SLEUTHING MASS OUTFLOW FROM EVOLVED STARS Optical/IR Spectroscopy from the MMT, KECK II, and Magellan Andrea Dupree (SAO/CfA) Sz. Meszaros (SAO), Jay Strader (CfA), and Graeme H. Smith (UCSC) Cool Stars 15/Splinter: St. Andrews July 2008

STELLAR EVOLUTION PROBLEMS …. CMD depends on metallicity, but what is the ‘second parameter’???? Poster children for second parameter: NGC 362 & NGC 288 (Bellazzini et al. 2001; Catelan et al. 2001) Candidates for second parameter: age, environment (including free-floating planets); primordial He abundance; surface pollution (helium); CNO abundances; rotation; mass loss…..

FOCUS ON MASS LOSS …  Mass loss is required theoretically on red giant branch to match CMD of clusters, but the mass presumably lost has ‘VANISHED’!  Where and when does mass loss occur?  What are the spectroscopic signatures of mass loss or mass flow? Omega Centauri

Contribution functions for a metal deficient giant star Diagnostics of atmospheric motions Need to know where the diagnostic forms….

MMT/Hectochelle observations of globular clusters: M13, M15, & M fibres available to capture spectra in selected orders: H-α and Ca II (H&K) Ca K in M13 H-α in M92 Bisectors marked Sz. Meszaros et al. 2008, 2009

Outflow velocities (H–α) increase with luminosity, and are higher for AGB stars No dependence on [Fe/H] H–α Bisector Velocities

Stars with IR excess in M15 (Spitzer) show same outflow velocity as other red giants Meszaros et al 2008

Ca K 3 shows higher (accelerating) outflow than H-α Ca K 3 H–αH–α

Helium 10830Ǻ observed with NIRSPEC/KECK II in M13 and metal-poor field giants  Maps wind to higher levels of chromosphere  Visible in warmer stars  Reveals high velocities ~100 km s -1  Comparable to stellar escape velocity at 2R star AGB and RGB RHB stars with Graeme Smith (UCSC) and Jay Strader (CfA) [2008]

Winds detected in metal-poor stars  He I 10830Ǻ ubiquitous in warm stars  Frequent extension to ~90 km s -1  M ~2x10 -9 M sun yr -1 MVMV with Graeme Smith (UCSC) and Jay Strader (CfA)

CONCLUSIONS  H-α reveals increasing outflow velocity with luminosity.  Ca K 3 suggests accelerating expansion  Outflows similar for metallicity [Fe/H] = –1.5 to –2.3  IR-excess giants not distinguishable from other giants in M15  No ‘superwind’ detected  Mass loss (V ~ V escape ) discovered in rgb, rhb, agb objects with He I 10830Ǻ