New orbits for comets C/1960 M1 (Humason), C/1980 E1 (Bowell), and musings on extrasolar comets

摘要

New orbits are calculated for Comets Humason (C/1960 M1) and Bowell (C/1980 E1). Humason's orbit is based on 34 observation made over 348 days and Bowell's on 203 observations made over nearly eight years. Both comets have hyperbolic orbits. Backwards integrations indicate that both comets had originally highly elliptical orbits which changed to hyperbolas by the injection of energy from the Solar System. Given that both of their perihelions are more than 3 AU from the Sun, the possibility of nongravitational forces is remote. For Comet Secchi (C/1853 E1), however, the orbit is hyperbolic at more than 100000 AU from the Sun and with no indication of nongravitational forces. If the orbit is a hyperbola at that distance, could the comet's origin not be from beyond the Oort cloud?.