Gabriel Bihain (AIP)

Mid-infrared search for substellar companions to Barnard's Star
When May 07, 2015 from 02:00 PM to 03:00 PM
  • Colloquium
Where SH Lecture Hall
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Beyond Alpha Centauri, Barnard's Star is the second nearest star system to the Sun. Its relatively old age typical of solar neighborhood stars implies very low-mass brown dwarf companions and giant Jupiter-like planets would have reached temperatures below 500 K and emit most of their light in the mid-infrared. Direct imaging searches explore a range of physical separations complementary to that of radial velocity or transit methods, a range also where most giant planets are expected to form. Therefore, we obtained mid-infrared images in the 8.7 micron band (Si-2 filter) with 10.4 m GTC/CanariCam at two epochs and searched for low-mass companions at orbital separations of 1.8-25 astronomical units (au). Despite a spatial resolution of 0.5 au and a detection sensitivity of about 1.0 mJy, near the brown dwarf - planet mass boundary, no sources other than the star were found, indicating no brown dwarf companions. As a corollary and considering previous searches, giant planets in wide orbits may still be discovered by deeper searches.