J/A+A/623/A135 IR spectral of 4 Ae/Be Herbig stars (Bouteraon+, 2019)
Carbonaceous nano-dust emission in proto-planetary discs:
the aliphatic-aromatic components.
Bouteraon T., Habart E., Ysard N., Jones A.P., Dartois E., Pino T.
<Astron. Astrophys. 623, A135 (2019)>
=2019A&A...623A.135B 2019A&A...623A.135B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, IR ; YSOs ; Spectra, infrared
Keywords: protoplanetary disks - infrared: planetary systems
Abstract:
In the interstellar medium, carbon (nano-)grains are a major component
of interstellar dust. This solid phase is more vulnerable to
processing and destruction than its silicate counterpart. It exhibits
a complex, size-dependent evolution that is due to interactions within
different radiative and dynamical environments. Infrared signatures of
these carbon nano-grains are seen in a large number of discs around
Herbig HAeBe stars. We probe the composition and evolution of carbon
nano-grains at the surface of (pre-)transitional proto-planetary discs
around Herbig stars. We present spatially resolved infrared emission
spectra obtained with the Nasmyth Adaptive Optics System (NAOS)
Near-Infrared Imager and Spectrograph (CONICA) at the Very Large
Telescope (VLT) in the 3-4 microns range with a spatial resolution of
0.1-arcsec, which allowed us to trace aromatic, olefinic, and
aliphatic bands that are attributed to sub-nanometer hydrocarbon
grains. We applied a Gaussian fitting to analyse the observed spectral
signatures. Finally, we propose an interpretation in the framework of
theThe Heterogeneous dust Evolution Model of Interstellar Solids
(THEMIS). We show the presence of several spatially extended spectral
features that are related to aromatic and aliphatic hydrocarbon
material in discs around Herbig stars, from 10 to 50-100au, and even
in inner gaps that are devoid of large grains. The correlation and
constant intensity ratios between aliphatic and aromatic CH stretching
bands suggests a common nature of the carriers. Given their expected
high destruction rates through UV photons, our observations suggest
that they are continuously replenished at the disc surfaces.
Description:
Reduced spectra of spatially resolved infrared emission in the L-band
(3-4 microns) of proto-planetary discs around Ae/Be Herbig stars HD
100546, HD 100453, HD 169142, HD 179218. Acquistion has been made with
NAOS CONICA at the VLT. The raw data-set reference is 075.C-0624(A).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 35 4 List of studied stars
rspec.fit 2880 47 Fits files with spectra
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Star name
11- 12 I2 h RAh Simbad right ascension (J2000)
14- 15 I2 min RAm Simbad right ascension (J2000)
17- 21 F5.2 s RAs Simbad right ascension (J2000)
23 A1 --- DE- Simbad declination sign (J2000)
24- 25 I2 deg DEd Simbad declination (J2000)
27- 28 I2 arcmin DEm Simbad declination (J2000)
30- 33 F4.1 arcsec DEs Simbad declination (J2000)
35 I1 --- Rank [0/4] Rank in the fits spectra file,
rspec.fit
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Acknowledgements:
Thomas Bouteraon, thomas.bouteraon(at)ias.u-psud.fr
(End) Patricia Vannier [CDS] 13-Feb-2019