J/MNRAS/482/658 NGC 1893 young open cluster rich in variable stars (Xue+, 2019)
NGC 1893: a young open cluster rich in multitype variable stars.
Xue H.-F., Fu J.-N., Mowlavi N., Saesen S., Barblan F., Yang Y., Niu J.-S.
<Mon. Not. R. Astron. Soc., 482, 658-697 (2019)>
=2019MNRAS.482..658X 2019MNRAS.482..658X (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Stars, variable ; Clusters, open ; Optical
Keywords: binaries: eclipsing - stars: oscillations -
stars: variables: general -
open clusters and associations: individual: NGC 1893
Abstract:
In this work, we have studied the variable stars in the young open
cluster NGC 1893 based on a multiyear photometric survey covering a
sky area around the cluster up to 31arcminx31arcmin wide. More than
23000 images in the V band taken from 2008 January to 2017 February
with different telescopes, complemented with 90 images in the B band
in 2014 and 2017, were reduced, and light curves were derived in V for
5653 stars. By analysing these light curves, we detected 147 variable
stars (85 of them being new discoveries), including 110 periodic
variables, 15 eclipsing binaries, and 22 non-periodic variables.
Proper motions, radial velocities, and colour-magnitude and two-colour
diagrams were used to identify the cluster membership of these
variable stars, resulting in 84 members. Periodic variable members
were then classified into different variability types, mainly
according to their magnitudes and to their periods of variability, as
well as to their positions in the Hertzsprung-Russell diagram for the
early-type stars. As a result, among main-sequence periodic variable
members, we identified five β Cep candidates, seven slowly
pulsating B-type candidates, and thirteen fast-rotating pulsating
B-type (FaRPB) candidates (one of which is a confirmed classical Be
star). While most of the FaRPB stars display properties similar to the
ones discovered in NGC 3766 by Mowlavi et al., five of them have
periods below 0.1d, contrary to expectations. Additional observations,
including spectroscopic, are called for to further characterize these
stars. We also find a binary candidate harbouring a δ-Scuti
candidate.
Description:
Time-series photometry of NGC 1893 was taken using V filter with three
telescopes from 2008 January 5 to 2017 February 23, for a total of 72
nights and 23537 frames. The observations from 2008 January 5 to 2008
April 5 were done with the 1.2m Flemish Mercator telescope located at
La Palma, Canary Islands, Spain. All subsequent observations were
carried out at the 50 or 85cm telescope located at the Xinglong
station, National Astronomical Observatories of China. Most of our
observations were collected using the 85cm telescope. It must be noted
that three different CCD cameras were used on the 85cm telescope
between 2008 and 2017. The exposure times were adjusted according to
weather condition and height of the target on the sky. In the 2014 and
2017 campaigns, we alternated short and long exposures to focus on
bright stars and faint stars, respectively, and we alternately took a
small number of images in B and V bands for the colour index analysis
of the stars in the cluster.
The instrumental magnitudes are transformed to the standard magnitudes
using the catalogue provided by Lim et al. (2014MNRAS.443..454L 2014MNRAS.443..454L, Cat.
J/MNRAS/443/454). We match our stars with the secondary standard stars
from the catalogue. Then, the transformed relations are derived by
linear fitting.
Table A1 shows the photometric and kinematic data of variable stars in
the field of view of NGC 1893.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 152 147 The photometric and kinematic data of variable
stars in the FOV of NGC 1893
tableb1.dat 78 178 *Periodic variable stars in the FOV of NGC 1893
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Note on tableb1.dat: For each star, only independent frequencies are listed.
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID Star ID
6- 9 I4 --- ID1 ? WEBDA number (http://www.univie.ac.at/webda/)
11- 14 A4 --- ID2 Identification number of variable stars given
by Lata et al. (2012MNRAS.427.1449L 2012MNRAS.427.1449L,
2014MNRAS.442..273L 2014MNRAS.442..273L, Cat. J/MNRAS/442/273)
[LPC2012] VNN in Simbad
16- 23 F8.5 deg RAdeg Right ascension (J2000)
25- 32 F8.5 deg DEdeg Declination (J2000)
34- 39 F6.3 mag Bmag Standardized B magnitude
41- 45 F5.3 mag e_Bmag Error on Bmag
47- 52 F6.3 mag Vmag Standardized V magnitude
54- 58 F5.3 mag e_Vmag Error on Vmag
60- 65 F6.1 mas/yr pmRA ? Proper motion on right ascension from the
PPMXL catalogue (Roeser et al.
2010AJ....139.2440R 2010AJ....139.2440R, Cat. I/317)
67- 70 F4.1 mas/yr e_pmRA ? Error on pmRA
72- 76 F5.1 mas/yr pmDE ? Proper motion on declination from the PPMXL
catalogue (Roeser et al. 2010AJ....139.2440R 2010AJ....139.2440R,
Cat. I/317)
78- 81 F4.1 mas/yr e_pmDE ? Error on pmDE
83- 85 I3 km/s RV ? Radial velocity from Xiang et al.
(2017MNRAS.467.1890X 2017MNRAS.467.1890X)
87- 88 I2 km/s e_RV ? Error on RV
90- 95 F6.3 mag U-B ? U-B colour index from Lim et al.
(2014MNRAS.443..454L 2014MNRAS.443..454L, Cat. J/MNRAS/443/454)
97-101 F5.3 mag e_U-B ? Error on U-B
103-107 F5.3 mag B-V ? B-V colour index from Lim et al.
(2014MNRAS.443..454L 2014MNRAS.443..454L, Cat. J/MNRAS/443/454)
109-113 F5.3 mag e_B-V ? Error on B-V
115-120 F6.3 mag Jmag ? 2MASS J magnitude (Cutri et al.
2003tmc..book.....C 2003tmc..book.....C, Cat. II/246)
122-126 F5.3 mag e_Jmag ? Error on Jmag
128-133 F6.3 mag Hmag ? 2MASS H magnitude (Cutri et al.
2003tmc..book.....C 2003tmc..book.....C, Cat. II/246)
135-139 F5.3 mag e_Hmag ? Error on Hmag
141-146 F6.3 mag Kmag ? 2MASS K magnitude (Cutri et al.
2003tmc..book.....C 2003tmc..book.....C, Cat. II/246)
148-152 F5.3 mag e_Kmag ? Error on Kmag
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID Star ID
6- 16 F11.8 d Per Period
18- 28 F11.8 d e_Per Period error
31- 36 F6.2 mmag Amp Amplitude of variation
38- 42 F5.2 mmag e_Amp Amplitude of variation error
44- 47 F4.1 --- S/N Signal-to-noise ratio
49- 51 A3 ---- Memb Membership
53- 60 A8 --- SpType Spectral type
61 A1 --- n_SpType [ab] Note on SpType (1)
63- 74 A12 --- Class Classification
76- 78 A3 --- Disc Discovery (2)
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Note (1): Note on SpType as follows:
a = Spectral type from Marco et al. (2001AJ....121.2075M 2001AJ....121.2075M)
b = Spectral type from Marco & Negueruela (2002A&A...393..195M 2002A&A...393..195M)
Note (2): Discovery code as follows:
Z08 = indicates that the variable star was detected in Zhang, Fu &
Jiang (2008JPhCS.118a2078Z 2008JPhCS.118a2078Z)
L12 = Lata et al. (2012MNRAS.427.1449L 2012MNRAS.427.1449L)
L14 = Lata et al. (2014MNRAS.442..273L 2014MNRAS.442..273L, Cat. J/MNRAS/442/273)
pp = indicates that the variable star is detected in this paper
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History:
01-Aug-2022: From electronic version of the journal
14-Dec-2022: table B1 added
(End) Ana Fiallos [CDS] 23-Jun-2022