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PSR B1257+12

1 Feb 2017, 07:00 UTC
PSR B1257+12

PSR B1257+12 is a special system for several reasons.
First, the central star, discovered by Aleksander Wolszczan in 1990 [1] and named Lich since December 2015 [2], is a pulsar. Even if Lich is 1.4 times as massive as the Sun, its radius is only about 10 kilometers!
Secondly, this system was the first one confirmed to have clearly planetary-mass objects. On January 9th 1992, Aleksander Wolszczan and Dale Frail announced the discovery of two super-Earths [3], PSR B1257+12 c (Poltergeist) and d (Phobetor). In 1994, Aleksander Wolszczan announced an additional object [4], PSR B1257+12 b (Draugr)​, only about twice as massive as the Moon — i.e. about half as massive as Mercury!
[1] Daniel W. E. Green, ​IAU Circular No. 5073, 13 August 1990.
[2] “Naming Stars”, International Astronomical Union (https://www.iau.org/public/themes/naming_stars/)
[3] A. Wolszczan & D. A. Frail, Nature 355, 145-147, 9 January 1992.
[4] A. Wolszczan, Science 264 (5158), 538-542, 22 April 1994.
<table class=” aligncenter” style=”height: 160px; width: 502px;”>
<tbody>
<tr style=”height: 26px;”>
<td style=”width: 124px; height: 26px;”></td>
<td style=”text-align: right; width: 95px; height: 26px;”>Mass (M<sub>Jup</sub>)</td>
<td style=”width: 70px; height: 26px; text-align: right;”>Radius(R<sub>Jup</sub>)</td>
<td style=”text-align: right; width: 83px; height: 26px;”>Period(day)</td>
<td style=”text-align: right; width: 71px; height: 26px;”>Discovery</td>
</tr>
<tr style=”height: 24px;”>
<td style=”width: 124px; height: 24px;”>PSR B1257+12b</td>
<td style=”text-align: right; width: 95px; height: 24px;”>0.00007</td>
<td style=”width: 70px; height: 24px; text-align: right;”></td>
<td style=”text-align: right; width: 83px; height: 24px;”>25.26</td>
<td style=”text-align: right; width: 71px; height: 24px;”>1992</td>
</tr>
<tr style=”height: 24px;”>
<td style=”width: 124px; height: 24px;”>PSR B1257+12c</td>
<td style=”text-align: right; width: 95px; height: 24px;”>0.013</td>
<td style=”width: 70px; height: 24px; text-align: right;”></td>
<td style=”text-align: right; width: 83px; height: 24px;”>66.54</td>
<td style=”text-align: right; width: 71px; height: 24px;”>1992</td>
</tr>
<tr style=”height: 24px;”>
<td style=”width: 124px; height: 24px;”>PSR B1257+12d</td>
<td style=”text-align: right; width: 95px; height: 24px;”>0.012</td>
<td style=”width: 70px; height: 24px; text-align: right;”></td>
<td style=”text-align: right; width: 83px; height: 24px;”>98.21</td>
<td style=”text-align: right; width: 71px; height: 24px;”>1992</td>
</tr>
</tbody>
</table>
<iframe src=”https://dace.unige.ch/animation” width=”950″ height=”600″ scrolling=”no”></iframe>
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