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H α Observations of the Binary System VV Cephei Ernst Pollmann. ASPA. Active Spectroscopy in Astronomy. 3. VV Cephei 4,9 mag. µ Cephei 4,0 mag. 1. 1a.

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  1. Hα Observations of the Binary System VV Cephei Ernst Pollmann ASPA Active Spectroscopy in Astronomy

  2. 3 VV Cephei 4,9 mag µ Cephei 4,0 mag 1

  3. 1a

  4. The orbit of the Be-star + Gasdisk leads to the eclipse by the M-type star Duration of eclipse: 673 daysPeriode: 20,4 years M2Iab Supergiant 2-3 Solar masses 1600 Solar radii Last eclipse: Jun/1996 – August/1998 2

  5. Rotating Hydrogen-Gasdisk and its hot Be-Star with 8 Solarmasses red shiftet blue shiftet Observer 3

  6. 4

  7. 5

  8. Time behavior of the Hα-emission since 1996 until today Eclipse 1997-99 6

  9. V/R of the Hα-emission as function of orbital phase 7

  10. 08/199401/2015 09/1999 09/2003 11/2009 Periastron passage 10/2004 11/2005 8

  11. Increase of the emission strength by mass overflow into the Be-disk at periastron 9

  12. Hα observations on the Be binary ζ Tauri First some introduction wordsasking for patienceErnst PollmannASPA – Active Spectroscopy in Astronomy

  13. 1

  14. The binary system z Tau • Development of a rotating one-armed density wave by disturbed orbits • Due to a radial disturbance the gas particles of the disk are moving on excentric Kepler-orbits 2

  15. Temporal development of the Ha-profile  (2003/09 to 2007/03) Dispersion = 27Ǻ/mm R= λ/Dλ ≈ 14000 3

  16. Temporal development of the Hα-profile between 2000 and 2006 All Profiles from 2000-2006. The vertical offset is proportional to time and corresponds to 25 days per continuum unit. The lowermost spectra date from Nov./2000 (left), Sep./2002 (middle) and Aug./2004 (right). The spectra are published electronically in the form of ASCII-tables IBVS-Nr. 5813 4

  17. Hα equivalent widths of ζ Tau since 1975 5

  18. Enlargement of the previous figure showing the data presented in this work in greater detail, also for comparison between values taken with professional and amateur equipment. 6

  19. Development of a rotating one-armed density wave by disturbed orbits • Due to a radial disturbance the gas particles of the disk are moving on excentric Kepler-orbits • This leads to V/R-variations • V/R of Hα show the same period as the radial velocies • Period duration = 1500 d 7

  20. 8

  21. Hα V/R-ratio The residuals of the left panel, folded with P = 69.3 d and the respective sine fit. Shown are 1.4 cycles for clarification, i.e. 40% of the points are redundant. The measured values vs. Julian date (open symbols) and the sine wave with P = 1471 d (plus signs). 9

  22. Causes of the V/R variations • V/R variations in binary stars may be locked to the orbital phase • follow quasi-cyles typical 5-10 years • or combines these two types of variations with long-term trends • length and amplitude of the quasi-cycle vary from cycle to cycle 10

  23. Questions of the V/R variations • Conditions of the synchronisation of the V/R variations with the orbital periods ? • Several peculiarities of emission lines and their profiles can hardly be explained with one-armed oscillation model 11

  24. Phase variations of the radial velocity of the HeI line 6678 and Ha-V/R (1) (1) Stefl/Okazaki/Rivinius/Baade: V/R- Variations of binary Be stars (ASP-Conference Series, Vol. 361, 2007) 12

  25. Radial velocity of the HeI line 6678Ǻ Long term Period 1503 d ? Radialgeschwindigkeit [km/s] Gemeinschaftsprojekt: R. Bücke, Hamburg / E. Pollmann, Leverkusen 13

  26. thanks for attention 14

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