J/A+A/617/A31 HCO+, CN, and 13CO maps of R Mon (Alonso-Albi+, 2018)
Revisiting the case of R Monocerotis: Is CO removed at R < 20 au?
Alonso-Albi T., Riviere-Marichalar P., Fuente A., Pacheco-Vazquez S.,
Montesinos B., Bachiller R., Trevino-Morales S.P.
<Astron. Astrophys. 617, A31 (2018)>
=2018A&A...617A..31A 2018A&A...617A..31A (SIMBAD/NED BibCode)
ADC_Keywords: Protostars ; Stars, Be ; Stars, pre-main sequence ; Interferometry
Keywords: circumstellar matter - stars: emission-line, Be - stars: formation
Abstract:
To our knowledge, R Mon is the only B0 star in which a gaseous
Keplerian disk has been detected. However, there is some controversy
about the spectral type of R Mon. Some authors propose that it could
be a later B8e star, where disks are more common. Our goal is to
re-evaluate the R Mon spectral type and characterize its
protoplanetary disk. The spectral type of R Mon has been re-evaluated
using the available continuum data and UVES emission lines. We used a
power-law disk model to fit previous 12CO 1-0 and 2-1
interferometric observations and the PACS CO data to investigate the
disk structure. Interferometric detections of 13CO J=1-0, HCO+
1-0, and CN 1-0 lines using the IRAM Plateau de Bure Interferometer
(PdBI) are presented. The HCN 1-0 line was not detected. Our analysis
confirms that R Mon is a B0 star. The disk model compatible with the
12CO 1-0 and 2-1 interferometric observations falls short of
predicting the observed fluxes of the 14<Ju<31 PACS lines; this is
consistent with the scenario in which some contribution to these lines
is coming from a warm envelope and/or UV-illuminated outflow walls.
More interestingly, the upper limits to the fluxes of the Ju>31 CO
lines suggest the existence of a region empty of CO at R≤20au in the
proto-planetary disk. The intense emission of the HCO+ and CN lines
shows the strong influence of UV photons on gas chemistry. The
observations gathered in this paper are consistent with the presence
of a transition disk with a cavity of Rin≥20 au around R Mon. This
size is similar to the photoevaporation radius that supports the
interpretation that UV photoevaporation is main disk dispersal
mechanism in massive stars
Description:
The integrated intensity maps of the transitions 13CO 1-0, CN 1-0,
and HCO+ 1-0 are presented in Gildas format.
Objects:
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RA (2000) DE Designation(s)
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06 39 09.95 +08 44 09.7 R Mon = NGC 2261
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 82 3 List of fits images
fits/* . 3 Individual fits images
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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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 Kibyte size Size of FITS file
33- 43 A11 --- FileName Name of FITS file, in subdirectory fits
45- 82 A38 --- Title Title of the FITS file
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Acknowledgements:
Tomas Alonso, t.alonso(at)oan.es
(End) Tomas Alonso [OAN, Spain] , Patricia Vannier [CDS] 07-Jun-2018