J/AJ/117/446 AFGL 5157 near-IR imaging (Chen+, 1999)
Near-infrared imaging of the star-forming region AFGL 5157.
Chen Y., Yao Y., Yang J., Hirao T., Ishii M., Nagata T., Sato S.
<Astron. J. 117, 446 (1999)>
=1999AJ....117..446C 1999AJ....117..446C
ADC_Keywords: Nebulae ; Photometry, infrared ; Stars, pre-main sequence
Keywords: infrared radiation - ISM: individual (AFGL 5157) -
ISM: jets and outflows - reflection nebulae - stars: formation
Abstract:
We present near-infrared images of the star-forming region AFGL 5157
in the JHK broadband filters and H2v=1-0S(1) narrowband filter. The
images reveal a dense cluster of stars and infrared nebulosities
associated with previously known infrared sources. Of 54 near-infrared
sources detected in the nebula, NGC 1985, 12 exhibit infrared excesses
typical of T Tauri stars, Herbig Ae/Be stars, and protostars. The
magnitude and color distribution of the cluster of stars in the nebula
are found to be different from those outside the nebular region. The
K'-magnitude distribution of the cluster is quite flat, while the
noncluster is peaked toward the low magnitude. The [H-K'] color of the
cluster also displays 0.3 mag redder than that of the noncluster. The
infrared nebula displays a bright nucleus with two spirals extended to
the north and south. In light of the color properties of the nebula,
we propose a shell model for the nebular structure that could be
formed by star-forming activity of the central cluster.
Objects:
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RA (2000) DE Designation(s)
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05 37 47.8 +31 59 24 AFGL 5157
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 39 170 Near-infrared photometry of AFGL 5157
table2.dat 35 13 Positions and flux measurements of H2 emission
in AFGL 5157
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- NIRS [1/170] Identification number
([CYY99] NIRS NNN in Simbad)
4 A1 --- n_NIRS [b] saturation (1)
6- 10 F5.1 arcsec oRA Offset in right ascension (G1)
12- 17 F6.1 arcsec oDE Offset in declination (G1)
19- 23 F5.2 mag K'mag K' magnitude
25- 29 F5.2 mag [H-K'] Colour index [H-K']
31- 35 F5.2 mag [J-H] ? Colour index [J-H]
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Note (1): b: Abnormal bluer colors due to saturation
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- H2 [1/22]? H2 knot designation
([CYY99] H2 NN in Simbad)
3 A1 --- n_H2 [D] D: Diffuse (no H2 number)
5- 9 F5.1 arcsec oRA Offset in right ascension (G1)
11- 15 F5.1 arcsec oDE Offset in declination (G1)
17- 22 F6.2 10-20W/cm2/um Flux H2 knots (2.12µm) flux
24- 25 I2 arcsec Aper Aperture employed for H2 measurements
27- 29 F3.1 arcsec FWHM ? H2 knots FWHM size
31- 33 A3 --- Morph Morphology (2)
35 I1 --- Ref [1/2] References (3)
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Note (2): Abbreviations used:
BS = Bow-shaped
E = Elongated
K = Knot
S = Shell
Note (3):
1 = Torrelles et al., 1992ApJ...384..528T 1992ApJ...384..528T
2 = This work
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Gloval Notes:
Note (G1): Coordinates offset from the bright references star 1 (NIRS 104),
located at RA=05 34 32.6, DE=+31 57 38 (B1950.0)
History: From AJ electronic version
(End) James Marcout, Patricia Bauer [CDS] 12-Mar-1999