ʻO ke ʻano ʻē o nā hoʻohele honua
Ke noʻonoʻo kākou i nā hōkūhele e kaʻapuni ana i nā hōkū, ʻo ke kiʻi e hiki pinepine mai ana i ka noʻonoʻo, ʻo ia nā ala pōʻai maʻemaʻe a paʻa. ʻO ka ʻoiaʻiʻo, ʻaʻole poepoe pono ka hapa nui o nā pōʻai honua. He mau ellipses lākou—e like me kahi pōʻai "i kīkoʻo ʻia" i hoʻokahi ʻaoʻao. ʻO ke ana o ke ʻano "elliptical" o ka ellipse ua kapa ʻia ʻo ka eccentricity o ka orbit. Me he mea lā maʻalahi kēia manaʻo, akā he mau hopena koʻikoʻi kona: hoʻopilikia ia i nā ʻokoʻa o ka mamao o ka hōkūhele mai kona hōkū, nā loli i kona wikiwiki orbital, a me kona hiki ke hoʻololi i ke aniau a me ka noho ʻana.
He aha ka ʻokoʻa?
Ma keʻano laulā, ʻo ka eccentricity (e) kahi helu e wehewehe ana i ke ʻano o ka orbit:
– ʻo e = 0 ke ʻano he pōʻai kūpono ka ʻōpuni.
– 0 < e < 1 ʻo ia hoʻi he ʻōpuni elliptical (ʻo kēia ka mea maʻamau no nā hōkūhele). – e = 1 ʻo ia hoʻi he ala parabolic (hele ka mea i hoʻokahi manawa a ʻaʻole hoʻi mai; no ka laʻana, kekahi mau comets). – e > 1 ʻo ia hoʻi he ala hyperbolic (hele mai ka mea mai kahi mamao aku a laila hele aku no ka wā pau ʻole).
No nā hōkūhele ma ka ʻōnaehana lā , aia ka waiwai o e ma waena o 0 a emi mai ka 1, no laila he mau ʻōpuni elliptical ko lākou a pau. Eia nō naʻe, ʻokoʻa ke kekelē o ka "ellipticality" o ka ellipse.
ʻEllipse, kiko, perihelion, a me aphelion
ʻElua mau kiko kikoʻī o ka hoʻohele elliptical i kapa ʻia he foci. I ke ʻano o kahi honua e hoʻohele ana i ka Lā, aia ka Lā ma kekahi kiko, ʻaʻole ke kikowaena o ka ellipse. ʻO ia ke kumu e loli ai ka mamao o ka honua mai ka Lā ma o kona hoʻohele ʻana.
ʻElua mau kūlana koʻikoʻi ma ka orbit:
ʻO Perihelion: ke kiko kokoke loa o ka honua i ka Lā
ʻAphelion: ka wahi mamao loa o ka honua mai ka Lā
ʻOi aku ka nui o ka eccentricity, ʻoi aku ka nui o ka ʻokoʻa ma ka mamao ma waena o ka perihelion a me ka aphelion.
ʻO ke ʻano ʻē a me nā kānāwai o Kepler
ʻAʻole kū hoʻokahi ka eccentricity. Pili ia i ke ʻano o ka neʻe ʻana o nā hōkūhele e like me nā Kānāwai o Kepler, ʻo ia hoʻi ke kānāwai ʻelua: kahi laina hoʻokalakupua e hoʻopili ana i kahi hōkūhele a me ka Lā e hoʻopau i nā wahi like i nā manawa like. No laila, ke kokoke kahi hōkūhele i ka perihelion, neʻe wikiwiki ia; ke kokoke i ka aphelion, neʻe lohi ia. Hōʻike kēia i ke kumu ʻaʻole he "wikiwiki orbital" he mea mau no kahi orbit elliptical.
Ma nā ʻōpuni kokoke i ka pōʻai (e haʻahaʻa), ʻaʻole ʻike ʻia nā loli o ka wikiwiki a me ka mamao. Akā no nā ʻōpuni eccentric (e kiʻekiʻe), hiki ke nui loa nā ʻokoʻa.
Nā hiʻohiʻona o ka eccentricity i loko o ka ʻōnaehana solar
He ʻokoʻa nā waiwai eccentricity o nā hōkūhele ma ka ʻōnaehana lā. Eia kahi ʻike laulā (hiki ke hoʻopuni ʻia nā helu):
– Venus: kokoke loa i kahi pōʻai (e ~ 0,007)
– Honua: kokoke i ka pōʻai (e ~ 0,017)
– Mars: ʻoi aku ka oval (e ~ 0,093)
– Mercury: ka eccentric loa o nā hōkūhele (e ~ 0,206)
Ua manaʻo pinepine ʻia he ʻōpuni "spherical" ko ka Honua, akā he elliptical nō naʻe. ʻO ka ʻokoʻa ma waena o ka mamao o ka Honua mai ka Lā ma waena o ka perihelion a me ka aphelion ma kahi o kekahi mau miliona kilomita. ʻOiai ke kani nui nei kēia, he mau pakeneka wale nō ia o ka mamao awelika, no laila ua liʻiliʻi kona hopena ma ka ikehu lā holoʻokoʻa i loaʻa i ka Honua ke hoʻohālikelike ʻia me nā mea ʻē aʻe e like me ke kūlou ʻana o kona axis.
ʻO ke ʻano ʻē a me nā kau ma ka Honua
ʻO kahi kuhi hewa maʻamau, ʻo ia ka hana ʻana o nā kau no ka mea ua kokoke ka Honua i ka Lā i ke kauwela a mamao aku i ka hoʻoilo. ʻO ka ʻoiaʻiʻo, ua hoʻoholo nui ʻia nā kau e ke axial tilt o ka Honua (ma kahi o 23,5°), ʻaʻole kona eccentricity.
ʻO ka mea hoihoi, kokoke ka Honua i ka perihelion ma kahi o ka hoʻomaka o Ianuali, i ka wā e hoʻoilo ai ka ʻĀkau o ka Hemisphere. Hōʻike kēia ʻaʻole ʻo ka mamao ke kumu nui e hoʻoholo ai i nā kau. Eia nō naʻe, he hopena liʻiliʻi ko ka eccentricity: ʻokoʻa iki ka ikaika o ka lā ma waena o ka wā e perihelion ai ka Honua a me ka aphelion. ʻIke ʻia kēia hopena ma ke ʻano he mau ʻokoʻa liʻiliʻi i ka hoʻolaha ʻana o ka ikehu lā i loaʻa i ka Honua i ka makahiki holoʻokoʻa.
No ke aha e hiki ai ke loli ka eccentricity?
ʻAʻole mau ka eccentricity orbital. I loko o nā ʻōnaehana me nā hōkūhele he nui, ʻo ka huki umekaumaha ma waena o nā hōkūhele ke kumu o ka loli mālie o nā orbits. Ma nā pae manawa o nā tausani a i miliona mau makahiki, ʻike ka eccentricity o ka Honua i nā ʻano like ʻole e pili ana i nā pōʻaiapuni Milankovitch—he moʻo o nā loli manawa i nā palena orbital a me ka rotational o ka Honua e pili ana i nā ʻano aniau lōʻihi, me nā makahiki hau.
Ma waho aʻe o nā pilina ma waena o nā hōkūhele, hiki i ka kokoke ʻana i nā mea nui ʻē aʻe, nā resonances orbital, a me ka mōʻaukala o ka hoʻokumu ʻia ʻana o ka ʻōnaehana hōkūhele (e like me nā collisions a i ʻole nā neʻe ʻana o nā hōkūhele) ke hoʻohuli i ka eccentricity.
ʻO ke ʻano ʻē ma nā exoplanets: mai ka mālie a hiki i ka palena loa
I ka hoʻomaka ʻana o nā mea kilo hōkū e ʻike i nā exoplanets (nā hōkūhele ma waho o kā mākou ʻōnaehana lā), ua ʻike lākou he nui o lākou he eccentricities nui aʻe ma mua o ko mākou mau hōkūhele ponoʻī. ʻO kekahi mau kinoea nui e hoʻopuni kokoke ana i ko lākou mau hōkū ("nā Jupiters wela") he mau orbits kokoke i ka pōʻai ma muli o nā hopena kai e hoʻopaʻa ana i kā lākou mau orbits, akā he nui nā exoplanets ʻē aʻe e hōʻike ana i nā orbits elliptical.
Hōʻike pinepine ka eccentricity kiʻekiʻe i kahi mōʻaukala paʻakikī "paʻakikī", no ka laʻana:
- nā pilina umekaumaha ikaika ma waena o nā hōkūhele,
- nā haunaele mai nā hōkū hoahele i nā ʻōnaehana hōkū binary,
– a i ʻole nā kuʻi ʻana a me nā kipaku ʻana o nā hōkūhele i ka wā i hoʻokumu mua ʻia ai ka ʻōnaehana.
Hoʻonui pū nā orbits eccentric i nā kūlana kaiapuni o ka honua i ʻoi aku ka ʻino: ʻo nā loli i ka mamao i ka hōkū ke kumu o nā loli nui i ka mahana a me ka ikaika o ka radiation i loaʻa i ka wā o kahi orbit.
Ka hopena o ka eccentricity i ka noho ʻana
I ke aʻo ʻana i ka nohona o ka honua, he mea nui ka eccentricity. Inā he nui ka eccentricity o kahi honua, a laila hiki ke penei:
- hoʻolilo i kahi hapa o kona kaapuni kokoke loa i ka hōkū (wela loa),
– a ʻo kekahi poʻe ʻē aʻe ua mamao loa (anu loa).
Eia nō naʻe, ʻaʻole i hoʻoholo wale ʻia ka noho ʻana e ka mamao. Hiki i ka lewa mānoanoa, nā moana, a i ʻole nā ʻano hana hoʻolaha wela ke kōkua i ka hoʻopaʻa ʻana i nā mahana. Aia kekahi mau hiʻohiʻona kahi e hiki ai i nā hōkūhele me nā eccentricities kaulike ke loaʻa kahi wahi noho kūpono, ʻoiai inā kākoʻo ka lawe ʻana o ka ikehu awelika i ka wai wai a hiki i ka lewa ke hāʻawi i ka wela.
Ma ka ʻaoʻao ʻē aʻe, hiki i nā eccentricities nui ke hoʻoulu i nā ʻokoʻa o ke aniau, hoʻonui i ka paʻa ʻole o ke aniau, hoʻololi i nā ʻano kau, a hoʻohuli i nā pilina kai me ka hōkū, hiki ke hoʻomehana i loko o ka honua (kai wela) a hoʻolalelale paha i kona ulu ʻana o ka rotation.
Ke ana ʻana i ka eccentricity: pehea e ʻike ai nā mea kilo hōkū?
I loko o ka ʻōnaehana lā, ua hoʻoholo pololei ʻia ka eccentricity ma ka nānā ʻana i nā kūlana o nā hōkūhele i ka hala ʻana o ka manawa. No nā exoplanets, ʻo nā ʻano hana maʻamau:
– ʻO ka wikiwiki Radial: ana i ka "wobble" o ka hōkū ma muli o ka huki ʻana o ka honua; hiki i ke ʻano o ka piʻo hōʻailona ke hōʻike i ka eccentricity.
– Ke hele nei ka honua i mua o ka hōkū, hiki i ka lōʻihi a me ke ʻano o ka hele ʻana, a me nā ʻikepili ʻē aʻe, ke hāʻawi i nā hōʻailona e pili ana i ke ʻano o ka orbit.
– Nā ʻokoʻa o ka manawa: hiki i nā loli i ka manawa transit (TTV) ma muli o nā pilina interplanetary ke kōkua i ka hōʻike ʻana i nā palena orbital me ka eccentricity.
ʻO ka nui o ka ʻikepili a mākou e hōʻiliʻili ai, ʻoi aku ka maikaʻi o kā mākou mau kuhi o ka eccentricity a me ko mākou ʻike i nā dinamika o ka ʻōnaehana.
Pani
ʻO ke ʻano eccentric o ka hoʻohele ʻana o ka honua he manaʻo nui ia no ka hoʻomaopopo ʻana i ke kumu ʻaʻole i poepoe mau nā hoʻohele, no ke aha e loli ai ka mamao o ka honua mai kona hōkū, a no ke aha ʻaʻole i mau ka wikiwiki o ka honua ma o kona hoʻohele ʻana. I loko o ka ʻōnaehana lā, he liʻiliʻi nā eccentricities o ka honua, e hoʻolilo ana i nā dynamics orbital i mea "mālie." Eia nō naʻe, hōʻike ka nui o nā exoplanets i nā hoʻohele eccentric, e hōʻike ana he paʻakikī loa ka ulu ʻana o nā ʻōnaehana honua a piha i nā pilina koʻikoʻi.
Ma ka hoʻomaopopo ʻana i ka eccentricity, ʻaʻole mākou e aʻo wale i ke geometry o nā orbits, akā heluhelu pū kekahi i ka "mōʻaukala" umekaumaha e hoʻopili ana i kahi ʻōnaehana honua—a loiloi pehea e hiki ai i ke ʻano o ka orbit ke hoʻopili i ke aniau a me nā manawa kūpono o ka puka ʻana mai o kahi kaiapuni aloha ola.
