Asteroid
<p ><b>Pallas</b>, formally designated <b>2 Pallas</b>, is the second <a href="http://en.wikipedia.org/wiki/Asteroid" title="Asteroid" >asteroid</a> to have been discovered (after <a href="http://en.wikipedia.org/wiki/Ceres_(dwarf_planet)" title="Ceres (dwarf planet)" >Ceres</a>), and one of the largest in the <a href="http://en.wikipedia.org/wiki/Solar_System" title="Solar System" >Solar System</a>. It is estimated to comprise 7% of the mass of the <a href="http://en.wikipedia.org/wiki/Asteroid_belt" title="Asteroid belt" >asteroid belt</a>,<sup id="cite_ref-Pitjeva05_13-0" class="reference" ><a href="http://en.wikipedia.org/wiki/2_Pallas#cite_note-Pitjeva05-13" >[13]</a></sup> and its diameter of 530 kilometres (330 mi)–565 kilometres (351 mi) is comparable to, or slightly larger than, that of <a href="http://en.wikipedia.org/wiki/4_Vesta" title="4 Vesta" >4 Vesta</a>. It is however 20% less massive than Vesta,<sup id="cite_ref-Baer2007_6-1" class="reference" ><a href="http://en.wikipedia.org/wiki/2_Pallas#cite_note-Baer2007-6" >[6]</a></sup> placing it third among the asteroids. It is possibly the largest irregularly shaped body in the <a href="http://en.wikipedia.org/wiki/Solar_System" title="Solar System" >Solar System</a> (that is, the largest body not rounded under its own <a href="http://en.wikipedia.org/wiki/Gravity" title="Gravity" class="mw-redirect" >gravity</a>)<sup class="noprint Inline-Template" >[<i><a href="http://en.wikipedia.org/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed" >not verified in body</a></i>]</sup>, and a remnant <a href="http://en.wikipedia.org/wiki/Protoplanet" title="Protoplanet" >protoplanet</a>.</p>
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When Pallas was discovered by <a href="http://en.wikipedia.org/wiki/Astronomy" title="Astronomy" >astronomer</a> <a href="http://en.wikipedia.org/wiki/Heinrich_Wilhelm_Matth%C3%A4us_Olbers" title="Heinrich Wilhelm Matthäus Olbers" class="mw-redirect" >Heinrich Wilhelm Matthäus Olbers</a> on March 28, 1802, it was counted as a <a href="http://en.wikipedia.org/wiki/Planet" title="Planet" >planet</a>, as were other asteroids in the early 19th century. The discovery of many more asteroids after 1845 eventually led to their re-classification.
The Palladian surface appears to be a silicate material; the surface spectrum and estimated density resemble <a href="http://en.wikipedia.org/wiki/Carbonaceous_chondrite" title="Carbonaceous chondrite" >carbonaceous chondrite</a> meteorites. The Palladian orbit, at 34.8°, is unusually highly inclined to the plane of the asteroid belt, and the <a href="http://en.wikipedia.org/wiki/Orbital_eccentricity" title="Orbital eccentricity" >orbital eccentricity</a> is nearly as large as that of <a href="http://en.wikipedia.org/wiki/Pluto" title="Pluto" >Pluto</a>, making Pallas relatively inaccessible to spacecraft.<sup id="cite_ref-14" class="reference" ><a href="http://en.wikipedia.org/wiki/2_Pallas#cite_note-14" >[14]</a></sup><sup id="cite_ref-15" class="reference" ><a href="http://en.wikipedia.org/wiki/2_Pallas#cite_note-15" >[15]</a></sup>
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As with other asteroids, the <a href="http://en.wikipedia.org/wiki/Astronomical_symbols" title="Astronomical symbols" >astronomical symbol</a> for Pallas is a disk with its discovery number, ②. However, it also has an older, more iconic symbol, ⚴ (<a href="http://en.wikipedia.org/wiki/File:Pallas_symbol.svg" class="image" ><img src="/99d42d10-4f39-50e1-a60e-81d2b3dfe9a9.png"/></a> or sometimes <a href="http://en.wikipedia.org/wiki/File:2_Pallas.svg" class="image" title="Variant of Pallas symbol" ><img src="/04580d05-44bd-5f70-a39e-f03609bf76da.png"/></a>).<sup id="cite_ref-21" class="reference" ><a href="http://en.wikipedia.org/wiki/2_Pallas#cite_note-21" >[21]</a></sup>
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