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The P-L-relations on the AGB
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Learning outcome Knowledge of the observed P-L-relations for AGB stars Knowledge of the interpretation of the various sequences Knowledge of the relation between P-L and other parameters
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Why? L ~ R² T eff 4 ~ 1/R³ (for M const) L ~ 1/ 2/3 Period – Luminosity Relation
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Miras Field stars Observed logP-colour relation (at 0.25) Combine with colour- luminosity relation M bol = +0.5 mag – 2.25 log P Eggen (1975)
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Miras Robertson & Feast 1981
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Miras - LMC Wood et al. 1983
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Miras - LMC Feast et al. 1989 K = 19.7 mag – 3.57 log P M bol = 19.86 mag – 2.34 log P
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PC- and PLC-relation Period-Colour-Relation O-rich: (J-K) = 0.56 log P – 0.12 C-rich: (J-K) = 2.32 log P – 3.77 Period-Luminosity-Colour-Relation (LMC) O-rich: K = -4.58 log P + 2(J-K) + 19.71 C-rich: K = -2.88 log P -0.14(J-K) +18.22 Feast et al. 1989
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Bedding & Zijlstra 1998 SRVs
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Long period variables - LMC Wood et al. 1999
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Long period variables - LMC Ita et al. 2004 OGLE/SIRIUS survey J-K: temp / chemistry theta: lc regularity F, G: Cepheids LMC SMC
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Long period variables - LMC Ita et al. 2004 OGLE/SIRIUS survey
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Wood 2007
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P-L and amplitude I-band amplitudes from OGLE Kiss & Bedding 2003
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Sequence E Soszynski et al. 2004 ellipsoidal/eclipting variables confirmed from rv variations
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Sequence D Wood et al. 2004 Origin? binary rotation of spotted star non-radial pulsation episodic dust formation no satisfying solution yet
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LPVs in Clusters 47 Tuc Lebzelter & Wood 2005
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Linear/non-linear models Wood 2007
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LPVs in Clusters NGC 1846 (LMC cluster) Lebzelter & Wood 2007
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Lebzelter et al. 2005
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P-L-relations in comparison Glass & van Leeuwen 2007
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Other P-L-studies Glass et al. 1995 (Galactic Bulge) Groenewegen & Whitelock 1996 (Field) Cioni et al. 2001 (LMC) Noda et al. 2002 (LMC) Lebzelter et al. 2002 (LMC) Rejkuba et al. 2003 (Cen A) Groenewegen 2004 (MCs) Schultheis et al. 2004 (MCs, Bulge) Fraser et al. 2005 (LMC)
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Distance determination Using the relation by Feast et al. 1989 with Zero-Point = 1.0: ObjectAGB dist.Other dist. LMC18.48 m ±0.1 m 18.52 m (Cep) LMC - SMC0.4 m 0.44 m (RGB-Tip) Gal. Centre8.5±0.7 kpc8.5±0.5 kpc (Cep) Cen A28.0 m ±0.2 m 27.9 m ±0.2 m (RGB-Tip) Feast 2004
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