DA型脉动白矮星氢大气厚度主导脉动周期间隔弥散 Yanhui Chen1,2,3 yanhuichen1987@ynao.ac.cn 1 Institute of Astrophysics, Chuxiong Normal University, Chuxiong 675000, China; 2 School of Physics and Electronical Science, Chuxiong Normal University, Chuxiong 675000, China; 3 Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011, China. 云南省天文学会2016年学术年会 云南省玉溪市新平县嘎洒镇, 2016年10月14-16日

Constents Evolution of DAV star models Calculation on dispersion of period spacing for DAV stars Effect of diferent values of H, He, M*, and Teff Dispersion of period spacing for KUV03442+0719

Evolution of DAV star models MESA: Paxton et al. 2011 (ApJS 192 3) http://mesa.sourceforge.net/ Version 4298 A module named make_co_wd Evolving to WD cooling stage, the structure parameters are took out WDEC: White Dwarf Research Corporation http:/whitedwarf.org/ The structures, including mass, radius, luminosity, pressure, temperature, entropy, and carbon profile, are added into WDEC Element diffusion scheme of Thoul, Bahcall & Loeb 1994 (ApJ 421 828) were added into WDEC by Su et al. 2014 (MNRAS 437 2566)

Evolution of DAV star models With those historically viable core composition profiles, some groups of white dwarf models are evolved by WDEC. The method has been used by Chen & Li 2014 (MNRAS 437 3183), Su et al. 2014 (MNRAS 437 2566), Chen & Li 2014 (MNRAS 443 3477), and Chen 2016 (MNRAS 458 1190). Chen 2016 (MNRAS 458 1190)

Evolution of DAV star models Three groups of DAV star models are evolved by MESA(core)+WDEC(diffusion). First group: M*=0.600 Msun, Teff=12000 K, Log(MHe/M*) is from -4 to -2 with steps of 0.5, Log(MH/M*) is from -10 to -4 with steps of 0.5. Second group: M*=0.600 Msun, Log(MHe/M*)=-2, Teff is from 12300 to 10800 with steps of 50 K, Third group: Log(MHe/M*)=-2, Teff=12000 K, M* is from 0.550 Msun to 0.830 Msun with steps of 0.010 Msun,

Evolution of DAV star models Some discontinuities in the core need to be smoothed in the future work. Pure Coulomb potential is used. The reviewer recommends the use of screened Coulomb potential in the future work.

Calculation on dispersion of period spacing for DAV stars (k,l,m) is used to identify a mode. Modes with same l and consecutive k (high values) have an asymptotic period spacing. Average period spacing (APS): Standard deviation of dispersion of period spacing ( ): n is the number of modes (P(k)) in a range from 800 s to 1600 s.

Effect of diferent values of H, He, M*, and Teff In the period range from 800 s to 1600 s, the thinner the H atmosphere, basically, the more dispersive the period spacing. Thin H atmosphere, obvious mode trapping effect, very small period spacing, large dispersion of period spacing.

Effect of diferent values of H, He, M*, and Teff

Effect of diferent values of H, He, M*, and Teff Teff, M*, He have less influences on the dispersion of period spacing for l=1 and 2 modes. H dominates the dispersion The dispersion of period spacing can be used to confine H preliminarily.

Dispersion of period spacing for KUV03442+0719 KUV03442+0719 was observed by Su Jie in 2010 November (3 nights), 2011 November (7 nights), and 2012 December (9 nights) on the 2.4-m telescope on Lijiang station of Yunnan Observatories, Chinese Academy of Sciences. Su, Li & Fu 2014 (New Astron. 33 52)

Dispersion of period spacing for KUV03442+0719 Su, Li & Fu 2014 (New Astron. 33 52)

Dispersion of period spacing for KUV03442+0719 n is 27 for l = 2 modes and 14 for l = 1 modes. n'' is 12 for l = 2 modes and 8 for l = 1 modes.

Dispersion of period spacing for KUV03442+0719 For KUV03442+0719, in the period range from 800 s to 1600 s, is 2.40 s for l = 2 modes, 7.28 s for l = 1 modes, and is 2.97 s for l = 2 modes, 8.34 s for l = 1 modes. Comparing those and values to the values of calculated, log(MH/M*) is basically from -8.5 to -5.5, not extremely thin, nor thick. The period scheme may tell us that KUV03442+0719 may be the first star to 'observe' modes partly trapped in C/O core. This work was published in MNRAS in February (Chen 2016 (MNRAS 458 1190))

Thanks 感谢云南天文台 感谢云南省天文学会 请观看科普图片

40cm口径Explore Scientific(感谢晶华)

月球：九月初三

月球：九月初四

月球：九月初五

月球：初六

月球：比对

月球：十一

行星：火星

行星：金星

行星：土星

土星：9月26日

土星：9月27日

土星：9月28日

土星：10月4日

土星：10月5日

土星：10月6日

土星：10月8日

土星：10月9日

土星：10月10日

土星：10月11日

星团：M6

星团：M7

星团：M8

星团：M20

星团：M21

星团：M45

星系：M31（距地球254万光年，银河系尺度10万光年）

科普宣传毕业论文题目 认识月球（明暗交界面处的细节） 认识土星（土卫六公转周期16天） 认识全天最亮的15颗恒星（星等、颜色对应温度） 认识星团（疏散星团、球状星团） 认识星系（距离） 谢谢！