J/ApJ/863/151 Period analysis of 7 field RRab stars (Li+, 2018)
Period analysis of seven field ab-type RR Lyrae stars based on O-C diagrams:
cyclic variations and long-term period changes.
Li L.-J., Qian S.-B., Zhu L.-Y.
<Astrophys. J., 863, 151 (2018)>
=2018ApJ...863..151L 2018ApJ...863..151L
ADC_Keywords: Stars, variable; Photometry; Optical
Keywords: methods: data analysis ; stars: variables: RR Lyrae ;
techniques: photometric
Abstract:
Using the times of light maximum collected from the GEOS RR Lyrae
database and determined from sky surveys, we utilize the O-C method to
study the period variations of seven field ab-type RR Lyrae stars. The
time coverage of data for most stars is more than 100 years, allowing
us to investigate period changes over a large time span. We find that
the O-C diagrams for most stars can be described by a combination of
cyclic variations and long-term period changes. Assuming the former
were caused by the light-travel-time effect, the pulsation and orbital
parameters are obtained by the nonlinear fitting. We find that the
orbital periods in our sample range from 33 to 78 years, and the
eccentricities are relatively higher than the results for other
candidates (e>0.6). The minimal masses of the potential companions of
XX And, BK Dra, and RY Psc are less than one solar mass, and those of
SV Eri, AR Her, and RU Scl are 3.3, 2.1, and 3.4M☉, respectively.
Moreover, we suggest that the companion of AR Her may be a blue
straggler that experienced mass transfer or a merger of two stars. The
O-C diagram for ST Vir also shows distinct long- term period decrease,
and in the O-C residuals, additional quasi-periodic variations that
can be described by damped oscillation are found. Combining the data
from the literature and our analysis, we plot the log P-AO-C diagram.
The distribution of our binary candidates suggests that their period
variations are not caused by the Blazhko effect.
Description:
The GEOS maxima database (Le Borgne+ 2007, J/other/IBVS/5767) provides
tens of thousands of times of light maximum to thousands of RR Lyrae
stars collected from the literature and obtained from the automated
observations with TAROT (Rapid Action Telescope for Transient Objects).
In this paper, we focus on 123 RRab stars with clear O-C diagrams. We
utilize the times of light maximum provided by GEOS (in 2017 November 8)
for the pre-analysis, and find that besides the stars discussed in
Liska+ (2016, J/MNRAS/459/4360), the O-C diagrams of seven RRab stars
(XX And, BK Dra, SV Eri, AR Her, RY Psc, RU Scl, and ST Vir) also show
cyclic variations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
rrab.dat 236 8 The 7 RRab star sample, and pulsation and orbital
parameters for six of them (Tables 1 and 5)
table2.dat 111 1721 Times of light maximum of the seven RRab stars
obtained from GEOS database
table4.dat 30 297 The times of light maximum of the seven RRab stars
determined from the sky surveys
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
B/gcvs : General Catalogue of Variable Stars (Samus+, 2007-2017)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
J/AJ/106/604 : Study of globular cluster NGC 6366 (Harris 1993)
J/AJ/108/1786 : Blue stragglers & var. stars in M3 (Guhathakurta+, 1994)
J/AJ/108/1016 : Kinematics of local RR lyrae stars. I. (Layden, 1994)
J/A+AS/125/313 : RR Lyrae radial velocities and [Fe/H] I. (Fernley+ 1997)
J/MNRAS/368/1757 : Catalogue of RR Lyrae from NSVS (Wils+, 2006)
J/other/IBVS/5767 : GEOS RR Lyr survey (Le Borgne+, 2007)
J/A+A/476/307 : Period variations in galactic RRab stars (Le Borgne+, 2007)
J/MNRAS/377/1263 : Multiperiodic RR Lyrae in ASAS catalog (Szczygiel+, 2007)
J/MNRAS/386/2115 : Type II Cepheid and RR Lyrae variables (Feast+, 2008)
J/ApJ/696/870 : Catalina Real-time Transient Survey (CRTS) (Drake+, 2009)
J/MNRAS/402/226 : NGC 5053 variables VrI light curves (Arellano Ferro+, 2010)
J/AJ/139/2639 : DY Peg times of light maximum (Li+, 2010)
J/A+A/548/A79 : INTEGRAL-OMC optically var. sources (Alfonso-Garzon+, 2012)
J/AJ/144/39 : Gal. RRab stars from GEOS RR Lyr Survey (Le Borgne+, 2012)
J/ApJS/213/31 : Blazhko effect from 4yr of Kepler data (Benko+, 2014)
J/other/IBVS/6106 : RR Lyrae stars in GCVS observed by the QES (Bramich+, 2014)
J/A+A/562/A90 : Times of maximum light of Blazhko RRab stars (Skarka, 2014)
J/AcA/64/177 : VI LCs of Galactic Bulge RR Lyrae (Soszynski+, 2014)
J/A+A/589/A94 : TU UMa light curves & maxima, CL Aur minima (Liska+, 2016)
J/MNRAS/459/4360 : Field RR Lyrae stars (Liska+, 2016)
J/MNRAS/456/2070 : Eccentricity distribution of wide bin. (Tokovinin+, 2016)
J/AJ/154/263 : NIR photometry of 77 RR Lyrae stars (Karczmarek+, 2017)
http://rr-lyr.irap.omp.eu/dbrr/ : GEOS RR Lyr database
Byte-by-byte Description of file: rrab.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Star name
8 A1 --- f_Name Flag on name (1)
10- 11 I2 h RAh Hour of right ascension (J2000)
13- 14 I2 min RAm Minute of right ascension (J2000)
16- 19 F4.1 s RAs Second of right ascension (J2000)
21 A1 --- DE- Sign of declination (J2000)
22- 23 I2 deg DEd Degree of declination (J2000)
25- 26 I2 arcmin DEm Arcminute of declination (J2000)
28- 29 I2 arcsec DEs Arcsecond of declination (J2000)
31- 36 F6.3 --- VmagLo Lower range of V-band magnitude from B/vsx
37 A1 --- --- [-]
38- 43 F6.3 --- VmagUp Upper range of V-band magnitude from B/vsx
45- 55 F11.3 d T0 Heliocentric Julian Date
57- 67 F11.9 d Ppul [0.4/0.8] Pulsation period
69- 73 F5.2 [Sun] [Fe/H] [-2.2/-0.8] Abundance [Fe/H]
75 I1 --- r_[Fe/H] [1/2] [Fe/H] reference
77- 80 F4.2 Msun M1 [0.5/0.7] Star mass (2)
82- 84 I3 yr Cov [85/120] Span of the times of light maximum
86- 94 A9 --- Dates Date coverage
96-105 F10.8 d Ppulc [0.4/0.8]? Corrected pulsation period
107-116 F10.8 d e_Ppulc [4e-8/6e-7]? Ppul uncertainty
118-127 F10.4 d T0c [25523/42682]? Corrected epoch; JD-2400000
129-134 F6.4 d e_T0c [0.001/0.02]? T0 uncertainty
136-141 F6.3 --- beta [-0.4/1.9]? Linear changes of pulsation
period in day Myr-1
143-147 F5.3 --- e_beta [0.006/0.03]? beta uncertainty
149-153 F5.3 --- A [0.02/0.09]? a1sini/c in light days (3)
155-159 F5.3 --- e_A [0.002/0.03]? A uncertainty
161-164 F4.1 au a1sini [4.7/14.8]? a1sini (3)
166-169 F4.2 au e_a1sini [0.2/5]? a1sini uncertainty
171-174 F4.2 --- e [0.6/0.9]? Orbital eccentricity
176-179 F4.2 --- e_e ? e uncertainty
180 A1 --- f_e f: fixed
182-184 I3 deg omega [43/341]? Longitude of the periastron passage
in the plane of the orbit
186-187 I2 deg e_omega [4/13]? omega uncertainty
189-192 F4.1 yr Porb [33.1/78.4]? Orbital period of the binary system
194-196 F3.1 yr e_Porb [0.3/1.8]? Porb uncertainty
198-202 I5 d T [21113/43717]? Time of passage through
the periastron
204-206 I3 d e_T [207/672]? T uncertainty
208-212 F5.3 Msun fm [0.02/2.6]? Mass function of companion
214-217 F4.2 Msun e_fm [0.04/2.2]? fm uncertainty
219-222 F4.1 km/s K1 [3/22.7]? Semi-amplitude velocity
224-226 F3.1 km/s e_K1 [0.4/9.1]? K1 uncertainty
228-231 F4.2 d dPpul [1.5/9.4]? Range of the pulsation period
(ΔPpul)
233-236 F4.2 d e_dPpul [0.1/3]? dPpul uncertainty
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Note (1): Flag as follows:
a = model 1 = parabola + LiTE.
b = model 2 = linear revise + LiTE
Note (2): The masses of stars are calculated by Equation (22) in
Jurcsik (1998A&A...333..571J 1998A&A...333..571J).
Note (3): where a1 is the semimajor axis, i is the inclination angle, and
c is the speed of light.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Star name
8- 19 F12.4 d HJDmax Maximum Heliocentric Julian Date (1)
21- 26 F6.4 d e_HJDmax [0.0002/0.05]? Error in HJD-Max
28- 31 A4 --- Meth Method (2)
33-111 A79 --- Ref Reference
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Note (1): Data acquired from the GEO is November 08, 2017. More detailed
information also can be obtained by accessing the GEOS RR Lyr website:
http://rr-lyr.irap.omp.eu/dbrr/).
Note (2): Method(s) as follows:
vis = visual;
pg = photographic;
pe = photoelectric;
ccd = Charge Coupled Device;
dslr = Digital Single Lens Reflex Camera.
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Name Star name
8- 17 F10.4 d HJDmax Maximum Heliocentric Julian Date; JD-2400000
19- 24 F6.4 d e_HJDmax [0.0001/0.08] Error in HJD-Max
26- 30 A5 --- Ref Reference (1)
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Note (1): Reference as follows:
ASAS = Pojmanski (1997AcA....47..467P 1997AcA....47..467P --See also J/AcA/48/35);
CRTS = Drake+ (2009, J/ApJ/696/870);
DASCH = Grindlay+ (2009ASPC..410..101G 2009ASPC..410..101G);
NSVS = Wozniak+ (2004AJ....127.2436W 2004AJ....127.2436W);
OMC = Mas-Hesse+ (2003A&A...411L.261M 2003A&A...411L.261M);
Zejda & Domingo (2011IBVS.5996....1Z 2011IBVS.5996....1Z);
QES = Bramich+ (2014, J/other/IBVS/6106);
SWASP = Pollacco+ (2006PASP..118.1407P 2006PASP..118.1407P); Butters+ (2010A&A...520L..10B 2010A&A...520L..10B).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Aug-2019