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

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

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**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 long secondary period: 400-1500 days Period ratio: Long/short ~ 9**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**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.**P-L relation**Soszynski et al. 2004**The origin of the LSPs**• Radial pulsation • Nonradial pulsation • Binary • Rotating red giant with a hot spot • Rotating spheroid model • K mechanism • Magnetic activity**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.**W-D code**• Photometric solution. • Synthesized light curve and velocity curve.**Synthesized**Observed**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.**Intrinsic pulsation**• Period 04 77.7795.29 f=0.01 c/d**Intrinsic pulsation**• 77.8031.42 f=0.0112 c/d**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**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.