| 1 | MODULE planete_h |
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| 2 | IMPLICIT NONE |
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| 3 | |
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| 4 | REAL,SAVE :: aphelie ! Aphelion, in Mkm |
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| 5 | REAL,SAVE :: periheli ! Perihelion, in Mkm |
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| 6 | REAL,SAVE :: year_day ! Number of days in the year |
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| 7 | !$OMP THREADPRIVATE(aphelie,periheli,year_day) |
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| 8 | REAL,SAVE :: peri_day ! Date of perihelion, in days |
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| 9 | REAL,SAVE :: obliquit ! Obliquity of the planet, in degrees |
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| 10 | REAL,SAVE :: lmixmin |
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| 11 | !$OMP THREADPRIVATE(peri_day,obliquit,lmixmin) |
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| 12 | REAL,SAVE :: emin_turb |
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| 13 | REAL,SAVE :: coefvis |
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| 14 | REAL,SAVE :: coefir |
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| 15 | !$OMP THREADPRIVATE(emin_turb,coefvis,coefir) |
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| 16 | REAL,SAVE :: lsperi ! Solar longitude of the perihelion, angle in rad |
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| 17 | REAL,SAVE :: e_elips ! Orbit eccentricity |
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| 18 | REAL,SAVE :: p_elips ! Ellipse semi-latus rectum |
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| 19 | !$OMP THREADPRIVATE(lsperi,e_elips,p_elips) |
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| 20 | REAL,PARAMETER :: unitastr=149.597927 ! Astronomical unit AU, in Mkm |
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| 21 | |
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| 22 | ! NB: Ideally all module variables should be "protected"... |
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| 23 | |
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| 24 | CONTAINS |
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| 25 | |
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| 26 | SUBROUTINE iniorbit(paphelie,pperiheli,pyear_day,pperi_day,pobliq) |
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| 27 | use comcstfi_h, only: pi |
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| 28 | IMPLICIT NONE |
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| 29 | ! initialize orbital parameters |
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| 30 | |
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| 31 | REAL,INTENT(IN) :: paphelie,pperiheli,pyear_day,pperi_day,pobliq |
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| 32 | |
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| 33 | CHARACTER(LEN=8),PARAMETER :: myname="iniorbit" |
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| 34 | REAL :: zxref,zanom,zz,zx0,zdx |
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| 35 | INTEGER :: iter |
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| 36 | |
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| 37 | ! copy over input values |
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| 38 | aphelie =paphelie |
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| 39 | periheli=pperiheli |
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| 40 | year_day=pyear_day |
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| 41 | obliquit=pobliq |
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| 42 | peri_day=pperi_day |
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| 43 | |
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| 44 | write(*,*)myname,': Perihelion in Mkm ',periheli |
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| 45 | write(*,*)myname,': Aphelion in Mkm ',aphelie |
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| 46 | write(*,*)myname,': Obliquity in degrees :',obliquit |
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| 47 | |
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| 48 | ! compute orbit geometrical parameters |
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| 49 | e_elips=(aphelie-periheli)/(periheli+aphelie) |
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| 50 | p_elips=0.5*(periheli+aphelie)*(1-e_elips*e_elips)/unitastr |
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| 51 | |
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| 52 | write(*,*)myname,': e_elips',e_elips |
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| 53 | write(*,*)myname,': p_elips',p_elips |
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| 54 | |
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| 55 | ! compute mean anomaly zanom |
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| 56 | |
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| 57 | zz=(year_day-pperi_day)/year_day |
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| 58 | zanom=2.*pi*(zz-nint(zz)) |
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| 59 | zxref=abs(zanom) |
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| 60 | write(*,*)myname,': zanom ',zanom |
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| 61 | |
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| 62 | ! solve equation zx0 - e * sin (zx0) = zxref for eccentric anomaly zx0 |
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| 63 | ! using Newton method |
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| 64 | |
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| 65 | zx0=zxref+e_elips*sin(zxref) |
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| 66 | DO iter=1,100 |
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| 67 | zdx=-(zx0-e_elips*sin(zx0)-zxref)/(1.-e_elips*cos(zx0)) |
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| 68 | if(abs(zdx).le.(1.e-12)) exit |
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| 69 | zx0=zx0+zdx |
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| 70 | ENDDO |
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| 71 | |
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| 72 | zx0=zx0+zdx |
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| 73 | if(zanom.lt.0.) zx0=-zx0 |
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| 74 | write(*,*)myname,': zx0 ',zx0 |
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| 75 | |
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| 76 | lsperi=-2.*atan(sqrt((1.+e_elips)/(1.-e_elips))*tan(zx0/2.)) |
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| 77 | lsperi = modulo(lsperi,2.*pi) |
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| 78 | write(*,*)myname,': Perihelion solar long. Ls (deg)=', & |
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| 79 | lsperi*180./pi |
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| 80 | |
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| 81 | END SUBROUTINE iniorbit |
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| 82 | |
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| 83 | END MODULE planete_h |
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