J/MNRAS/355/1272 BVIJHKs photometry around CG 12 (Maheswar+, 2004)
Photometric distances to dark clouds: cometary globule CG 12.
Maheswar G., Manoj P., Bhatt H.C.
<Mon. Not. R. Astron. Soc., 355, 1272-1282 (2004)>
=2004MNRAS.355.1272M 2004MNRAS.355.1272M
ADC_Keywords: Molecular clouds ; Photometry, VRI ; Photometry, infrared
Keywords: stars: distances - stars: formation - ISM: clouds - dust, extinction -
ISM: globules - ISM: individual: CG 12
Abstract:
A method for determining distances to dark clouds and Bok globules
based on broad-band optical and near-infrared photometry is presented.
In this method, intrinsic colour indices of stars projected towards
the direction of a cloud are computed by dereddening the observed
colour indices using various trial values of extinction AV and a
standard extinction law. The computed intrinsic colour indices for a
star are then compared with the intrinsic colour indices of normal
main-sequence stars and a spectral type is assigned to the star for
which the computed colour indices best match the standard intrinsic
colour indices. Distances (d) to the stars are determined using the
AV and absolute magnitudes (MV) corresponding to the spectral
types thus obtained. A plot of AV against d undergoes a sharp rise
at a distance corresponding to the distance to the cloud. Using this
method, we have determined a distance of 550pc to the cometary
globule CG 12.
Description:
Images of CG 12 centred at two positions (2000 coordinates), 13h57m35s
-39°54'19'' (Region I) and 13h57m43s -40°00'54'' (Region II)
were carried out on 2003 April 24 and 2004 February 2004,
respectively, at the prime focus of VBT using a Tektronix CCD chip .
Objects:
-----------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------
13 57 42.2 -39 56 21 CG 12
13 57 35 -39 54 19 Region I
13 57 43 -40 00 54 Region II
-----------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 108 62 Photometric results for stars in Region I
table2.dat 108 81 Photometric results for stars in Region II
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Byte-by-byte Description of file: table1.dat table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Star number, in the region (1)
4- 10 F7.3 deg RAdeg Right ascension in decimal degrees (J2000)
12- 18 F7.3 deg DEdeg Declination in decimal degrees (J2000)
20- 24 F5.2 mag Vmag V magnitude
26- 29 F4.2 mag e_Vmag rms uncertainty on Vmag
31- 35 F5.2 mag Rmag R magnitude
37- 40 F4.2 mag e_Rmag rms uncertainty on Rmag
42- 46 F5.2 mag Imag I magnitude
48- 51 F4.2 mag e_Imag rms uncertainty on Imag
53- 57 F5.2 mag Jmag 2MASS J magnitude
59- 62 F4.2 mag e_Jmag rms uncertainty on Jmag
64- 69 F6.3 mag Hmag 2MASS H magnitude
71- 74 F4.2 mag e_Hmag rms uncertainty on Hmag
76- 80 F5.2 mag Ksmag 2MASS Ks magnitude
82- 85 F4.2 mag e_Ksmag rms uncertainty on Ksmag
87- 89 F3.1 mag AV Absorption in V band
91- 96 F6.4 --- Chi2 Chi2 value related to AV and VMAG estimations
98- 99 A2 --- SpType Spectral type
101-103 F3.1 mag VMAG Estimated absolute V magnitude
105-108 I4 pc Dist Estimated distance
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Note (1): [MMB2004b] I-NN (table1.dat) and [MMB2004b] II-NN (table2.dat)
in Simbad
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 21-Jun-2005