ES-03-0028

High-Resolution Detections of Low-Mass Dwarf Companions to Young B and A Stars

Marah Brinjikji, Adam Smith, Jasmine Garani, Emma Softich, Jenny Patience, Eric Nielsen, Thomas Esposito, Jason Wang, Rob de Rosa, Michael Liu, Brendan Bowler, William Best, Abhijith Rajan, Bruce Macintosh, Franck Marchis, Trent Dupuy, Jean-Baptiste Ruffio

In this poster, we will present results from a high-resolution imaging search for low-mass companions around nearby B and A stars using high resolution adaptive optics images from the NIRC2 camera on the Keck II telescope. We initially performed a first-epoch companion search around 220 young B and A stars within 150 pc, identifying 172 candidate brown dwarf companions for follow up confirmation and characterization around 67 of our original target stars. We will discuss results from 2nd-epoch observations of 28/67 of our targets marked for follow up, including the discovery of at least two new M-dwarf companions and their separations, masses and delta magnitudes. This survey allows for identification and characterization of brown dwarfs and low-mass M dwarfs in the intermediate stages of formation and evolution, as the ages of the stars in our population sample, being B and A stars, have relatively short main sequence lifetimes. Through this survey, the goal of which is to expand the number of confirmed companion brown dwarfs, future work will allow for benchmark comparisons to formation models of planets and brown dwarfs, more accurate population/frequency statistics, and follow-up spectroscopy for atmospheric characterization of planetary temperature objects observable with high signal-to-noise ratio. We utilize a custom data reduction pipeline which includes PSF subtraction through Reference Differential Imaging performed using the pyKLIP software to identify faint candidate companions. This pipeline combined with the adaptive optics system on the telescope allows us to achieve the high contrast necessary for detecting wide separation brown dwarf companions around bright host stars. Here we present the results for confirmed companions and their estimated masses, separations, and magnitudes, along with the initial achieved contrast for this survey.