J/A+A/488/675 Infrared photometry of mass-losing AGB stars (Guandalini+, 2008)
Infrared photometry and evolution of mass-losing AGB stars.
II. Luminosity and colors of MS and S stars.
Guandalini R., Busso M.
<Astron. Astrophys. 488, 675 (2008)>
=2008A&A...488..675G 2008A&A...488..675G
ADC_Keywords: Stars, giant ; Stars, S ; Photometry, infrared
Keywords: stars: fundamental parameters - stars: AGB and post-AGB -
stars: evolution - infrared: stars - stars: variables: general
Abstract:
Asymptotic giant branch (AGB) phases mark the end of the evolution for
low- and intermediate-mass stars. Our understanding of the mechanisms
through which they eject the envelope and our assessment of their
contribution to the mass return to the interstellar medium and to the
chemical evolution of Galaxies are hampered by poor knowledge of their
luminosities and mass loss rates, both for C-rich and for O-rich
sources. We plan to establish criteria permitting a more quantitative
determination of luminosities (and subsequently of mass loss rates)
for the various types of AGB stars on the basis of infrared fluxes. In
this paper, in particular, we concentrate on O-rich and s-element-rich
MS, S stars and include a small sample of SC stars.
We reanalyze the absolute bolometric magnitudes and colors of MS, S,
SC stars on the basis of a sample of intrinsic (single) and extrinsic
(binary) long period variables. We derive bolometric corrections as a
function of near- and mid-infrared colors, adopting as references a
group of stars for which the spectral energy distribution could be
reconstructed in detail over a large wavelength range. We determine
the absolute HR diagrams, and compare luminosities and colors of
S-type giants with those, previously derived, of C-rich AGB stars.
Luminosity estimates are also verified on the basis of existing
period-luminosity relations valid for O-rich Miras.
S star bolometric luminosities are almost indistinguishable from those
of C-rich AGB stars. On the contrary, their circumstellar envelopes
are thinner and less opaque. Despite this last property the IR
wavelengths remain dominant, with the bluest stars having their
maximum emission in the H or K(short) bands. Near-to-mid infrared
color differences are in any case smaller than for C stars. Based on
period-luminosity relations for O-rich Miras and on Magnitude-color
relations for the same variables we show how approximate distances
(hence intrinsic parameters) for sources of so far unknown parallax
can be inferred. We argue that most of the sources have a rather small
mass (<2M☉); dredge-up might then be not effective enough to let
the C/O ratio exceed unity.
Description:
Tables 11 and 12 present the data of the "Sub-sample D" discussed in
the paper. In particular, Table 11 shows for each source the different
denominations, the coordinates, spectral type, variability type and
period. Instead, photometric fluxes in near- and mid-infrared,
apparent bolometric magnitudes and an indication if the star is
Intrinsic or Extrinsic are reported in Table 12.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table11.dat 88 530 Sample D - First part
table12.dat 94 530 Sample D - Second part
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See also:
III/168 : General Catalog of S Stars, second edition (Stephenson 1984)
Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS IRAS designation
12- 20 A9 --- Name Other designation
23- 30 A8 --- CSS Stephenson designation, Cat. III/168
33- 34 I2 h RAh ICRS right ascension (ep=2000 eq=2000)
36- 37 I2 min RAm ICRS right ascension (ep=2000 eq=2000)
39- 45 F7.4 s RAs ICRS right ascension (ep=2000 eq=2000)
47 A1 --- DE- ICRS declination sign (ep=2000 eq=2000)
48- 49 I2 deg DEd ICRS declination (ep=2000 eq=2000)
51- 52 I2 arcmin DEm ICRS declination (ep=2000 eq=2000)
54- 59 F6.3 arcsec DEs ICRS declination (ep=2000 eq=2000)
61- 77 A17 --- SpType Spectral Type from GCVS
79- 81 A3 --- Var Variability Type from GCVS
83- 88 F6.1 d Per ? Period (from GCVS)
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Byte-by-byte Description of file: table12.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Designation of the source
11- 17 F7.3 Jy FJ ? Flux in J band
19- 25 F7.2 Jy FH ? Flux in H band
27- 33 F7.2 Jy FK ? Flux in K band
35- 40 F6.2 Jy F8.8 ? Flux in 8.8um band
42- 46 F5.1 Jy F9.8 ? Flux in 9.8um band
48- 52 F5.1 Jy F11.7 ? Flux in 11.7um band
54- 59 F6.2 Jy F12.5 ? Flux in 12.5um band
61- 66 F6.2 Jy FD ? Flux in D (14.65um) MSX band
68- 73 F6.2 Jy FE ? Flux in E (21.34um) MSX band
75- 82 A8 --- refIR Origin of the Mid-IR data (MSX or IRAS-LRS)
84- 88 F5.2 mag mbol ? Apparent bolometric magnitude
90- 94 A5 --- I/E Intrinsic (I) and/or Extrinsic (E) source
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Acknowledgements:
Roald Guandalini, guandalini(at)fisica.unipg.it
References:
Guandalini et al., Paper I 2006A&A...445.1069G 2006A&A...445.1069G
(End) Patricia Vannier [CDS] 15-Jul-2008