Stars
Within Ursa Major the stars of the Big Dipper have Bayer designations in consecutive Greek alphabetical order from the bowl to the handle.
| Proper Name |
Bayer Designation |
Apparent Magnitude |
Distance (L Yrs) |
|---|---|---|---|
| Dubhe | α UMa | 1.8 | 124 |
| Merak | β UMa | 2.4 | 79 |
| Phecda | γ UMa | 2.4 | 84 |
| Megrez | δ UMa | 3.3 | 81 |
| Alioth | ε UMa | 1.8 | 81 |
| Mizar | ζ UMa | 2.1 | 78 |
| Alkaid | η UMa | 1.9 | 101 |
In the same line of sight as Mizar, but about one light-year beyond it, is the star Alcor (80 UMa). Together they are known as the Horse and Rider. At fourth magnitude, Alcor would normally be relatively easy to see with the unaided eye, but its proximity to Mizar renders it more difficult to resolve, and it has served as a traditional test of sight. Mizar itself has four components and thus enjoys the distinction of being part of an optical binary as well as being the first-discovered telescopic binary (1617) and the first-discovered spectroscopic binary (1889).
Five of the stars of the Big Dipper are at the core of the Ursa Major Moving Group. The two at the ends, Dubhe and Alkaid, are not part of the swarm, and are moving in the opposite direction. Relative to the central five, they are moving down and to the right in the map. This will slowly change the Dipper's shape, with the bowl opening up and the handle becoming more bent. In 50,000 years the Dipper will no longer exist as we know it, but be re-formed into a new Dipper facing the opposite way. The stars Alkaid to Phecda will then constitute the bowl, while Phecda, Merak, and Dubhe will be the handle.
Read more about this topic: Big Dipper
Famous quotes containing the word stars:
“The day in his hotness,
The strife with the palm;
The night in her silence,
The stars in their calm . . .”
—Matthew Arnold (1822–1888)
“The stars are distant and unobtrusive, but bright and enduring as our fairest and most memorable experiences.”
—Henry David Thoreau (1817–1862)
“There seems to be a kind of order in the universe, in the movement of the stars and the turning of the earth and the changing of the seasons, and even in the cycle of human life. But human life itself is almost pure chaos. Everyone takes his stance, asserts his own rights and feelings, mistaking the motives of others, and his own.”
—Katherine Anne Porter (1890–1980)