The nature of faint companions to G-type stars from adaptive optics

摘要

High spatial resolution (0."30) near-IR photometric observations using the adaptive optics of the Mount Wilson 100 inch (2.5 m) telescope and the Penn State IR Imager and Spectrograph have revealed faint companions to HD 190067 and HIP 13855. HD 190067B is found to be of mass 0.075-0.1 M-circle dot with an age from 0.5 Gyr to a few gigayears. HIP 13855B is a low-mass star (age 100-500 Myr) of mass between 0.1 and 0.2 M-circle dot. Further near-IR spectroscopic observations will be necessary to classify their spectral types precisely. References: 31