The Table class

Bioverse uses the Table class to manage large simulated datasets across the code. Each row in the Table corresponds to a different simulated planet, while each column corresponds to a planetary parameter. Generally, rows correspond to indices while columns correspond to string keys. Some examples for selecting data in a table:

# Returns semi-major axis for every planet
table['a']

# Returns the mass of the tenth planet
table['M'][9]

# Returns all parameters for the first 50 planets
table[:50]

A Table is somewhat similar to a Pandas DataFrame. Indeed, if Pandas is installed, the Table will be displayed as one. To export a Table as a Pandas DataFrame, we can use the to_pandas() method:

table.to_pandas()

          d      M_st      R_st      L_st   T_eff_st SpT  ...  N_pl  order         R            P         a           S
0    13.779  0.891276  0.912031  0.668409  5469.6313   G  ...     1      0  2.279597   680.071360  1.456531    0.315067
1    17.990  1.368140  1.285004  2.995380  6704.4496   F  ...     1      0  1.603131  4461.320947  5.887965    0.086402
2    21.648  1.384050  1.296945  3.119100  6741.3827   F  ...     1      0  3.114289    13.869061  0.125901  196.776529
3    17.565  0.892344  0.912906  0.671218  5472.7466   G  ...     1      0  1.246218   303.569497  0.851064    0.926700
4     3.563  0.397945  0.478474  0.039754  3729.2254   M  ...     4      0  2.560260   645.564506  1.075260    0.034384
..      ...       ...       ...       ...        ...  ..  ...   ...    ...       ...          ...       ...         ...
517   5.905  0.353798  0.435516  0.026342  3526.6437   M  ...     5      2  2.587812   128.221803  0.351970    0.212635
518   5.905  0.353798  0.435516  0.026342  3526.6437   M  ...     5      3  0.802393   165.421708  0.417119    0.151400
519   5.905  0.353798  0.435516  0.026342  3526.6437   M  ...     5      4  5.704183   311.476887  0.636036    0.065115
520  10.908  0.763220  0.805601  0.388396  5081.1400   K  ...     2      0  1.343379  1518.340450  2.362701    0.069576
521  10.908  0.763220  0.805601  0.388396  5081.1400   K  ...     2      1  0.513268    30.733272  0.175483   12.612595

[522 rows x 22 columns]

Each planet or stellar property is referred to throughout Bioverse by a unique string key. This formalism allows properties to be easily accessed across the code. The keys are not formally defined anywhere in the code, so creating a new property is as simple as adding it to a Table of planets:

# Assigns a random ocean covering fraction to every planet in the Table
table['f_ocean'] = np.random.uniform(0, 1, len(t))

This new column must have the same length as others in the Table. Some other examples of Table usage:

# Change the value of `f_ocean` to zero for planets that are not exo-Earth candidates
EEC = table['EEC'] # boolean array
table['f_ocean'][~EEC] = 0.

# Calculate planet densities in g/cm3
table['rho'] = 5.51 * table['M'] / table['R']**3

# List the definition of all keys in the table (found in legend.dat)
table.legend()

# Append one table to another in-place
table.append(table2, inplace=True)

See the Table documentation for a full list of its methods.

List of properties

The following table lists all keys currently used in Bioverse and the properties they correspond to:

Key	Data type	Description
star_name	str	Name of star
simulated	bool	Is this system simulated?
d	float	Distance to star (pc)
x	float	Cartesian x position (pc)
y	float	Cartesian y position (pc)
z	float	Cartesian z position (pc)
ra	float	Right ascension (deg)
dec	float	Declination (deg)
binary	bool	Is it a binary star?
M_st	float	Stellar mass (solar mass)
T_eff_st	float	Effective temperature (K)
R_st	float	Stellar radius (solar radius)
logL	float	Bolometric luminosity (log solar luminosity)
L_st	float	Bolometric luminosity (solar luminosity)
M_G	float	Gaia G-band absolute magnitude
SpT	str	Approximate spectral type (e.g. M)
subSpT	str	Full spectral type (e.g. M5V)
age	float	Age (Gyr)
N_pl	int	Number of planets in system
coplanar	bool	Is the system coplanar?
cos(i)_st	float	cosine of mean system inclination
P_in	float	Period of innermost planet (d)
R_typical	float	Radius of innermost planet (Earth radius)
N_EEC	int	Number of exo-Earth candidates in system
planetID	int	Unique index for this planet
starID	int	Unique index of this planet’s host star
order	int	Order of planet from the star
planet_name	str	Name of planet
age_pl	float	Age (Gyr)
cos(i)	float	Cosine of orbital inclination
d_inc	float	Angle between the planet’s orbital plane and the mean system orbital plane
P	float	Orbital period (d)
Ratio	float	Period ratio versus the next planet in
R	float	Radius (Earth radius)
a	float	Semi-major axis (AU)
S	float	Instellation (Earth insolation)
S_abs	float	Instellation (W/m2)
e	float	Eccentricity
M0	float	Mean anomaly at reference time (radians)
w_LAN	float	Longitude of ascending node (radians)
w_AP	float	Longitude of periapsis (radians)
nu	float	True anomaly (radians)
b	float	Impact parameter on stellar disk
transiting	bool	Does the planet transit its star?
T_dur	float	Transit duration (d)
M	float	Mass (Earth mass)
rho	float	Density (g/cm3)
g	float	Surface gravity (cm/s2)
class1	str	instellation-based classification
class2	str	Size-based classification
a0	float	Mean distance from star (AU)
zone	str	Location in system
type	str	Corresponding Solar System template
EEC	bool	Is this planet an exo-Earth candidate?
habitable	bool	Is this planet habitable?
life	bool	Is this planet inhabited?
mu	float	Atmospheric mean molecular weight (u)
H	float	Atmospheric scale height
pCO2	float	Abudance of CO2 (log)
pN2	float	Abundance of N2 (log)
T_eq	float	Equilibrium temperature (K)
T_atm	float	Mean atmospheric temperature (K)
separation	float	Maximum angular separation of the planet from the star
logcontrast	float	Planet-to-star contrast ratio
depth	float	Transit depth corresponding to the planet’s radius
atmosphere_depth	float	Transit depth corresponding to the atmospheric scale height
a_inner	float	Inner edge of the habitable zone (AU)
a_outer	float	Outer edge of the habitable zone (AU)
S_inner	float	Inner edge of the habitable zone (Earth insolation)
S_outer	float	Outer edge of the habitable zone (Earth insolation)
has_H2O	bool	Does the planet have atmospheric water vapor?
has_O2	bool	Does the planet have atmospheric O2 (or O3)?
A_g	float	Geometric albedo
contrast	float	Planet-to-star contrast ratio
a_eff	float	Semi-major axis scaled to the Sun’s luminosity (AU)
R_eff	float	Estimated radius assuming Earth’s geometric albedo (Earth radius)
true_sep	float	True planet-star separation at a given ephemeris (AU)
phase_angle	float	Planet illumination phase angle (radians)
ang_sep_mas	float	Planet-star angular separation (milliarcseconds)