A few examples of what you can ask Wolfram|Alpha about:
compute location and get properties of a star
specify a star using a Bayer name
specify a star using a catalogue number
compare several stars
Properties of Stars
request a property of a star
compute the color of a star
compare properties of multiple stars
do computations with star properties
generate a list of nearby stars
Stellar Classification
get information about a spectral class of stars
find the spectral class of a given star
generate a Hertzsprung-Russell diagram
determine the end state of a star
get information about a star with a given property
specify a property and luminosity class
get information about a variable star
get a specified property of a variable star
get information about a pulsar
compare pulsars
get information about a supernova
look up a property of a supernova
generate a star chart for a constellation