{"id":27109,"date":"2025-11-19T19:32:16","date_gmt":"2025-11-19T16:32:16","guid":{"rendered":"http:\/\/www.inasan.ru\/?p=27109"},"modified":"2025-11-19T19:32:16","modified_gmt":"2025-11-19T16:32:16","slug":"20251126","status":"publish","type":"post","link":"http:\/\/www.inasan.ru\/en\/20251126\/","title":{"rendered":"Seminar (26.11.2025, 15:00)"},"content":{"rendered":"<p><strong>Author 1<\/strong>: <u>Kirsanova M.S., <\/u>Pavlyuchenkov Y.N.(INASAN)<\/p>\n<p><strong>Title: <\/strong>Observations and Analysis of CH\u2083OH, CO, and HCN Line Emission in the Oort-Cloud Comet C\/2017 K2 (PANSTARRS)<\/p>\n<p><strong>Abstracts:<\/strong><\/p>\n<p>We present pre-perihelion observations of methanol, CO, and HCN in the Oort-cloud comet C\/2017 K2 (PANSTARRS), obtained with the APEX 12-m telescope and the Onsala 20-m telescope from April to July 2022. As the comet\u2019s heliocentric distance decreased from 3.4 to 2.7 au, the intensities of CH\u2083OH lines increased substantially (by factors of 1.1\u20134.0), with the strongest enhancement observed for transitions whose upper-level energies exceed 40 K. In contrast, the brightness of CO and HCN lines remained constant, indicating possible depletion of these hypervolatiles.\u00a0 <br \/>\nWe estimate a coma-gas kinetic temperature of 250\u20131000 K and a water production rate of Q(H\u2082O) = (7\u201310)\u00d710\u00b2\u2078 s\u207b\u00b9. The inferred methanol-to-water abundance ratio is 1.3\u20131.7%. The observed depletion of hypervolatiles is consistent with the loss of an original surface ice layer, possibly during a previous passage near the Sun. Our results show that non-LTE effects dominate in the coma and must be accounted for to accurately derive molecular production rates. We also find indications of weak non-thermal excitation, including potential maser activity in the CH\u2083OH 8\u2080\u20137\u2081 line.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Author 1: Kirsanova M.S., Pavlyuchenkov Y.N.(INASAN) Title: Observations and Analysis of CH\u2083OH, CO, and HCN Line Emission in the Oort-Cloud Comet C\/2017 K2 (PANSTARRS) Abstracts: We present pre-perihelion observations of methanol, CO, and HCN in the Oort-cloud comet C\/2017 K2 (PANSTARRS), obtained with the APEX 12-m telescope and the Onsala 20-m telescope from April to<\/p>\n<div class=\"read-more\"><a href=\"http:\/\/www.inasan.ru\/en\/20251126\/\">Continue Reading&rsaquo;&rsaquo;<\/a><\/div>\n","protected":false},"author":22,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[],"class_list":["post-27109","post","type-post","status-publish","format-standard","hentry","category-akoseminar"],"translation":{"provider":"WPGlobus","version":"3.0.0","language":"en","enabled_languages":["ru","en"],"languages":{"ru":{"title":true,"content":true,"excerpt":false},"en":{"title":true,"content":true,"excerpt":false}}},"_links":{"self":[{"href":"http:\/\/www.inasan.ru\/en\/wp-json\/wp\/v2\/posts\/27109","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.inasan.ru\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.inasan.ru\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.inasan.ru\/en\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"http:\/\/www.inasan.ru\/en\/wp-json\/wp\/v2\/comments?post=27109"}],"version-history":[{"count":3,"href":"http:\/\/www.inasan.ru\/en\/wp-json\/wp\/v2\/posts\/27109\/revisions"}],"predecessor-version":[{"id":27272,"href":"http:\/\/www.inasan.ru\/en\/wp-json\/wp\/v2\/posts\/27109\/revisions\/27272"}],"wp:attachment":[{"href":"http:\/\/www.inasan.ru\/en\/wp-json\/wp\/v2\/media?parent=27109"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.inasan.ru\/en\/wp-json\/wp\/v2\/categories?post=27109"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.inasan.ru\/en\/wp-json\/wp\/v2\/tags?post=27109"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}