Massive neutral particles on heterotic string theory

The motion of massive particles in the background of a charged black hole in heterotic string theory, which is characterized by a parameter α, is studied in detail in this paper. Since it is possible to write this space-time in the Einstein frame, we perform a quantitative analysis of the time-like geodesics by means of the standard Lagrange procedure. Thus, we obtain and solve a set of differential equations and then we describe the orbits in terms of the elliptic p-Weierstrass function. Also, by making an elementary derivation developed by Cornbleet (Am. J. Phys. 61(7):650-651, 1993) we obtain the correction to the angle of advance of perihelion to first order in α, and thus, by comparing with Mercury's data we give an estimation for the value of this parameter, which yields an heterotic solar charge Qsun ≅ 0.728 [Km]=0.493 Msun. Therefore, in addition to the study on null geodesics performed by Fernando (Phys. Rev. D 85:024033, 2012), this work completes the geodesic structure for this class of space-time. (orig.)