2007ApJ...654L..87C


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.03CET11:21:53

2007ApJ...654L..87C - Astrophys. J., 654, L87-L90 (2007/January-1)

654 GHz continuum and C18O(6-5) observations of G240.31+0.07 with the submillimeter array.

CHEN H.-R., SU Y.-N., LIU S.-Y., HUNTER T.R., WILNER D.J., ZHANG Q., LIM J., HO P.T.P., OHASHI N. and HIRANO N.

Abstract (from CDS):

We report a dual-band observation at 223 and 654 GHz (460 µm) toward an ultracompact (UC) H II region, G240.31+0.07, using the Submillimeter Array. With a beam size of 1.5"x0.8", the dust continuum emission is resolved into two clumps, with clump A well coincident with an H2O maser and the UC H II region. The newly discovered clump, B, about 1.3" (≃8.3x103 AU) to the southwest of clump A, is also associated with H2O masers and may be a more recent star-forming site. The continuum flux densities imply an opacity spectral index of β=1.5±0.3, suggestive of a value lower than the canonical 2.0 found in the interstellar medium and in cold, massive cores. The presence of hot (≃100 K) molecular gas is derived by the brightness ratio of two H2CO lines in the 223 GHz band. A radial velocity difference of 2.5±0.4 km/s is found between the two clumps in C18O(6-5) emission. The total (nebular and stellar) mass of roughly 58 Min the central region is close to, but not much larger than, the minimum mass required for the two clumps to be gravitationally bound for binary rotation. Our continuum data do not suggest a large amount of matter associated with the H2knots that were previously proposed to arise from a massive disk or envelope.

Abstract Copyright:

Journal keyword(s): Stars: Circumstellar Matter - Stars: Early-Type - stars: individual (G240.31+0.07) - Stars: Pre-Main-Sequence - Submillimeter - Techniques: Interferometric

Nomenclature: Fig.1, text: [CSL2007] Clump A (Nos A-B).

Simbad objects: 7

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Number of rows : 7

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 V* VY CMa s*r 07 22 58.32877 -25 46 03.2355 12.01 10.19 7.95     M5Iae 1023 0
2 QSO B0736+01 QSO 07 39 18.03389693 +01 37 04.6178588   16.90 16.47 16.19   ~ 637 1
3 IRAS 07427-2400 mul 07 44 51.9 -24 07 41           ~ 55 0
4 [CSL2007] Clump B mm 07 44 51.973 -24 07 42.50           ~ 5 0
5 WISE J074451.99-240742.1 mul 07 44 51.997 -24 07 42.11           ~ 64 0
6 [CSL2007] Clump A smm 07 44 52.040 -24 07 42.20           ~ 5 0
7 Caswell OH 240.316+00.071 Mas 07 44 53.2 -24 07 39           ~ 9 0

    Equat.    Gal    SGal    Ecl

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2021.03.03-11:21:53

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