Sloan et al. 2016, ApJ, ... Magellanic carbon stars

The infrared spectral properties of Magellanic carbon stars

G.C. Sloan (Cornell), K.E. Kraemer (Boston Coll.), I. McDonald (Univ. of Manchester), M.A.T. Groenewegen (Royal Obs. Belgium), P.R. Wood (ANU), A.A. Zijlstra (Univ. of Manchester), E. Lagadec (Obs. Cote d'Azur), M.L. Boyer (NASA Goddard), F. Kemper (Academia Sinica), M. Matsuura (Cardiff Univ.), R. Sahai (Caltech), B.A. Sargent (RIT), S. Srinivasan (Academia Sinica), J. Th. van Loon (Keele Univ.), K. Volk (STScI)

2016, ApJ, 826, 44

Full manuscript (minus the long versions of the data tables) available locally (PDF) or from the arXiv (1604.06464).

The Infrared Spectrograph on the Spitzer Space Telescope observed 184 carbon stars in the Magellanic Clouds. This sample reveals that the dust-production rate (DPR) from carbon stars generally increases with the pulsation period of the star. The composition of the dust grains follows two condensation sequences, with more SiC condensing before amorphous carbon in metal-rich stars, and the order reversed in metal-poor stars. MgS dust condenses in optically thicker dust shells, and its condensation is delayed in more metal-poor stars. Metal-poor carbon stars also tend to have stronger absorption from C₂H₂ at 7.5 µm. The relation between DPR and pulsation period shows significant apparent scatter, which results from the initial mass of the star, with more massive stars occupying a sequence parallel to lower-mass stars, but shifted to longer periods. Accounting for differences in the mass distribution between the carbon stars observed in the Small and Large Magellanic Clouds reveals a hint of a subtle decrease in the DPR at lower metallicities, but it is not statistically significant. The most deeply embedded carbon stars have lower variability amplitudes and show SiC in absorption. In some cases they have bluer colors at shorter wavelengths, suggesting that the central star is becoming visible. These deeply embedded stars may be evolving off of the AGB and/or they may have non-spherical dust geometries.

Full manuscript with the long tables.

Long versions of the data tables in IPAC table format and ApJ's electronic text format:

Table 1. The Spitzer sample of Magellanic carbon stars IPAC ApJ

Table 3. Optical and near-infrared photometry IPAC ApJ

Table 4. Mid-infrared photometry and bolometric magnitudes IPAC ApJ

Table 5. Spectroscopic data - IRS sample IPAC ApJ

Table 6. Spectroscopic data - SWS sample IPAC ApJ

Table 9. Multi-epoch K-band photometry IPAC ApJ

Table 10. Multi-epoch 3-5 µm photometry IPAC ApJ

Special thanks to Greg Schwarz at the AAS Journals office for generating the tables in ApJ's format so quickly after the paper was accepted for publication! Notes - Some target names and aliases updated 11 May, 2016, in Table 1, 3, 4, 5, and 10. Tables 4 and 10 updated 17 Jul 2019 to correct 3-4 missing data rows at the beginning of the files.

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Table 1. The Spitzer sample of Magellanic carbon stars	IPAC	ApJ
Table 3. Optical and near-infrared photometry	IPAC	ApJ
Table 4. Mid-infrared photometry and bolometric magnitudes	IPAC	ApJ
Table 5. Spectroscopic data - IRS sample	IPAC	ApJ
Table 6. Spectroscopic data - SWS sample	IPAC	ApJ
Table 9. Multi-epoch K-band photometry	IPAC	ApJ
Table 10. Multi-epoch 3-5 µm photometry	IPAC	ApJ