42 Orionis Explained

42 Orionis is a class B1V (blue main-sequence) star in the constellation Orion. Its apparent magnitude is 4.59 and it is approximately 900 light years away based on parallax.

The primary star, Aa, has one spectroscopic companion Ab of magnitude 6.3 and separation 0.16", and a more distant companion B of 7.5 magnitude at 1.6" separation.^{[1] [2]}

c Orionis is surrounded by NGC 1977 one of a smaller fainter group of named nebulae just north of the Orion Nebula. c Ori is the star which excites and illuminates NGC 1977.

Notes and References

1. 2001AJ....122.3466M . 10.1086/323920 . The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog . The Astronomical Journal . 122 . 6 . 3466 . 2001 . Mason . Brian D. . Wycoff . Gary L. . Hartkopf . William I. . Douglass . Geoffrey G. . Worley . Charles E. . free . Vizier catalog entry
2. 2015AJ....150...50T . 10.1088/0004-6256/150/2/50 . Speckle Interferometry at Soar in 2014 . The Astronomical Journal . 150 . 2 . 50 . 2015 . Tokovinin . Andrei . Mason . Brian D. . Hartkopf . William I. . Mendez . Rene A. . Horch . Elliott P. . 1506.05718 . 30737411 .