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Pulsar Roche Limit Magnetic Field

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Pulsar Roche Limit Magnetic Field Planetary Environment Around a Pulsar David Dunkum, Jacob Houdyschell, Caleb Houdyschell, and Abigail Chaffins Spring Valley High School Huntington, WV Abstract: Pulsars are densely-packed, spinning neutron stars Finally, an orbiting body must survive the that are the remaining cores of massive stars that extreme magnetic fields a pulsar constantly ended in a catastrophic supernova. Due to the emits. Many pulsars have such powerful extreme processes that these stellar objects are magnetic fields that it warps the electron formed, it was believed that any planets orbiting it clouds of atoms into needle-like shapes less would have been annihilated by the explosive events than 1% of their original size, rendering much of their creation or survive the intense conditions of the chemistry of life impossible in close around a pulsar. In 1992, it was discovered that not proximity to the star. only were planetary bodies possible around pulsars, an actual pulsar system (PSR 1257+12) was found by To calculate the magnetic field strength Aleksander Wolszczan and Dale Frail with two bodies (measured in Gauss) of a pulsar, the radius of orbiting the pulsar. the pulsar (R), the angle between the pulsar’s 162 pointings, which contain about 5670 plots, were magnetic poles and it’s rotational axis (α), analyzed to collect data for this research. Out of the and the pulsar’s moment of inertia (I) must be 5670 plots, three known pulsars were found and determined. Since, like before, these values analyzed to collect the relevant data needed to are not easily accessible, a “typical” pulsar’s determine the average conditions one would expect to values are used, which are 10 km, 900, and encounter around a pulsar. 1045 g cm2 respectively. These values, along with the pulsar’s period (P) and P-dot, which are how long in seconds it takes for one revolution and the rate of deceleration of the pulsar's angular velocity in revolutions per second per second, are then used to calculate the characteristic magnetic field using the following equation: Results: Pulsar Roche Limit Magnetic Field (Gauss) Data Analysis: 6 14 Conditions Around a Pulsar: J1738+0333 1.205 x 10 km 1.067 x 10 G The three pulsars used for the calculations are: There are several aspects of a pulsar that make the J1801-1417; J1719-1438; J1738+0333 environment around it particularly dangerous for orbiting bodies. One of the more obvious dangers to Since many of the values used for the equations 6 14 anything orbiting a pulsar is the intense radiation J1719-1438 1.205 x 10 km 3.392 x 10 G are based off of a “typical” pulsar and not each that it emits, especially along the two iconic jets pulsar’s unique values, the results will end up that pulsars produce. This radiation, being so being an approximation for each pulsar. Also, powerful, would have the effect of blasting away since the P-dot for each pulsar can only be 6 13 any atmosphere the orbiting planets could have J1801-1417 1.205 x 10 km 5.206 x 10 G determined exactly through years of possibly formed. observation, the value given on each pulsar’s prepfold plot is merely an estimate, leading to Another danger to any orbiting body is the strong an approximate value as the final result. gravitational field that such a dense and massive These results, although accurate, provide only a rough object generates. Such a gravitational field has a estimate of what these pulsars’ individual Roche Limits and specific area where the gravitational pull to the magnetic fields actually are due to using generalized data. closest end of an orbiting body is much stronger than the farthest end, which tears the body apart. Overall, this shows how hostile pulsar’s can be for both This zone is called the “Roche Limit” (d) which can orbiting bodies and for life as we know it possibly existing be calculated with the primary object’s radius (RM), on the planets. With the intense solar radiation emissions, the primary object’s density (pM), and the orbiting strong gravitational pull, and powerful magnetic field of satellite’s density (pm). Since there is no easily these pulsars, any Earth-like planets orbiting them would accessible data on the exact mass and radius of a be little more than barren terrestrials, with very little pulsar to calculate density, the values of a “typical” chance of life as we know it existing on their surfaces. pulsar, which are 1.4 solar masses (2.785 x 1030 kg) Despite these extreme conditions, there is a possibility and 10 km respectively, are used. As for the that some form of life could exist in an ocean deep inside theoretical orbiting body, the values of an Earth-like of a planet that is warmed by tidal friction, similar to planet (mass = 5.972 x 1026 kg, radius = 6,371 km) Jupiter’s moon Europa, thereby providing heat for life and are used. After calculating densities, the following shielding the ocean from the pulsar’s intense radiation. equation is then used to calculate the Roche Limit: Such a possibility is remote though, since so many different variables must be exactly right to achieve this. Example of the Roche Limit .
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