J/ApJ/935/161 13CO line in massive binary W3 IRS 5 (Li+, 2022)
High-resolution M-band Spectroscopy of CO toward the Massive Young Stellar
Binary W3 IRS 5.
Li J., Boogert A., Barr A.G., Tielens A.G.G.M.
<Astrophys. J., 935, 161 (2022)>
=2022ApJ...935..161L 2022ApJ...935..161L
ADC_Keywords: Stars, double and multiple; Star Forming Region;
Spectra, infrared
Keywords: Star formation ; Infrared sources ; Interstellar molecules
Abstract:
We present in this paper the results of high spectral resolution
(R=88100) spectroscopy at 4.7µm with iSHELL/IRTF of hot molecular
gas close to the massive binary protostar W3-IRS-5. The binary was
spatially resolved, and the spectra of the two sources (MIR1 and MIR2)
were obtained simultaneously for the first time. Hundreds of 12CO
ν=0-1, ν=1-2 lines, and ν=0-1 transitions of the isotopes of
12CO were detected in absorption and are blueshifted compared to the
cloud velocity vLSR=-38km/s. We decompose and identify kinematic
components from the velocity profiles and apply rotation diagram and
curve-of-growth analyses to determine their physical properties. The
temperatures and column densities of the identified components range
from 30 to 700K and 1021 to 1022/cm2, respectively. Our
curve-of-growth analyses consider two scenarios. One assumes a
foreground slab with a partial covering factor, which well reproduces
the absorption of most of the components. The other assumes a
circumstellar disk with an outward-decreasing temperature in the
vertical direction and reproduces the absorption of all of the hot
components. We attribute the physical origins of the identified
components to the foreground envelope (<100K), post-J-shock regions
(200-300K), and clumpy structures on the circumstellar disks (∼600K).
We propose that the components with a J-shock origin are akin to water
maser spots in the same region and complement the physical information
of water masers along the direction of their movements.
Description:
We observed W3 IRS 5 with the iSHELL spectrograph at the NASA InfraRed
Telescope Facility (IRTF) 3.2m telescope as part of program 2018B095
on UT 09:00 2018 October 5. The instrument was used in its spectral
mode M1 (see Table 1 in Rayner et al. 2022) with a slit width of
0.375". This provides a resolving power of R=88100±2000 over a
wavelength range of 4.52-5.25um, excluding small gaps between the
echelle orders.
Objects:
--------------------------------------------------
RA (2000) DE Designation(s)
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02 25 40.54 +62 05 51.4 W3 IRS 5 = NAME W3IRS 5
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table9.dat 99 307 13CO Line Parameters
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See also:
J/A+A/490/213 : 1.4 and 3.4mm interferometry of W3 IRS5 (Rodon+, 2008)
J/A+A/627/L6 : ALMA Long Baseline maps of G17.64+0.16 (Maud+, 2019)
J/MNRAS/487/2771 : Gaia-DR2 distance to the W3 Complex (Navarete+, 2019)
J/MNRAS/504/338 : A Galactic survey of radio jets from MYSOs (Purser+, 2021)
J/A+A/655/A84 : AFGL 2591-VLA 3 IRAM/NOEMA datacubes (Suri+, 2021)
Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Target MIR1 (NE) or MIR2 (SW) in W3 IRS5
6- 15 A10 --- Line Species of the line
17- 19 A3 --- Trans Exact transition
21- 26 F6.4 um lambda [4/6] Wavelength
28- 33 F6.1 K El [0/6332] The energy of lower level
35- 37 I3 --- gl [1/134] The quantum number of lower level
39- 42 F4.1 s-1 Aij [10.8/68.2] Einstein A coefficient
44- 48 F5.1 km/s vLSR [-55.4/-37.0] LSR velocity of line center
50- 53 F4.1 km/s e_vLSR [0.1/25.4] Mean error (σ) on vLSR
55- 57 F3.1 km/s deltaV [1.0/7.0] The velocity dispersion
59- 62 F4.1 km/s e_deltaV [0.1/47.9] Mean error (σ) on deltaV
64- 68 F5.3 --- tau0 [0.01/1.59] The optical depth of line center
70- 74 F5.3 --- e_tau0 [0.003/0.3] Mean error (σ) on tau0
76- 80 F5.1 10+14/cm2 Nl [0.6/151] The column density of population
at lower-level
82- 86 F5.1 10+14/cm2 e_Nl [0.1/265] Mean error (σ) on Nl
88- 92 F5.3 km/s EW [0.04/8.34]? The equivalent width of a line
94- 99 F6.3 km/s e_EW [0.02/16]? Mean error (σ) on Wv
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 07-Jun-2024