP acceleration υ =(3.2 ± 0.3) × 10^(-9)rad · day^(-2)(1σ error) is updated,which is consistent with previous YORP detection based on different light-curve data;for(85989) 1999 JD6, it is determined that the sidereal period is 7.667 749 ± 0.000009 hr, the rotation pole direction is located atλ = 232° ± 2°, β =-59° ± 1°, the acceleration is detected to be υ =(2.4 ± 0.3) × 10^(-8)rad · day^(-2)(1σ error) and in addition to obtaining an excellent agreement between the observations and model. YORP should produce both spin-up and spin-down cases. However, including(85989) 1999 JD6, the dω/dt values of 11 near-Earth asteroids are positive totally, which suggests that there is either a bias in the sample of YORP detections or a real feature needs to be explained.展开更多
基金supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences (GrantNo.XDB41010104)the National Natural Science Foundation of China (Grant No.11633009)+2 种基金the Space Debris and NearEarth Asteroid Defense Research Project (Grant Nos. KJSP2020020204,KJSP2020020102)the Civil Aerospace Pre-research Project (Grant Nos.D020304,D020302)Minor Planet Foundation。
文摘The Yarkovsky-O'Keefe-Radzievskii-Paddack(YORP) effect is a net torque caused by solar radiation directly reflected and thermally re-emitted from the surface of small asteroids and is considered to be crucial in their dynamical evolution. By long-term photometric observations of selected near-Earth asteroids, it is hoped to enlarge asteroid samples with a detected YORP effect to facilitate the development of a theoretical framework. Archived light-curve data are collected and photometric observations are made for(1685) Toro and(85989) 1999 JD6,which enables measurement of their YORP effect by inverting the light curve to fit observations from a convex shape model. For(1685) Toro, a YORP acceleration υ =(3.2 ± 0.3) × 10^(-9)rad · day^(-2)(1σ error) is updated,which is consistent with previous YORP detection based on different light-curve data;for(85989) 1999 JD6, it is determined that the sidereal period is 7.667 749 ± 0.000009 hr, the rotation pole direction is located atλ = 232° ± 2°, β =-59° ± 1°, the acceleration is detected to be υ =(2.4 ± 0.3) × 10^(-8)rad · day^(-2)(1σ error) and in addition to obtaining an excellent agreement between the observations and model. YORP should produce both spin-up and spin-down cases. However, including(85989) 1999 JD6, the dω/dt values of 11 near-Earth asteroids are positive totally, which suggests that there is either a bias in the sample of YORP detections or a real feature needs to be explained.
