Mesarthim is the white star in the head of Aries, the Ram, a striking pair of nearly identical stars that a small telescope splits easily.
At a glance
| type | white star (class A) |
|---|---|
| distance from the Sun | 164 light-years (50.3 pc) |
| its light left it | 164 years ago |
| luminosity | 74.1 × the Sun |
| radius | 3.32 × the Sun |
| surface temperature | 9,300 K |
| constellation | Aries (Ram) |
Read off the piece’s own catalogue, the same values it draws with.
About Mesarthim
Mesarthim is a class A star, white and hotter than the Sun. Through a small telescope it becomes a close pair of almost equal white stars, one of the finest easy doubles in the northern sky. It was among the first double stars ever noticed with a telescope, early in the history of the instrument.
With Sheratan and Hamal it forms the short bent line that is all most people see of Aries, the Ram, and Mesarthim is the faintest of the three. Aries is a zodiac constellation, so the Sun passes through it every year, and the Moon and planets cross this part of the sky.
What you see in the piece
To the eye from Earth Mesarthim is a single point. Fly to it in the piece and the pair becomes visible, two white stars orbiting at a distance far wider than the Solar System.
Questions
Is Mesarthim a double star?
Yes. A small telescope splits Mesarthim into two nearly identical white stars, one of the easiest and prettiest doubles in the sky.