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J/A+A/603/A67    CRL618, MWC922 and M2-9 RRL spectra  (Sanchez Contreras+, 2017)

A pilot search for mm-wavelength recombination lines from emerging ionized winds in pre-planetary nebulae candidates. Sanchez Contreras C., Baez-Rubio A., Alcolea J., Bujarrabal V., Martin-Pintado J. <Astron. Astrophys. 603, A67 (2017)> =2017A&A...603A..67S (SIMBAD/NED BibCode)
ADC_Keywords: Planetary nebulae ; Spectroscopy ; Radio lines Keywords: stars: AGB and post-AGB - circumstellar matter - stars: winds, outflows - stars: mass-loss - radio lines: general - HII regions Abstract: We report the results from a pilot search for radio recombination line (RRL) emission at millimeter wavelengths in a small sample of pre-planetary nebulae (pPNe) and young PNe (yPNe) with emerging central ionized regions. Observations of the H30α, H31α, H39α, H41α, H48β, H49β, H51β, and H55γ lines at ∼1 and ∼3mm have been performed with the IRAM 30m radio telescope. These lines are excellent probes of the dense inner (≲150 au) and heavily obscured regions of these objects, where the yet unknown agents for PN-shaping originate. We detected mm-RRLs in three objects: CRL 618, MWC922, and M2-9. For CRL 618, the only pPN with previous published detections of H41α, H35α, and H30α emission, we find significant changes in the line profiles indicating that current observations are probing regions of the ionized wind with larger expansion velocities and mass-loss rate than ∼29 years ago. In the case of MWC922, we observe a drastic transition from single-peaked profiles at 3mm (H39α and H41α) to double-peaked profiles at 1mm (H31α and H30α), which is consistent with maser amplification of the highest frequency lines; the observed line profiles are compatible with rotation and expansion of the ionized gas, probably arranged in a disk+wind system around a ∼5-10M central mass. In M2-9, the mm-RRL emission appears to be tracing a recent mass outburst by one of the stars of the central binary system. We present the results from non-LTE line and continuum radiative transfer models, which enables us to constrain the structure, kinematics, and physical conditions (electron temperature and density) of the ionized cores of our sample. We find temperatures Te∼6000-17000K, mean densities ne∼105-108cm-3, radial density gradients ne∝r-alphan_^ whit alphan∼2-3.5, and motions of velocities of ∼10-30km/s in the ionized wind regions traced by these mm-wavelength observations. We deduce mass-loss rates of dMpAGB/dt~=10-6-10-7M/yr, which are significantly higher than the values adopted by stellar evolution models currently in use and would result in a transition from the asymptotic giant branch to the PN phase faster than hitherto assumed. Description: Spectra of recombination lines at millimeter wavelengths with the IRAM 30m telescope for CRL618, MWC922 and M2-9. The intensity is presented in Ta* (K). Objects: ----------------------------------------------------- RA (2000) DE Designation(s) ----------------------------------------------------- 04 42 53.64 +36 06 53.4 CRL618 = PN G166.4-06.5 18 21 16.06 -13 01 25.7 MWC922 = EM* MWC 922 17 05 37.95 -10 08 34.6 PN M2-9 = PN G010.8+18.0 ----------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 139 24 List of spectra fits/* 0 24 Individual fits spectra
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- 23 I4 --- Nx Number of pixels along X-axis 25- 47 A23 --- Obs.Date Observation date (YYYY-MM-DDThh:mm:ss.sss) 49- 60 E12.6 Hz bFreq Lower value of frequency interval 62- 72 E11.6 Hz BFreq Upper value of frequency interval 74- 84 E11.6 Hz dFreq Frequency resolution 86- 87 I2 Kibyte size Size of FITS file 89-104 A16 --- FileName Name of FITS file, in subdirectory fits 106-139 A34 --- Title Title of the FITS file
Acknowledgements: Carmen Sanchez Contreras, csanchez(at)cab.inta-csic.es
(End) Patricia Vannier [CDS] 28-Apr-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

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