- Eta Cassiopeiae (Wikipedia)
Eta Cassiopeiae (η Cassiopeiae, abbreviated Eta Cas, η Cas) is a binary star system in the northern constellation of Cassiopeia. Its binary nature was first discovered by William Herschel in August 1779. Based upon parallax measurements, the distance to this system is 19.42 light-years (5.95 parsecs) from the Sun. The two components are designated Eta Cassiopeiae A (officially named Achird /ˈeɪtʃərd/) and B.
- Alpha Cassiopeiae (Wikipedia)
Alpha Cassiopeiae or α Cassiopeiae, also named Schedar (/ˈʃɛdɑːr/), is a second-magnitude star in the northern constellation of Cassiopeia. Though listed as the “alpha star” by Johann Bayer, α Cas’s visual brightness closely matches the ‘beta’ (β) star in the constellation (Beta Cassiopeiae) and it may appear marginally brighter or dimmer, depending on which passband is used. However, recent calculations from NASA’s WISE telescope confirm that α Cas is the brightest in Cassiopeia, with an apparent magnitude of 2.240. Its absolute magnitude is 18 times greater than β Cas, and it is located over four times farther away from the Sun.