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 velocitThe period of radial velocity is equal to the period of liy is equal to the period of light variation.ght variation.

2.Full amplitude of the radial Full amplitude of the radial velocity: 3-4 km/s.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.1. 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.

2. The full amplitudes of the synthesized velocity curves

for the secondary stars are: 18.5 km/s and 18.3 km/s.

3. 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 mean density and pulsation constant

The evolutionary property

The primary stars:

Mbol L/Lsun R/Rsun M/Msun

77.7795.29: -3.75 2502 153 0.31 77.7795.29: -3.75 2502 153 0.31

77.8031.42: -4.46 4839 213 0.3677.8031.42: -4.46 4839 213 0.36

The secondary stars:

L/Lsun M/Msun

1607 0.1881607 0.188

3790 0.1753790 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.

THANK YOU!