Discovery of a magnetic field in $ρ$ Pup

Abstract

$ρ$ Pup is a $δ$ Scuti F2 pulsator, known to host a main radial mode as well as non-radial pulsations, with chemical peculiarities typical of evolved Am stars. We present high-precision spectropolarimetric observations of this star, obtained with ESPaDOnS at the Canada France Hawaii Telescope (CFHT) in the frame of the BRITE spectropolarimetric survey. A magnetic field is clearly detected in $ρ$ Pup, with a longitudinal field strength below 1 G. This makes $ρ$ Pup the second known magnetic $δ$ Scuti discovered, after HD 188774, and a possible cool evolved counterpart of the recently discovered ultra-weakly magnetic Am family.

4 pages, 2 figures, accepted in MNRAS Letters