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!