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an open source database of all discovered extrasolar planets

KOI-1257

The planetary system KOI-1257 hosts at least one planet. Note that the system is a multiple star system. It hosts at least 2 stellar components.

  System parameters
Primary system name KOI-1257
Alternative system names Kepler-420
Right ascension 19 24 54
Declination +44 55 38
Distance [parsec] 900±110edit
Distance [lightyears] 2935±359
Number of stars in system 2
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.

  •  Stellar binary, semi-major axis: 5.3±1.3 AU, 9±3 years
    •  KOI-1257 A, stellar object
      •  KOI-1257 b, planet, semi-major axis: 0.382±0.006 AU
      •  KOI-1257 B, stellar object

      PlanetsPlanets in the system

      This table lists all planets in the system KOI-1257.

        KOI-1257 b
      Alternative planet names KOI-1257 A b, Kepler-420 A b, Kepler-420 b, KOI-1257.01, KIC 8751933 b
      Description KOI-1257 b is a highly eccentric transiting exoplanet in an old, metal-rich binary system. The transits were initially spotted in the Kepler data. Follow-up observations consisting of a joint amateur and professional campaign confirmed the planetary nature of the transits.edit
      Lists Confirmed planets; Planets in binary systems, S-type
      Mass [Mjup] 1.4±0.3edit
      Mass [Mearth] 461±111
      Radius [Rjup] 0.94±0.12edit
      Radius [Rearth] 10.3±1.3
      Orbital period [days] 86.6477±0.0000edit
      Semi-major axis [AU] 0.382±0.006edit
      Eccentricity 0.77±0.04edit
      Equilibrium temperature [K] 511±50edit
      Discovery method transit
      Discovery year 2014
      Last updated [yy/mm/dd] 14/06/25

      starStars in the system

      This table lists all stars in the system KOI-1257.

        KOI-1257 A KOI-1257 B
      Alternative star names Kepler-420 A, KIC 8751933 A Kepler-420 B, KIC 8751933 B
      Mass [MSun] 0.99±0.05edit 0.70±0.07edit
      Radius [RSun] 1.13±0.14edit 0.68±0.07edit
      Age [Gyr] 9±3edit N/A
      Metallicity [Fe/H] 0.27±0.09edit N/A
      Temperature [K] 5520±80edit 4270±290edit
      Spectral type G5V K6V/K7V
      Visual magnitude N/A N/A

      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).

      PlutoMercuryMarsVenusEarthNeptuneUranusSaturnJupiterKOI-1257 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 zoneKOI-1257 b

      referencesScientific references and contributors

      Links to scientific papers and other data sources

      history https://arxiv.org/abs/1512.00189
      history http://arxiv.org/abs/1406.6172
      history http://exoplanet.eu

      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
      Andrew Tribick ajtribick(at)googlemail.com 1
      Hanno Rein hanno(at)hanno-rein.de 2
      Ryan Varley ryanjvarley(at)gmail.com 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.

      correctionsCorrections

      If you spot an error or if you can contribute additional data to this entry, please send an e-mail to exoplanet@hanno-rein.de. 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.