I have seen a number of places on the Internet where Epsilon Eridani is referred to as Sadira. (e.g. https://en.wikipedia.org/wiki/List_of_stars_in_Eridanus ) However, it would seem that its an unofficial name and the star got renamed Ran by the IAU in a competition.

  1. How did Epsilon Eridani become known as Sadira by some?

  2. What or who was Sadira?


1 Answer 1


All star names are unofficial. A few stars have ancient names (such as Sirius) all other stars are referred to by their position in a catalogue or star atlas.

As well as I can tell, Al Sadira means "the ostrich", or perhaps in context "The (riverbank) ostrich" indicating a type of tree that grows by rivers (baby name sites offer "lotus tree").

There may be a list of Arabic star names that lists this star as Al Sadira(h) but the name is not in common use and won't be recognised by most people.

The IAU name, Ran, from that of a Norse river goddess, is a recent innovation, and doesn't seem to be much used. The Bayer Designation "Epsilon Eridani" is by far the most well known.

  • $\begingroup$ "All star names are unofficial." Interesting, is there an IAU policy statement on that somewhere that one could quote? $\endgroup$ Commented Jun 1, 2019 at 10:33
  • $\begingroup$ I think the point that I was making is that the IAU has no special legal status. I have an official name that is registered with my government, and appears on my passport. Nothing similar exists for stars. The IAU can publish lists of names for their own use, and others can choose to follow, but there is no legal or "official" backing, and if someone wants to use different name, they are free to do so. $\endgroup$
    – James K
    Commented Jun 1, 2019 at 22:28

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