DOI: https://doi.org/10.18524/1810-4215.2019.32.182049

DIFFUSE INTERSTELLAR BAND 6202 ˚ A AS AN INDICATOR OF ORGANIC MATTER IN COSMOS: CEPHEID SPECTRA

S M. Andrievsky, A. Shereta, S. V, Khrapaty, S. A. Korotin, V. V. Kovtyukh, V. I. Kashuba

Анотація


We have described the method of
investigation of the diffuse interstellar band (DIB) at
6202
˚
A. This DIB is seen in the spectra of cepheid
stars, and it is blended with two stellar lines of Ce II
(6201.773
˚
A) and Ni I (6204.6
˚
A). After removal
of the blending lines of ionized cerium and neutral
nickel, we can determine the equivalent widths (EW)
of the DIB. This procedure can be applied for the
sample of cepheids (with well known distances), which
enables one to construct the map of the organic matter
distribution in the Galactic disc and use these values
to investigate the E(B–V)–DIB EW relation. The
relation found from Cepheids matches that found in B
stars. This relation can help to find the reddening for
newly discovered Cepheids without extensive photo-
metric data, and thus determine their distances. The
relation between E(B–V) and the DIB EW does not
yield precise reddening values. It is not a substitute
for better photometric or spectroscopic methods. At
best, it is indicative, but it provides some information
that may not be otherwise available.


Ключові слова


classical cepheids; ISM lines and bands; ISM molecules; ISM structure

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Посилання


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