ON INFRARED EXCESSES ASSOCIATED WITH Li-RICH K GIANTS

Infrared (IR) excesses around K-type red giants (RGs) have previously been discovered using Infrared Astronomy Satellite (IRAS) data, and past studies have suggested a link between RGs with overabundant Li and IR excesses, implying the ejection of circumstellar shells or disks. We revisit the question of IR excesses around RGs using higher spatial resolution IR data, primarily from the Wide-field Infrared Survey Explorer. Our goal was to elucidate the link between three unusual RG properties: fast rotation, enriched Li, and IR excess. Our sample of RGs includes those with previous IR detections, a sample with well-defined rotation and Li abundance measurements with no previous IR measurements, and a large sample of RGs asserted to be Li-rich in the literature; we have 316 targets thought to be K giants, about 40% of which we take to be Li-rich. In 24 cases with previous detections of IR excess at low spatial resolution, we believe that source confusion is playing a role, in that either (a) the source that is bright in the optical is not responsible for the IR flux, or (b) there is more than one source responsible for the IR flux as measured in IRAS. We looked for IR excesses in the remaining sources, identifying 28 that have significant IR excesses by ∼20 μm (with possible excesses for 2 additional sources). There appears to be an intriguing correlation in that the largest IR excesses are all in Li-rich K giants, though very few Li-rich K giants have IR excesses (large or small). These largest IR excesses also tend to be found in the fastest rotators. There is no correlation of IR excess with the carbon isotopic ratio, 12C/13C. IR excesses by 20 μm, though relatively rare, are at least twice as common among our sample of Li-rich K giants. If dust shell production is a common by-product of Li enrichment mechanisms, these observations suggest that the IR excess stage is very short-lived, which is supported by theoretical calculations. Conversely, the Li-enrichment mechanism may only occasionally produce dust, and an additional parameter (e.g., rotation) may control whether or not a shell is ejected.

[1]  H. Liu,et al.  SiO EMISSION IN THE GALACTIC CENTER , 2015 .

[2]  R. Reza,et al.  COMPLEX ORGANIC AND INORGANIC COMPOUNDS IN SHELLS OF LITHIUM-RICH K GIANT STARS , 2015, 1504.05983.

[3]  B. E. Reddy,et al.  Far-infrared study of K giants in the solar neighborhood: Connection between Li enrichment and mass-loss , 2015, 1503.01548.

[4]  B. Sato,et al.  THE LITHIUM ABUNDANCES OF A LARGE SAMPLE OF RED GIANTS , 2014, 1404.1687.

[5]  G. Carraro,et al.  A super lithium-rich red-clump star in the open cluster Trumpler 5 , 2014, 1403.6461.

[6]  Yong-Sun Park,et al.  SiO AND H2O MASER SURVEY TOWARD POST-ASYMPTOTIC GIANT BRANCH AND ASYMPTOTIC GIANT BRANCH STARS , 2014 .

[7]  J. De Ridder,et al.  OLD PUZZLE, NEW INSIGHTS: A LITHIUM-RICH GIANT QUIETLY BURNING HELIUM IN ITS CORE , 2014, 1402.6339.

[8]  D. A. García-Hernández,et al.  THE TENTH DATA RELEASE OF THE SLOAN DIGITAL SKY SURVEY: FIRST SPECTROSCOPIC DATA FROM THE SDSS-III APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT , 2013, 1307.7735.

[9]  Dominic J. Benford,et al.  Explanatory Supplement to the AllWISE Data Release Products , 2013, WISE 2013.

[10]  B. Anthony-Twarog,et al.  A LITHIUM-RICH RED GIANT BELOW THE CLUMP IN THE KEPLER CLUSTER, NGC 6819 , 2013, 1303.2984.

[11]  S. Martell,et al.  Lithium-rich field giants in the Sloan Digital Sky Survey , 2013, 1301.0163.

[12]  D. Lazzati,et al.  THREE-DIMENSIONAL ADAPTIVE MESH REFINEMENT SIMULATIONS OF LONG-DURATION GAMMA-RAY BURST JETS INSIDE MASSIVE PROGENITOR STARS , 2012, 1212.0539.

[13]  M. Meyer,et al.  EXPLORING THE EFFECTS OF STELLAR ROTATION AND WIND CLEARING: DEBRIS DISKS AROUND F STARS , 2012, 1208.6248.

[14]  A. Zijlstra,et al.  Fundamental parameters and infrared excesses of Hipparcos stars , 2012, 1208.2037.

[15]  K. Cunha,et al.  OBSERVABLE SIGNATURES OF PLANET ACCRETION IN RED GIANT STARS. I. RAPID ROTATION AND LIGHT ELEMENT REPLENISHMENT , 2012, 1208.1775.

[16]  Y. Litvinenko.  EFFECTS OF NON-ISOTROPIC SCATTERING, MAGNETIC HELICITY, AND ADIABATIC FOCUSING ON DIFFUSIVE TRANSPORT OF SOLAR ENERGETIC PARTICLES , 2012 .

[17]  E. Kirby,et al.  DISCOVERY OF SUPER-Li-RICH RED GIANTS IN DWARF SPHEROIDAL GALAXIES , 2012, 1205.1057.

[18]  L. Hartmann,et al.  COMPLEX STRUCTURE IN CLASS 0 PROTOSTELLAR ENVELOPES. III. VELOCITY GRADIENTS IN NON-AXISYMMETRIC ENVELOPES, INFALL, OR ROTATION? , 2012, 1201.2174.

[19]  Padova,et al.  Lithium abundances along the RGB: FLAMES-GIRAFFE spectra of a large sample of low-mass Bulge stars , 2011, 1111.3572.

[20]  B. Gibson,et al.  METAL-POOR LITHIUM-RICH GIANTS IN THE RADIAL VELOCITY EXPERIMENT SURVEY , 2011, The Astrophysical Journal.

[21]  B. E. Reddy,et al.  ORIGIN OF LITHIUM ENRICHMENT IN K GIANTS , 2011, 1102.2299.

[22]  T. Downes,et al.  MULTIFLUID MAGNETOHYDRODYNAMIC TURBULENT DECAY , 2011, 1101.3429.

[23]  K. Cunha,et al.  THE SUPER LITHIUM-RICH RED GIANT RAPID ROTATOR G0928+73.2600: A CASE FOR PLANET ACCRETION? , 2010, 1010.2954.

[24]  Martin G. Cohen,et al.  THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE): MISSION DESCRIPTION AND INITIAL ON-ORBIT PERFORMANCE , 2010, 1008.0031.

[25]  O. Suárez,et al.  Searching for heavily obscured post-AGB stars and planetary nebulae II. Near-IR observations of IRAS candidates , 2011 .

[26]  B. E. Reddy,et al.  HD 77361: A NEW CASE OF SUPER Li-RICH K GIANT WITH ANOMALOUS LOW 12C/13C RATIO , 2009, 0908.2685.

[27]  M. Busso,et al.  Extra-Mixing in Luminous Cool Red Giants: Hints from Evolved Stars With and Without Li , 2009, Publications of the Astronomical Society of Australia.

[28]  M. Rowan-Robinson,et al.  The Imperial IRAS-FSC Redshift Catalogue , 2008, 0809.2016.

[29]  K. Y. L. Su,et al.  Debris Disks around Sun-like Stars , 2007, 0710.5498.

[30]  S. Oh,et al.  The infrared astronomical mission AKARI , 2007, 0708.1796.

[31]  G. Rieke,et al.  Far-Infrared Properties of M Dwarfs , 2007, 0707.0464.

[32]  Infrared Study of J-Type Carbon Stars Based on Infrared Astronomical Satellite, Two Micron All Sky Survey, and Infrared Space Observatory Data , 2007 .

[33]  U. Heiter,et al.  Giants in the Local Region , 2007 .

[34]  G. Stasińska,et al.  An evolutionary catalogue of galactic post-AGB and related objects , 2007, astro-ph/0703717.

[35]  S. R. Pottasch,et al.  A spectroscopic atlas of post-AGB stars and planetary nebulae selected from the IRAS point source catalogue , 2006, astro-ph/0608080.

[36]  C. Charbonnel,et al.  Rotational mixing in low-mass stars: II. Self-consistent models of Pop II RGB stars , 2006, astro-ph/0602389.

[37]  M. Skrutskie,et al.  The Two Micron All Sky Survey (2MASS) , 2006 .

[38]  U. S. Paulo,et al.  Polarimetry of Li-rich giants , 2005, astro-ph/0512237.

[39]  B. E. Reddy,et al.  Three Li-rich K Giants: IRAS 12327−6523, 13539−4153, and 17596−3952 , 2005, astro-ph/0503253.

[40]  F. Herwig,et al.  Enhanced Extra Mixing in Low-Mass Red Giants: Lithium Production and Thermal Stability , 2004 .

[41]  E. Wright,et al.  The Spitzer Space Telescope Mission , 2004, astro-ph/0406223.

[42]  D. VandenBerg,et al.  Canonical Extra Mixing in Low-Mass Red Giants , 2003 .

[43]  J. Valenti,et al.  An IUE Atlas of Pre-Main-Sequence Stars. III. Co-added Final Archive Spectra from the Long-Wavelength Cameras , 2003 .

[44]  C. Sneden,et al.  Carbon Isotope Ratios for Giants in Globular Cluster M3: The Unique Lithium-Rich Giant IV-101 , 2003 .

[45]  I. Reid,et al.  Binarity in Brown Dwarfs: T Dwarf Binaries Discovered with the Hubble Space Telescope Wide Field Planetary Camera 2 , 2002, astro-ph/0211470.

[46]  D. Lambert,et al.  Rapidly Rotating Lithium-rich K Giants: The New Case of the Giant PDS 365 , 2002, astro-ph/0202158.

[47]  B. E. Reddy,et al.  Spectroscopic Study of IRAS 19285+0517 (PDS 100): A Rapidly Rotating Li-rich K Giant , 2001, astro-ph/0112259.

[48]  S. Maddox,et al.  The PSCz catalogue , 1999, astro-ph/9909191.

[49]  M. Livio,et al.  The accretion of brown dwarfs and planets by giant stars — II. Solar-mass stars on the red giant branch , 1999, astro-ph/9905235.

[50]  M. Shetrone,et al.  Lithium in a Cool Red Giant Member of the Globular Cluster NGC 362 , 1999 .

[51]  M. Jura.  Dust around First-Ascent Red Giants , 1999 .

[52]  U. T. Austin,et al.  An Extremely Lithium-rich Bright Red Giant in the Globular Cluster M3 , 1999, astro-ph/9904152.

[53]  B. Carney,et al.  Lithium and r-Process Abundances in the Population II Cepheid M5 V42 , 1998 .

[54]  F. Fekel,et al.  A Search for Lithium-rich Giants among Stars with Infrared Excesses , 1998 .

[55]  L. Pulone,et al.  Old open clusters: the interesting case of Berkeley 21 , 1998, astro-ph/9804071.

[56]  B. Barbuy,et al.  Li-rich giants: A survey based on IRAS colours , 1998 .

[57]  A. Manchado,et al.  Near infrared photometry of IRAS sources with colours like planetary nebulae. III. , 1997 .

[58]  E. Martín,et al.  On a Rapid Lithium Enrichment and Depletion of K Giant Stars , 1997, astro-ph/9703131.

[59]  N. Drake,et al.  Lithium Enrichment-Mass-Loss Connection in K Giant Stars , 1996 .

[60]  P. Caselli,et al.  IRAS-selected Galactic star-forming regions - II. Water maser detections in the extended sample , 1995 .

[61]  C. Beichman,et al.  A search for T Tauri stars in high-latitude molecular clouds. 2: The IRAS Faint Source Survey catalog , 1995 .

[62]  M. Feast,et al.  South galactic cap G and K stars with infrared excesses , 1991 .

[63]  T. Evans.  Carbon stars with silicate dust shells – II. More stars with enhanced 13C (J stars) , 1991 .

[64]  C. Beichman,et al.  Infrared Astronomical Satellite (IRAS) catalogs and atlases , 1988 .

[65]  Francesco Paresce,et al.  Broad-band imaging of the Beta Pictoris circumstellar disk , 1987 .

[66]  F. Gillett.  IRAS observations of cool excess around main sequence stars , 1986 .

[67]  de T. Jong,et al.  The Infrared Astronomical Satellite (IRAS) mission , 1984 .