Pulsation properties of {lambda}bootis stars I

We find two heartbeat stars and two eclipsing binaries among the sample. We calculate that 81 per cent of {lambda} Boo stars pulsate as {delta} Sct variables, which is about twice that of normal stars over the same parameter space.

We determine the temperatures and luminosities of the {lambda} Boo stars from photometry and Gaia DR2 parallaxes. A subset of 40 {lambda} Boo stars have 2-min TESS data, reliable temperatures and luminosities, and {delta} Sct pulsation. We use Petersen diagrams (period ratios), echelle diagrams, and the period-luminosity relation to identify the fundamental mode in 20 of those 40 stars and conclude that a further 8 stars are not pulsating in this mode.