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Home > Moon and Regulus

Moon and Regulus [1]

A star can be much more than meets the eye. An example is Regulus, the “heart” of Leo, the lion. Although it looks like a single star, it’s actually a system of at least four stars. But only one of them is bright enough to see without a telescope.

The bright star is quite impressive. Known as Regulus A, it’s bigger and heavier than the Sun, and much brighter. And it’s spinning like crazy — so fast that it’s barely holding itself together.

The star has a close companion — the likely corpse of a once-impressive star. Today, it’s so small and faint that it’s impossible to see through the glare of Regulus A, even with the biggest telescopes. So it wasn’t discovered until a little more than a decade ago.

The other members of the system are Regulus B and C. Regulus B is a little smaller and fainter than the Sun, while C is a cool, dim cosmic ember known as a red dwarf. They form a loosely bound pair that’s hundreds of billions of miles from the other two stars.

At that range, it takes the two pairs of stars more than a hundred thousand years to orbit each other. So it’s hard to be absolutely certain that B and C are really bound to the other two. But all four stars appear to move through space in sync — making the Regulus system more than meets the eye.

You should have no trouble eyeing Regulus tonight. It’s close to the right of the just-past-full Moon in early evening, and keeps tabs on the Moon throughout the night.


Script by Damond Benningfield [2]

Keywords:

  • Binary and Multi-Star Systems [3]
  • Regulus [4]
StarDate: 
Sunday, February 9, 2020
Teaser: 
A star that’s more than meets the eye
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Source URL:https://legacy.stardate.org/radio/program/2020-02-09

Links
[1] https://legacy.stardate.org/radio/program/2020-02-09 [2] https://damondbenningfield.com [3] https://legacy.stardate.org/astro-guide/binary-and-multi-star-systems [4] https://legacy.stardate.org/astro-guide/regulus