![Page 1: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/1.jpg)
Observations of the ZZ Ceti star KUV 08368+4026
Chun Li
Beijing Normal University
![Page 2: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/2.jpg)
Overview
Introduction of ZZ Ceti starsNew observations for KUV 08368+4026Data ReductionPreliminary ResultsFuture Work
![Page 3: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/3.jpg)
Introduction of ZZ Ceti Stars
ZZ Ceti stars (DAV white dwarfs):
- have the lowest Teff among the four classes of variable white dwarfs (DAV, DBV, DOV, PNNV)
- at the cross of the extension of the Cepheid instability strip and the evolution tracks of white dwarfs.
![Page 4: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/4.jpg)
Pure instability strip
![Page 5: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/5.jpg)
Stucture of White Dwarfs
![Page 6: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/6.jpg)
The DAVs (ZZ Ceti)More than 140 membersPeriods: 100 s – 1500 sStucture:
C/O core, He layer, H envelope
Instability: κ-mechanism
Teff: ~12500 K ~11000 K;
Pulsation modes: g modes
![Page 7: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/7.jpg)
ZZ Ceti Star KUV 08368+4026Discovered in Feb.1996With the 1.9m telescope at Haute Provence ObservatoryV=15.55 magB-V=0.22U-B=-0.59(Vauclair et. al. 1997)
![Page 8: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/8.jpg)
![Page 9: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/9.jpg)
Journal of new observations in BDate Observatory Telescope Flames
Feb.10-18.2009 Lijiang 2.40m 6805
Dec.12-18.2009 Xinglong 2.16m 1651
Dec.26-31.2009 Lijiang 2.40m 2328
Dec.27-28.2009 Xinglong 2.16m 815
Jan.07-17.2010 SPM 1.50m 2771
Jan.12-19.2010 Xinglong 2.16m 2745
![Page 10: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/10.jpg)
2.4m Telescope of Lijiang
![Page 11: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/11.jpg)
2.16m Telescope of Xinglong
![Page 12: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/12.jpg)
1.5m Telescope of SPM
![Page 13: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/13.jpg)
Feb 2009 Light Curve
![Page 14: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/14.jpg)
Power spectrum(Feb 2009)
![Page 15: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/15.jpg)
Data analysis:Period04
![Page 16: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/16.jpg)
List of Frequencies
-------------------------------------------
Freq Err Ampl Err S/N
-------------------------------------------
1386.9042 0.0430 3.944 0.218 15.04
1454.6732 0.0464 3.653 0.218 10.06
1976.4851 0.0157 10.828 0.218 20.88
2159.0911 0.0566 2.995 0.218 9.38
2498.7566 0.0160 10.596 0.218 24.90
2500.7136 0.0194 8.757 0.218 20.78
2757.8711 0.0736 2.304 0.218 5.63
2759.9866 0.0467 3.633 0.218 8.82
3245.5122 0.0571 2.970 0.218 8.76
3246.7395 0.0130 13.052 0.218 38.44
-------------------------------------------
-------------------------------------------
Freq Err Ampl Err S/N
-------------------------------------------
3247.7690 0.0321 5.283 0.218 15.49
3249.1089 0.0623 2.722 0.218 7.97
3885.5344 0.0154 11.008 0.218 17.11
3886.7449 0.0359 4.729 0.218 7.38
3887.7290 0.0101 16.751 0.218 26.04
5223.7930 0.0718 2.363 0.218 7.09
5747.6812 0.0570 2.974 0.218 9.19
6386.5161 0.0651 2.606 0.218 8.70
7134.3735 0.0364 4.659 0.218 16.13
------------------------------------------
![Page 17: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/17.jpg)
Result:1 ) 19 periods were founded2 ) 8 independent modes3 ) Periods identification: l=1, 24 ) Triple Periods: average δf=1.12 µHz →rotational Period: P=3.09 day5 ) Average ΔP=32.6 s for l=1 → M=0.6-0.7 M ⊙
![Page 18: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/18.jpg)
Light Curve(Dec 2009 part 1)
![Page 19: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/19.jpg)
Light curve(Dec 2009 Part 2)
![Page 20: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/20.jpg)
Light Curve(Jan 2010)
![Page 21: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/21.jpg)
Future work
To finish data reductionPeriod analysisTo get stellar parametersTheoretical study with the white dwarf
Modelling Code (France)
![Page 22: Observations of the ZZ Ceti star KUV 08368+4026 Chun Li Beijing Normal University](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649cf75503460f949c73af/html5/thumbnails/22.jpg)
Thanks!