J/MNRAS/504/101 Detection of 228 variable stars in NGC 281 (Lata+, 2021)
Photometric observations of NGC 281: detection of 228 variable stars.
Lata S., Pandey A.K., Pandey J.C., Panwar N., Paul P.
<Mon. Not. R. Astron. Soc., 504, 101-117 (2021)>
=2021MNRAS.504..101L 2021MNRAS.504..101L (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; YSOs ; Stars, variable ;
Stars, pre-main sequence ; Photometry, VRI ; Proper motions
Keywords: open clusters and associations: individual: NGC 281 -
Hertzsprung-Russell and colour-magnitude diagram -
stars: pre-main-sequence - stars: variables: T Tauri, Herbig Ae/B
Abstract:
We identify 228 periodic variables in the region of young open cluster
NGC 281 using time series photometry carried out from 1 m class ARIES
telescopes, Nainital. The cluster membership of these identified
variables is determined on the basis of colour-magnitude, two colour
diagrams, and kinematic data. A total of 81 variable stars are found
to be members of the cluster NGC 281. Of 81 variables, 30 and 51 are
probable main-sequence and pre-main-sequence members, respectively.
This study classifies main-sequence variable stars into different
variability types according to their periods of variability, shape of
light curves, and location in the Hertzsprung-Russell diagram. These
identified main-sequence variables could be β Cep, δ Scuti,
slowly pulsating B type, and new class variables. Among 51
pre-main-sequence variables, majority of them are weak line T Tauri
stars. The remaining 147 variables could belong to the field
population. The variability characteristics of the field population
indicate that these variables could be RR Lyrae, δ Scuti, and
binaries-type variables.
Description:
NGC 281 contains significant number of PMS stars with circumstellar
disc and are unique laboratories to study the evolution of discs of
PMS stars.Time series V- and I-band observations of young open cluster
(YOC) NGC 281 were obtained using a 2048 times 2048 pixel CCD camera that
is mounted at the f/13 Cassegrain focus of the 1.04-m ARIES Telescope,
Nainital, India. We present time series data of stars in the region of
the cluster NGC 281. The observations of the field containing NGC 281
were initiated in October 2010 and continued till 2017 November. A
total of 1046 and 10 observations of the cluster region were secured
in V and I bands on 13 and 3 nights, respectively.
With strong probabilities, all 228 variables are validated
thanks to visual inspection of their light curves (See Fig. 5 for
δm time variation). The photometric variability of these stars
has also been checked using the Chi square test (Sesar et al.
2007AJ....134.2236S 2007AJ....134.2236S).
The identification number, coordinates, and optical data for these
variable stars are given in table2.dat. In particular, the V and I
band magnitude, amplitude, and period of variables in the open cluster
NGC 281 are denoted. Also included,the proper motion data were taken
from Gaia DR2 (Cat . I/345). The characterization of the identified
variables needs information whether these are the members of the
cluster or not. The UBVI (UBV data taken Sharma et al.
2012PASJ...64..107S 2012PASJ...64..107S, Cat. J/PASJ/64/107 and present VI data) and JHK
photometric observations of the cluster NGC 281 (Cutri et al.
2003yCat.2246....0C 2003yCat.2246....0C, Cat. II/246) have been used to establish the
membership of the identified variables. In addition, the membership of
a star is also verified with the help of proper motion data taken from
Gaia DR2. We use CD,TCD and HR diagrams (See section 3 and 4) to
determine membership probabilities and variables classifications
(three groups main sequence, pre-main sequence and field variable).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 124 228 Observational and physical properties
of identified variable stars in the
open cluster NGC 281
--------------------------------------------------------------------------------
See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/PASJ/64/107 : Multiwavelength study of NGC 281 complex (Sharma+, 2012)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- ID Variable star ID name (ID)
7- 15 F9.6 deg RAdeg Right ascension of the variable star (J2000)
(RA2000)
17- 25 F9.6 deg DEdeg Declination of the variable star (J2000)
(Dec2000)
27- 32 F6.3 mag Vmag Magnitude apparent in V filter (V)
34- 38 F5.3 mag e_Vmag Mean error on Vmag (Verror)
40- 45 F6.3 mag Imag ? Magnitude apparent in I filter (I)
47- 52 F6.3 mag e_Imag ? Mean error on Imag (Ierror)
54- 60 F7.3 mas/yr pmRA ? Proper motion in Right Ascension
taken from Gaia DR2 (Cat. I/345) (muRA)
62- 67 F6.3 mas/yr pmDE ? Proper motion in Declination
taken from Gaia DR2 (Cat. I/345) (muDec)
69- 72 F4.2 --- Prob ? The membership probabilities of variable
stars calculated using proper motion data
(Prob)
74- 78 F5.3 mag Amp Magnitude amplitude (Amplitude)
80- 86 F7.4 d Per1 First variation time of magnitude amplitude
(Period1)
88- 93 F6.4 d Per2 ? Second variation time of magnitude amplitude
(Period2)
95-100 F6.4 d Per3 ? Third variation time of magnitude amplitude
(Period3)
102-106 F5.3 d Per4 ? Fourth variation time of magnitude amplitud
(Period4)
108-112 F5.3 d Per5 ? Fifth variation time of magnitude amplitude
(Period5)
114-118 F5.3 d Per6 ? Sixth variation time of magnitude amplitude
(Period6)
120-124 A5 --- Class [MS PMS Field ] Classification name of the
variable star (Class)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Luc Trabelsi [CDS] 18-Apr-2024