department of astronomy beijing normal university
DESCRIPTION
Frequency analysis of RR Lyrae stars in the LMC. Bingqiu Chen & Biwei Jiang Beijing Normal University 2010.4. Department of Astronomy Beijing Normal University. Overview. Introduction The data & the method of analysis Variable classification Conclusion Discussion. RR Lyrae stars: - PowerPoint PPT PresentationTRANSCRIPT
Department of Astronomy Beijing Normal University
Bingqiu Chen & Biwei JiangBeijing Normal University
2010.4
Frequency analysis of RR Lyrae stars in the LMC
Frequency analysis of RR Lyrae stars in the LMC
[email protected] normal University
Department of Astronomy
2
Introduction The data & the method of
analysis Variable classification Conclusion Discussion
Overview
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Department of Astronomy
RR Lyrae stars: Period : 0.1 to 1 day Amplitude in V : up to 1.5 magnitudes Spectral type : A5 to F5 Absolute visual magnitude : about +0.5 Mass : about half a solar mass Low metal abundance Z : 0.00001 ~ 0.01 Evolutionary stage: Away from the main
sequence & burning Helium in their core. Useful tracer of galactic evolution.
Obey a period-luminosity-color relation & used as distanceindicators.( Like the Cepheids)
Types : RRab stars, RRc stars , RRd stars, RRe stars
RR Lyrae Star
[email protected] normal University
Department of AstronomyThe Blazhko effect
A long-term modulation of the amplitude, shape, and phase of the light and radial velocity curve. Blazhko effect period : 11 to 533 days Occurs in 1/3 RRab stars, & a few RRc stars .
(The incidence is lower in LMC).
A century of study: Nonradial modes triggered by resonance effects Magnetic field e.g. : Dziembowski and Mizerski (2004).
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Department of AstronomyData
24906 light curves from the OGLE-III (Soszynski et al. 2009)
Exclude I <18m & Observed dots’ number <1000
671 stars
0 500 1000 1500 2000 2500 3000 3500 4000 4500 500018.6
18.7
18.8
18.9
19
19.1
19.2
19.3
19.4
19.5
19.6
JD
Mag
nitu
de
light curve
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Department of AstronomyMethod
Frequency analysis based on a PDM method : f0 In the [1 5] 1/d band
Fit the light curve with five harmonics of f0:
Frequency analysis with the residual: f1 In the [0.5 5.5] 1/d band
Fit the residual with f1 …f2…f3…f4 Visual inspection of lightcurves to check
5
0 1 11
( ) [ cos(2 ) sin(2 )]k kk
I t I A f kt B f kt
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Department of AstronomyRR-S
Singly-periodic RR Lyrae : 495 stars 73.7%
RR0: (fundamental mode): 369~74.5% RR1: (1st overtone mode) : 124~25.1% RR2: (2nd overtone mode) : 2~0.4%
ID P f Θ s amp mag A
762 0.611821 1.634466 0.13622 0.0000 0.567 18.850 0.183
5976 0.555120 1.801411 0.07506 0.0000 0.786 18.720 0.253
5990 0.497251 2.011056 0.08135 0.0000 0.746 18.894 0.231
6004 0.581478 1.719756 0.16810 0.0000 0.505 18.740 0.175
6114 0.551528 1.813145 0.09532 0.0000 0.639 18.811 0.203
6125 0.515681 1.939182 0.14685 0.0000 0.410 18.469 0.155
6147 0.545563 1.832968 0.10768 0.0000 0.677 18.813 0.215
6180 0.493846 2.024921 0.08037 0.0000 0.778 18.818 0.253
6300 0.569926 1.754614 0.12083 0.0000 0.503 18.580 0.161
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Department of AstronomyPDM & fitting
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
18.8
18.9
19
19.1
19.2
19.3
19.4
19.5
phase
mag
nitu
de
fit figure
phase vs. magnitudefit line
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
18.35
18.4
18.45
18.5
18.55
18.6
18.65
18.7
18.75
18.8
18.85
phase
mag
nitu
de
fit figure
phase vs. magnitudefit line
0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
18.2
18.3
18.4
18.5
18.6
18.7
18.8
18.9
19
19.1
X
Y
phase vs. magnitude
fit line
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Department of AstronomyRR-01
Double modes RR Lyrae : 12 ~1.8% There main pulsation modes are all 1st overtone (RR1-01)
ID p1 f1 Θ1 s1 a1 m c1 p0 f0 Θ0 s0 a0 c0
59010.34510
2 2.897696 0.58847 0.0000 0.194 18.828 0.100 0.464248 2.154022 0.60736 0.0000 0.157 0.076
91650.34483
0 2.899981 0.49483 0.0000 0.223 18.779 0.105 0.463814 2.156039 0.55308 0.0000 0.156 0.072
12828
0.345722
2.892498 0.47942 0.0000 0.265 18.906 0.131 0.465272 2.149279 0.56547 0.0000 0.183 0.086
13033
0.367634
2.720098 0.44826 0.0000 0.265 18.797 0.136 0.493743 2.025345 0.56601 0.0000 0.164 0.081
13231
0.381419
2.621787 0.38967 0.0000 0.236 18.671 0.111 0.511593 1.954679 0.62089 0.0000 0.125 0.055
15012
0.342056
2.923502 0.58520 0.0000 0.257 18.870 0.118 0.460572 2.171212 0.46108 0.0000 0.240 0.112
16035
0.358375
2.790370 0.57242 0.0000 0.241 18.705 0.125 0.481604 2.076393 0.83545 0.0012 0.121 0.056
16953
0.398631
2.508585 0.25873 0.0000 0.255 18.488 0.128 0.534026 1.872568 0.65147 0.0000 0.093 0.045
17575
0.361737
2.764443 0.48807 0.0000 0.238 18.784 0.114 0.486225 2.056663 0.51665 0.0000 0.173 0.078
18546
0.343408
2.911990 0.55091 0.0000 0.261 18.891 0.125 0.462159 2.163757 0.46099 0.0000 0.219 0.103
17311
0.341071
2.931942 0.49689 0.0000 0.187 18.624 0.100 0.459522 2.176172 0.59474 0.0000 0.221 0.091
17317
0.345953
2.890563 0.46889 0.0000 0.158 18.680 0.066 0.465608 2.147729 0.64579 0.0000 0.146 0.071
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Department of AstronomyA1 to A0 ratios
Wide rangeA0,only 1 exceeds A1
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Department of AstronomyRR-BL1
RR Lyrae with 1 close frequency component: Number : 84 stars 12.5%
RR1-BL1: 18 ~ 21.4% RR0-BL1: 66 ~ 78.6%
id p0 f0 Θ0 s0 a0 mag c0 p1 f1 Θ1 s1 a1 c1
60330.6470
17 1.5455
54 0.503
5 0.000
0 0.106
18.059
0.044 0.6424
86 1.5564
53 0.811
8 0.001
1 0.042 0.018
68720.6280
18 1.5923
10 0.151
7 0.000
0 0.721
18.611
0.244 0.6202
23 1.6123
23 0.774
9 0.000
0 0.111 0.053
79700.3785
83 2.6414
31 0.252
3 0.000
0 0.254
18.597
0.126 0.3785
40 2.6417
31 0.873
5 0.020
2 0.049 0.021
80720.5348
49 1.8696
86 0.327
4 0.000
0 0.320
18.950
0.122 0.5283
11 1.8928
25 0.886
1 0.038
6 0.053 0.025
88000.5965
06 1.6764
30 0.266
3 0.000
0 0.152
17.720
0.056 0.5930
87 1.6860
92 0.860
4 0.014
7 0.024 0.011
88090.5669
44 1.7638
44 0.279
4 0.000
0 0.556
18.738
0.193 0.5584
72 1.7906
01 0.860
9 0.014
7 0.083 0.038
91610.4711
02 2.1226
81 0.302
3 0.000
0 0.375
18.623
0.147 0.4710
26 2.1230
25 0.827
2 0.002
9 0.084 0.036
91890.6650
77 1.5035
85 0.196
1 0.000
0 0.404
18.673
0.153 0.6739
90 1.4837
01 0.862
3 0.011
2 0.066 0.023
92390.4079
78 2.4511
10 0.447
8 0.000
0 0.245
18.564
0.123 0.4079
34 2.4513
75 0.731
8 0.000
0 0.128 0.052
92540.6408
66 1.5603
89 0.105
9 0.000
0 0.581
18.598
0.196 0.6515
48 1.5348
07 0.897
5 0.074
2 0.044 0.013
93400.3838
29 2.6053
26 0.300
0 0.000
0 0.260
18.709
0.128 0.3838
71 2.6050
40 0.859
9 0.012
3 0.065 0.024
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Department of AstronomyRR-BL1
Frequency difference: RR0: f1>f0 48 stars 72.7% RR1: f1>f0 3 stars 16.7%
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Department of AstronomyRR-BL2
RR Lyrae with 2 close symmetric frequencycomponents: 28 4.2% RR1-BL2 : 12~42.8% RR0-BL2 : 16~57.2%
id p0 f0 a0 f1 a1 f2 a2 f1-f0 f2-f0
5348 0.408541 2.447735 0.258 2.446987 0.036 2.448536 0.035 -0.000748 0.000801
8575 0.379702 2.633646 0.119 2.632782 0.098 1.631312 0.060 -0.000864 -1.002334
9295 0.557803 1.792749 0.508 1.810833 0.106 1.774582 0.090 0.018084 -0.018167
10212 0.334634 2.988337 0.186 2.988668 0.071 2.987979 0.063 0.000331 -0.000358
11476 0.308001 3.246746 0.102 3.173872 0.094 3.246984 0.063 -0.072874 0.000238
11701 0.613466 1.630083 0.311 1.629831 0.179 1.630289 0.129 -0.000252 0.000206
11708 0.313990 3.184819 0.269 3.185052 0.087 3.184604 0.080 0.000233 -0.000215
12991 0.645131 1.550073 0.267 1.541876 0.027 1.558276 0.028 -0.008197 0.008203
13088 0.586977 1.703644 0.405 1.705505 0.073 1.701772 0.045 0.001861 -0.001872
13183 0.274270 3.646038 0.267 3.646744 0.087 3.645336 0.079 0.000706 -0.000702
13235 0.551093 1.814577 0.566 1.810560 0.084 1.818543 0.053 -0.004017 0.003966
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Department of AstronomyRR-BL3+
RR Lyrae with several close components :29 4.2% RR1-BL3+ : 14~48.3% RR0-BL3+ : 15~51.7%
id p0 a0 a1 a2 a3 f1-f0 f2-f0 f3-f0
76340.33544
5 0.154
0 0.121
6 0.106
5 0.098
3
-0.000213
-0.000516
-0.002413
10248
0.558091
0.4282
0.1563
0.1049
0.1053
-0.001243
0.001263
-0.000623
11434
0.550632
0.3987
0.1441
0.1525
0.1118
0.009155 0.00028
8 0.00017
7
12620
0.377995
0.2287
0.1071
0.0887
0.0780
0.000353
-0.000964
-0.001810
12972
0.352589
0.2400
0.1152
0.0934
0.1056
-0.001872
-0.000501
-0.001518
12994
0.465035
0.5543
0.1632
0.1181
0.1091
0.022866 0.01142
6
-0.022867
13023
0.477521
0.5032
0.1112
0.0739
0.0798
-0.000122
0.000209
-0.000258
13039
0.364503
0.1514
0.1000
0.0928
0.1025
-0.000926
-0.000240
-0.000652
13078
0.465452
0.5608
0.1553
0.1208
0.0814
0.005300 0.00266
2
-0.005297
13095
0.319488
0.1982
0.0901
0.0548
0.0493
0.000336 0.00120
0 0.00069
8
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Department of AstronomyRR-D & RR-unknown
id p0 f0 Θ0 a0 mag p1 f1 Θ1 s1 a1
130700.56920
7 1.75683
1 0.2849 0.371
18.598
0.362316
2.760018
0.8473 0.003
5 0.079
132300.59924
1 1.66877
9 0.2014 0.421
18.813
0.464902
2.150992
0.8116 0.000
3 0.070
132540.52039
5 1.92161
7 0.0933 0.269
17.491
0.611430
1.635510
0.8807 0.031
5 0.019
150560.34796
7 2.87383
9 0.3674 0.278
18.855
0.882814
1.132741
0.7799 0.000
0 0.097
160350.35837
5 2.79037
0 0.5724 0.241
18.705
0.481604
2.076393
0.8355 0.001
2 0.121
168180.60297
7 1.65843
7 0.0924 0.634
18.522
0.270359
3.698790
0.8951 0.053
9 0.046
169530.39863
1 2.50858
5 0.2587 0.255
18.488
0.534026
1.872568
0.6515 0.000
0 0.093
173170.46560
8 2.14772
9 0.6458 0.146
18.680
0.345953
2.890563
0.4689 0.000
0 0.158
6 RR-D & 17 unknown type double period RR Lyrae stars
id p0 f0 Θ0 a0 m0 p1 f1 Θ1 s1 a1
70710.60114
1 1.66350
4 0.3352 0.474
19.043
0.997709
1.002296
0.7996
0.0004
0.147
16756
0.529150
1.889822
0.4502 0.432 18.50
6 0.99963
2 1.00036
8 0.697
8 0.000
0 0.276
16779
0.588831
1.698279
0.1346 0.654 18.69
5 0.99661
2 1.00340
0 0.896
7 0.082
6 0.061
17512
0.625897
1.597707
0.2898 0.287 18.44
7 0.99741
2 1.00259
5 0.882
7 0.046
2 0.050
13184
0.304925
3.279495
0.4371 0.254 18.61
7 0.49939
1 2.00243
7 0.616
3 0.000
0 0.137
17331
0.298121
3.354348
0.3886 0.257 18.66
9 0.49942
4 2.00230
6 0.757
3 0.000
0 0.098
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Department of AstronomyConclusion
Type Number Percent Notes
RR-S RR0-S 369 55.0% fundamental mode
RR1-S 124 18.5% 1st overtone mode
RR2-S 2 0.3% 2nd overtone mode
RR-01 12 1.8%Main pulsation modes are all 1st
overtone
RR-BL1 RR0-BL1 66 9.8% fundamental mode
RR1-BL1 18 2.7% 1st overtone mode
RR-BL2 RR0-BL2 12 1.8% fundamental mode
RR1-BL2 16 2.4% 1st overtone mode
RR-BL3+RR0-BL3+
14 2.1% fundamental mode
RR1-BL3+
15 2.2% 1st overtone mode
RR-D 6 0.9% P1=1,2 c/d
RR-unknown
17 2.5%
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Department of AstronomyDiscussion
Blazhko effect occurs more frequently in RR0 than RR1.
The Blazhko period is short in RR1, while sometimes long in RR0 than in RR1.
With the number of oscillating components, the numbers of the RR0-BLn and RR1-BLn stars have a trend to be the same, sothe Blazhko effect depends on the mode of pulsation and thenumber of oscillating components.
For the RR-BL1,RR-BL2, & RR-BL3+, it seems the Blazhko can lead the period to split for any number (1-4) of components, so nonradial mode of oscillation seems better explain for Blazhko effect.
Thank You!
