Exoplanet imaging using the solar gravitational lens is an enticing prospect.The fundamental physical properties of the lens,including its angular resolution and light amplification,promise exceptional capabilities.Th...Exoplanet imaging using the solar gravitational lens is an enticing prospect.The fundamental physical properties of the lens,including its angular resolution and light amplification,promise exceptional capabilities.These expectations,however,are tempered by the realization of numerous challenges,including imperfections of the lens itself,noise sources,the properties of the imaging target and difficult technical issues.We discuss,in particular,a subject not previously addressed,the impact of temporally varying surface features,notably a variable cloud cover,obscuring the target exoplanet.This has a substantial detrimental effect on image recovery,leading to our cautious assessment of the practical feasibility of using the Sun’s gravitational field as an effective telescope.展开更多
Asteroids,as the primitive building blocks for the formation of our solar system,could reveal its evolution mechanism,and have attracted more and more attention from the public and professional institutions in recent ...Asteroids,as the primitive building blocks for the formation of our solar system,could reveal its evolution mechanism,and have attracted more and more attention from the public and professional institutions in recent years.Their physical properties,such as rotational period,spin axis and overall shape,can be inverted from ground-and space-based photometric observations.Since the inversion process is very time-consuming,this paper combines the genetic algorithm with the Levenberg–Marquardt(LM) algorithm,and presents a hybrid optimization algorithm based on a Cellinoid shape model for the inversion of rotational periods,which greatly improves the inversion efficiency.The proposed hybrid algorithm is applied to the synthetic lightcurves generated for an assumed Cellinoid shape model and the inverted rotational period results are consistent with the preset ones with a reduced search time,compared with the LM algorithm.Finally,multiple numerical experiments on the periods are performed on lightcurves and sparse observations of real asteroids to confirm that the proposed method can perform well in improving computational efficiency.展开更多
文摘Exoplanet imaging using the solar gravitational lens is an enticing prospect.The fundamental physical properties of the lens,including its angular resolution and light amplification,promise exceptional capabilities.These expectations,however,are tempered by the realization of numerous challenges,including imperfections of the lens itself,noise sources,the properties of the imaging target and difficult technical issues.We discuss,in particular,a subject not previously addressed,the impact of temporally varying surface features,notably a variable cloud cover,obscuring the target exoplanet.This has a substantial detrimental effect on image recovery,leading to our cautious assessment of the practical feasibility of using the Sun’s gravitational field as an effective telescope.
基金funded by the grant from the Macao Young Scholars Program (Project code: AM201920)the National Natural Science Foundation of China (NSFC, grant No. E11903085)+5 种基金funded by the Science and Technology Development Fund, Macao SAR (File Nos. 0073/ 2019/A2 & 0096/2022/A)supported by the Science and Technology Development Fund, Macao SAR (File No. 0042/ 2018/A2)supported by the B-type Strategic Priority Program of CAS (Grant No. XDB41000000)the NSFC (Grant Nos. 62227901 & 11633009)Space debris and NEO research project (Nos. KJSP2020020204 & KJSP2020020102)Minor Planet Foundation。
文摘Asteroids,as the primitive building blocks for the formation of our solar system,could reveal its evolution mechanism,and have attracted more and more attention from the public and professional institutions in recent years.Their physical properties,such as rotational period,spin axis and overall shape,can be inverted from ground-and space-based photometric observations.Since the inversion process is very time-consuming,this paper combines the genetic algorithm with the Levenberg–Marquardt(LM) algorithm,and presents a hybrid optimization algorithm based on a Cellinoid shape model for the inversion of rotational periods,which greatly improves the inversion efficiency.The proposed hybrid algorithm is applied to the synthetic lightcurves generated for an assumed Cellinoid shape model and the inverted rotational period results are consistent with the preset ones with a reduced search time,compared with the LM algorithm.Finally,multiple numerical experiments on the periods are performed on lightcurves and sparse observations of real asteroids to confirm that the proposed method can perform well in improving computational efficiency.
