Bibcode
Vladilo, G.; Centurion, M.; Cassola, C.
Referencia bibliográfica
Astronomy and Astrophysics, Vol.273, NO. 1/JUNI, P. 239, 1993
Advertised on:
6
1993
Revista
Número de citas
13
Número de citas referidas
12
Descripción
We observed the λ 4232 Å CH+ interstellar line
in the direction of the Sco OB 1 association (d ≃ 2 kpc) with the
aim of detecting variations of the 12C/13C ratio
at large distances from the Sun. The collection of 30 high-resolution
spectra (λ/δλ = 1O5) of the V-6.3 stars
HD 152235 and HD 152424 by means of the ESO 3.6m telescope allowed us to
detect in both lines of sight a weak 13CH+
absorption (Wλ ≃ 0.2-0.3 mÅ) and to measure
the 12CH+/13CH+ abundance
ratio, RCH+. We found RCH+ =
126±29 for HD 152235 and RCH+ =
98±19 for HD 152424. These ratios are in excess of the value
RCH+ ≃ 65 measured in nearby interstellar
clouds (d ≲ 0.5 kpc). An increase of the isotopic ratio in the
general direction of the Galactic center is unexpected in the framework
of Galactic chemical evolution models and our results indicate the
presence of chemical inhomogeneities on distance scales of ≃ 1 kpc,
or even shorter.