Gas phase atomic metals in the circumstellar envelope of IRC+10216

Abstract

We report the results of a search for gas phase atomic metals in the circumstellar envelope of the AGB carbon star IRC+10216. The search was made using high resolution (R=50000) optical absorption spectroscopy of a backgound star that probes the envelope on a line of sight 35" from the center. The metal species that we detect in the envelope include NaI, KI, CaI, CaII, CrI, and FeI, with upper limits for AlI, MnI, TiI, TiII, and SrII. The observations are used to determine the metal abundances in the gas phase and the condensation onto grains. The metal depletions range from a factor of 5 for Na to 300 for Ca, with some similarity to the depletion pattern in interstellar clouds. Our results directly constrain the condensation efficiency of metals in a carbon-rich circumstellar envelope and the mix of solid and gas phase metals returned by the star to the ISM. The abundances of the uncondensed metal atoms that we observe are typically larger than the abundances of the metal-bearing molecules detected in the envelope. The metal atoms are therefore the major metal species in the gas phase and likely play a key role in the metal chemistry.

11 pages, 8 Figures. Accepted by Astronomy and Astrophysics

References in corpus (3)

• On the reliability of mass-loss-rate estimates for AGB stars
• Density-enhanced gas and dust shells in a new chemical model for IRC+10216
• The Iron abundance in Galactic Planetary Nebulae

Cited by in corpus (20)

• Molecular abundances in the inner layers of IRC +10216
• The inner wind of IRC+10216 revisited: New exotic chemistry and diagnostic for dust condensation in carbon stars
• Laboratory and Astronomical Discovery of HydroMagnesium Isocyanide
• The size, luminosity and motion of the extreme carbon star IRC+10216 (CW Leonis)
• C/O abundance ratios, iron depletions, and infrared dust features in Galactic planetary nebulae
• The magnesium paradigm in IRC+10216: Discovery of MgC${}_4$H${}^{+}$, MgC${}_3$N${}^{+}$, MgC${}_6$H${}^{+}$, and MgC${}_5$N${}^{+}$
• Magnesium radicals MgC${}_5$N and MgC${}_6$H in IRC+10216
• Discovery of the first Ca-bearing molecule in space: CaNC
• Laboratory and astronomical discovery of magnesium dicarbide, MgC${}_2$
• Discovery of two metallic cyanoacetylides in IRC+10216: HMgCCCN and NaCCCN
• Discovery of a Shell of Neutral Atomic Hydrogen Surrounding the Carbon Star IRC+10216
• Silicon and hydrogen chemistry under laboratory conditions mimicking the atmosphere of evolved stars
• Missing Fe: hydrogenated iron nanoparticles
• Connecting the evolution of thermally pulsing asymptotic giant branch stars to the chemistry in their circumstellar envelopes -- I. The case of hydrogen cyanide
• High-latitude supergiant V5112 Sgr: enrichment of the envelope with heavy s-process metals
• Lithium in coalesced non-compact stars
• Dissecting the central regions of OH 231.8 + 4.2 with ALMA: a salty rotating disk at the base of a young bipolar outflow
• The detection of heavy metals in the circumstellar envelopes of post-AGB stars
• Circumstellar CO J = 3-2 detected around the evolving metal-poor ([Fe/H] ~ -1.15 dex) AGB star RU Vulpeculae
• Extended Ionized Fe Objects in the UWIFE Survey