Measuring The Bolometric Luminosity Of Exoplanet Beta Pictoris B Via Direct-imaging With Magellan AO (speaker: Katie Morzinski, Steward Observatory)

Wednesday May 4, 2016 12:05 pm
Marlar Lounge (37-252)

Physical characteristics of exoplanets remain difficult to measure.  One well-studied planet is beta Pictoris b, which is 9 AU from and embedded in the debris disk of the young nearby A6V star beta Pictoris.  We imaged the system with Magellan Adaptive Optics (MagAO) instruments VisAO and Clio, at 5 wavelengths from 0.9-5 microns.  I will present a complete spectral energy (SED) distribution with the new MagAO data plus literature data from Gemini and VLT.  Atmosphere models demonstrate the planet is cloudy but are degenerate in effective temperature and radius.  As the measured SED now covers >80% of the planet’s energy, we can determine the bolometric luminosity empirically by combining the 22 independent measurements at 16 passbands from 0.99-4.8 microns.  The empirically-determined luminosity is in agreement with values from atmospheric models, but brighter than values from the field-dwarf bolometric correction.  Thus, beta Pic b is another example where directly comparing young exoplanets to old brown dwarfs gives inaccurate physical characteristics like luminosity.  Understanding exoplanet properties is a data-limited field, so directly measuring the luminosity for more exoplanets is critical to developing a fuller picture of their evolution.

Host: Amanda Bosh