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METEORHO

meteorhoMETEORHO (az yun. meteora — hodisoti atmosferi va osmoni), shihobho, hodisoti rushnoist, ki hangomi ba atmosferai Zamin zada daromadani zarrahoi sakht — jismhoi meteori ba amal meoyad. Jismhoi meteori yo khud meteoroidho obekthoeand, ki dar fazoi baynisayyoravi harakat mekunand va andozahoyashon kalontar az molekulavu khurdtar az asteroid meboshad. Jismi meteori az balandii 60—120 km bo surati 11 to 72 km/sov hangomi ba atmosferai Zamin zada daromadanash gudokhta, bur shuda, posh khurda va mayda shuda meravad. Atomhoi moddai meteori hangomi bo molekulahoi davo barkhurdan ionizasiya meshavand va meangezand. Partavafshonii meteor asosan bo afkanishi atomu ionhoi meteorii angekhta aloqamand ast, onho bo surati jismi meteori harakat mekunand va energiyai kinetikiashon az dahho to ba sadho elektronvolt ast. Dar in hol jismi meteori qisman yo khud purra massai khudro gum karda, izi meteoriro ba vujud meovarad.

Agar meteoroid qiyosan massai kalon va zichii ziyod doshta, suratash nisbatan buzurg naboshad, ongoh bazan yak qismi vay dar atmosfera purra bukhor nashuda ba rui Zamin meaftad, ki onro meteorit menomand. Meteorero, ki qadri sitoraviash beshtar az —4 ast, bolid (ba istilohi qadimai tojiki soqiba) menomand. Bolidhoi baso ravshanro to ruzona ham metavon did, ki dar balandii 20—40 km durakhshida, sipas nopadid megardand.

Hangomi duchor shudani Zamin bo tudai jismhoi meteori, ki dar atrofi Oftob taqr. az rui madorhoi yaikhela davr mezanand, seli meteor (to 50—100 meteor dar 1 s) mushohida karda meshavad, ki onho taqr. az yak nuqtai osmon — radiant mebaroyand. Selhoi meteori mansub ba burjhoand, ki radianthoyashon Dar on voqe gardidand. Selhoi meteorie, ki khele bo shiddat meborand (Dar mavride, ki dar yak daqiqa 1000 va beshtar az on meteor mushohida shavad), shihobboron nomida meshavand. Mas., shihobboroni Andromediho dar soli 1789—1885, Tininiho dar soli 1939 va 1962, Asadiho dar soli 1789, 1833, 1866 va 1966 va hojagii qishloq Meteorhoro sadho sol injonib pushonida mekunand va meomuzavd. Ammo tabiati in hodisoti atmosfera khosiyathoi fizikavi, tavsifi mador va sababhoi paydoishi on tanho dar se-chor dahsolai okhir oshkor va muayyan karda shudaand.

Meteorioro bo usulhoi gunogun mushohida mekunand. Qadimtarini on usuli vizuali meboshad. In usul imkon dod, ki dar borai tagyiroti shabonaruzi va mavsimii moteorho, dar borai gustarishi onho dar gunbazi osmon malumot ba dast ovarda shavad. Holo baroi omukhtani meteorho mushohidahoi fotografi, radiolokasioni, dar solhoi okhir elektronivu optiki va televizioniro istifoda mebarand, ki onho az asositarin usulho ba shumor meravand.

Baroi qaydi fotografii meteorho asbobi ba nom nazzori meteoriro istifoda mebarand, ki az chand agregathoi fotografi iborat ast. Bo usulhoi fotografi meteorhoi to qadri sitoravii 4-ro qayd menamoyand. Az du mahalle, ki masofaashon 30—50 km ast, dar gunbadi osmon meteorhoro ba surat megirand. Az rui fotosuratho dar foni sitoraho balandii meteor va radianti onro muayyan kardan imkonpazir megardad. Ba peshi kamerahoi yake az agregathoi nazzor obtyurator (olate, ki mahluli davrzananda dorad)-ro guzoshta, surati meteorro niz muayyan kardan mumkin meshavad. Agar ba peshi obektivi fotokamerahoi agregati digar prizmaho yo khud panjarahoi difraksioniero guzorem, dar fotonavor spektri meteor hosil meshavad, ki az rui on metavon tarkibi khimiyavii jismi meteoriro muayyan kard.

Usulhoi radiolokasioni imkoniyat medihad. ki meteorhoi to qadri sitoravii 12—15-umro dar nama Guna sharoitm obu havo va dar davomi shabonaruz mushohida kunem. Radiolokator pai meteoriro ba qayd megirad. Atomhoi bugshudai moddai meteori hangomi dar atmosfera harakat kardan ba molekulahoi havo barkhurda va sipas angekhta dar shakli iz namudor meshavad, ki on ba dahho kilometr tul kashida metavonad. Ba tufayli diffuziya shudan, ba yakdigar chaspidani zarrahoi ionizasiyashuda va g. izi meteori ba zudi vase meshavad, tarokumi elektronii on meaftad va zimni on iz parokanda megardad.

Mushohidahoi radiolokasionii meteorhoro baroi muayyan kardani surat va samti jarayonhoi havoi dar zonahoi meteorii atmosferai zamin (balandiash 120—60 km) istifoda mebarand.

Mushohidahoi fotografi va radiolokasionii meteorho beshtar dar SSSR (Dushanbe, Larkov, Qazon, Odessa, Kiev, Obnivsk, Frunze va g.), RSJS, ShMA, Kanada, Avstraliya, Angliya guzaronda meshavand. Holo bo yorii datchikhoe, ki dar kishtihoi kayhoni guzoshta meshavand, dar borai meteoroidhoi maydatarini andozaashon to 10- mm ham malumoti purqimat ba dast meorand. Tahti rohbarii akad. AF Tojikiston P. B. Bobojonov bori avval (s. 1964) dar Dushanbe va Odessa bo metodi lahzaviya vodosht (ekspozisiya) mushohidai fotografii meteorho guzaronda shud, ki dar on dar atmosferai Zamin navhoi gunoguni taqsimshavii jismi meteoriro baralo didan mumkin bud. Meteoroidho dar atmosferai Zamin az sababi kam budani zichiashon (1 g/sm3) va kovok budani sokhtashon pora meshavand. Zichii jismhoi meteorii tavlidashon kometavi az in ham kamtar ast.

Dar spektri meteorho asosan khathoi emissioni namudorand. Dar bayni onho khathoi atomhoi khunsoi Fe, Na, Mg, Sa, Sg, Mp, A1, N, O, Si, inchunin khathoi ionizonidashudai atomhoi Mg+, Si+, Sa+ va Fe+ oshkor karda shudaand. Jismhoi meteoriro ba monandi meteoritho ba du guruhi kalon: ohani va sangi judo kardan mumkin ast. Jismhoi meteorii sangi nazar ba ohani beshtar mushohida shudaand.

Muoinai madori meteoroidhoi sporady (meteorhoi judogona, ki mansubi yagon seli meteori nestand) nishon dodand, ki moddai meteori asosan dar hamvorii ekliptika ruh shudaast va harakati rost dorand. Aksari meteorhoi qaydshuda (beshtar az 99%) madori ellipsi dorand. In guvohi medihad, ki jismhoi meteoriro sistemai Oftob tavlid kardaast. Bo rohi mushohidahoi fotografiyu radiolokasioni madori dahho hazor meteorho muayyan karda shudaand.

Ba jismhoi meteori ba chuz jozibai gravitasionii Oftob va sayyoraho, inchunin afkanishoti elektromagnitiyu korpuskulavii Oftob ham tasir merasonand. Chunonchi, az tasiri fishori rushnoi khurdtarin jismhoi meteorii andozaashon khurdtar az 0,001 mm ba beruni sistemai Oftob fishonda meshavand. Effekti Poyitingu Robertson va amsolikorpuskulavii on, ki zimni furuburdi afkanishoti izotropii radiasiyai Oftob ba amal meoyad, ohista-ohista andozahoi madorro kam mekunad. Dar natija, jismhoi meteori toraft ba Oftob nazdik meshavand. Az tasiri afkanishoti oftobi va protonhoi bodi oftobi bur shudanu posh khurdani jismhoi meteori sababi toraft khurd shudani massai meteoroid megardad. Davomati umri meteoroidho dar mintaqahoi darunii sistemai Oftob chandon besh nest. Az in sabab ham zakhirai moddai meteori boyad bo kadom yak tarze hamesha pur shuda istad. Se manbai chunin purshaviro nishoi dodan mumkin ast: 1) porashavii yadrohoi nometaho; 2) mayda shudani asteroidho; 3) duhuli maydatarin jismho az durtarin kanorhoi sistemai Oftob.

Massai meteoroidi ba atmosferai Zamin zada daroyanda har qadar kalon boshad, meteori zodai u niz hamon qadar durakhshontar meshavad. Oshkor shudaast, ki hangomi ba yak qadri sitoravi kam shudani tobishi meteorho miqdori onho du marotiba ziyod meshudaast.

Zichii moddai meteori dar fazoy qaribizamini taqr. 0,5  10-22 g/sm3-ro tashkil mekunad. Dar davomi yak shabonaruz ba Zamin az dahho to sadkho tonna moddai meteory meaftad. Ba atmosferai Zamin dokhil shudani moddai meteori boisi yak andoza tagyir yoftani tarkibi qabathoi boloii atmosferai Zamin megardad va ba paydo shudani abrhoi parniyon (nuqratob), baze qabathoi ionosfera va g. musoidat mekunad.

Ad.: Lenin B. Yu., Fizicheskaya teoriya meteorov i meteornoe veshestvo v solnechnoy sisteme, M., 1956; Babadjanov P. B., Kramer E. N., Metodika i Nekotorie rezultati fotograficheskikh issledovaniy meteorov, M., 1963; Kasheev B. D., Lebedines V. N., Lagutin M. F„ Meteornie yavleniya v atmosfere Zemli, M., 1967; Katasyov A. A., Issledovanie meteorov v atmosfere Zemli fotograficheskim metodom, L., 1966; Fial ko E. I., Radiolokasiya meteorov, M.. 1967; Evolutionary and Physical Properties of Meteoroids, NASA SP —319, Washington, D. S.. 1973.

P. Bobojonov.

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