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Testing a pulsating binary model for long secondary periods in red variables

Testing a pulsating binary model for long secondary periods in red variables. Jundan Nie Beijing Normal University. What are the LSPs ?. Payne-Gaposhkin, 1954 Houk, 1963 Short primary period: 30-200 days radial pulsation

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Testing a pulsating binary model for long secondary periods in red variables

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  1. Testing a pulsating binary model for long secondary periods in red variables Jundan Nie Beijing Normal University

  2. What are the LSPs ? Payne-Gaposhkin, 1954 Houk, 1963 Short primary period: 30-200 days radial pulsation long secondary period: 400-1500 days Period ratio: Long/short ~ 9

  3. Observational facts Photometric observations Location: The Galaxy, LMC, SMC Data base: AAVSO, MACHO, OGLE MACHO: 1992-1999, V and R OGLE:1992-1995, I and V OGLEII:1997-2000,I and V OGLEIII:2001-2009,I and V LSPVs: ~25% AGB (MACHO), ~30% AGB (OGLEII

  4. Spectral observations 1998: Wood et al., 3 LSPs stars, 4 yrs. 1999: Hinkle et al., 9 LSPs stars, 5 yrs. 2003: Nicholls et al., 58 LSPs stars,3yrs. 1.The period of radial velocity is equal to the period of light variation. 2.Full amplitude of the radial velocity: 3-4 km/s.

  5. P-L relation Soszynski et al. 2004

  6. The origin of the LSPs • Radial pulsation • Nonradial pulsation • Binary • Rotating red giant with a hot spot • Rotating spheroid model • K mechanism • Magnetic activity

  7. Testing a “pulsating binary” model • Candidates:77.7795.29 and 77.8031.42 in the MACHO project. • Method : Wilson- Devinney code, Period04 • Aim: compare the results with the observations and stellar parameters of red giants.

  8. W-D code • Photometric solution. • Synthesized light curve and velocity curve.

  9. Synthesized Observed

  10. The problems of the synthesized velocity curves The synthesized velocity curves do not satisfy the observational facts. • The full amplitudes of the synthesized velocity curves for the primary stars are:11.0 km/s and 9.0 km/s, while the typical values for other LSPVs are 3-4 km/s. • The full amplitudes of the synthesized velocity curves for the secondary stars are: 18.5 km/s and 18.3 km/s. • The period of the velocity curve.

  11. Intrinsic pulsation • Period 04 77.7795.29 f=0.01 c/d

  12. Intrinsic pulsation • 77.8031.42 f=0.0112 c/d

  13. The mean density and pulsation constant

  14. The evolutionary property The primary stars: Mbol L/Lsun R/Rsun M/Msun 77.7795.29: -3.75 2502 153 0.31 77.8031.42: -4.46 4839 213 0.36 The secondary stars: L/Lsun M/Msun 1607 0.188 3790 0.175

  15. Conclusion • The synthesized velocity curves and masses do not agree with some observations and facts of red giants. • The pulsating binary model for LSPs is defective. • The binary hypothesis seems unreasonable.

  16. THANK YOU!

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