How to Measure a Planet's Mass
Fahimtar nauyin duniya yana da matuƙar muhimmanci ga fannoni da dama na kimiyyar duniyoyi da kuma kimiyyar taurari. Da ma'aunin taro daidai, masana kimiyya za su iya fahimtar tsarin halittar duniyar, yawanta, tasirin nauyi, har ma da tarihin samuwarta. Duk da cewa faɗin sararin samaniya yana rikitar da ma'auni kai tsaye, an ƙirƙiri hanyoyi masu ban mamaki a cikin shekaru da dama. Wannan labarin zai bincika dabaru daban-daban da ake amfani da su don auna nauyin duniya, gami da hulɗar nauyi, yanayin kewayawa, da hanyoyin taurari.
Gravitational Influence
Ɗaya daga cikin muhimman ƙa'idodi da ake amfani da su don auna nauyin duniya shine dokar nauyi ta Newton. A cewar wannan doka, ƙarfin nauyi tsakanin abubuwa biyu yana daidai gwargwado kai tsaye da samfurin yawansu kuma yana daidai gwargwado da murabba'in nisan da ke tsakaninsu. Idan aka yi amfani da shi ga tsarin duniyoyi, wannan ƙa'ida tana bawa masana kimiyya damar tantance nauyin duniya ta hanyar nazarin tasirin nauyi da yake da shi akan abubuwan da ke kusa.
Gravitational Effects on Satellites
Kasancewar tauraron dan adam na halitta ko na wucin gadi da ke zagayawa a duniya yana samar da hanya mai sauƙi don auna girman duniyar. Ta hanyar lura da kewayar tauraron dan adam, masana kimiyya za su iya samun muhimman bayanai game da tasirin nauyi na babban jikin.
Dokar Kepler ta uku ta danganta lokacin zagaye (T) da kuma rabin babban axis (a) na zagayen tauraron dan adam da ke kewaye da duniyar:
[ T^2 = \frac{4 \pi^2}{G(M+m)} a^3 ]
inda (T) shine lokacin, (a) shine rabin babban axis na kewayar, (G) shine ma'aunin nauyi, (M) shine nauyin duniya, kuma (m) shine nauyin tauraron dan adam (wanda yawanci ba shi da yawa idan aka kwatanta da (M)).
Sake rubuta lissafin (M):
[ M \approx \frac{4 \pi^2 a^3}{GT^2} ]
Ta hanyar auna daidai lokacin kewayar tauraron dan adam da kuma rabin babban axis na tauraron dan adam, masana kimiyya za su iya lissafin nauyin duniyar.
Gravitational Effects on Nearby Planets
Taurari a cikin tsarin taurari iri ɗaya suna yin ƙarfin nauyi a kan junansu. Ana iya amfani da canje-canje masu sauƙi a cikin kewayarsu saboda waɗannan hulɗa don kimanta yawansu. A tarihi, wannan hanyar ta ba masana ilmin taurari damar tantance yawan taurari kamar Jupiter ta hanyar lura da tasirinsa akan kewayar taurari da wata maƙwabtanta.
Orbital Dynamics of Multiple Bodies
A cikin tsarin da ke da gawarwakin duniyoyi da yawa, cikakken bincike kan motsinsu na iya haifar da taro. Sau da yawa ana yin nazarin hulɗar nauyi mai rikitarwa a cikin irin waɗannan tsarin ta amfani da dabarun daga makanikan sama.
Radial Velocity Method
Ana amfani da hanyar saurin radial a cikin nazarin duniyar waje amma kuma ana iya amfani da ita ga tsarin hasken rana. Wannan dabarar tana auna canjin tauraron ko duniyar Doppler - canje-canje a cikin bakan tauraron da motsi zuwa gare mu ko nesa da shi ya haifar. Waɗannan canje-canjen suna nuna jajircewar nauyi da wani duniya ke yi akan tauraron iyaye.
Ganin yadda tauraron ke juyawa a lokaci-lokaci, masana ilmin taurari za su iya kimanta nauyin duniyar da ba a gani ba. Girman motsin tauraron yana ba da bayanai kan rabon taro tsakanin tauraron da duniyar da ke zagaye.
Transit Timing Variations (TTV)
Idan wata duniya ta wuce tauraruwarta, akwai ɗan raguwa a cikin hasken tauraruwar. Idan duniyoyi da yawa suna kewaya tauraro ɗaya, hulɗar nauyi tsakanin su na iya haifar da bambance-bambance a daidai lokacin waɗannan hanyoyin. Ta hanyar auna bambance-bambancen, wanda aka sani da Transit Timeing Variations (TTV), masana kimiyya za su iya tantance yawan duniyoyin da ke hulɗa. Wannan hanyar ta kasance mai matuƙar amfani wajen nazarin tsarin exoplanet tare da duniyoyi da yawa.
Astrometric Methods
Tauraron taurari ya ƙunshi auna matsayi da motsin taurari daidai akan lokaci. Bambancin waɗannan motsin na iya nuna kasancewar taurari. Lokacin da tauraro ya ɗan motsa kaɗan saboda jan nauyi na duniyar da ke zagaye, matsayinsa yana canzawa lokaci-lokaci. Ta hanyar bin diddigin waɗannan canje-canje, masana kimiyya za su iya gano halayen kewayar duniyar, gami da nauyinta.
Astrometric Measurements of Stars
Ga masana ilmin taurari, masana ilmin taurari suna lura da 'motsi' na tauraro wanda jan nauyi na wata duniyar da ke zagaye ke haifarwa. Wannan girgizar tana haifar da ƙananan canje-canje a matsayin tauraro. Ta hanyar nazarin waɗannan canje-canjen matsayi, ana iya kimanta nauyin duniyar da ke zagaye. Tauraro yana buƙatar daidaito mai tsanani, wanda galibi ake samu ta hanyar abubuwan lura na sararin samaniya kamar aikin Gaia, wanda ke taswirar matsayin taurari da daidaito mara misaltuwa.
Gravitational Lensing
Gilashin nauyi, sakamakon dangantakar Einstein ta Janar, yana samar da wata hanya ta kai tsaye don kimanta nauyin duniya. Lokacin da haske daga tauraro mai nisa ya wuce kusa da wani babban abu kamar duniya, filin nauyi na duniya na iya tanƙwara hasken, yana ƙara girman hoton tauraron da kuma ɓata shi.
Microlensing Events
A cikin microlensing na nauyi, duniya da ke wucewa tsakaninmu da tauraro mai nisa tana aiki a matsayin ruwan tabarau, tana haskakawa da karkatar da hasken tauraro na ɗan lokaci. Halayen wannan abin da ke haskakawa ya dogara ne akan girman duniyar da ke haskakawa da nisanta daga tauraro da mai kallo.
Ta hanyar nazarin irin waɗannan abubuwan da suka faru na microlensing, masana kimiyya za su iya kimanta nauyin duniyar lensing. Wannan dabarar tana da amfani musamman don gano da auna duniyoyi waɗanda ke da ƙalubalen lura ta hanyar hanyoyin saurin kai tsaye ko na radial.
Combining Methods for Greater Precision
Sau da yawa, ana amfani da haɗakar hanyoyin da ke sama don auna nauyin duniya da daidaito mafi girma. Misali, bayanan saurin radial tare da lura da abubuwan da ke faruwa na iya samar da duka nauyin duniya da radius, wanda ke haifar da kimanta yawanta da kuma, sakamakon haka, yuwuwar haɗakarta.
A cikin tsarin hasken rana namu, an tantance tarin duniyoyi da daidaito sosai ta amfani da dabaru da yawa. Misali, an san tarin Jupiter da Saturn tsawon ƙarni ta hanyar tasirin nauyi a kan wata da duniyoyin da ke kusa. Ayyukan zamani kamar Juno (kewaya Jupiter) da Cassini (wanda ke kewaya Saturn) sun inganta waɗannan ma'auni.
Ga duniyoyin da ba su da tsari, haɗakar saurin radial da hanyoyin wucewa sun kasance mafi yawan amfani, suna samar da daidaiton taro ga ɗaruruwan duniyoyi.
Conclusion
Auna nauyin duniya ya ƙunshi fahimtar da amfani da ƙa'idodin tushe na nauyi da yanayin kewayawa. Daga nazarin kewayawar wata zuwa lura da girgizar taurari, bambancin lokacin wucewa, da abubuwan da ke faruwa a kan ruwan tabarau, masana kimiyya sun ƙirƙiro dabaru daban-daban don auna duniyoyi a ciki da wajen tsarin hasken rana. Kowace hanya tana ba da fahimta ta musamman kuma, idan aka yi amfani da su tare, suna ba da cikakken hoto na tarin duniyoyi. Yayin da fasahar lura ke ci gaba da ci gaba, ikonmu na auna tarin duniyoyi zai zama daidai, yana buɗe zurfafa fahimtar duniyoyi daban-daban da ke cike sararin samaniyarmu.
