Ama-orbital elements

Amanombolo ayisithupha. Lokhu konke okudingayo ukuchaza noma iyiphi i-orbit kuhlelo lwelanga, kusuka eMhlabeni kuya kwi-comet. Funda ukuzifunda futhi ungabeka phansi lapho izwe lizohlala khona, eminyakeni ezayo.

Amanombolo ayisithupha achaza noma iyiphi i-orbit esistimu yelanga.

Bona

Ukuchaza lapho i-satellite noma iplanethi ihamba khona, kufanele uphendule imibuzo embalwa:

1. Ingabe ikhulu iyini i-orbit?
2. Ifomu elinjani iyini: ijikelezayo noma isheshayo?
3. Ukwehliswa kanjani yini?
4. Indlela ikuphi i-tilt ebhekene nayo?
5. Ngabe ingxenye ethengiswayo ikhombisa indlela?
6. Ikuphi ku-orbit ilungu manje?

Isinqumo ngasinye siyinombolo eyodwa. Together these six numbers are called the orbital elements, and they describe any orbit.

Ku-sandbox, i-Molniya orbit iyafakwa. Izisekelo zokuxhuma zaseRussia zisebenzisa le orbit ehamba phambili, ejikelezayo ukuze zihlale isikhathi eside phezulu ngasentshonalanga, lapho izisekelo ze-geostationary zinzima ukubona khona. Khetha Imboniso yeSizinda ukubona ukunyakaza, futhi udlala ngezithayela.

Ukuqonda

Ingxenye	Isibonakalisi	Imisa ukuthini
Isixhumanisi esincane	Dala i-azimuth	Ubukhulu
I-excentricity	e	Isimo
Ukugqwala	I-_Scale	Ukugcizelela kweplanethi ye-orbit ngokumelene neplanethi yokubhekisa
I-longitude ye-node ekhulayo	Ω	Indlela lapho i-orbit idlula khona iplanethi yokubhekisa “phezulu”
Isibhengezo se-periapsis	ω	Indawo lapho indawo encane kakhulu ikhona khona, ilinganiselwa ngaphakathi kweplanethi ye-orbit kusuka ku-node ekhulayo
Isilinganiso sokungalingani ngesikhathi	M₀	Indawo lapho isiqu sikhona khona ngesikhathi esithile (isikhathi)

Iplanethi, i-reference plane yiyo i-ecliptic, iplanethi ye-orbit yezwe, futhi incazelo yosuku yi-March equinox. I-planethi ebhekiswe kuyo yi-equator yezwe.

Amanani abalulekile:

• i = 0°: i-orbit ikhona kwiplanethi yokubhekisa. I-geostationary satellite ine i = 0 ne e = 0 ngaphesheya kwe-equator yeplanethi.
• i = 90°: a polar orbit, edlula phezu kwezinhlangothi zombili.
• i > 90°: retrograde, ujikeleza emuva.
• I-Molniya orbit isebenzisa i = 63.4° ngenhloso: ngaleyo tilt, ubulukhuni beplanethi abukwenzanga i-periapsis ihambe eduze kwe-orbit.

Umphathi

Ama-angles amathathu yisethulo esilungisiwe sokugqugquzela. Ingxenye yeplanethi ejikelezayo (x’ ukuya ku-periapsis, y’ 90° phambili) ifakwa kwifreyimu yokubhekisela nge R_z(−Ω) · R_x(−i) · R_z(−ω). Le yisimo esifanayo se-JPL’s “Approximate Positions of the Planets”, esetshenziswa yindawo yokugcina:

x = (cos ω cos Ω − sin ω sin Ω cos i) x′ + (−sin ω cos Ω − cos ω sin Ω cos i) y′

kanye nezichazamazwi ezifana nalezi ze y ne z.

Amathebula eplanethi avame ukunika izinhlobo: i longitude ye-perihelion ϖ = Ω + ω (isetshenziswa uma incane futhi i-Ω icacisiwe kakubi), kanye ne mean longitude L = ϖ + M. Ithebula le-JPL libonisa a, e, i, L, ϖ, Ω kanye nezinga labo lokushintsha ngekhulu ngalinye, ngoba ezinye iziplanethi zithinta kancane zonke izingxenye.

Kungani 63.4°? I-equator yeplanethi (igama le-J₂) yenza isiphakamiso se-periapsis precess ngezinga elilinganayo ne-(5 cos² i − 1). Ishiya lapho i cos² i = 1/5, okungukuthi i = 63.43° noma 116.57°: “izimo ezibucayi”. Izingxenye ezihlala zikhona kunkinga yezinto ezimbili ezihamba kancane emhlabeni ongempela; ngakho-ke iziqephu zengxenye zihlala zivela nge epoch, isikhathi lapho zisebenza khona.