Oge Nhazi nke Barycentric

Oge nhazi oge Barycentric ( TCB, sitere na French Temps-coordonnée barycentrique ) bụ isi nhazi oge echere na a ga-eji dị ka oge ngbanwe nke onwe maka ngụkọ niile gbasara orbits nke mbara ala, asteroids, comets, na ụgbọ elu interplanetary na Sistemụ  ikpe .  Ọ dabara na oge kwesịrị nke elekere elekere na-ezu ike na-enwe n'ime usoro nhazi nke na-aga n'ihu na barycenter (center of mass) nke Sistemụ akwụkwọ.   : ya bụ, elekere na-eme otu ahụ ahụ dịka Sistemụ ikike mana ọ nọ n'ahụ ike ndoda nke sistemu nke ọma .  Ya mere ọ naghị emetụta oge ndoda ndòda nke na usoro ndị ọzọ na-ese ihe.  TCB bụ oge nhazi oge maka Sistemụ ntụaka Celestial Barycentric (BCRS).

A kọwapụtara TCB na 1991 site n'aka International Astronomical Union, na Nkwanye III nke Mgbakọ Mgbakọ nke XXIst.  [1] Ezubere ya ka ọ bụrụ otu n'ime akụkụ maka nsogbu nsogbu 1976 nke Barycentric Dynamical Time (TDB).  N'akpa ka ọtụ̀tụ̀ oge nke mbara igwe mbụ, akọwara TCB n'ihe gbasara echiche izugbe nke relativity .  Akọwapụtara dị n'etiti TCB na oge nlegharị anya ndị ọzọ site na metrik nlegharị anya zuru oke.  Mgbanwe n'etiti TCB na Geocentric Coordinate Time (TCG) nwere ike were ihe ejighi n'aka na-ebughị ụzọ.  5 × 10 − 18 {\ displaystyle 5\ times 10^{-18}} ￼ n'ọnụego dị ka:

ebee x E i {\displaystyle x_{E}^{i}} ￼ na v E i {\displaystyle v_{E}^{i}} ￼ bụ ọnọdụ nhazi barycentric na ọsọ nke geocenter, r E i = x i − x  E i {\displaystyle r_{E}^{i}=x^{i}-x_{E}^{i}} ￼ ya na x i {\displaystyle x^{i}} ￼ ọnọdụ barycentric nke onye na-ekiri  ya, t = T C B {\displaystyle t=TCB} ￼, t 0 {\displaystyle t_{0}} ￼ bụ okwu nke TCB na TCG nsogbu nke mere na 1977 January 1, 00:00:00 TAI bụ 1977 January 1,  00:00:32.184 TCG / TCB, w 0 e x t ( x E ) {\displaystyle w_{0ext}(\mathbf {x} _{E})} ￼ bụ nchikota ∑ A G M A r A {\ displaystyle \scriptstyle \ sum _  {A}{\frac {GM_{A}}{r_{A}}}} ￼ nke ike ndọda ike maka niile nke usoro mbara igwe dị iche na ụwa na-egosila na geocenter, na w e x t i ( x E ) {\displaystyle w_  {ext}^{i}(\mathbf {x} _{E})} ￼ bụ otú ahụ nchikota ∑ A G M A r A v A i {\displaystyle \scriptstyle \ sum _{A}{\frac {GM_{A}  {r_{A}}}v_{A}^{i}} ￼ .  Mkpebi ahụ na-atụfu dị ikike elu nke r E i {\displaystyle r_{E}^{i}} ￼ dị ka ihe na ha bụ ndị na- mkpa mkpa