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THE l BOOTIS STAR HD 183324 A CANDIDATE FOR THE EXPLORATORY PROGRAMME

THE l BOOTIS STAR HD 183324 A CANDIDATE FOR THE EXPLORATORY PROGRAMME. Ernst Paunzen IfA, University Vienna. What are l Bootis stars?. late B to early F-type (from H - lines) non-magnetic dwarfs (LK V) Population I

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THE l BOOTIS STAR HD 183324 A CANDIDATE FOR THE EXPLORATORY PROGRAMME

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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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