J/ApJS/224/41 Frequency spacing of δ Scuti stars. II. (Paparo+, 2016)
Unexpected series of regular frequency spacing of δ Scuti stars in
the non-asymptotic regime.
II. Sample-echelle diagrams and rotation.
Paparo M., Benko J.M., Hareter M., Guzik J.A.
<Astrophys. J. Suppl. Ser., 224, 41-41 (2016)>
=2016ApJS..224...41P 2016ApJS..224...41P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Radial velocities ; Effective temperatures
Keywords: space vehicles; stars: oscillations , including pulsations;
stars: variables: delta Scuti; techniques: photometric
Abstract:
A sequence search method was developed for searching for regular
frequency spacing in δ Scuti stars by visual inspection (VI) and
algorithmic search. The sample contains 90 δ Scuti stars
observed by CoRoT. An example is given to represent the VI. The
algorithm (SSA) is described in detail in section 3.2. The data
treatment of the CoRoT light curves, the criteria for frequency
filtering, and the spacings derived by two methods (i.e., three
approaches: VI, SSA, and FT (Fourier Transform)) are given for each
target. Echelle diagrams are presented for 77 targets for which at
least one sequence of regular spacing was identified. Comparing the
spacing and the shifts between pairs of echelle ridges revealed that
at least one pair of echelle ridges is shifted to midway between the
spacing for 22 stars. The estimated rotational frequencies compared to
the shifts revealed rotationally split doublets, triplets, and
multiplets not only for single frequencies, but for the complete
echelle ridges in 31 δ Scuti stars. Using several possible
assumptions for the origin of the spacings, we derived the large
separation (Δnu) that are distributed along the mean density
versus large separations relation derived from stellar models.
Description:
The CoRoT satellite was launched in 2006. LRa01, the first long run in
the direction of anti-center, started on 2007 October 15 and finished
on 2008 March 3, resulting in a ΔT=131d time span. Both
chromatic and monochromatic data were obtained on the EXO field with a
regular sampling of 8 minutes, although for some stars an oversampling
mode (32s) was applied. We systematically searched in the CoRoT data
archive all light curves in the EXO field for δ Scuti and
γ Doradus light curves (Hareter M., 2013, PhD thesis Univ. Vienna).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 101 83 List of our sample
table3.dat 37 2765 Data file
--------------------------------------------------------------------------------
See also:
B/corot : CoRoT observation log (N2-4.4) (CoRoT 2016)
J/A+A/559/A63 : Photometric frequencies of HD 174966 (Garcia Hernandez+, 2013)
J/A+A/543/A125 : Spectral types of CoRoT stars (Guenther+, 2012)
J/A+A/541/A34 : Spectral types of stars in CoRoT fields (Sebastian+, 2012)
J/A+A/528/A147 : CoRoT 101155310 light curve (Poretti+, 2011)
J/other/A+ARV/18.67 : Accurate masses and radii of normal stars (Torres+, 2010)
J/A+A/506/519 : Supervised classif. of CoRoT variables (Debosscher+, 2009)
J/A+A/506/471 : Frequency analysis of CoRoT B stars (Degroote+, 2009)
J/A+A/506/79 : Asteroseismic analysis of HD 174936 (Garcia Hernandez+, 2009)
http://idoc-corotn2-public.ias.u-psud.fr/ : CoRoT N2 public archive
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq [1/96] Stellar identifier as given in paper (1)
4- 5 I2 --- ID2 [1/96]? Synonymous ID in paper (2)
7- 15 I9 --- CoRoT Official CoRoT identifier
17- 21 I5 K Teff [6000/12800] Effective temperature (3)
23- 27 F5.3 [cm/s2] logg [2.9/4.5] Log of surface gravity (3)
29- 33 F5.1 km/s RV [-20/95] Radial velocity (Hareter 2013,
PhD thesis Univ. Vienna)
35- 37 I3 --- SSF [45/473] Number of SigSpec frequencies
39- 40 I2 --- FF [10/68] Number of filtered frequencies
42- 46 A5 --- EFVI Number of frequencies included in
the sequences from the visual inspection (VI)
48- 50 A3 --- SNVI Number of sequences from the visual inspection
52- 62 A11 d-1 SPVI Dominant spacing from the visual inspection
64- 71 A8 --- EFA Number of frequencies included in
the sequences from the SSA (4)
73- 77 A5 --- SNA Number of sequences from the SSA (4)
79- 95 A17 d-1 SPA Dominant spacing from the SSA (4)
97-101 F5.3 d-1 SPFT [0.6/7] Spacing from the Fourier Transform (FT)
--------------------------------------------------------------------------------
Note (1): For the sake of simpler treatment during the investigation, we
introduced a running number, which we use to the stars in the rest of
the paper. That there are 96 running numbers instead of 90 is due to
a special test checking the ambiguity of our results.
Note (2): The double running numbers show that the filtering of SigSpec
frequencies and the search for periodic spacing were independently
done for the same six stars. The running numbers representing the
same stars were identified (connected to each other) only at the end
of the searching process. See section 2.1.
Note (3): Based on the AAO spectroscopy, Hareter M. (2013, PhD thesis Univ.
Vienna) derived the Teff and logg values for our sample, using the
same rotational velocity (100km-1) for all stars. The error bars are
also given in Hareter M. (2013; PhD thesis Univ. Vienna).
For 70% of the stars, the error of Teff falls in the range of 50-200K.
See section 5.1 for further details.
Note (4): SSA = Sequence Search Algorithm. See section 3.2 for the explanation.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq [1/96] Stellar identifier as given in paper
4- 12 I9 --- CoRoT Official CoRoT identifier
14- 20 F7.4 d-1 f [0.5/76] Used frequency value
22- 27 F6.3 mmag Amp [0.01/24] Fourier amplitude of frequency
29 A1 --- VI1 [0-6]? Echelle ridge flag for dominant spacing
from Visual Inspection (1)
31 A1 --- VI2 [0-6-] Echelle ridge flag for second spacing
from Visual Inspection (1)
33 A1 --- SSA1 [0-9] Echelle ridge flag for dominant spacing
from Series Search Algorithm (1)
35 A1 --- SSA2 [0-7-] Echelle ridge flag for second spacing
from Series Search Algorithm (1)
37 A1 --- SSA3 [0-3-] Echelle ridge flag for third spacing
from Series Search Algorithm (1)
--------------------------------------------------------------------------------
Note (1): Concerning a given star, as many columns contain flags as many spacing
values were found by our methods. VI means the sequence of the visual
inspection (VI), while 1,2,..., flag means that this frequency belongs
to the 1st, 2nd, ..., sequence. If the VI resulted in more than one
spacing, then VI1 and VI2 columns were filled in. See section 3.1 for
further explanations. Idem for the Sequence Search Algorithm (SSA);
see section 3.2 for further explanations.
0 = the given frequency is not a member of any ridges;
- = a non-existent solution.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Paparo et al. Paper I: the methodology. 2016ApJ...822..100P 2016ApJ...822..100P
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 21-Jul-2016