J/ApJ/811/45 Infrared spectral properties of M giants (Sloan+, 2015)
Infrared spectral properties of M giants.
Sloan G.C., Goes C., Ramirez R.M., Kraemer K.E., Engelke C.W.
<Astrophys. J., 811, 45 (2015)>
=2015ApJ...811...45S 2015ApJ...811...45S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, M-type ; Spectra, infrared
Keywords: infrared: stars - stars: AGB and post-AGB
Abstract:
We observed a sample of 20 M giants with the Infrared Spectrograph on
the Spitzer Space Telescope. Most show absorption structure at
6.6-6.8um which we identify as water vapor, and in some cases, the
absorption extends from 6.4um into the SiO band at 7.5um.
Variable stars show stronger H2O absorption. While the strength of
the SiO fundamental at 8um increases monotonically from spectral
class K0 to K5, the dependence on spectral class weakens in the M
giants. As with previously studied samples, the M giants show
considerable scatter in SiO band strength within a given spectral
class. All of the stars in our sample also show OH band absorption,
most noticeably in the 14-17um region. The OH bands behave much
like the SiO bands, increasing in strength in the K giants but showing
weaker dependence on spectral class in the M giants, and with
considerable scatter. An examination of the photometric properties
reveals that the V-K color may be a better indicator of molecular band
strength than the spectral class. The transformation from Tycho colors
to Johnson B-V color is double-valued, and neither B-V nor BT-VT
color increases monotonically with spectral class in the M giants like
they do in the K giants.
Description:
This dataset includes 20 spectra observed with the IRS on the Spitzer
Space Telescope. The spectra were obtained with the low-resolution
modules on the IRS and cover wavelengths of 5 to 37um. One table
provides details of the sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 80 20 Particulars for the 20 M giants
sp/* . 20 Individual spectra
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See also:
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Name of target used in filenames name.sp.dat
10- 19 A10 --- Target Preferred name of the target
21- 29 A9 --- Alias Alternative name of the target
31- 32 I2 h RAh Right ascension (J2000.0)
34- 35 I2 min RAm Right ascension (J2000.0)
37- 41 F5.2 s RAs Right ascension (J2000.0)
43 A1 --- DE- Declination sign (J2000.0)
44- 45 I2 deg DEd Declination (J2000.0)
47- 48 I2 arcmin DEm Declination (J2000.0)
50- 53 F4.1 arcsec DEs Declination (J2000.0)
55- 60 A6 --- Sptype Spectral type from the literature
62- 66 A5 --- Varclass Variability class
68- 71 F4.2 Jy F12 IRAS flux density at 12um in Jy (1)
73- 80 I8 --- AORkey AOR key for the Spitzer Space Telescope
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Note (1): From the Faint-Source Catalog; not color-corrected.
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Byte-by-byte Description of file (#): sp/*
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Bytes Format Units Label Explanations
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2- 8 F7.3 um lambda Wavelength
14- 22 E9.3 Jy Flux Flux density
25- 33 E9.3 Jy e_Flux rms uncertainty in flux density
38 I1 --- order [1/5] Unique identifier for the spectral segment
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Acknowledgements:
Gregory C. Sloan, sloan(at)isc.astro.cornell.edu
(End) Gregory Sloan [Cornell Univ., USA], Patricia Vannier [CDS] 29-Dec-2015