In this work,we report observations of three comets:38P/Stephan-Oterma,64P/Swift-Gehrels,and C/2017 M4(ATLAS),conducted with the Nanshan one-meter wide-field telescope in 2018 August and November,and 2019January.We ex...In this work,we report observations of three comets:38P/Stephan-Oterma,64P/Swift-Gehrels,and C/2017 M4(ATLAS),conducted with the Nanshan one-meter wide-field telescope in 2018 August and November,and 2019January.We extracted morphological features through image enhancement techniques and calculated the dust activity parameter,Afρ,along with dust mass loss rates and coma color indices using broadband photometric data.Our morphological analysis uncovered a spectrum of dust characteristics among the observed comets,ranging from a significant twisted structure in comet 38P/Stephan-Oterma’s coma to the regular coma envelope surrounding comet 64P/Swift-Gehrels.The Afρvalues varied between 148.8±0.3 cm for 64P/Swift-Gehrels and1118.5±6.2 cm for C/2017 M4(ATLAS)(measured within a reference aperture radius ofρ=6″),indicating a range from moderate to high activity levels.Dust mass loss rates were estimated from 328.1 kg s^(-1)for comet 64P/Swift-Gehrels to 1395.5 kg s^(-1)for comet C/2017 M4(ATLAS).The color indices of comets 38P/Stephan-Oterma and C/2017 M4(ATLAS)closely resemble the average colors of active short-period comets and active longperiod comets,respectively.In contrast,64P/Swift-Gehrels exhibits a significantly bluer hue than typical Jupiter family comets.展开更多
根据EN12385-4:2002、ISO10425:2003中的公称金属截面系数,结合对Diepa、Casar、ArcelorMittal、OLIVEIRA等企业资料给出部分结构钢丝绳相关数据关系研究,探析GB/T 8706—2017中的计算最小破断拉力、最小破断拉力总和、计算最小破断拉...根据EN12385-4:2002、ISO10425:2003中的公称金属截面系数,结合对Diepa、Casar、ArcelorMittal、OLIVEIRA等企业资料给出部分结构钢丝绳相关数据关系研究,探析GB/T 8706—2017中的计算最小破断拉力、最小破断拉力总和、计算最小破断拉力总和、消减后的实测破断拉力总和、计算实测破断拉力、计算实测破断拉力总和与实测部分捻制损失系数等术语释义。基于对JIS G 3525:2013(JWPA/JSA)与JIS G 3546:2012(JWPA/JSA)给出钢丝绳破断拉力计算公式分析,认为将通常所称的捻制损失系数改称捻制损失剩余系数更合理。展开更多
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region of China(grant No.2021D01B112)Tianshan Talent Training Program through the grant 2023TSYCCX0101。
文摘In this work,we report observations of three comets:38P/Stephan-Oterma,64P/Swift-Gehrels,and C/2017 M4(ATLAS),conducted with the Nanshan one-meter wide-field telescope in 2018 August and November,and 2019January.We extracted morphological features through image enhancement techniques and calculated the dust activity parameter,Afρ,along with dust mass loss rates and coma color indices using broadband photometric data.Our morphological analysis uncovered a spectrum of dust characteristics among the observed comets,ranging from a significant twisted structure in comet 38P/Stephan-Oterma’s coma to the regular coma envelope surrounding comet 64P/Swift-Gehrels.The Afρvalues varied between 148.8±0.3 cm for 64P/Swift-Gehrels and1118.5±6.2 cm for C/2017 M4(ATLAS)(measured within a reference aperture radius ofρ=6″),indicating a range from moderate to high activity levels.Dust mass loss rates were estimated from 328.1 kg s^(-1)for comet 64P/Swift-Gehrels to 1395.5 kg s^(-1)for comet C/2017 M4(ATLAS).The color indices of comets 38P/Stephan-Oterma and C/2017 M4(ATLAS)closely resemble the average colors of active short-period comets and active longperiod comets,respectively.In contrast,64P/Swift-Gehrels exhibits a significantly bluer hue than typical Jupiter family comets.
文摘根据EN12385-4:2002、ISO10425:2003中的公称金属截面系数,结合对Diepa、Casar、ArcelorMittal、OLIVEIRA等企业资料给出部分结构钢丝绳相关数据关系研究,探析GB/T 8706—2017中的计算最小破断拉力、最小破断拉力总和、计算最小破断拉力总和、消减后的实测破断拉力总和、计算实测破断拉力、计算实测破断拉力总和与实测部分捻制损失系数等术语释义。基于对JIS G 3525:2013(JWPA/JSA)与JIS G 3546:2012(JWPA/JSA)给出钢丝绳破断拉力计算公式分析,认为将通常所称的捻制损失系数改称捻制损失剩余系数更合理。
