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Investigating the Characteristics of the LBootis Star HD 183324A: A Study by Ernst Paunzen

This research presents an in-depth analysis of the LBootis star HD 183324A, conducted by Ernst Paunzen at the University of Vienna. LBootis stars are late B to early F-type non-magnetic dwarfs that are rich in C, N, O, and S but show underabundance in other metals, except Na. The study includes basic parameters such as effective temperature, log g, and radial velocity, alongside photometric and spectroscopic data that confirm its membership. Variability and pulsation characteristics are investigated, considering diffusion and asteroseismic techniques.

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Investigating the Characteristics of the LBootis Star HD 183324A: A Study by Ernst Paunzen

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  1. THE l BOOTIS STAR HD 183324A CANDIDATE FOR THE EXPLORATORY PROGRAMME Ernst Paunzen IfA, University Vienna

  2. What are l Bootis stars? • late B to early F-type (from H - lines)non-magnetic dwarfs (LK V) Population I • solar abundant: C, N, O and S other metals underabundant (100 times), exception of Na • ZAMS to TAMS • 2% of all stars in parameter range

  3. All about HD 183324 (I) • Investigated in detail • Basic parameters: V = 5.79, a = 19 29 01, d = +01 57 02 (2000) (b - y) = +0.051, m1 = 0.165, c1 = 1.002, b = 2.890 T(eff) = 9280(80) K, log g = 4.26(5) dex v sin i = 90(3) kms-1, d = 59(3) pc, RV = +12 kms-1MV = 1.86(14) log L/L= 1.26(6)

  4. All about HD 183324 (II) • No signs of shell or IR excess • IUE data confirm membership • Near ZAMS (a few 108 yr) • 2.1 M

  5. Variability of HD 183324 • Photometry:SAAO: 8 nights, 24 hours of data, 47.37, 45.06, 43.72, 50.56 c/d 30.40, 31.96, 32.94, 28.48 minpeak/peak 5.4, 4.8, 4.4, 3.8 mmag • Spectroscopy: CFHT: 12 spectra 103.3 c/d (13.94 min) » 1.2% amplitude

  6. Pulsation and Diffusion Frequency differences of radial modes for LB abundances vs solar, if LB diffuses down to logT=4.4, 5.0 and 5.8 (+, o, ) Turcotte (2002) Opacity changes

  7. Why MOST? • Low ampl. components of frequ.spectrum needed • higher frequency(-ies) in spectral line profiles noise reduction needed  MOST • slightly outside empirical d Scuti strip,non-solar abundances: surface or global feature?  asteroseismic techniques MOST • competing l Bootis theories  MOST

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