Observational test of the CH cation oscillator strengths

¹ Institute of Physics, Kazimierz Wielki University, Weyssenhoffa 11, 85-072 Bydgoszcz, Poland e-mail: towes@gazeta.pl
² Korea Astronomy and Space Science Institute, Optical Astronomy Division, 61-1, Hwaam-Dong, Yuseong-Gu, Daejeon, 305-348, Korea e-mail: gala@kasi.re.kr
³ Special Astrophysical Observatory, Nizhnij Arkhyz, 369167, Russia e-mail: faig@sao.ru
⁴ European Southern Observatory (ESO), Alonso de Cordova 3107, Santiago, Chile e-mail: ybialets@eso.org
⁵ Center for Astronomy, Nicolaus Copernicus University, Gagarina 11, 87-100 Toruń, Poland e-mail: jacek@astri.uni.torun.pl

Received: 9 June 2008
Accepted: 21 November 2008

Abstract

We revise measurements of the positions and oscillator strengths using spectral features in the CH⁺ system, and by using high-resolution, echelle spectra of 36 stars and assuming that its wavelength and oscillator strength as given in the literature for the (0, 0) transition, i.e. 4232.548 Å and 0.00545 respectively, are correct. The recommended oscillator strengths of the lines at 3957.689, 3745.308, 3579.024, and 3447.077 Å are found to be (in units of 10^-5) 342, 172, 75, and 40, respectively. The estimated column densities of the CH cation toward the observed targets are also presented.