Scatter plot of mass, <i>m</i>, and semimajor axis, <i>a</i>, for <a href="https://en.wikipedia.org/wiki/Exoplanet" class="extiw" title="wikipedia:Exoplanet">exoplanet</a> discoveries through 2014-09-23, indicating exoplanets detected by the <a href="https://en.wikipedia.org/wiki/Kepler_Mission" class="extiw" title="w:Kepler Mission">Kepler Mission</a>:
<div class="legend" style="direction:ltr;line-height:23px;"><div class="legend-content" style="display:inline-block;vertical-align:top;box-sizing:border-box;width:34px;height:23px;overflow:hidden;font-size:15px;border:1px solid white;background:black;color:#202122;text-align:center;"> </div> planets detected by Kepler (black, labeled)</div>
<div class="legend" style="direction:ltr;line-height:23px;"><div class="legend-content" style="display:inline-block;vertical-align:top;box-sizing:border-box;width:34px;height:23px;overflow:hidden;font-size:15px;border:1px solid white;background:#e6e6e6;color:#202122;text-align:center;"> </div> other exoplanets</div>
<div class="legend" style="direction:ltr;line-height:23px;"><div class="legend-content" style="display:inline-block;vertical-align:top;box-sizing:border-box;width:34px;height:23px;overflow:hidden;font-size:15px;border:1px solid #cdcdcd;background:white;color:#202122;text-align:center;"> </div> Solar System planets for reference</div>
<p>Estimates (see "important note" below) of <i>m</i> and <i>a</i> are indicated with circles.
</p><p>Scales indicate (log<sub>10</sub> of) mass, <i>m</i>, expressed as Jupiter masses (left) and Earth masses (right); and (log<sub>10</sub> of) semimajor axis, <i>a</i>, expressed in <a href="https://en.wikipedia.org/wiki/Astronomical_unit" class="extiw" title="w:Astronomical unit">AU</a> (bottom), and the corresponding period, <i>p</i> for a planet orbiting a Sun-mass star, expressed in <a href="https://en.wikipedia.org/wiki/Sidereal_year" class="extiw" title="w:Sidereal year">Earth years</a>.
</p><p>Reference lines are provided as a rough measure of the difficulty of detecting exoplanets using transits.  Dashed lines trace the <i>m</i> (for Jupiter-density) and <i>a</i> values where the geometric probability, <i>P</i>, of transit for a solar-radius star (assuming a circular orbit, so that <i>e</i> and ω can be ignored) is the indicated value (less than the indicated proportion of all planets to the right of a given line will have transiting orbits).
</p><p>Exoplanet data is from the Open Exoplanet Catalogue,<sup id="cite_ref-1" class="reference"><a href="#cite_note-1">[1]</a></sup> version <a rel="nofollow" class="external text" href="https://github.com/hannorein/open_exoplanet_catalogue/tree/811d35297d9efd9325f5287f75a7fb1cc407dc20/systems">811d352</a>, including some (mostly from the Kepler mission) whose semi major axes are computed from period data. The figure excludes 4 planets with semimajor axes outside the range of the figure and 1 (<a href="https://en.wikipedia.org/wiki/PSR_B1257%2B12_b" class="extiw" title="w:PSR B1257+12 b">PSR B1257+12 b</a>) with a mass lower than the range of the figure.
</p><p><b>Important note:</b> This figure is intended to serve as a visualization of the catalog of generally accepted candidate exoplanets using the distribution of some of their basic properties related to detection. No attempt has been made to characterize the degree of confidence (which varies widely) in the existence of a given planet or its properties. Nor is any attempt made to convey systematic errors associated with a particular method. In particular, the indicated mass, <i>m</i>, for an exoplanet characterized using <a href="https://en.wikipedia.org/wiki/Radial_velocity_method" class="extiw" title="w:Radial velocity method">radial velocity</a> is the <a href="https://en.wikipedia.org/wiki/Minimum_mass" class="extiw" title="w:Minimum mass">minimum mass</a> (so that the actual distrubiton of masses for non-transiting planets may be shifted and "smeared" significantly upward).
</p>
<ol class="references"><li id="cite_note-1"><span class="mw-cite-backlink"><a href="#cite_ref-1">↑</a></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.openexoplanetcatalogue.com">Open Exoplanet Catalogue</a> (<span class="mw-formatted-date" title="2014-09-23">2014-09-23</span>). Retrieved on <span class="mw-formatted-date" title="2014-09-23">2014-09-23</span>.</span>
</li>
</ol>
<a href="//commons.wikimedia.org/wiki/User:Aldaron" title="User:Aldaron"> Aldaron</a>, a.k.a. <a href="https://en.wikipedia.org/wiki/User:Aldaron" class="extiw" title="wikipedia:User:Aldaron">Aldaron</a>
2014-09-23
<span class="int-own-work" lang="en">Own work</span>, based on a figure by E.A.L. and used with permission