The recent examination news came into explain about, how the uneven shaped minor celestial bodies in the field of gravitation causes annihilation of relative equilibria. According to the researchers Yu Jiang and Hexi Baoyin view from Xi’an Satellite Control Center and Tsinghua University, The rotational speed of these irregular-shaped minor celestial bodies can be changed by the YORP effect. Would you like to know about YORP? Here is your answer. The acronym is Yarkovsky–O’Keefe–Radzievskii–Paddack effect. It describes about an effect that is small but significant force changes the attitude motion.During the prior decade or so, the Yarkovsky and YORP effects have been used to investigate and conceivably determinate a number of unresolved mysteries in space science dealing with small bodies.
Coming back to the previous note, the variation in speed can make the changes on various aspects. They are numbers, positions, stabilities, and topological cases of the minor body’s relative equilibrium points. The numbers of relative equilibrium points can be reduced through the collision and annihilation of relative equilibrium points, or increase through the creation and separation of relative equilibrium points. Here the researcher Yu Jiang, State Key Laboratory of Astronautic Dynamics, Xi’an Satellite Control Center, China and Hexi Baoyin, Tsinghua University developed a classification system of multiple annihilation behaviors of the equilibrium points for irregular-shaped minor celestial bodies. Regarding to this classification, most minor bodies have five equilibrium points; there are twice the number of annihilations per equilibrium point when the number of equilibrium points is between one and five. He presented the detailed annihilation classifications or destruction classification for equilibria of objects which have five equilibrium points and also the annihilation classification for the seven equilibria of Kleopatra-shaped objects and the nine equilibria of Bennu-shaped objects. The Equilibria of different objects fall into different annihilation classifications. By letting the rotational speeds vary, he studied the annihilations and creations of relative equilibria in the gravitational field of ten minor bodies, including eight asteroids, one satellite of a planet, and one cometary nucleus. Let’s see the major study on asteroids, satellite,and comet.
The asteroids were 216 Kleopatra (metallic ham-bone shaped asteroid), 243 Ida (koronis family of the asteroid belt), 951 Gaspra (S-type asteroid belt), 1620 Geographos (highly elongated stony asteroid), 2063 Bacchus (stony and near earth object of Apollo group), 2867 Steins(small main-belt asteroid), 6489 Golevka (Apollo, Mars – crosser and Alinda asteroid) and 101955 Bennu (carbonaceous asteroid in the Apollo group); the satellite of the planet was S16 Prometheus (inner satellite of Saturn), and the comet was 1682 Q1/Halley(short period comet visible from earth from 74 to 79 years). Compare with other asteroids, for the asteroid 101955 Bennuhas the largest number of equilibria among the known asteroids. During the study,Yu Jiang and Hexi Baoyin found that the equilibrium points with different indices approach each other as the rotational speed varies and thus annihilate each other successively. The equilibrium in the gravitational field and the smooth surface equilibrium collide when the equilibrium touches the surface of the body. Finally, we can hope the new research will drive the future of Planetary and Space Science.