J/A+A/591/A20 DIB and NaD spectra of 3 nearby stars (Kohl+, 2016)
On the nature of absorption features toward nearby stars.
Kohl S., Czesla S., Schmitt J.H.M.M.
<Astron. Astrophys. 591, A20 (2016)>
=2016A&A...591A..20K 2016A&A...591A..20K (SIMBAD/NED BibCode)
ADC_Keywords: Stars, nearby ; Interstellar medium ; Spectroscopy
Keywords: ISM: general - stars: late-type - local interstellar medium -
ISM: lines and bands - solar neighborhood - stars: atmospheres
Abstract:
Diffuse interstellar absorption bands (DIBs) of largely unknown
chemical origin are regularly observed primarily in distant early-type
stars. More recently, detections in nearby late-type stars have also
been claimed. These stars' spectra are dominated by stellar
absorption lines. Specifically, strong interstellar atomic and DIB
absorption has been reported in tau Boo.
We test these claims by studying the strength of interstellar
absorption in high-resolution TIGRE spectra of the nearby stars tau
Boo, HD 33608, and alpha CrB.
We focus our analysis on a strong DIB located at 5780.61Å and on
the absorption of interstellar Na. First, we carry out a differential
analysis by comparing the spectra of the highly similar F-stars, tau
Boo and HD 33608, whose light, however, samples different lines of
sight. To obtain absolute values for the DIB absorption, we compare
the observed spectra of tau Boo, HD 33608, and alpha CrB to PHOENIX
models and carry out basic spectral modeling based on Voigt line
profiles.
Description:
The present data collection contains coadded spectra of tau Boo,
HD 33608 and alpha CrB. This data was used to obtain the equivalent
widths of interstellar features.
The spectra show the wavelength regions around the Na D lines and
around 5780Å. The latter location corresponds to a wavelength range
where a strong diffuse interstellar band (DIB) is found in the
spectrum of the early-type supergiant HD 183143.
Each single spectrum has been corrected for telluric absorption and
the wavelength axis has been shifted to the barycentric reference
frame. However, the data has not been corrected for radial velocity of
the star.
The spectra have been acquired at the 1.2m Tigre telescope located in
La Luz, Mexico. The spectral resolution of the HEROS spectrograph is
20000.
A detailed description of the spectra is given in the aforementioned
paper.
Objects:
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RA (2000) DE Designation(s)
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13 47 15.74 +17 27 24.9 tau Boo = HR 5185
05 11 19.18 -02 29 26.8 HD 33608 = HR 1687
15 34 41.27 +26 42 52.9 alpha CrB = HR 5793
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 97 3 List of spectra
sp/* . 6 Individual fits spectra
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Name Star name
11- 12 I2 h RAh Right ascension (J2000)
14- 15 I2 min RAm Right ascension (J2000)
17- 21 F5.2 s RAs Right ascension (J2000)
23 A1 --- DE- Declination sign (J2000)
24- 25 I2 deg DEd Declination (J2000)
27- 28 I2 arcmin DEm Declination (J2000)
30- 33 F4.1 arcsec DEs Declination (J2000)
35- 38 I4 0.1nm bwaveDIB Lower value of wavelength interval for
DIB spectrum
40- 43 I4 0.1nm BwaveDIB Upper value of wavelength interval for
DIB spectrum
45- 48 F4.2 0.1nm dwaveDIB Spectral resolution for DIB spectrum
50- 53 I4 --- NxDIB Number of pixels along X-axis for DIB spectrum
55- 65 A11 --- FileDIB Name of DIB fits spectrum, in subdirectory sp
67- 70 I4 0.1nm bwaveNaD Lower value of wavelength interval for
NaD spectrum
72- 75 I4 0.1nm BwaveNaD Upper value of wavelength interval for
NaD spectrum
77- 80 F4.2 0.1nm dwaveNaD Spectral resolution for NaD spectrum
82- 85 I4 --- NxNaD Number of pixels along X-axis for NaD spectrum
87- 97 A11 --- FileNaD Name of NaD fits spectrum, in subdirectory sp
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Acknowledgements:
Sebastian Kohl, skohl(at)hs.uni-hamburg.de
(End) Patricia Vannier [CDS] 18-May-2016