क्षुद्र ग्रह

thumb|mukhy kshudragrah patata (saphed), trajan kshudragrah (hara)

• kshudr grah (Asteroids) ya avaantar grah -- patharile aur dhatuoan ke aise piand hai jo soory ki parikrama karate haian lekin itane laghu haian ki inhean grah nahian kaha ja sakata. inhean laghu grah ya kshudr grah ya grahika kahate haian. hamari saur pranali mean lagabhag 100,000 kshudragrah haian lekin unamean se adhikatar itane chhote haian ki unhean prithvi se nahian dekha ja sakata. pratyek kshudragrah ki apani kaksha hoti hai, jisamean ye soory ke ird-gird ghoomate rahate haian. inamean se sabase b da kshudr grah haian 'seres'. italavi khagolavetta piajji ne is kshudragrah ko janavari 1801 mean khoja tha. keval 'vestal' hi ek aisa kshudragrah hai jise nangi aankhoan se dekha ja sakata hai yadyapi ise seres ke bad khoja gaya tha. inaka akar 1000 kimi vyas ke seras se 1 se 2 ianch ke patthar ke tuk doan tak hota hai. ye kshudr grah prithvi ki kaksha ke aandar se shani ki kaksha se bahar tak hai. inamean se do tihaee kshudragrah mangal aur brihaspati ke bich mean ek patte mean hai. 'hidalgo' namak kshudragrah ki kaksha mangal tatha shani grahoan ke bich p dati hai. 'harmes' tatha 'airos' namak kshudragrah prithvi se kuchh lakh kilomitar ki hi doori par haian. kuchh ki kaksha prithvi ki kaksha ko katati hai aur kuchh ne bhootakal mean prithvi ko takkar bhi mari hai. ek udaharan maharashtr mean lonar jhil hai.

• airos ek chhota kshudragrah hai jo kshudragrahoan ki kaksha se bhatak gaya hai tatha pratyek sat varshoan ke bad prithvi se 256 lakh kilomitar ki doori par a jata hai. isaka arth yah hua ki chandrama ke atirikt yah prithvi ke sabase najadik ka piand ban jata hai. isaki khoj 1898 mean ji.vit ne ki thi. vaijnanikoan ne apane hal hi ke adhyayanoan mean plooto ki kaksha se pare bhi kshudragrahoan ka ek bailt (patti) ki upasthiti ki sanbhavana prakat ki hai. ye piand shaktishali doorabino ke madhyam se u danatashtariyoan jaise haian. unamean se kuchh bahut chamakadar haian, jabaki kuchh any bahut madhyam haian. unake akaroan ko unaki chamak ke adhar par nirdharit kiya jata hai.

• adhikatar kshudragrah unhian padarthoan se bane haian, jinamean prithvi par pae jane vale patthar bane haian. halaanki unaki satah ke tapaman bhinn haian. vaijnanikoan ke anusar ye mangal aur guru ke bich mean kisi samay rahe prachin grah ke avashesh hai jo kisi karan se tuk doan mean bant gaya. is kalpana ka ek karan yah bhi hai ki mangal aur guru ke bich ka aantaral samany se zyada hai. doosara karan yah hai ki soory ke grah apani doori ke anusar dravyaman mean badhate huye aur guru ke bad ghatate kram mean hai. is tarah se mangal aur guru ke madhy mean guru se chhota lekin mangal se b da ek grah hona chahiye. lekin is prachin grah ki kalpana sirf ek kalpana hi lagati hai kyoanki yadi sabhi kshudr graho ko ek sath mila bhi liya jaye tab bhi inase bana sanyukt grah 1500 kimi se kam vyas ka hoga jo ki hamare chandrama ke adhe se bhi kam hai. ek doosari kalpana ke anusar kshudr grah saur mandal ban jane ke bad bache huye padarth hai. yadyapi unake janm ke bare mean kuchh bhi thik se kaha nahian ja sakata.

thumb|kshudr grah|250px

• kshudr grahoan ke bare mean hamari janakari ulkapat mean bache huye abashesho se hai. jo kshudr grah prithvi ke gurutvakarshan se prithvi ke vatavaran mean akar prithvi se takara jate hai unhean ulka (Meteoroids) kaha jata hai. adhikatar ulkaye vatavaran mean hi jal jati hai lekin kuchh ulkaye prithvi se takara bhi jati hai. in ulkaoan ka 22% bhag siliket ka aur 5% bhag lohe aur nikel ka bana hua hota hai. ulka avashesho ko pahachana mushkil hota hai kyoanki ye samany pattharoan jaise hi hote haian.

• kshudr grah, saur mandal ke janm ke samay se hi maujud hai. isaliye vaijnanik inake adhyan ke liye utsuk rahate haian. aantarikshayan jo inake patte ke bich se gaye hai unhoanne paya hai ki ye patta saghan nahian hai, in kshudr graho ke bich mean kafi sari khali jagah hai. aktoobar 1991 mean galeliyo yan kshudr grah kranmaank 951 gaisapara ke pas se gujara tha. agast 193 mean gaililiyo ne kshudr grah kramaank 243 ida ki najadik se tasvire li thi. ye dono ‘S’ varg ke kshudr grah hai.

• ab tak hazaroan kshudragrah dekhe ja chuke hai aur unaka namakaran aur vargikaran ho chuka hai. iname pramukh hai tautetis, kaisteliya, jiographos aur vesta. 2 palas, 4 vesta aur 10 hayjiya ye 400 kimi aur 525 kimi ke vyas ke bich hai. baki sabhi kshudr grah 340 kimi vyas se kam ke hai. dhoomaketu, chandrama aur kshudr grahoan ke vargikaran mean vivad hai. kuchh grahoan ke chandramaoan ko kshudragrah kahana behatar hoga jaise- mangal ke chandrama phobos aur dimos, guru ke bahari ath chandrama, shani ka bahari chandrama phoebe vagairah.

• saur mandal ke bahari hissoan mean bhi kuchh kshudr grah hai jinhean sentaras kahate haian. iname se ek 2060 shir aaun hai jo shani aur yoorenas ke bich soory ki parikrama karata hai. ek kshudr grah 5335 demokalas hai jisaki kaksha mangal ke pas se yoorenas tak hai. 5145 pholus ki kaksha shani se nepachyun ke madhy hai. is tarah ke kshudr grah asthayi hote haian. ye ya to grahoan se takara jate haian ya unake gurutv mean phansakar unake chandrama ban jate haian. kshudr grahoan ko aankhoan se nahian dekha ja sakata lekin inhean chhoti doorabin se dekha ja sakata hai.

vargikaran

300px|thumb|kshudr grah
Asteroids 1. C varg :-- is shreni mean 75% jnat kshudr grah ate haian. ye kafi dhuandhale hote haian. (albedo 0.03). ye soory ke jaise sanrachana rakhate haian lekin haidrojan aur hiliyam nahian hota hai.
2. S varg :-- 17%, kuchh chamakadar (albedo 0.10 se 0.22), ye dhatuoan loha aur nikel tatha maiganeshiyam siliket se bane hote haian.
3. M varg :-- adhikatar bache huye :- chamakadar (albedo 0.10 se 0.18), nikel aur lohe se bane.

inaka vargikaran inaki sauramandal mean jagah ke adhar par bhi kiya gaya hai.

1. mukhy patta : mangal aur guru ke madhy. soory se 2 - 4 AU doori par. iname kuchh upavarg bhi hai :- hangeriyas, floras, phokia, koronis, eos, themis, sayabeles aur hildas. hildas iname mukhy hai.
2. prithvi ke pas ke kshudr grah (NEA)
3. ऎtens :- soory se 1.0 AU se kam doori par aur 0.983 AU se zyada doori par.
4. apolos :- soory se 1.0 AU se zyada doori par lekin 1.017 AU se kam doori par.
5. amars :- soory se 1.017 AU se zyada doori par lekin 1.3 AU se kam doori par.
6. trajan :- guru ke gurutv ke pas.

kuchh mukhy kshudragrah ek nazar mean

kramaank	nam	soory se doori (ki.mi.)	trijya	dravyaman	avishkarak	dinaank
2062	eten Aten	144514	0.5	?	helin Helin	1976
3554	amun Amun	145710	?	?	shumekar Shoemaker	1986
1566	aeekeras Icarus	161269	0.7	?	bade Baade	1949
433	eras Eros	172800	33x13x13		vit Witt	1898
1862	apolo Apollo	220061	0.7	?	renamuth Reinmuth	1932
2212	hephaistos Hephaistos	323884	4.4	?	shernyakh Chernykh	1978
951	gaispara Gaspra	330000	8	?	neuzamin Neujmin	1916
4	vesta Vesta	353400	265	3.0e20	olbaras Olbers	1807
3	juno Juno	399400	123	?	hardiang Harding	1804
15	yunomiya Eunomia	395500	136	8.3e18	degasaparis De Gasparis	1851
1	seres Ceres (ab bauna grah)	413900	487	8.7e20	piajji Piazzi	1801
2	palas Pallas	414500	261	3.18e20	olbars Olbers	1802
243	ida Ida	428000	35	?	?	1880
52	yuropa Europa	463300	156	?	goldaskmdit Goldschmidt	1858
10	hayagia Hygiea	470300	215	9.3e19	degasaparis De Gasparis	1849
511	devida Davida	475400	168	?	dugan Dugan	1903
911	agmemnan Agamemnon	778100	88	?	renamath Reinmuth	1919
2060	shiran Chiron	2051900	85	?	koval Kowal	1977

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