J/A+A/637/A95 16 open clusters UBVI and Gaia DR2 photometry (Perren+, 2020)
Sixteen overlooked open clusters in the fourth Galactic quadrant.
A combined analysis of UBVI photometry and Gaia DR2 with ASteCA.
Perren G.I., Giorgi E.E., Moitinho A., Carraro G., Pera M.S., Vazquez R.A.
<Astron. Astrophys. 637, A95 (2020)>
=2020A&A...637A..95P 2020A&A...637A..95P (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Photometry, UBVRI
Keywords: methods: statistical - open clusters and associations: general -
galaxies: star clusters: general - techniques: photometric -
parallaxes - proper motion
Abstract:
This paper has two main objectives: (1) To determine the intrinsic
properties of sixteen faint and mostly unstudied open clusters in the
poorly known sector of the Galaxy at 270°-300°, to probe the
Milky Way structure in future investigations. (2) To address
previously reported systematics in Gaia DR2 parallaxes by comparing
the cluster distances derived from photometry with those derived from
parallaxes.
Deep UBVI photometry of 16 open clusters was carried out. Observations
were reduced and analyzed in an automatic way using the ASteCA package
to get individual distances, reddening, masses, ages and
metallicities. Photometric distances were compared to those obtained
from a Bayesian analysis of Gaia DR2 parallaxes.
Ten out of the sixteen clusters are true or highly probable open
clusters. Two of them are quite young and follow the trace of the
Carina Arm and the already detected warp. The rest of the clusters are
placed in the interarm zone between the Perseus and Carina Arms as
expected for older objects. We found that the cluster van den
Berg-Hagen 85 is 7.5x109yrs old becoming then one of the oldest open
cluster detected in our Galaxy so far. The relationship of these ten
clusters with the Galaxy structure in the solar neighborhood is
discussed. The comparison of distances from photometry and parallaxes
data, in turn, reveals a variable level of disagreement.
Various zero point corrections for Gaia DR2 parallax data recently
reported were considered for a comparison between photometric and
parallax based distances. The results tend to improve with some of
these corrections. Photometric distance analysis suggest an average
correction of ~+0.026mas (to be added to the parallaxes). The
correction may have a more intricate distance dependency, but
addressing that level of detail will require a larger cluster sample.
Description:
Observed UBVI photometric data tables combined with Gaia's DR2
G magnitude, parallax, and proper motions for the sixteen listed
clusters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 47 16 List of clusters
bh73.dat 199 6282 UBVI photometry and Gaia DR2 for BH 73
bh85.dat 199 1226 UBVI photometry and Gaia DR2 for BH 85
bh87.dat 199 601 UBVI photometry and Gaia DR2 for BH 87
bh91.dat 199 1290 UBVI photometry and Gaia DR2 for BH 91
bh92.dat 199 730 UBVI photometry and Gaia DR2 for BH 92
bh106.dat 199 1221 UBVI photometry and Gaia DR2 for BH 106
loden565.dat 199 1234 UBVI photometry and Gaia DR2 for Loden 565
lynga15.dat 199 5859 UBVI photometry and Gaia DR2 for Lynga 15
ngc4230.dat 199 1310 UBVI photometry and Gaia DR2 for NGC 4230
ngc4349.dat 199 8289 UBVI photometry and Gaia DR2 for NGC 4349
rup85.dat 199 1109 UBVI photometry and Gaia DR2 for Ruprecht 85
rup87.dat 199 1301 UBVI photometry and Gaia DR2 for Ruprecht 87
rup88.dat 199 1900 UBVI photometry and Gaia DR2 for Ruprecht 88
rup162.dat 199 2499 UBVI photometry and Gaia DR2 for Ruprecht 162
trump12.dat 199 2614 UBVI photometry and Gaia DR2 for Trumpler 12
trump13.dat 199 2569 UBVI photometry and Gaia DR2 for Trumpler 13
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Simbad right ascension (J2000)
4- 5 I2 min RAm Simbad right ascension (J2000)
7- 8 I2 s RAs Simbad right ascension (J2000)
10 A1 --- DE- Declination sign (J2000)
11- 12 I2 deg DEd Declination (J2000)
14- 15 I2 arcmin DEm Declination (J2000)
17- 18 I2 arcsec DEs Declination (J2000)
20- 34 A15 --- Name Cluster name
36- 47 A12 --- FileName Name of the table with data
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Byte-by-byte Description of file: [blnrt]*.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- ID ? Star ID
7- 14 F8.3 pix xpos Pixel coordinate x
16- 23 F8.3 pix ypos Pixel coordinate y
25- 30 F6.3 mag Vmag V magnitude
32- 36 F5.3 mag e_Vmag rms uncertainty on V magnitude
38- 43 F6.3 mag B-V ?=99 B-V color index
45- 50 F6.3 mag e_B-V ?=99 rms uncertainty on B-V color index
52- 57 F6.3 mag U-B ?=99 U-B color index
59- 64 F6.3 mag e_U-B ?=99 rms uncertainty on U-B color index
66- 71 F6.3 mag V-I ?=99 V-I color index
73- 78 F6.3 mag e_V-I ?=99 rms uncertainty on V-I color index
80- 94 F15.11 deg RAdeg Gaia DR2 Right ascension (ICRS) at Ep=2015.5
96-110 F15.11 deg DEdeg Gaia DR2 Declination (ICRS) at Ep=2015.5
111-118 F8.4 mas Plx ? Gaia DR2 Parallax
120-125 F6.4 mas e_Plx ? Standard parallax error
127-134 F8.3 mas/yr pmRA ? Gaia DR2 Proper motion in RA, pmRA*cosDE
136-140 F5.3 mas/yr e_pmRA ? rms uncertainty on Proper motion in RA,
pmRA*cosDE
142-148 F7.3 mas/yr pmDE ? Gaia DR2 Proper motion in DE
150-154 F5.3 mas/yr e_pmDE ? rms uncertainty on Proper motion in De
156-162 F7.4 mag Gmag Gaia DR2 G magnitude
164-169 F6.4 mag e_Gmag rms uncertainty on Gmag
171-177 F7.4 mag BPmag ? Gaia DR2 BP magnitude
179-184 F6.4 mag e_BPmag ? rms uncertainty on BPmag
186-192 F7.4 mag RPmag ? Gaia DR2 RP magnitude
194-199 F6.4 mag e_RPmag ? rms uncertainty on RPmag
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Acknowledgements:
Gabriel I. Perren, gabrielperren(at)gmail.com
References:
Perren et al., 2015A&A...576A...6P 2015A&A...576A...6P,
ASteCA: Automated Stellar Cluster Analysis
(End) Gabriel I. Perren [IALP, Argentina], Patricia Vannier [CDS] 01-Apr-2020