CFHT UM2019 - Presentation Details

Abstract Details

Title: Planetary-mass objects in Taurus found through a water-band imaging survey

Presenter: Loïc Albert


Are star formation processes able to form very-low mass stars down to the planetary regime mass? If the Local neighborhood (<20 pc) is any indication (Kirkpatrick et al. 2018) then star nurseries should abound with objects of a few to tens of Jupiter masses. When looking at the closest star-forming region (SFR), Taurus, the most sensitive surveys to date instead suggest a declining initial mass function towards low-mass objects. Some of this tension may be real, but some probably comes from observational completion limits being in the 20-40 Jupiter mass range (Luhman et al. 2017). Photometric surveys for red, low-mass, objects in SFRs yield IMFs that are very dependent on the adopted color cuts and extinction correction (Cook et al. 2017). We made use of a novel photometric technique with WIRCam at CFHT - it uses a custom made W filter (W for water) centered on the deep water vapor absorption band at 1.45 microns. Coupled with simultaneous J and H-band imaging to sample the pseudo-continuum, J-W and H-W colors become an extinction-free water-band measurement. We embarked on a 25 square degree survey of Taurus and, after spectroscopic follow-up with Gemini and IRTF, confirmed several tens of objects consistent with being as small as 4-5 Jupiter masses. This is more objects than were expected from a log-normal IMF and better fits an exponential IMF.