Washington Double Star Catalog
kâtâlog-e setâregân-e dotâyi-ye Washington
Fr.: Washington Double Star Catalogue
A stellar catalog which is the world's principal database of astrometric → double star information. It is maintained by the United States Naval Observatory. The WDS Catalog contains positions (J2000), discoverer designations, epochs, position angles, separations, magnitudes, spectral types, proper motions, and, when available, Durchmusterung numbers and notes for the components of 142552 systems (as of Feb 27 2018).
[O III] doublet
dotâye-ye [O III]
Fr.: doublet [O III]
The two → forbidden lines with → transitions from the upper → energy level 1D2 of the doubly ionized oxygen atom. They occur in the green part of the → visible spectrum and are called → nebular lines. They are λ5006.8 1D2-3P2 and λ4958.9 1D2-3P1. Theoretical values for the [O III] 5007/4959 line-intensity ratio is 3.01 (Storey and Zeippen, 2000, MNRAS 312, 813).
[O III], spectroscopic notation of the ion O++; → doublet.