|dc.description.abstract||So far, the most promising theory for the existence of subdwarf B (sdB) stars is that they
were formed during binary star evolution. This research was conducted to test this theory
by searching for companions around six sdB pulsators (V391 Peg, HS 0702+6043, EC
20117-4014, PG 1219+534, PG 0911+456, and PG 1613+426) using the Observed-minus-Calculated
(O-C) method. A star’s position in space will wobble due to the gravitational
forces of any companion. If the star is emitting a periodic signal, the orbital motion of the
star around the system’s center of mass causes periodic changes in the light pulse arrival
times. After obtaining the O-C diagrams for these stars, useful limits on suspected
companions’ minimum masses and semimajor axes were calculated. In addition, “period vs.
amplitude” and “mass vs. semimajor axis” modeling were conducted to investigate the
ranges and combinations of possible companion masses and semimajor axes that are
consistent with the observational data.
For V391 Peg and HS0702+6043, companions noted in previous publications validated
the method used in this research and confirmed their existence. The results of this study of
both these targets yield the same masses and semimajor axes as the published ones, within
the uncertainties. For EC20117-4014, current data show that there is a companion and the
signal of a companion candidate was detected with higher than 90% of confidence level.
However, there is still several possible mass and semimajor axis combinations of the
companion star. For PG1219+534, current data suggest that there may be a companion,
however, the no-companion possibility still cannot be eliminated.
The results of this project discovered two new possible companion candidates to
EC20117-4014 and PG1219+534, confirmed companions previously detected in V391 Peg
and HS0702+6043, as well as provided preliminary evidence for companions to EC20117-
4014 and PG1219+534 at the will require further observation. Though still a small sample,
these results suggest that planets might survive the post-main-sequence evolution of their