A white dwarf which exceeds the Chandrasekhar limit will become the Type
 Ia [read: "one-A"] variety of this object, and the Type II variety of these objects form from massive stars
 when a collapsing core initiates further burning of successive interior layers.
A project at the Harvard Center for Astrophysics headed by Brian Schmidt searches for high-redshift
 examples of these objects in order to use their light curves as tests of the expanding universe. Two subtypes
 of these objects are distinguished by their absence of a strong silicon line and by serving as radio sources.
 These objects are classified into two broad categories depending on whether or not they exhibit hydrogen
 spectra, and the relatively uniform brightnesses of one subtype of these objects allow them to be used to
 calculate the distance ladder. A white dwarf which exceeds the Chandrasekhar limit will become the Type
 Ia [read: "one-A"] variety of this object, and the Type II variety of these objects form from massive stars
 when a collapsing core initiates further burning of successive interior layers. For ten points, identify these
 powerful explosions that occur at the end of a star's life cycle.
A project at the Harvard Center for Astrophysics headed by Brian Schmidt searches for high-redshift
 examples of these objects in order to use their light curves as tests of the expanding universe.
supernovae