You are here

Delphinus

StarDate: 
July 10, 2016

Most constellations bear little resemblance to their namesakes. You need a great imagination to see a giraffe in the stars of Camelopardalis, for example, or a “sea goat” in Capricornus.

One constellation that does resemble its namesake is the dolphin, Delphinus. It’s a small grouping of stars that’s about a third of the way up the eastern sky as twilight fades away, and swims high across the south later on. And that group of stars really does look like a dolphin, jumping through the edge of the starry Milky Way.

In Greek mythology, Delphinus carried a poet to safety when he jumped overboard to escape some nasty sailors. The poet and the dolphin were commemorated in several coins that were issued around 500 B.C. And the dolphin gained longer-lasting recognition through its constellation.

None of the individual stars of Delphinus is particularly interesting. The brightest is known as Beta Delphini. It’s near the center of the constellation, and marks the end of the dolphin’s torso. The dolphin’s body stretches to the left as it climbs higher in the sky, and its tail to the right.

Beta Delphini is actually a binary. The two stars were born from the same cloud of gas and dust, and they remain bound to each other by their mutual gravitational pull. They orbit each other once every 27 years.

Look for the beautiful dolphin swimming into view in the east as darkness falls, and climbing high across the south during the night.

Script by Damond Benningfield

Get Premium Audio

Listen to today's episode of StarDate on the web the same day it airs in high-quality streaming audio without any extra ads or announcements. Choose a $8 one-month pass, or listen every day for a year for just $30.