Add a known solar system body by name — add

A convenience wrapper around [add_body_keplerian()] that looks up real orbital elements for well-known solar system bodies. Instead of typing out mass, semi-major axis, eccentricity, and inclination by hand, just give the name and parent:

Usage

add_planet(
  system,
  name,
  parent,
  nu = 0,
  a = NULL,
  e = NULL,
  i = NULL,
  lan = NULL,
  arg_pe = NULL,
  mass = NULL
)

Arguments

system: An `orbit_system` object.
name: The name of the body. Must be one of: `"Mercury"`, `"Venus"`, `"Earth"`, `"Mars"`, `"Jupiter"`, `"Saturn"`, `"Uranus"`, `"Neptune"`, `"Moon"`, or `"Pluto"`. Case-sensitive.
parent: Character id of the parent body, which must already exist in the system. For planets and Pluto this is typically `"Sun"`; for the Moon it is `"Earth"`.
nu: True anomaly in degrees (default 0, body starts at periapsis). This is the most commonly overridden element — use it to spread planets around their orbits instead of starting them all at periapsis.
a: Override semi-major axis (meters).
e: Override eccentricity.
i: Override inclination (degrees).
lan: Override longitude of ascending node (degrees).
arg_pe: Override argument of periapsis (degrees).
mass: Override mass (kg).

Value

The updated `orbit_system` with the body added.

Details

“` create_system() |> add_sun() |> add_planet("Earth", parent = "Sun") |> add_planet("Moon", parent = "Earth") “`

Any Keplerian element can be overridden to explore "what if" scenarios while keeping the rest of the real values:

“` # What if Mars had zero eccentricity? add_planet("Mars", parent = "Sun", e = 0) “`

Examples

# \donttest{
# Build the inner solar system
create_system() |>
  add_sun() |>
  add_planet("Mercury", parent = "Sun") |>
  add_planet("Venus",   parent = "Sun") |>
  add_planet("Earth",   parent = "Sun") |>
  add_planet("Mars",    parent = "Sun") |>
  simulate_system(time_step = seconds_per_day, duration = seconds_per_year) |>
  plot_orbits()


# Earth-Moon system
create_system() |>
  add_body("Earth", mass = mass_earth) |>
  add_planet("Moon", parent = "Earth") |>
  simulate_system(time_step = seconds_per_hour, duration = seconds_per_day * 28) |>
  plot_orbits()


# What if Jupiter were twice as massive?
create_system() |>
  add_sun() |>
  add_planet("Jupiter", parent = "Sun", mass = mass_jupiter * 2)
#> $bodies
#> # A tibble: 2 × 8
#>   id         mass             x             y             z     vx     vy    vz
#>   <chr>     <dbl>         <dbl>         <dbl>         <dbl>  <dbl>  <dbl> <dbl>
#> 1 Sun     1.99e30            0             0             0      0      0    0  
#> 2 Jupiter 3.80e27 717206783344. 183226943299. -16760108524. -3394. 13287.  21.0
#> 
#> $forces
#> $forces$gravity
#> $forces$gravity$type
#> [1] "n_body_gravity"
#> 
#> $forces$gravity$G
#> [1] 6.6743e-11
#> 
#> 
#> 
#> $time
#> [1] 0
#> 
#> attr(,"class")
#> [1] "orbit_system"
# }