Binary Catalogue of Exoplanets: Introduction on Binary Star Systems

This page contains information on the tables for binary star systems. Here we will explain the various columns in the tables, what the different abbreviations mean, and which units are used. Scroll down to the example tables and click on a column header to find out more.

jump to Star data

jump to Planet data

Example Table: Star Data

System Discovery Spectral Type Distance [parsec] Mass ratio [m2/(m1+m2)] a_binary [AU] e_sec Number of planets Planet motion S-type, P-type m1 [m_sun] m2 [m_sun] Comments
DP Leo AB b 2009 DA / M5V 400.00 0.015 0.0027 0.00 1 P 0.6 0.009 p=1.4967h
FW Tau AB b 2013 M4 / ? 145.00 0.500 11   1 P 0.12 0.12  
g Cep Ab B 2003 K2V / ? 13.79   20.3 0.36 1 S 1.4    

STAR DATA

System

Name or designation of the system and the structure of the system, where capital letters refer to a star, and small letters refer to a planet.
Example: DP Leo AB b

"Ab B" or "A Bb" refered to a S-Type planet, while "AB b" refer to a P-Type planet as marked in the column on the planetary motion. This part of the catalogue represents only the stellar data of the system.

All systems are linked to The Extrasolar Planets Encyclopaedia (http://exoplanet.eu/) or to the Open Exoplanet Catalogue (http://www.openexoplanetcatalogue.com/) where one can find additional data on the systems.

Discovery

Gives the year of the first discovery.

Spectral type

This shows the spectral types of the stars. Unfortunately the data for some systems is incomplete.

Distance [parsec]

Distance from the Sun to the system in units of parsecs (1 parsec = 3.26 light-years).

Mass ratio

Given as dimensionless proportion m2/(m1+m2), where m1 is the mass of the first star and m2 is the secondary star's mass.

a_binary [AU]

Represents the distance between the double stars given in astronomical units. (1 astronomical unit = 149 597 870.7 kilometres)

e_sec

Represents the eccentricity of the second star. This parameter is very rarely known.

Number of planets

Systems with one planet are dominant, but multiplanet systems become more and more frequent.

Planet motion S-type, P-type

In general, one can distinguish three types of planetary orbits in a binary star system (as shown in figure 1 in the introduction):

  1. S-Type, where the planet orbits one of the two stars;
  2. P-Type, where the planet orbits the entire binary;
  3. T-Type, where the planet orbits close to one of the two equilibrium points L4 and L5 (Trojan planets). Up to now no planets were found in ths configuration.

Mass: m1 [Msun] and m2 [Msun]

Mass of the first and the second star given in units of the masses of our Sun. (1 solar mass = 1.988 × 1030 kg)

Example Table: Planet Data

System Discovery Mass - M x sin i [M_Jupiter] Semi-major axis [AU] Orbital period [d] Eccentricity Argument of perihelion [deg] Radius [R_J] Inclination Detection method
Kepler 432 b 2014 5.41 0.310 52.501 0.512 65.60 1.45 88.17 transit / rad. vel.
Kepler-14 b 2011 8.400   6.79012 0.035   1.136 90 transit
Kepler-16 b 2011 0.333 0.7048 228.776 0.007 318.00 0.7538 90.0322 transit

PLANET DATA

System

The name or designation of the system; this part of the catalogue represents only the planetary data of the system.

All systems are linked to The Extrasolar Planets Encyclopaedia (http://exoplanet.eu/) or to the Open Exoplanet Catalogue (http://www.openexoplanetcatalogue.com/) where one can find additional data on the systems.

Discovery

Gives the year of the first discovery.

Mass – M × sin i [M_Jupiter]

Represents the minimum mass of the planet in units of one Jupiter mass. (1 Jupiter mass = 1.898 × 1027 kg)

From the observational point of view we only know the mass of the planet to within the unknown factor related to the inclination (i) of the orbit of the system. The actual mass of the planet is the observed quantity divided by sin (i); and clearly, since the maximum value of sin (i) = 1, the planet's actual mass must be larger than or equal to the measured quantity.

Semi-major axis [AU]

Represents the semi-major axis of the planet's orbit given in astronomical units.

Orbital period [d]

Represents the orbital period of the planet given in days.

Eccentricity

Represents the eccentricity of the planet.

Argument of perihelion [deg]

Represents the angle from the body's ascending node to its periapsis, measured in the direction of motion.

Radius [R_J]

Represents the planet's radius given in units of one Jupiter radius. (1 Jupiter radius = 71 492 km)

Inclination

This value does not represent the orbital inclination of the planet, but it shows only the inclination relative to the line of sight.

Detection method

Shows the different detection methods which were used for the observations.