J/MNRAS/400/603 New variables in ONC (Parihar+, 2009)
Exploring pre-main-sequence variables of the ONC: the new variables.
Parihar P., Messina S., Distefano E., Shantikumar N.S., Medhi B.J.
<Mon. Not. R. Astron. Soc., 400, 603-621 (2009)>
=2009MNRAS.400..603P 2009MNRAS.400..603P
ADC_Keywords: Clusters, open ; Stars, variable ; Photometry, VRI ;
Photometry, infrared
Keywords: stars: activity - stars: late-type stars - stars: pre-main-sequence -
stars: rotation - stars: variables -
open clusters and associations: individual: Orion Nebula Cluster
Abstract:
Since 2004, we have been engaged in a long-term observing programme
to monitor young stellar objects (YSOs) in the Orion Nebula Cluster
(ONC). We have collected about 2000 frames in V, R and I broad-band
filters on more than 200 nights distributed over five consecutive
observing seasons. The high-quality and time-extended photometric
data give us an opportunity to address various phenomena associated
with young stars.
Description:
The photometric observations of the ONC reported here, were obtained
between 2004 January 18 and 2008 April 15, using the 2m Himalayan
Chandra Telescope (HCT) and the 2.3m Vainu Bappu Telescope (VBT).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 105 346 The photometric data along with other relevant
information of all 346 stars in our FoV
table4.dat 40 47 The list of stars showing Hα line in emission
table5.dat 89 148 Result of the periodogram analysis of periodic
variables of the ONC
--------------------------------------------------------------------------------
See also:
J/AJ/117/2941 : Rotation periods of Orion PMS stars (Stassun+, 1999)
J/A+A/396/513 : Stellar Rotation in the Orion Nebula Cluster (Herbst+, 2002)
J/ApJ/660/704 : Optical and X-ray variability of ONC PMS (Stassun+, 2007)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Sequential number, <[PMD2009] NNN> in Simbad
5- 6 I2 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 16 F6.3 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- 29 F5.2 arcsec DEs Declination (J2000)
31- 34 I4 --- JW ? Hillenbrand (1997AJ....113.1733H 1997AJ....113.1733H) number,
[H97b] NNNN in Simbad
36- 40 F5.3 d Per1 ?=- Period from Herbst, J/A+A/396/513
42- 47 F6.3 d Per2 ?=- Period from Stassun, J/AJ/117/2941
49- 51 A3 --- Sky Sky conditions flag (G1)
53 A1 --- nb [y] Presence of another star closer than 6"
55 A1 --- TTS [CW] T Tauri type: Classical or Weak
57- 61 F5.2 mag Imag Landolt I magnitude
63- 67 F5.2 mag R-I ?=- Landolt R-I colour index
69- 73 F5.2 mag V-I ?=- Landolt V-I colour index
75- 81 A7 --- SpT MK spectral type
83- 87 F5.2 mag Jmag ?=- J magnitude
89- 93 F5.2 mag J-H ?=- J-H colour index
95- 99 F5.2 mag H-K ?=- H-K colour index
101-105 F5.2 [10-7W] logLX ?=- X-ray luminosity
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Note [N] N for stars not in the survey (1)
3- 5 I3 --- Seq Sequential number, <[PMD2009] NNN> in Simbad
7- 10 I4 --- JW Hillenbrand (1997AJ....113.1733H 1997AJ....113.1733H) number,
[H97b] NNNN in Simbad
12- 18 F7.2 0.1nm EW Hα Equivalent width
20- 24 F5.2 d Per ?=- Period
26- 28 A3 --- Sky Sky conditions flag (G1)
30- 34 F5.2 mag Imag I magnitude
36- 40 A5 --- SpT MK spectral type
--------------------------------------------------------------------------------
Note (1): Stars previously found to be a strong Hα emitter but not in
our survey.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Seq Sequential number, <[PMD2009] NNN> in Simbad
4 A1 --- n_Seq [ab] Need confirmation (1)
6- 9 I4 --- JW ? Hillenbrand (1997AJ....113.1733H 1997AJ....113.1733H) number,
[H97b] NNNN in Simbad
11- 16 F6.2 --- Power Normalized power of the highest peak in the
Scargle power spectrum
18- 23 F6.3 d Per Rotation period
25- 29 F5.3 d e_Per rms uncertainty on Per
31- 37 F7.2 --- chi2 Reduced χ2 of the light curve computed
with respect to the median seasonal magnitude
39- 43 F5.3 mag Average precision of the time-series data
45- 48 F4.2 mag Iamp Amplitude of the light curve in the I band
50- 52 I3 --- Nobs Number of total useful observation
54- 56 I3 --- Nmean Number of the data points after averaging the
close observations
58- 59 I2 --- Ndis [1/10] "dis" number (unexplained)
61- 62 A2 --- n1 Season to which the listed period and all the
values in the previous columns refer (c1-c5)
64- 74 A11 --- n2 Cycles where the same periodicity,
approximately within the computed uncertainty,
was found (2)
76- 79 A4 --- n3 New or previously known code (3)
83- 85 A3 --- Sky Sky conditions flag (G1)
87 A1 --- TTS [CW] T Tauri type: Classical or Weak
89 A1 --- nb [y] Presence of another star closer than 6"
--------------------------------------------------------------------------------
Note (1): Notes as follows:
a = The rotation period was detected in only one season and, although
with a false alarm probability, FAP<1%, it needs to be confirmed
by future observations
b = The rotation period, although detected in multiple seasons and
with a false alarm probability, FAP<1%, may be a beat period,
being very close to the window function main peak
Note (2): Codes as follows:
c1-c5 = cycle number
H = Herbs et al., 2002, Cat. J/A+A/396/513 (H02) and
2000AJ....119..261H 2000AJ....119..261H (H00) data,
S = Stassun et al., 1999, Cat. J/AJ/117/2941 (S99) data,
all = for all cycles including H02, H00 and S99 data
Note (3): Indicates whether the star is a 'new' (new) periodic or a
previously known periodic variable whose period is in agreement
(=H, =S, =HS) or disagreement (!=H, !=S, !=HS) with the one
determined by Stassun (S) or Herbst (H).
--------------------------------------------------------------------------------
Global notes:
Note (G1): Sky conditions as follows:
SC = clear sky
SPN = sky partially affected by nebula
SN = region where the nebula is very strong
SNB = bright stars located in the region where the nebular emission
is strong
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 06-Dec-2010