J/MNRAS/443/454 UBVIHα photometry in NGC 1893 (Lim+, 2014)
Sejong Open Cluster Survey (SOS).
III. The young open cluster NGC 1893 in the HII region W8.
Lim B., Sung H., Kim J.S., Bessell M.S., Park B.-G.
<Mon. Not. R. Astron. Soc., 443, 454-473 (2014)>
=2014MNRAS.443..454L 2014MNRAS.443..454L
ADC_Keywords: Clusters, open ; Photometry, UBVRI ; Photometry, H-alpha
Keywords: accretion, accretion discs - circumstellar matter -
stars: luminosity function, mass function -
open clusters and associations: individual: NGC 1893
Abstract:
We present a UBVI and Hα photometric study of the young open
cluster NGC 1893 in the HII region W8 (IC 410 or Sh 2-236). A total of
65 early-type members are selected from photometric diagrams. A mean
reddening of the stars is <E(B-V)≥0.563±0.083mag. The published
photometric data in the near- and mid-infrared passbands are used to
test the reddening law towards the cluster, and we confirm that the
reddening law is normal (RV=3.1). Zero-age main-sequence fitting
gives a distance modulus of V0-MV= 12.7±0.2mag, equivalent to
3.5±0.3kpc. From Hα photometry, 125 Hα emission stars
and candidates are identified as pre-main-sequence (PMS). The lists of
young stellar objects and X-ray sources published by previous studies
allow us to select a large number of PMS members down to 1M☉.
Isochrone fitting in the Hertzsprung-Russell diagram gives a turn-off
age of 1.5Myr and the median age of 1.9Myr from the PMS members with a
spread of ∼5Myr. We derive the initial mass function (IMF) for stars
with mass larger than 1M☉. The slope of the IMF
(Γ=-1.3±0.1) is well consistent with the Salpeter/Kroupa IMF.
A total mass of the cluster appears to be in excess of 1300M☉.
Finally, we estimate the mass accretion rate of 82 PMS members in the
mass range of 0.6-5M☉.
Description:
The observation of NGC 1893 was made on 2009 January 19 using the
AZT-22 1.5m telescope (f/7.74) at Maidanak Astronomical Observatory
in Uzbekistan. All imaging data were acquired using the Fairchild 486
CCD (SNUCam) with the standard Bessell UBVI and Hα filters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 152 6503 Photometric data
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See also:
J/MNRAS/438/1451 : UBVIHa photometry of IC 1848 (Lim+, 2014)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID [-18/6485] Sequential number (1)
6- 7 I2 h RAh Right ascension (J2000)
9- 10 I2 min RAm Right ascension (J2000)
12- 16 F5.2 s RAs Right ascension (J2000)
18 A1 --- DE- Declination sign (J2000)
19- 20 I2 deg DEd Declination (J2000)
22- 23 I2 arcmin DEm Declination (J2000)
25- 28 F4.1 arcsec DEs Declination (J2000)
30- 35 F6.3 mag Vmag [9/23.2]? Bessel V magnitude
37- 42 F6.3 mag Imag [10.3/21.3]? Bessel I magnitude
44- 48 F5.3 mag V-I ? V-I colour index
50- 55 F6.3 mag B-V ? B-V colour index
57- 62 F6.3 mag U-B ? U-B colour index
64- 69 F6.3 mag H-C ? Hα index (C=(V+I)/2)
71- 76 F6.3 mag e_Vmag ? rms uncertainty on Vmag
78- 82 F5.3 mag e_Imag ? rms uncertainty on Imag
84- 88 F5.3 mag e_V-I ? rms uncertainty on V-I
90- 94 F5.3 mag e_B-V ? rms uncertainty on B-V
96-100 F5.3 mag e_U-B ? rms uncertainty on U-B
102-106 F5.3 mag e_H-C ? rms uncertainty on H-C
108 I1 --- o_Vmag [0/2] Number of observations for Vmag
110 I1 --- o_Imag [0/2] Number of observations for Imag
112 I1 --- o_V-I [0/2] Number of observations for V-I
114 I1 --- o_B-V [0/2] Number of observations for B-V
116 I1 --- o_U-B [0/2] Number of observations for U-B
118 I1 --- o_H-C [0/2] Number of observations for H-C
120-135 A16 --- 2MASS 2MASS name (HHMMSSss+DDMMSSs)
137 A1 --- em [Hh] Hα emission flag (2)
139-152 A14 --- SpType Spectral type for stars -1 to -18 (3)
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Note (1): The negative numbered ID represents the data from
Johnson & Morgan (1955ApJ...122..142J 1955ApJ...122..142J); Hiltner (1956ApJS....2..389H 1956ApJS....2..389H);
Hoag et al. (1961PUSNO..17..343H 1961PUSNO..17..343H); Cuffey (1973AJ.....78..408C 1973AJ.....78..408C);
Massey et al. (1995ApJ...454..151M 1995ApJ...454..151M, Cat. J/ApJ/454/151);
Hog et al. (2000A&A...355L..27H 2000A&A...355L..27H, Cat. I/259)
Note (2): Halpha flag as follows:
H = Hα emission stars
h = Hα emission star candidates
Note (3): Spectral type for stars -1 to -12, from
Hoag & Applequist (1965ApJS...12..215H 1965ApJS...12..215H);
Massey et al. (1995ApJ...454..151M 1995ApJ...454..151M, Cat. J/ApJ/454/151);
Negueruela et al. (2007A&A...471..485N 2007A&A...471..485N);
Sota et al. (2011ApJS..193...24S 2011ApJS..193...24S, Cat. III/274)
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History:
From electronic version of the journal
References:
Sung et al., 2013JKAS...46..103S 2013JKAS...46..103S
Lim et al., Paper II 2014MNRAS.438.1451L 2014MNRAS.438.1451L, Cat. J/MNRAS/438/1451
(End) Patricia Vannier [CDS] 10-Mar-2015