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an open source database of all discovered extrasolar planets

beta Ursae Minoris

The planetary system beta Ursae Minoris hosts at least one planet.

  System parameters
Primary system name beta Ursae Minoris
Alternative system names beta Umi, HD 131873
Right ascension 14 50 42.32580
Declination +74 09 19.8142
Distance [parsec] 40.14±0.19edit
Distance [lightyears] 130.9±0.6
Number of stars in system 1
Number of planets in system 1

ArchitectureArchitecture of the system

This list shows all planetary and stellar components in the system. It gives a quick overview of the hierarchical architecture.

  •  beta Ursae Minoris, stellar object
    •  beta Ursae Minoris b, planet, semi-major axis: 1.40±0.10 AU

    PlanetsPlanets in the system

    This table lists all planets in the system beta Ursae Minoris.

      beta Ursae Minoris b
    Alternative planet names HD 131873 b, beta UMi b, bet UMi b, Kochab b
    Description This planet is orbiting the brighest star in the bowl of the Little Dipper. The star is K giant, 130 times more luminous than the Sun and about 130 light years away. The planet was found using data collected from the Bohyunsan Observatory.edit
    Lists Confirmed planets
    Mass [Mjup] 6.1±1.0edit
    Mass [Mearth] 1939±318
    Radius [Rjup] N/A
    Radius [Rearth] N/A
    Orbital period [days] 522±3edit
    Semi-major axis [AU] 1.40±0.10edit
    Eccentricity 0.19±0.02edit
    Equilibrium temperature [K] N/A
    Discovery method RV
    Discovery year 2014
    Last updated [yy/mm/dd] 15/11/26

    starStars in the system

    This table lists all stars in the system beta Ursae Minoris.

      beta Ursae Minoris
    Alternative star names HD 131873, beta UMi, bet UMi, β Ursae Minoris, β UMi, 7 Ursae Minoris, 7 UMi, Kochab, HIP 72607, TYC 4416-1799-1, SAO 8102, HR 5563, BD+74 595, 2MASS J14504235+7409199
    Mass [MSun] 1.4±0.2edit
    Radius [RSun] 38.3±1.1edit
    Age [Gyr] 3.0±1.0edit
    Metallicity [Fe/H] -0.27±0.07edit
    Temperature [K] 4126±25edit
    Spectral type K4IIIvar
    Visual magnitude 2.08edit

    Planet sizes

    The following plot shows the approximate sizes of the planets in this system The Solar System planets are shown as a comparison. Note that unless the radius has been determined through a transit observation, this is only an approximation (see Lissauer et al. 2011b).

    PlutoMercuryMarsVenusEarthNeptuneUranusSaturnJupiterbeta Ursae Minoris b

    Habitable zone

    The following plot shows the approximate location of the planets in this system with respect to the habitable zone (green) and the size of the star (red). This is only an estimate, using the star's spectral type and mass. Note that if no green band is shown in the plot, then the planet's orbit is far outside the habitable zone. The equations of Selsis, Kasting et al are used to draw the inner and outer boundaries.

    Habitable zonebeta Ursae Minoris b

    referencesScientific references and contributors

    Links to scientific papers and other data sources


    This table lists all links which are relevant to this particular system. Note that this is just a summary. More references to the scientific publications and comments can be found in the commit messages. To see these, head over the github or click here to directly go to the git blame output of this system. In the left column of the output you can see the commit message corresponding to each parameter. It also lists the date of the last commit and the person making the changes. Within the commit message, you will find a link to the scientific publication where the data is taken from. Note that this is a new feature and not all system parameters might have a reference associated with it yet. Please help making this catalogue better and contribute data or references!

    Open Exoplanet Catalogue contributors

    Contributor E-mail Number of commits
    Allen B. Davis abd1(at) 1
    Andrew Tribick ajtribick(at) 1
    Hanno Rein hanno(at) 3
    Ryan Varley ryanjvarley(at) 1

    This table lists all people who have contributed to the Open Exoplanet Catalogue. Please consider contributing! Click here to find out how. You can also view all commits contributing to this file on github.

    xmlData download

    You can download the xml file corresponding to this planetary system, which is part of the Open Exoplanet Catalogue. All information on this page has been directly generated from this XML file. You can also download the entire catalogue over at github. If you prefer to download the dataset as an ASCII tables, you might find the oec_tables repository usefule.


    If you spot an error or if you can contribute additional data to this entry, please send an e-mail to Please include the corrected xml file and a reference to where the new data is coming from, ideally a scientific paper. If you are fluent with git and github, you can also create a pull request or open an issue on the Open Exoplanet Catalogue repository. Please include the reference to the relevant scientific paper in your commit message.