Access to Astronomical Catalogues

← Click to display the menu
J/A+A/608/A133    Gas and dust in star-forming region rho OphA (Larsson+, 2017)

Gas and dust in the star-forming region rho OphA II. The gas in the PDR and in the dense cores. Larsson B., Liseau R. <Astron. Astrophys. 608, A133 (2017)> =2017A&A...608A.133L (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Interstellar medium ; Nebulae ; YSOs ; Abundances ; Radio lines ; Spectroscopy ; Models Keywords: ISM: individual objects: rho Oph A - ISM: molecules - ISM: abundances - photon-dominated region (PDR) - stars: formation - ISM: general Abstract: We investigate to what degree local physical and chemical conditions are related to the evolutionary status of various objects in star-forming media. rho Oph A displays the entire sequence of low-mass star formation in a small volume of space. Using spectrophotometric line maps of H2, H2O, NH3, N2H+, O2, OI, CO, and CS, we examine the distribution of the atomic and molecular gas in this dense molecular core. The physical parameters of these species are derived, as are their relative abundances in rho Oph A. Using radiative transfer models, we examine the infall status of the cold dense cores from their resolved line profiles of the ground state lines of H2O and NH3, where for the latter no contamination from the VLA 1623 outflow is observed and line overlap of the hyperfine components is explicitly taken into account. The stratified structure of this photon dominated region (PDR), seen edge-on, is clearly displayed. Polycyclic aromatic hydrocarbons (PAHs) and OI are seen throughout the region around the exciting star S1. At the interface to the molecular core 0.05pc away, atomic hydrogen is rapidly converted into H2, whereas OI protrudes further into the molecular core. This provides oxygen atoms for the gas-phase formation of O2 in the core SM1, where X(O2)∼5x10-8. There, the ratio of the O2 to H2O abundance [X(H2O)∼5x10-9] is significantly higher than unity. Away from the core, O2 experiences a dramatic decrease due to increasing H2O formation. Outside the molecular core, on the far side as seen from S1, the intense radiation from the 0.5pc distant early B-type star HD147889 destroys the molecules. Towards the dark core SM1, the observed abundance ratio X(O2)/X(H2O)>1, which suggests that this object is extremely young, which would explain why O2 is such an elusive molecule outside the solar system. Description: Atomic and molecular line data from different telescope towards the star-forming region rho OphA is presented. From the Infrared Space Observatory (ISO) archive, H2 lines have been extracted from three frames of spectrophotometric data using the ISOCAM-CVF (Circular Variable Filter, Cesarsky et al., 1996A&A...315L..32C). The sub-millimetre molecular data have been obtained with the Heterodyne Instrument for the Far Infrared (HIFI, de Graauw et al., 2010A&A...518L...6D) on board the ESA spacecraft Herschel (Pilbratt et al., 2010A&A...518L...1P). Mapping in H2O of the rho Oph cloud was done with the Odin satellite (Nordh et al., 2003A&A...402L..21N). The Photodetector Array Camera and Spectrometer (PACS, Poglitsch et al., 2010A&A...518L...2P) was used to map the fine structure line of oxygen. Low level transitions of CS was observed with the Swedish ESO Submillimetre Telescope (SEST) on La Silla. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 16 26 24.6 -24 23 54 rho Oph A (in L1688) = HD 147933 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 172 25 List of FITS files fits/* 0 25 Individual fits files
See also: J/ApJ/613/393 : X-ray and radio sources in ρ Oph Core A (Gagne+, 2004) J/A+A/510/A98 : 12C18O(3-2) map of rho Oph A (Liseau+, 2010) J/A+A/578/A131 : Gas & dust in the star-forming region rho OphA (Liseau+, 2015) Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000) 10- 18 F9.5 deg DEdeg Declination of center (J2000) 20- 22 I3 --- Nx Number of pixels along X-axis 24- 26 I3 --- Ny Number of pixels along Y-axis 28- 31 I4 --- Nz ? Number of slices 33- 43 E11.6 Hz bFreq ? Lower value of frequency interval 45- 55 E11.6 Hz BFreq ? Upper value of frequency interval 57- 67 E11.6 Hz dFreq ? Frequency resolution 69- 72 I4 Kibyte size Size of FITS file 74- 96 A23 --- FileName Name of FITS file, in subdirectory fits 98-103 A6 --- Fig Figure number in the paper 105-112 A8 --- Mol Species 114-140 A27 --- Trans Transition 142-172 A31 --- Title Title of the FITS file
Acknowledgements: Bengt Larsson, bem(at)astro.su.se References: Liseau et al., Paper I 2015A&A...578A.131L, Cat. J/A+A/578/A131
(End) Patricia Vannier [CDS] 07-Sep-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© UDS/CNRS

Contact