Astronomical Topics.
1931
Citations
0
Citations
Journal
Nature
Full text
Semantic Scholar
Key Takeaway Key Takeaway: The distance of the Great Nebula in Orion is 1800 light-years, three times greater than previously thought, and the stars in the nebula are slightly redder due to the nebula's absorptive effect on their light.
Abstract
Distance of the Great Nebula in Orion.—A Bulletin dated June 11, from Science Service, Washington, D.C., gives a summary of a new determination of the distance of this nebula, made by Dr. R. J. Trumpler at the Lick Observatory, and reported by him to the Astronomical Society of the Pacific at Pasadena. He states that three different methods give the distance as 1800 light-years, which is about three times as great as the value generally given; thus Kapteyn gave the parallax of the nebula as 0.0055″, implying a distance of 590 light-years. As there is evidence of association between the nebula and many of the bright stars in Orion, their distance is generally taken to be about the same; if the new distance applies to Rigel, it must be of extraordinary brilliance. The table in Russell, Dugan, and Stewart's standard work gives its absolute magnitude as 5.8 with a parallax of 0.006; at three times the distance it would have absolute magnitude about -8.2. The new value gives the diameter of the nebula, neglecting its faint extensions, as 26 light-years. Dr. Trumpler has also investigated the colour of the stars in the nebula; he finds that they are slightly redder than stars of the same type elsewhere, which he ascribes to the absorptive effect of the nebula on their light.