Images of Chi Cygni a pulsa'on observed by interferometry
3/17/10 1 Origin and fate of the sun -‐-‐ S. Lacour
S. Lacour, E. Thiébaut, X. Haubois,
G. Perrin, S. Ridgway, S. Meimon,
W. Traub et al.
Chi Cygni
• Mira star. S-‐type. • Period 408 days • mK=-‐1.9 mag
• Distance: ~100pce
• Per Perryman (1997)
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Period/Luminosity by Bedding & Zijlstra (1998)
Chi Cygni, complex or not complex?
• 3D simula^on VX Sgr A. Chiavassa et al. (2010)
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CO (∆v=3) velocity on Chi Cygni
(Hinkle et al., 1982):
Atomic line velocity on the cepheid δ Cep
(Kiss & Joszef):
IOTA
• 3 telescopes with baseline length between 5 and 38 meters
• H band data • Integrated op^cs beam combiner
• Dismounted in June 2006 3/17/10 Origin and fate of the sun -‐-‐ S. Lacour 4
Dataset:
• 4 epochs, covering almost 1 stellar cycle
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Dataset:
• 4 epochs, covering almost 1 stellar cycle
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Image reconstruc^on soiware by E. Thièbaut
Parametric modeling
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Parametric modeling
3/17/10 Origin and fate of the sun -‐-‐ S. Lacour 8
Parametric modeling
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Image reconstruc^on: Parametric reconstruc^on:
Time-‐evolu^on
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Parametric reconstruc^on:
Time evolu^on
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Hinkle et al. 1982 (observa^on)
Bowen 1990 (simula^ons) Lacour et al. 2009
(observa^on)
Time evolu^on
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=> Distance ~200pc (5.9+/-‐ 1.5 mas)
Time evolu^on
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⇒ Mass = 2.1 (+1.5-‐0.7) Msun In agreement with the P/M/R rela^on:
Conclusion • There is no reason to be afraid of simplis^c geometrical model
(at least, un^l observa^ons start to disagree)
• IOTA does not exist anymore, but AMBER can do many things, eg, RR Sco:
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