J/A+A/548/A125 UBVI data of open cluster Trumpler 27 (Perren+, 2012)
Photometric distances to young stars in the inner Galactic disk.
II. The region towards the open cluster Trumpler 27 at l = 355°.
Perren G., Vazquez R.A., Carraro G.
<Astron. Astrophys., 548, A125-125 (2012)>
=2012A&A...548A.125P 2012A&A...548A.125P
ADC_Keywords: Clusters, open ; Photometry, UBVRI ; Stars, distances
Keywords: Galaxy: disk - open clusters and associations: general -
open clusters and associations: individual: Trumpler 27 -
stars: early-type - Galaxy: structure
Abstract:
The spiral structure of the Milky Way inside the solar circle is still
poorly known because of the high density of the material that causes
strong extinction towards the Galactic center.
We present results of the first extensive and deep color-color diagram
(CCD) photometric survey carried out in the field of the open cluster
Trumpler 27, an object immersed in a region of extremely high visual
absorption in the constellation of Sagittarius not far from the Galaxy
center. The survey covers almost a quarter of square degree.
We look for young stars clumps that might plausibly be associated with
spiral structure. Wide-field UBVI photometry combined with infrared
information allows us to reconstruct the distribution in the reddening
and distance of young stars in the field using the CCD and
color-magnitude diagrams (CMD).
Description:
File cat_full.dat contains the full photometric UBVI data used in the
article. Files table2.dat and table3.dat contain the complete Tables 2
and 3 of which only an excerpt is shown in the article. Values of
'-9.9999' in any column in all files are indefinite or missing values.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
cat_full.dat 109 9769 Full photometry for the 9769 stars observed in
the complete field
table2.dat 71 121 Stars inside the 600px circle which indicates the
region assumed to be the core of the cluster
table3.dat 72 477 Stars outside the 600px cluster core
--------------------------------------------------------------------------------
See also:
J/A+A/536/A101 : UBVI photometry towards (l=314,b=0) (Carraro, 2011)
Byte-by-byte Description of file: cat_full.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID [1/9769] Photometric identification of star
6- 13 F8.3 pix xpos x position of star in the frames
15- 23 F9.3 pix ypos y position of star in the frames
25- 35 F11.7 deg RAdeg Right ascension (J2000.0) (1)
37- 44 F8.4 deg DEdeg Declination (J2000.0) (1)
46- 52 F7.4 mag U-B ?=-9.9999 Color index (U-B)
54- 60 F7.4 mag e_U-B ?=-9.9999 Color index (U-B) photometric error
62- 68 F7.4 mag B-V ?=-9.9999 Color index (B-V)
70- 76 F7.4 mag e_B-V ?=-9.9999 Color index (B-V) photometric error
78- 84 F7.4 mag Vmag ?=-9.9999 Visual magnitude (V)
86- 92 F7.4 mag e_Vmag ?=-9.9999 Visual magnitude (V) photometric error
94-101 F8.4 mag V-I ?=-9.9999 Color index (V-I)
103-109 F7.4 mag e_V-I ?=-9.9999 Color index (V-I) photometric error
--------------------------------------------------------------------------------
Note (1): Values for RA and DE were obtained by cross-correlating our stars
to 2MASS objects.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID [1/9769] Photometric identification of star
6- 9 F4.2 mag E(B-V) Assigned value of E(B-V) extinction
11- 15 F5.2 mag (B-V)0 Intrinsic value of (B-V) (1)
17- 21 F5.2 mag (U-B)0 ?=-9.99 Intrinsic value of (B-V) (2)
23- 27 F5.2 mag VMAG Absolute V magnitude
29- 35 F7.4 kpc Dist Distance
37- 43 F7.4 kpc e_Dist ?=-9.9999 Error in distance assignation
45- 51 A7 -- SpT1 Spectral type (photometric) found in this article
53- 55 I3 -- MFJ77 ?=- Identification in Moffat et al.
(1977ApJ...215..106M 1977ApJ...215..106M),
<Cl Trumpler 27 NNN> in Simbad
57- 64 A8 -- SpT2 Spectral type found in Moffat et al.
(1977ApJ...215..106M 1977ApJ...215..106M) (3)
65 A1 --- --- [;]
66- 72 A7 --- SpT3 Spectral type found in Massey et al.
(2001AJ....121.1050M 2001AJ....121.1050M) (3)
--------------------------------------------------------------------------------
Note (1): Value of (B-V) after correction for extinction: (B-V)0=(B-V)-E(B-V)
Note (2): Value of (U-B) after correction for extinction: (U-B)0=(U-B)-E(U-B)
Note (3): Not all stars have both values and most have none.
--------------------------------------------------------------------------------
Acknowledgements:
Gabriel Perren, gabrielperren(at)gmail.com
References:
Carraro, Paper I 2011A&A...536A.101C 2011A&A...536A.101C, Cat. J/A+A/536/A101
(End) Gabriel Perren [AfCA, Argentina], Patricia Vannier [CDS] 25-Feb-2013