atomic number 2- Delta Scuti (stars.astro.illinois.edu)
Modest Delta Scuti (in Scutum, the Shield), shining only at 5th magnitude (4.71) in a relatively obscure modern constellation best known for its placement in the Milky Way, stands out as the prototype of one of these, the pulsating “Delta Scuti stars,” of which Caph in Cassiopeia is the brightest.