{"title":"恒星形成率与分子云不同性质的关系","authors":"Ashok Mondal , Tanuka Chattopadhyay","doi":"10.1016/j.newast.2023.102182","DOIUrl":null,"url":null,"abstract":"<div><p><span>Properties of molecular clouds (</span><span><math><mrow><mi>M</mi><mi>C</mi><mi>s</mi></mrow></math></span><span>) lying in our Galaxy and their star formation scenarios have been investigated with the help of multivariate unsupervised machine learning techniques concerning several observable parameters. At first, the </span><span><math><mrow><mi>M</mi><mi>C</mi><mi>s</mi></mrow></math></span><span> have been classified into four coherent groups using the standard K-means clustering method. Subsequently, the optimum number of groups has been estimated by applying the Elbow method as well as the computation of Silhouette widths for a robustness check. Later, the properties of the groups are studied through several observable parameters as mentioned along with computed ones e.g. star formation rates (</span><span><math><mrow><mi>S</mi><mi>F</mi><mi>R</mi><mi>s</mi></mrow></math></span>), virial masses, mass-spectra, dynamical time scales (<span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span><span><span><span>), etc. to get a deeper understanding of the star formation process and dynamical evolution of these clouds. It is found that cluster 1 is suitable for the formation of field stars, binary pairs, or </span>stellar associations, whereas the clouds in cluster 2 and cluster 3 are favorable sites for the formation of </span>Galactic clusters<span> of moderate masses, and cluster 4 may produce massive Galactic clusters as well as a few globular clusters. Surprisingly, for each cluster, clouds at around Galacto-centric radius </span></span><span><math><mo>∼</mo></math></span>8 kpc, and on the near Galactic plane has a significantly low <span><math><mrow><mi>S</mi><mi>F</mi><mi>R</mi></mrow></math></span>. These occurrences indicate that the star formation phenomenon has yet not started or the proneness to start in that region.</p></div>","PeriodicalId":54727,"journal":{"name":"New Astronomy","volume":"108 ","pages":"Article 102182"},"PeriodicalIF":1.9000,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Dependence of star formation rate on different properties of molecular clouds\",\"authors\":\"Ashok Mondal , Tanuka Chattopadhyay\",\"doi\":\"10.1016/j.newast.2023.102182\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p><span>Properties of molecular clouds (</span><span><math><mrow><mi>M</mi><mi>C</mi><mi>s</mi></mrow></math></span><span>) lying in our Galaxy and their star formation scenarios have been investigated with the help of multivariate unsupervised machine learning techniques concerning several observable parameters. At first, the </span><span><math><mrow><mi>M</mi><mi>C</mi><mi>s</mi></mrow></math></span><span> have been classified into four coherent groups using the standard K-means clustering method. Subsequently, the optimum number of groups has been estimated by applying the Elbow method as well as the computation of Silhouette widths for a robustness check. Later, the properties of the groups are studied through several observable parameters as mentioned along with computed ones e.g. star formation rates (</span><span><math><mrow><mi>S</mi><mi>F</mi><mi>R</mi><mi>s</mi></mrow></math></span>), virial masses, mass-spectra, dynamical time scales (<span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span><span><span><span>), etc. to get a deeper understanding of the star formation process and dynamical evolution of these clouds. It is found that cluster 1 is suitable for the formation of field stars, binary pairs, or </span>stellar associations, whereas the clouds in cluster 2 and cluster 3 are favorable sites for the formation of </span>Galactic clusters<span> of moderate masses, and cluster 4 may produce massive Galactic clusters as well as a few globular clusters. Surprisingly, for each cluster, clouds at around Galacto-centric radius </span></span><span><math><mo>∼</mo></math></span>8 kpc, and on the near Galactic plane has a significantly low <span><math><mrow><mi>S</mi><mi>F</mi><mi>R</mi></mrow></math></span>. These occurrences indicate that the star formation phenomenon has yet not started or the proneness to start in that region.</p></div>\",\"PeriodicalId\":54727,\"journal\":{\"name\":\"New Astronomy\",\"volume\":\"108 \",\"pages\":\"Article 102182\"},\"PeriodicalIF\":1.9000,\"publicationDate\":\"2023-12-22\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"New Astronomy\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1384107623001835\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ASTRONOMY & ASTROPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"New Astronomy","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1384107623001835","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
Dependence of star formation rate on different properties of molecular clouds
Properties of molecular clouds () lying in our Galaxy and their star formation scenarios have been investigated with the help of multivariate unsupervised machine learning techniques concerning several observable parameters. At first, the have been classified into four coherent groups using the standard K-means clustering method. Subsequently, the optimum number of groups has been estimated by applying the Elbow method as well as the computation of Silhouette widths for a robustness check. Later, the properties of the groups are studied through several observable parameters as mentioned along with computed ones e.g. star formation rates (), virial masses, mass-spectra, dynamical time scales (), etc. to get a deeper understanding of the star formation process and dynamical evolution of these clouds. It is found that cluster 1 is suitable for the formation of field stars, binary pairs, or stellar associations, whereas the clouds in cluster 2 and cluster 3 are favorable sites for the formation of Galactic clusters of moderate masses, and cluster 4 may produce massive Galactic clusters as well as a few globular clusters. Surprisingly, for each cluster, clouds at around Galacto-centric radius 8 kpc, and on the near Galactic plane has a significantly low . These occurrences indicate that the star formation phenomenon has yet not started or the proneness to start in that region.
期刊介绍:
New Astronomy publishes articles in all fields of astronomy and astrophysics, with a particular focus on computational astronomy: mathematical and astronomy techniques and methodology, simulations, modelling and numerical results and computational techniques in instrumentation.
New Astronomy includes full length research articles and review articles. The journal covers solar, stellar, galactic and extragalactic astronomy and astrophysics. It reports on original research in all wavelength bands, ranging from radio to gamma-ray.