Most small bodies in the solar system have low orbital inclinations,concentrated near the ecliptic plane.However,some small bodies exhibit high orbital inclinations(i>20°)and are referred to as high-inclinatio...Most small bodies in the solar system have low orbital inclinations,concentrated near the ecliptic plane.However,some small bodies exhibit high orbital inclinations(i>20°)and are referred to as high-inclination small bodies.The discovery and study of these high-inclination objects are reshaping traditional understanding and challenging classical dynamical models.With the advancement of wide-field sky survey projects,an increasing number of small bodies with high-inclination and even retrograde orbits have been observed.Their unique orbital configurations suggest complex formation mechanisms and evolutionary histories.High-inclination small bodies differ significantly from ecliptic plane objects in terms of surface composition,size distribution,and dynamical behavior.Their formation mechanisms involve various pathways,such as gravitational perturbations and planetary scattering,resonance capture and inclination excitation,and the influence of potential Planet Nine.These objects not only serve as"fossil records"of the early evolution of the solar system but also provide new research perspectives for planetary formation theories,interstellar material exchange,and deep-space resource exploration.展开更多
The Antarctic Tianmu Staring Observation Project(ATSOP)entails the deployment of 30 small-aperture,wide-field optical telescopes in the Antarctic region.The system will perform long-term continuous observation campaig...The Antarctic Tianmu Staring Observation Project(ATSOP)entails the deployment of 30 small-aperture,wide-field optical telescopes in the Antarctic region.The system will perform long-term continuous observation campaigns over a period of 100 d(24 h per day)per year,as well as short-time-scale sampling at intervals of 5 min,across a sky area of approximately 1200 square degrees centered near the south celestial pole.We have assessed the types of small solar system bodies detectable by the ATSOP telescopes,as well as the associated scientific research opportunities.Our analysis indicates that the ATSOP is capable of detecting near-Earth objects(NEOs)with all orbital inclinations,as well as high-inclination small bodies located beyond the main asteroid belt.Potential research topics include the discovery and identification of small bodies,orbit determination,physical characterization,investigation into the activity characteristics and evolutionary patterns of active small bodies,and studies on their dynamical evolution.Observations of NEOs can also contribute to planetary defense efforts.On the basis of pilot observational data collected by the Antarctic Tianmu prototype(AT-Proto)between February 20 and October 26,2023,a total of 478 asteroids and 9 comets were successfully identified,demonstrating the effectiveness of the ATSOP system in observing small solar system bodies.Looking ahead,with anticipated performance enhancements in the second-generation AT-Proto,the limiting magnitude will increase from 16 to 18,thereby enabling the detection of an even greater number of small solar system bodies.展开更多
Comets are small celestial bodies orbiting around the Sun.They are remnants left over from the formation of the solar system;their interiors store original material of the planetary disk within the solar system.They a...Comets are small celestial bodies orbiting around the Sun.They are remnants left over from the formation of the solar system;their interiors store original material of the planetary disk within the solar system.They are thus"fossils"for studying the early solar system.According to their orbital periods,comets are classified as long-period comets(orbital period P>200 years)and short-period comets(P<200 years).Long-period comets originate from the Oort Cloud.Compared to short-period comets,they enter the inner solar system less frequently and contain more primitive materials.Studying long-period comets helps us understand the origin of the solar system and reveals characteristics of the Oort Cloud.This paper begins with a summary of our extensive survey of the literature regarding methods of observing comets and foci of comet studies.We introduce systematically the main parameters currently used to assess the activity of long-period comets,including gas production rate,dust production rate,dust properties,morphological characteristics,etc.Subsequently,we discuss in depth the activity mechanisms of long-period comets,covering not only the water ice sublimation-driven mechanism(similar to that of short-period comets)but also various mechanisms that may dominate the activity of long-period comets in the low-temperature environment at the aphelion.These mechanisms include the sublimation of CO or CO_(2) gas ice,the polymerization reaction of cyanides,the crystallization of amorphous water ice,the annealing process of amorphous water ice,the thermal decomposition effect,and the electrostatic supercharge phenomenon.We then summarize the evolving activity of long-period comets as they travel from the Oort Cloud to the vicinity of their perihelions.We analyze unique properties of long-period comets,including such special phenomena as changes in dust color,coma structure,and tail structure.Finally,we summarize currently unresolved scientific questions,and then the entire paper.展开更多
基金supported by the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF)and administrated by the Chinese Academy of Sciences(CAS)the National Natural Science Foundation of China(Nos.12173093 and 11973094)the science research grants from the China Manned Space Project(No.CMS-CSST-2021-B08).
文摘Most small bodies in the solar system have low orbital inclinations,concentrated near the ecliptic plane.However,some small bodies exhibit high orbital inclinations(i>20°)and are referred to as high-inclination small bodies.The discovery and study of these high-inclination objects are reshaping traditional understanding and challenging classical dynamical models.With the advancement of wide-field sky survey projects,an increasing number of small bodies with high-inclination and even retrograde orbits have been observed.Their unique orbital configurations suggest complex formation mechanisms and evolutionary histories.High-inclination small bodies differ significantly from ecliptic plane objects in terms of surface composition,size distribution,and dynamical behavior.Their formation mechanisms involve various pathways,such as gravitational perturbations and planetary scattering,resonance capture and inclination excitation,and the influence of potential Planet Nine.These objects not only serve as"fossil records"of the early evolution of the solar system but also provide new research perspectives for planetary formation theories,interstellar material exchange,and deep-space resource exploration.
基金supported by the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted by the Ministry of Finance of China(MOF)and administered by the Chinese Academy of Sciences(CAS),the National Natural Science Foundation of China(Nos.12173093 and 11973094)a science research grant from the China Manned Space Project(No.CMS-CSST-2021-B08).
文摘The Antarctic Tianmu Staring Observation Project(ATSOP)entails the deployment of 30 small-aperture,wide-field optical telescopes in the Antarctic region.The system will perform long-term continuous observation campaigns over a period of 100 d(24 h per day)per year,as well as short-time-scale sampling at intervals of 5 min,across a sky area of approximately 1200 square degrees centered near the south celestial pole.We have assessed the types of small solar system bodies detectable by the ATSOP telescopes,as well as the associated scientific research opportunities.Our analysis indicates that the ATSOP is capable of detecting near-Earth objects(NEOs)with all orbital inclinations,as well as high-inclination small bodies located beyond the main asteroid belt.Potential research topics include the discovery and identification of small bodies,orbit determination,physical characterization,investigation into the activity characteristics and evolutionary patterns of active small bodies,and studies on their dynamical evolution.Observations of NEOs can also contribute to planetary defense efforts.On the basis of pilot observational data collected by the Antarctic Tianmu prototype(AT-Proto)between February 20 and October 26,2023,a total of 478 asteroids and 9 comets were successfully identified,demonstrating the effectiveness of the ATSOP system in observing small solar system bodies.Looking ahead,with anticipated performance enhancements in the second-generation AT-Proto,the limiting magnitude will increase from 16 to 18,thereby enabling the detection of an even greater number of small solar system bodies.
基金supported by the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF)and administrated by the Chinese Academy of Sciences(CAS)the National Natural Science Foundation of China(grant Nos.12173093)science research grants from the China Manned Space Project with No.CMS-CSST-2021-B08.
文摘Comets are small celestial bodies orbiting around the Sun.They are remnants left over from the formation of the solar system;their interiors store original material of the planetary disk within the solar system.They are thus"fossils"for studying the early solar system.According to their orbital periods,comets are classified as long-period comets(orbital period P>200 years)and short-period comets(P<200 years).Long-period comets originate from the Oort Cloud.Compared to short-period comets,they enter the inner solar system less frequently and contain more primitive materials.Studying long-period comets helps us understand the origin of the solar system and reveals characteristics of the Oort Cloud.This paper begins with a summary of our extensive survey of the literature regarding methods of observing comets and foci of comet studies.We introduce systematically the main parameters currently used to assess the activity of long-period comets,including gas production rate,dust production rate,dust properties,morphological characteristics,etc.Subsequently,we discuss in depth the activity mechanisms of long-period comets,covering not only the water ice sublimation-driven mechanism(similar to that of short-period comets)but also various mechanisms that may dominate the activity of long-period comets in the low-temperature environment at the aphelion.These mechanisms include the sublimation of CO or CO_(2) gas ice,the polymerization reaction of cyanides,the crystallization of amorphous water ice,the annealing process of amorphous water ice,the thermal decomposition effect,and the electrostatic supercharge phenomenon.We then summarize the evolving activity of long-period comets as they travel from the Oort Cloud to the vicinity of their perihelions.We analyze unique properties of long-period comets,including such special phenomena as changes in dust color,coma structure,and tail structure.Finally,we summarize currently unresolved scientific questions,and then the entire paper.
