BETA (β) MONOCEROTIS MULTIPLE STAR Right Ascension: 06h 28m 49s Best Seen: 01/01 - 05/15 Declination: -07º 01' 58" Magnitude 3.76 Computer File: betamon Target RA 06h28'49" Target Dec 07d01'58" MOVE Constellation Monoceros Apparent Separation: B and C are 2.8 seconds of arc apart A stands off from them by 7.4 seconds of arc.

Actual Compared to Earth Distance 691 ly -- Separation -- -- Orbital Period B and C pair – 4,200 yrs A–BC pair - 14,000 yrs -- Actual Brightness -- 3200 / 1 (Sun) Magnitude 4.6 (A) / 5.4 (B) / 5.6 (C) -- Mass -- ~ 7 / 1 (Sun) Surface Gravity -- -- Surface Composition (by mass) -- -- Spectral Type B3Ve G2 V (Sun) Density (gram/cubic cm) -- --

WHAT TO LOOK FOR THROUGH THE TELESCOPE: 1. Recommended eyepiece: 24mm or 40 mm.

  1. When people look through the telescope they should see three stars in a curved line. The stars should be about the same brightness.

BETA MONOCEROTIS INFORMATION: 1. Beta Mon is a triple star system in the constellation of Monoceros (The Unicorn).

  1. To the naked eye, it appears as a single star with an apparent visual magnitude of approximately 3.74, making it the brightest visible star in the constellation.

  2. A telescope shows a curved line of three pale blue stars (or pale yellow stars, depending on the scope's focus).

  3. William Herschel who discovered it in 1781 commented that it is "one of the most beautiful sights in the heavens".

  4. The star system consists of three Be stars (West to East), β Monocerotis A, β Monocerotis B, and β Monocerotis C.

  5. B and C mostly likely orbit each other, while A orbits the pair.

  6. There is also an additional visual companion star (~Mag 12) that is probably not physically close to the other three stars

FACT CHECKER Item Updated Notes Apparent Separation 2017-04-03 http://stars.astro.illinois.edu/sow/betamon.html and https://www.universeguide.com/star/betamonocerotis Distance 2017-04-03 http://stars.astro.illinois.edu/sow/betamon.html and https://www.universeguide.com/star/betamonocerotis

Separation 2017-04-03 http://stars.astro.illinois.edu/sow/betamon.html and https://www.universeguide.com/star/betamonocerotis Orbital Period 2017-04-03 http://stars.astro.illinois.edu/sow/betamon.html and https://www.universeguide.com/star/betamonocerotis Actual Brightness 2017-04-03 http://stars.astro.illinois.edu/sow/betamon.html and https://www.universeguide.com/star/betamonocerotis Magnitude 2017-04-03 http://stars.astro.illinois.edu/sow/betamon.html and https://www.universeguide.com/star/betamonocerotis Mass 2017-04-03 http://stars.astro.illinois.edu/sow/betamon.html and https://www.universeguide.com/star/betamonocerotis Surface Gravity
Surface Composition ??? Spectral Type 2017-04-03 http://stars.astro.illinois.edu/sow/betamon.html and https://www.universeguide.com/star/betamonocerotis

Density
Other Information