J/A+A/592/A149 UBVI CCD photometry of Carina region stars (Molina-Lera+, 2016)
Stellar populations in the Carina region. The Galactic plane at l = 291°.
Molina-Lera J.A., Baume G., Gamen R., Costa E., Carraro G.
<Astron. Astrophys. 592, A149 (2016)>
=2016A&A...592A.149M 2016A&A...592A.149M (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, photometry ; Photometry, CCD
Keywords: general: open clusters and associations - galaxy: structure -
stars: early-type - stars: pre-main sequence
Abstract:
Previous studies of the Carina region have revealed its complexity and
richness as well as a significant number of early-type stars. However,
in many cases, these studies only concentrated on the central region
(Trumpler 14/16) or were not homogeneous. This latter aspect, in
particular is crucial because very different ages and distances for
key clusters have been claimed in recent years.
The aim of this work is to study in detail an area of the Galactic
plane in Carina, east ward Carina. We analyze the properties of
different stellar populations and focus on a sample of open clusters
and their population of young stellar objects and highly reddened
early stars. We also studied the stellar mass distribution in these
clusters and the possible scenario of their formation. Finally, we
outline the Galactic spiral structure in this direction.
We obtained deep and homogeneous photometric data (UBVIKC) for six
young open clusters: NGC 3752, Trumpler 18, NGC 3590, Hogg 10, 11, and
12, located in Carina at l∼291, and their adjacent stellar fields,
which we complemented with spectroscopic observations of a few
selected targets. We also culled additional information from the
literature, which includes stellar spectral classifications and
near-infrared photometry from 2MASS. We finally developed a numerical
code that allowed us to perform a homogeneous and systematic analysis
of the data. Our results provide more reliable estimates of distances,
color excesses, masses, and ages of the stellar populations in this
direction.
We estimate the basic parameters of the studied clusters and find that
they identify two overdensities of young stellar populations located
at about 1.8kpc and 2.8kpc, with E(B-V)∼0.1-0.6. We find evidence of
pre-main-sequence populations inside them, with an apparent coeval
stellar formation in the most conspicuous clusters. We also discuss
apparent age and distance gradients in the direction NW-SE. We study
the mass distributions of the covered clusters and several others in
the region (which we took form the literature). They consistently show
a canonical IMF slope (the Salpeter one). We discover and characterise
an abnormally reddened massive stellar population, scattered between
6.6 and 11kpc. Spectroscopic observations of ten stars of this latter
population show that all selected targets were massive OB stars. Their
location is consistent with the position of the Carina-Sagittarius
spiral arm.
Description:
Photometric parameters for 62730 stars in the carina region covering 6
stellar clusters (NGC 3752, Trumpler 18, NGC 3590, Hogg 10, 11 and 12)
and the surrounding field. The photometry was secured in March 2006
and March 2009 with the Y4KCAM camera attached to the Cerro Tololo
Inter American Observatory (CTIO, Chile) 1.0-m telescope.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 198 62730 Photometric measurements for 62730 stars in the
Carina region
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See also:
J/A+A/572/A116 : The VISTA Carina Nebula Survey (Preibisch+, 2014)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq Sequential number
7- 22 A16 --- 2MASS 2MASS identification (HHMMSSss+DDMMSSs)
24- 33 F10.6 deg RAdeg Right ascension (J2000.0)
35- 44 F10.6 deg DEdeg Declination (J2000.0)
46- 56 F11.6 pix Xpos X coordinate
58- 69 F12.6 pix Ypos Y coordinate
71- 76 F6.3 mag Umag ?=- Johnson U magnitude
78- 83 F6.4 mag e_Umag ?=- rms uncertainty on Umag
85- 90 F6.3 mag Bmag ?=- Johnson B magnitude
92- 97 F6.4 mag e_Bmag ?=- rms uncertainty on Bmag
99-104 F6.3 mag Vmag Johnson V magnitude
106-111 F6.4 mag e_Vmag rms uncertainty on Vmag
113-118 F6.3 mag Imag ?=- Cousins I magnitude
120-125 F6.4 mag e_Imag ?=- rms uncertainty on Imag
127-132 F6.3 mag Jmag ?=- 2MASS J magnitude
134-139 F6.4 mag e_Jmag ?=- rms uncertainty on Jmag
141-146 F6.3 mag Hmag ?=- 2MASS H magnitude
148-153 F6.4 mag e_Hmag ?=- rms uncertainty on Hmag
155-160 F6.3 mag Kmag ?=- 2MASS K magnitude
162-167 F6.4 mag e_Kmag ?=- rms uncertainty on Kmag
169-174 F6.4 --- chi ?=- chi2 value
176-182 F7.4 --- Sharp ?=- Sharp parameter
184-198 A15 --- SpType Spectral type classification
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Acknowledgements:
Jose Alejo Molina Lera, jalejoml(at)fcaglp.unlp.edu.ar
(End) J. Alejo Molina Lera [La Plata, Argentina], P. Vannier [CDS] 26-Aug-2016