How can I get solar system body mass/radius in Python?

Question

Can I use Astroquery/Astropy to get the radius and mass of solar system objects? Or another common library?

I've been trying to use astroquery.horizons

I've tried elements() and ephemeris() but no dice, they don't contain columns for mass or radius. The only place I could find the values (and others, see below) is in the raw API response:

from astroquery.jplhorizons import Horizons
from astropy import units as u

object_id = "199" # Mercury
obj_id = Horizons(id=obj, id_type="majorbody", location="0") # Location 0 is the solar system barycenter

response = obj_id.ephemerides_async(get_raw_response=True)

Produces

API VERSION: 1.2
API SOURCE: NASA/JPL Horizons API

*******************************************************************************
 Revised: April 12, 2021             Mercury                            199 / 1

 PHYSICAL DATA (updated 2021-Apr-12):
  Vol. Mean Radius (km) =  2440+-1        Density (g cm^-3)     = 5.427
  Mass x10^23 (kg)      =     3.302       Volume (x10^10 km^3)  = 6.085  
  Sidereal rot. period  =    58.6463 d    Sid. rot. rate (rad/s)= 0.00000124001
  Mean solar day        =   175.9421 d    Core radius (km)      = ~1600 
  Geometric Albedo      =     0.106       Surface emissivity    = 0.77+-0.06
  GM (km^3/s^2)         = 22031.86855     Equatorial radius, Re = 2440 km
  GM 1-sigma (km^3/s^2) =                 Mass ratio (Sun/plnt) = 6023682
  Mom. of Inertia       =     0.33        Equ. gravity  m/s^2   = 3.701     
  Atmos. pressure (bar) = < 5x10^-15      Max. angular diam.    = 11.0"   
  Mean Temperature (K)  = 440             Visual mag. V(1,0)    = -0.42 
  Obliquity to orbit[1] =  2.11' +/- 0.1' Hill's sphere rad. Rp = 94.4 
  Sidereal orb. per.    =  0.2408467 y    Mean Orbit vel.  km/s = 47.362 
  Sidereal orb. per.    = 87.969257  d    Escape vel. km/s      =  4.435
                                 Perihelion  Aphelion    Mean
  Solar Constant (W/m^2)         14462       6278        9126
  Maximum Planetary IR (W/m^2)   12700       5500        8000
  Minimum Planetary IR (W/m^2)   6           6           6
*******************************************************************************
... More Lines Below

This is really hard to extract data from, being two columns of text with no clear delimiter.

• Is there a good way to get mass/radius?

Also

• Is there a better way to get the true ID for bodies by name (getting results for their barycenter which isn't useful)

Answer 1

The following Wikipedia article has both mass and radius.
Wikipedia – List of Solar System objects by size.

Here is a regex scrape.

The radius is in units of km, and the mass is in units of kg-10²¹.
The additional field there is the error, ±.

And, Saturn includes a comment for the radius, "136775 for A Ring".

{
    'Sun': { 'r': [ 695508, 0 ], 'm': [ 1989100000, 0 ] },
    'Jupiter': { 'r': [ 69911, 6 ], 'm': [ 1898187, 88 ] },
    'Saturn': { 'r': [ 58232, 6 ], 'm': [ 568317, 13 ] }, 
    'Uranus': { 'r': [ 25362, 7 ], 'm': [ 86813, 4 ] },
    'Neptune': { 'r': [ 24622, 19 ], 'm': [ 102413, 5 ] },
    'Earth': { 'r': [ 6371.0084, 0.0001 ], 'm': [ 5972.4, 0.3 ] },
    'Venus': { 'r': [ 6052, 1 ], 'm': [ 4867.5, 0.2 ] },
    'Mars': { 'r': [ 3389.5, 0.2 ], 'm': [ 641.71, 0.03 ] },
    'Mercury': { 'r': [ 2439.4, 0.1 ], 'm': [ 330.11, 0.02 ] }
}