Example #1
0
def get_bodies_in_orbit(m0, m_ffp, m_bp, a_bp, e_bp, phi_bp, lan_bp, b_ffp, r_inf):

    #Bodies
    bodies = Particles()

    ##Get BP in orbit
    #Binary
    star_planet = new_binary_from_orbital_elements(m0, m_bp, a_bp, e_bp, true_anomaly=phi_bp, inclination = 28, longitude_of_the_ascending_node = lan_bp)
    #Planet attributes
    star_planet.eccentricity = e_bp
    star_planet.semimajoraxis = a_bp
    #Center on the star
    star_planet.position -= star_planet[0].position
    star_planet.velocity -= star_planet[0].velocity
    cm_p = star_planet.center_of_mass()
    cm_v = star_planet.center_of_mass_velocity()

    ##Get FFP in orbit
    #Particle set
    m0_ffp = Particles(2)
    #Zeros and parabolic velocity
    zero_p = 0.0 | nbody_system.length
    zero_v = 0.0 | nbody_system.speed
    parabolic_velocity = get_parabolic_velocity(m0, m_ffp, b_ffp, r_inf, m_bp, a_bp, phi_bp)
    #Central star
    m0_ffp[0].mass = m0
    m0_ffp[0].position = (zero_p,zero_p,zero_p)
    m0_ffp[0].velocity = (zero_v,zero_v,zero_v)
    #Free-floating planet
    m0_ffp[1].mass = m_ffp
    m0_ffp[1].position = (-r_inf-cm_p[0],-b_ffp-cm_p[1],zero_p)
    m0_ffp[1].velocity = (parabolic_velocity,zero_v,zero_v)
    #Orbital Elements
    star_planet_as_one = Particles(1)
    star_planet_as_one.mass = m0 + m_bp
    star_planet_as_one.position = cm_p
    star_planet_as_one.velocity = cm_v
    binary = [star_planet_as_one[0], m0_ffp[1]]
    m1, m2, sma, e = my_orbital_elements_from_binary(binary)
    #For the star it sets the initial values of semimajoraxis and eccentricity of the ffp around star+bp
    m0_ffp.eccentricity = e
    m0_ffp.semimajoraxis = sma

    #Order: star, ffp, bp
    bodies.add_particle(m0_ffp[0])
    bodies.add_particle(m0_ffp[1])
    bodies.add_particle(star_planet[1])

    return bodies
Example #2
0
def get_ffp_in_orbit(m0, m_ffp, b, r_inf, parabolic_velocity):

    m0_and_ffp_in_orbit = Particles(2)

    zero_p = 0.0 | nbody_system.length
    zero_v = 0.0 | nbody_system.speed

    #Central star
    m0_and_ffp_in_orbit[0].mass = m0
    m0_and_ffp_in_orbit[0].position = (zero_p,zero_p,zero_p)
    m0_and_ffp_in_orbit[0].velocity = (zero_v,zero_v,zero_v)

    #Free-floating planet
    m0_and_ffp_in_orbit[1].mass = m_ffp
    m0_and_ffp_in_orbit[1].position = (-r_inf,-b,zero_p)
    m0_and_ffp_in_orbit[1].velocity = (parabolic_velocity,zero_v,zero_v)

    m1, m2, sma, e, ta, i, lan, ap = orbital_elements_from_binary(m0_and_ffp_in_orbit)

    #For the star it sets the initial values of semimajoraxis and eccentricity of the ffp
    m0_and_ffp_in_orbit.eccentricity = e
    m0_and_ffp_in_orbit.semimajoraxis = sma

    return m0_and_ffp_in_orbit
Example #3
0
def get_bodies_in_orbit(m0, m_ffp, m_bp, a_bp, e_bp, phi_bp, inc_bp, lan_bp, b_ffp, r_inf):

    #Bodies
    bodies = Particles()

    ##Get BP in orbit
    #Binary
    star_planet = new_binary_from_orbital_elements(m0, m_bp, a_bp, e_bp, true_anomaly=phi_bp, inclination = inc_bp, longitude_of_the_ascending_node = lan_bp)
    #Planet attributes
    star_planet.eccentricity = e_bp
    star_planet.semimajoraxis = a_bp
    #Center on the star
    star_planet.position -= star_planet[0].position
    star_planet.velocity -= star_planet[0].velocity
    cm_p = star_planet.center_of_mass()
    cm_v = star_planet.center_of_mass_velocity()

    ##Get FFP in orbit
    #Particle set
    m0_ffp = Particles(2)
    #Zeros and parabolic velocity
    zero_p = 0.0 | nbody_system.length
    zero_v = 0.0 | nbody_system.speed
    parabolic_velocity = get_parabolic_velocity(m0, m_bp, b_ffp, r_inf)
    #Central star
    m0_ffp[0].mass = m0
    m0_ffp[0].position = (zero_p,zero_p,zero_p)
    m0_ffp[0].velocity = (zero_v,zero_v,zero_v)
    #Free-floating planet
    m0_ffp[1].mass = m_ffp
    m0_ffp[1].position = (-r_inf+cm_p[0], b_ffp+cm_p[1], cm_p[2])
    m0_ffp[1].velocity = (parabolic_velocity+cm_v[0], cm_v[1], cm_v[2])

    #To find the orbital period of the BP
    G = (1.0 | nbody_system.length**3 * nbody_system.time**-2 * nbody_system.mass**-1)
    orbital_period_bp = 2*math.pi*((a_bp**3)/(G*m0)).sqrt()

    #To find the distance and time to periastron
    kep = Kepler()
    kep.initialize_code()

    star_planet_as_one = Particles(1)
    star_planet_as_one.mass = m0 + m_bp
    star_planet_as_one.position = cm_p
    star_planet_as_one.velocity = cm_v

    kepler_bodies = Particles()
    kepler_bodies.add_particle(star_planet_as_one[0])
    kepler_bodies.add_particle(m0_ffp[1])

    kep.initialize_from_particles(kepler_bodies)

    kep.advance_to_periastron()
    time_pericenter = kep.get_time()
    
    kep.stop()

    binary = [star_planet_as_one[0], m0_ffp[1]]
    sma, e, inclination, long_asc_node, arg_per = my_orbital_elements_from_binary(binary)
    m0_ffp.eccentricity = e
    m0_ffp.semimajoraxis = sma

    #Adding bodies. Order: star, ffp, bp
    bodies.add_particle(m0_ffp[0])
    bodies.add_particle(m0_ffp[1])
    bodies.add_particle(star_planet[1])

    return bodies, time_pericenter, orbital_period_bp