Large-scale morphologies of binary AGB stars …as seen in the Herschel/MESS sample Andreas Mayer Alain Jorissen Franz Kerschbaum Roland Ottensamer Marko Mecina Shazrene Mohamed Claudia Paladini Nick Cox Martin Groenewegen GalAGB III | 29-07-14 P-AGB/P-PN PN AGB asymmetries already on AGB The GalAGB II view Duquennoy & Mayor (1991) 57:38:4:1 multiplicity fraction Many hydrodynamical simulations, but serious lack of (non-nova) observations AFGL 3068 (LL Peg) • HST, scattered light • a=109 au CIT 6 (RW LMi) • VLA, H3CN • a=68 au Dust (light scattering & thermal emission) & molecular emission New in GalAGB III: Herschel ALMA (talk by S. Ramstedt) Mauron & Huggins (2006), Dinh-V.-Trung & Lim (2009), Claussen+ (2011) Herschel/PACS & MESS sample • Herschel/PACS – Imaging at 70 μm and 160 μm [cold dust] – Resolution/pixel size: 5.6‘‘/1‘‘ (70 μm) and 12‘‘/2‘‘ (160 μm) • Mass loss of Evolved StarS GTKP (MESS) – 78 objects: mainly AGB stars + few RSGs – 18/78 are physically related binary objects – 10/18 show extended envelopes More of Herschel & MESS in talk by N. Cox Herschel (*2009 - †2013) 4 Groenewegen+ (2011), Cox+ (2012), Mayer+ (2013) R Aqr Mayer+ (2011) o Cet EP Aqr R Scl Mayer+ (accept.) VY UMa Morphologies are very diverse thus case studies π1 Gru W Aql Mayer+ (2013) o1 Ori θ Aps U Cam o Ceti (Mira) UV – Very high space velocity (105 km/s) forms bow shock + tail structure (4 pc) – Knotty streams north & south (bipolar outflow) X-ray  WD companion (a=55 au)  unknown orbital period (>500yr) Martin+ (2007), Karovska+ (2005), Prieur+ (2002) Herschel‘s view of Mira • UV bow shock not visible in far-IR • Cavity in far-IR emission at position of southern UV knots • 4 broken arms – distances 2000-8000 au – Shazrene‘s SPH simulations predicted spiral pattern for Mira configuration More about Mira‘s central part in the next talk! 7 Mayer+ (2011), Mohamed & Podsiadlowski (2011) π1 Gruis • Among brightest intrinsic S stars, at tip of AGB • Faint G0V companion, a = 460 au, P ≈ 6200 yr • Complex CO observations – Elliptical emission interpreted as disc structure inclined by 35° to plane of sky – Inner radius ≈ 200 au, outer radius ≈ 3200 au – High velocity component Chiu+ (2006), Knapp+ (1999), van Eck+ (1998), Sahai (1992) π1 Gruis in the far-IR Two main features: elliptical CSE and arc • Elliptical CSE has same properties (axis ratio and orientation) as CO disc (but is slightly larger) • BUT: focussing factor of G0V companion 4 orders of magnitude too low to cause a disc • Arc might be part of Archimedean spiral • Separation of G0V companion and wind velocity can reproduce the arc Mayer+ (accept.) Q: What shapes the disc? A: magnetic fields, fast rotation or close companion • Search for archival observations that might give a hint • AMBER/VLTI data show non-zero closure phase that points towards deviation from centro-symmetry – can be explained by primary filling the Roche lobe – see Poster by Claudia Paladini for information on modelling – But also stellar spots/flares can cause signatures Mayer+ (accept.) Proper motion variations of π1 Gru • π1 Gru is a Δμ binary: – Long-term proper motion (Tycho-2) differs significantly from short term (Hipparcos) pm – Detectable if 4 < P (yr) < 82 • Hipparcos IAD reveals motion of the photocenter with P ≈ 5-10 yr – Such a close companion (≈ 1 Mo) is able to focus AGB wind to orbital plane Mayer+ (accept.) The environment of π1 Gru Mayer+ (accept.) CONCLUSIONS + OUTLOOK • Companion alters the wind morphology already in the AGB phase – Observable by dust and molecular emission • Shape of CSE depends on orbital separation – Type/separation of companion can be derived from observed CSE shape – Asymmetries can be embedded in other asymmetries (e.g. Mira, R Scl) – can become very complex for triple systems (π1 Gru) • Limitations of resolution in far-IR favours structures caused by wide binaries – Herschel is dead, no successor in the next 10 years, no far-IR observations FUTURE:ALMA but Herschel sample still has many unexplored objects PhD ends in Jan. … Post-doc position wanted!