J/A+A/623/A22 IC 4996 Vilnius phot. and Gaia DR2 astrometry (Straizys+, 2019)
Young open cluster IC 4996 and its vicinity:
multicolor photometry and Gaia DR2 astrometry.
Straizys V., Boyle R. P., Milasius K., Cernis K., Macijauskas M.,
Munari U., Janusz R., Zdanavicius J., Zdanavicius K., Maskoliunas M.,
Raudeliunas S., Kazlauskas A.
<Astron. Astrophys. 623, A22 (2019)>
=2019A&A...623A..22S 2019A&A...623A..22S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Photometry, Vilnius
Keywords: stars: fundamental parameters -
open clusters and associations: individual: IC 4996
Abstract:
The open cluster IC 4996 in Cygnus and its vicinity are investigated
applying two-dimensional photometric classification of stars measured
in the Vilnius seven-color photometric system. Cluster members are
identified by applying distances based on the Gaia DR2 parallaxes and
the point vector diagram of the Gaia DR2 proper motions. For some
B-type stars, spectroscopic MK types are also obtained from the Asiago
spectra and collected from the literature. New parameters of the
cluster are derived. Th interstellar extinction A(v) covers a wide
range of values, from 1.3 to 2.4mag, the mean value in the central
part of the cluster is 1.8mag. The cluster distance is 1915±110pc,
and its age is within 8-10Myr. The cluster exhibits a long sequence
from early B to G stars, where stars cooler than B8 are in the
pre-main-sequence stage. The plot of the extinction versus distance
shows a steep rise of A(v) up to 1.6mag at 700-800pc, which is
probably related to dust clouds at the edge of the Great Cygnus Rift.
The next extinction rise by an additional 0.8 mag at d≥1.7kpc is
probably related to the associations Cyg OB1 and Cyg OB3. The cluster
IC 4996 does not belong to the Cyg OB1 association, which is located
closer to the Sun, at 1682±116pc. It seems likely that the cluster
and the surrounding O-B stars have a common origin with the nearby
association Cyg OB3 since the Gaia data show that these stellar groups
are located at a similar distance.
Description:
Table 1 contains the results of photoelectric photometry of 76 stars
down to V=12.5mag obtained at the Maidanak Observatory in the Vilnius
seven-color system in a 1x1 deg area centered on the open cluster IC
4996. The identification numbers, equatorial coordinates J2000, V
magnitudes, six color indices in the Vilnius system, and the
photometric spectral types are given. The identification numbers have
the prefix AK, the asterisks at star numbers designate the stars
common with Table2. The coordinates are from PPMXL catalog (Roeser et
al. 2010AJ....139.2440R 2010AJ....139.2440R, Cat.I/317).
Table 2 contains the results of CCD photometry of 1337 stars down to
V=18.8mag in the Vilnius system in 13x13 arcmin area centered on the
cluster IC 4996 observed with the VATT 1.8m telescope. The same data
as in Table 1 are given.
Table 4 contains the list of probable cluster members, identified in
this investigation. The identification numbers, equatorial
coordinates, spectral types, extinction values in the V band and
dereddened V magnitudes are given. The bolometric corrections and
effective temperatures of stars were taken according to their spectral
type from Straizys (1992, Multicolor Stellar Photometry,
http://www.itpa.lt/MulticolorStellarPhotometry), the luminosities (in
the solar units) are calculated in this investigation. The proper
motions are taken from Gaia DR2, the distances from Bailer-Jones et.
al (2018, Cat. I/347). The membership probabilities were determined in
this investigation.
Table 5 contains the list of probable members of Cyg OB1 association.
The star names, equatorial coordinates, V magnitudes, MK spectral
types, proper motions and distances are given.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 85 76 Catalogue of stars observed in the Vilnius
seven-color system at the Maidanak Observatory
table2.dat 86 1337 Catalogue of stars observed in the Vilnius
seven-color system at the Mount Graham observatory
table4.dat 123 72 List of probable members of the cluster IC 4996
table5.dat 85 44 List of members of the association Cyg OB1
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- Seq Sequential number (AK1-AK76)
5 A1 --- n_Seq [*] indicates the star common with table2.dat
7- 8 I2 h RAh Right ascension (J2000.0)
10- 11 I2 min RAm Right ascension (J2000.0)
13- 17 F5.2 s RAs Right ascension (J2000.0)
19 A1 --- DE- Declination sign (J2000.0)
20- 21 I2 deg DEd Declination (J2000.0)
23- 24 I2 arcmin DEm Declination (J2000.0)
26- 29 F4.1 arcsec DEs Declination (J2000.0)
31- 36 F6.3 mag Vmag V magnitude (Vilnius system)
38- 42 F5.3 mag U-V U-V colour index (Vilnius system)
44- 48 F5.3 mag P-V P-V colour index (Vilnius system)
50- 54 F5.3 mag X-V X-V colour index (Vilnius system)
56- 60 F5.3 mag Y-V Y-V colour index (Vilnius system)
62- 66 F5.3 mag Z-V Z-V colour index (Vilnius system)
68- 72 F5.3 mag V-S V-S colour index (Vilnius system)
74- 82 A9 --- SpType Photometric spectral type (1)
84- 85 A2 --- Bin [**] ** for visual binary or multiple star
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Note (1): Photometric spectral classes are given in the lower case letters.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Seq [1/1337] Sequential number
6- 7 I2 h RAh Right ascension (J2000.0)
9- 10 I2 min RAm Right ascension (J2000.0)
12- 16 F5.2 s RAs Right ascension (J2000.0)
18 A1 --- DE- Declination sign (J2000.0)
19- 20 I2 deg DEd Declination (J2000.0)
22- 23 I2 arcmin DEm Declination (J2000.0)
25- 28 F4.1 arcsec DEs Declination (J2000.0)
30- 35 F6.3 mag Vmag V magnitude (Vilnius system)
37- 41 F5.3 mag U-V ? U-V colour index (Vilnius system)
43- 47 F5.3 mag P-V ? P-V colour index (Vilnius system)
49- 53 F5.3 mag X-V X-V colour index (Vilnius system)
55- 59 F5.3 mag Y-V Y-V colour index (Vilnius system)
61- 65 F5.3 mag Z-V Z-V colour index (Vilnius system)
67- 71 F5.3 mag V-S ? V-S colour index (Vilnius system)
73- 83 A11 --- SpType Photometric spectral type (1)
85- 86 A2 --- Bin [**] ** for visual binary or multiple star
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Note (1): Photometric spectral classes are given in the lower case letters.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Name Star number from table2, table1, HD or BD
12 A1 --- Bin [*] * for visual binary or multiple star
14- 15 I2 h RAh Right ascension (J2000.0)
17- 18 I2 min RAm Right ascension (J2000.0)
20- 24 F5.2 s RAs Right ascension (J2000.0)
26 A1 --- DE- Declination sign (J2000.0)
27- 28 I2 deg DEd Declination (J2000.0)
30- 31 I2 arcmin DEm Declination (J2000.0)
33- 36 F4.1 arcsec DEs Declination (J2000.0)
38- 43 F6.3 mag Vmag V magnitude (Vilnius system)
45- 53 A9 --- SpType MK spectral type (1)
55- 58 F4.2 mag Av ? Interstellar extinction in the V band
60- 63 F4.2 mag (Y-V)0 ? Intrinsic (Y-V) color index (Vilnius system)
65- 69 F5.2 mag Vmag0 ? Vmag-Av (Vilnius system)
71- 75 F5.2 mag BC ? Bolometric correction
77- 81 F5.3 [K] logTeff ? Effective temperature of the star (log)
83- 87 F5.3 [Lsun] logL ? Luminosity of the star (log)
89- 94 F6.3 mas/yr pmRA Proper motion in right ascension direction
(pmRA*cosDE) (1)
96-100 F5.3 mas/yr e_pmRA Standard error of proper motion in right
ascension direction (1)
102-107 F6.3 mas/yr pmDE Proper motion in declination direction (1)
109-113 F5.3 mas/yr e_pmDE Standard error of proper motion in declination
direction (1)
115-118 I4 pc Dist Distance of the star (2)
120-123 F4.2 --- Prob ?=- Probability of membership
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Note (1): Proper motions from Gaia DR2 (Cat. I/345)
Note (2): Distances from Bailer-Jones et al. (2018AJ....156...58B 2018AJ....156...58B, Cat. II/347)
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Name Star ID
13- 14 I2 h RAh Right ascension (J2000.0)
16- 17 I2 min RAm Right ascension (J2000.0)
19- 23 F5.2 s RAs Right ascension (J2000.0)
25 A1 --- DE- Declination sign (J2000.0)
26- 27 I2 deg DEd Declination (J2000.0)
29- 30 I2 arcmin DEm Declination (J2000.0)
32- 35 F4.1 arcsec DEs Declination (J2000.0)
37- 41 F5.2 mag Vmag V magnitude (1)
43- 51 A9 --- Sptype MK spectral type (1)
53- 58 F6.3 mas/yr pmRA Proper motion in right ascension direction
(pmRA*cosDE) (2)
60- 64 F5.3 mas/yr e_pmRA Standard error of proper motion in right
ascension direction (2)
66- 72 F7.3 mas/yr pmDE Proper motion in declination direction (2)
74- 78 F5.3 mas/yr e_pmDE Standard error of proper motion in declination
direction (2)
80- 85 F6.1 pc Dist Distance of the star (3)
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Note (1): V magnitudes and MK spectral types from Humphreys & McElroy
(1984ApJ...284..565H 1984ApJ...284..565H).
Note (2): Proper motions from Gaia DR2 (Cat. I/345).
Note (3): Distances from Bailer-Jones et al. (2018AJ....156...58B 2018AJ....156...58B, Cat. I/347).
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Acknowledgements:
Vytautas Straizys, Vytautas.Straizys(at)tfai.vu.lt
(End) V. Straizys [Vilnius Univ., Lithuania], P. Vannier [CDS] 23-Jan-2019