1 / 37

Variable Periods and Amplitudes in Evolved Stars

Variable Periods and Amplitudes in Evolved Stars. Dave Kilkenny University of the Western Cape South Africa. Historical – Tony ~ 1974. “Round up the usual suspects” ~ 1979. Tony & Dave ……. Collaborative papers 1975 – 2010 n=28

guido
Download Presentation

Variable Periods and Amplitudes in Evolved Stars

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Variable Periods and Amplitudes in Evolved Stars Dave Kilkenny University of the Western Cape South Africa

  2. Historical – Tony ~ 1974

  3. “Round up the usual suspects” ~ 1979

  4. Tony & Dave …… Collaborative papers 1975 – 2010 n=28 • AA Dor (= LB3459) 4 • V652 Her (= BD+13° 3224) 4 • V2076 Oph (= HD160641) 5 • “EC14026” stars (= sdBV stars) 9 • SDSS J160043.6+074802.9 (= sdOV star) 2

  5. …. et al.

  6. Stars in a close binary system

  7. AA Dor (= LB3459 = HD269696 = …) sdOB + M?

  8. (O-C) diagram “Ephemeris” Tmin = T0 + n x Period (O-C) = Observed – Calculated (Ephemeris)

  9. AA Dor (Period = 0.261539731 d)

  10. AA Dor JHK light curves

  11. HW Vir

  12. HW Vir (= BD-7° 3477) sdB + M?

  13. HW Vir [update]

  14. The Hydrogen-deficient star, V652 Her

  15. V652 Her ( = BD+13° 3224) Determined periods (day): 0.107995 1975 (Landolt) 0.107827 1979-80 0.107790 1981

  16. V652 Her

  17. V652 Her

  18. BD+10° 2179 - a new V652 Her star ?

  19. BD+10° 2179 – NOT a new V652Her star

  20. Hydrogen-deficient variables (Hideyuki Saio)

  21. BX Cir (=LSS 3184)

  22. BX Cir (= LSS3184)

  23. BX Cir

  24. Tmax = T₀ + nP₀ + n²k₁ + n³k₂ + n⁴k₃ + …. V652 Her BX Cir T₀ = 9477.4668 P₀ = 0.106 579 86 k₁ = -1.72 x 10⁻¹⁰ Teff = 23300 K log g = 3.4 T₀ = 2216.80425 P₀ = 0.107 992 84 k₁ = -44.70 x 10⁻¹⁰ k₂ = +3.49 x 10⁻¹⁵ k₃ = -0.53 x 10⁻²⁰ Teff = 24500 K log g = 3.7

  25. The hottest H-def star, V2076 Oph (= HD160641)

  26. V2076 Oph 1982 data 2000 data

  27. The pulsating sdB stars (sdBVr)

  28. EC09582-1157 (sdBVr)

  29. EC 09582-1157

  30. EC 20338-1925

  31. NY Vir (= PG 1336-018) sdBV + M?

  32. NY Vir

  33. NY Vir

  34. NY Vir – orbital period change

  35. Suggestions for future work …..

More Related