Speaker
Description
Stellar intensity interferometry (SII) has great potential to
precisely test stellar atmosphere model predictions. Published measurements of
stars near 400 nm, e.g.VERTIAS SII observations of the A-type subgiant
$\beta$ UMa, reveal smaller uniform disk angular diameters (stronger limb
darkening) relative to Michelson interferometry measurements at longer
wavelengths. Published simultaneous measurements of the B-type giant $\beta$ Cru at
375 nm and 470 nm with HESS SII yield the same uniform disk diameter
in the two bands, within the uncertainties. The 375 nm band however
coincides with the confluence of the hydrogen Balmer series towards
the Balmer limit, the filter capturing lines H8 to H13, while the
470 nm band lacks any strong spectral lines. To explore single stars
for which significantly different angular sizes are expected in the
two bands, I have modeled the extended atmospheres of the four
brightest A-type supergiants with angular diameters under 1 mas. I
will present our visibility predictions for the HESS bands and
sub-bands within the VERITAS 416 nm band, with and without the H$\delta$
line. I will also discuss the potential for SII measurements to turn
spectroscopic binaries into visual binaries in order to constrain the
masses of the constituent stars.
