RS Cha A binary system suitable for

testing stellar physics modeling during the pre-main sequence

phase.

E. Alécian, C. Catala, M.J. Goupil

2nd Corot-Brazil Workshop, Ubatuba5 Nov. 2005

LESIA - Observatoire de Paris-Meudon

RS Cha : an PMS eclipsing SB2 system

Evelyne Alécian

Primary Secondary ReferencesM/M 1.89

0.011.87 0.01 Alécian et al. (2005)

R/R 2.15 0.06

2.36 0.06 Alécian et al. (2005)

Teff (K) 7638 76 7228 72 Ribas et al. (2000)log(L/L) 1.15

0.091.13 0.09 Alécian et al. (2005)

[Fe/H] 0.17 0.01 Alécian et al. (2005)P (day) 1.67

synchronized system Alécian et al. (2005)

i (°) 83.4 0.3 Clausen & Nordström (1980)

RS Cha : PMS Spectroscopic Binary

Evelyne Alécian

CESAM

RS Cha : PMS Spectroscopic Binary

Evelyne Alécian

CESAM

CESAM

RS Cha : PMS Spectroscopic Binary

Evelyne Alécian

Error boxes calculated from masses and radii

Scuti type pulsations in RS Cha

Evelyne Alécian

June 19-24 2005 Stellar Pulsation and Evolution

Log(Teff) (K)

Log

(L/L

)

Palla & Stahler (2001)

Andersen (1975) : primary PMS Scuti star

Marconi & Palla (1998) : theoretical instability strip

Palla & Stahler (2001) : secondary PMS Scuti star

Alécian et al. (2005) : both are pulsating

Scuti type pulsations in both components

Evelyne Alécian

Alécian et al. (2005)

Residuals = vobs - vcalc

vcalc : velocity calculated from Clausen & Nordström (1980) ephemerisPrimary Secondary

Evelyne Alécian

June 19-24 2005 Stellar Pulsation and Evolution

Alécian et al. (2005)

Scuti type pulsations in both components

Periodic variations

Pulsation period ~ 1 h

Residuals

Alécian et al. (2005)

Primary Secondary

Theoretical modes pulsations

Evelyne Alécian

MAD (M.-A. Dupret)

Non-adiabatic calculations

Primary star, M = 1.89 M

degr

ee l

Theoretical modes pulsations

Evelyne Alécian

MAD (M. A. Dupret)

Non-adiabatic calculations

Secondary star, M = 1.87 M

degr

ee l

Evelyne Alécian

Perspectives

- Improving temperature determination : next step

- Improving knowledge of pulsations : long term continuous multi-site monitoring of spectroscopic data

Evelyne Alécian

Autres diapo

Evelyne Alécian

June 19-24 2005 Stellar Pulsation and Evolution

RS Cha : PMS Spectroscopic Binary

Evelyne Alécian

June 19-24 2005 Stellar Pulsation and Evolution

RS Cha : PMS Spectroscopic Binary

RS Cha : Observations

Evelyne Alécian

June 19-24 2005 Stellar Pulsation and Evolution

Primary Secondary References

M/M 1.89 0.01 1.87 0.01 Alécian et al. (2005)

R/R 2.15 0.06 2.36 0.06 Alécian et al. (2005)

logTeff (K) 3.883 0.010

3.859 0.010

Ribas et al. (2000)

log(L/L) 1.15 0.09 1.13 0.09 Alécian et al. (2005)

[Fe/H] 0.17 0.01 Alécian et al. (2005)

vsini (km/s) 64 6 70 6 Alécian et al. (2005)

i (°) 83.4 0.3Clausen & Nordström (1980)