J/ApJ/826/44 Spitzer/IRS obs. of Magellanic carbon stars (Sloan+, 2016)
The infrared spectral properties of Magellanic carbon stars.
Sloan G.C., Kraemer K.E., McDonald I., Groenewegen M.A.T., Wood P.R.,
Zijlstra A.A., Lagadec E., Boyer M.L., Kemper F., Matsuura M., Sahai R.,
Sargent B.A., Srinivasan S., van Loon J.T., Volk K.
<Astrophys. J., 826, 44-44 (2016)>
=2016ApJ...826...44S 2016ApJ...826...44S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, carbon ; Spectra, infrared ; Photometry, UBVRI ;
Photometry, infrared ; Surveys ; Magellanic Clouds
Keywords: circumstellar matter; infrared: stars; stars: AGB and post-AGB;
stars: carbon
Abstract:
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
7.5µm. 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 asymptotic giant branch and/or they may have
non-spherical dust geometries.
Description:
Table 1 lists the 144 objects in the LMC and 40 in the SMC observed
with the IRS (spectral coverage at 5-14um and 14-37um, respectively,
with a resolution R∼80-120) and identified as carbon stars. A variety
of Spitzer observing programs contributed to the present sample of
carbon stars (see Note 2 in table 1). We adopt distance moduli for the
LMC and SMC of 18.5 and 18.9, respectively.
For all of our targets, we have constructed SEDs based on multi-epoch
photometry in the optical, near-IR, and mid-IR from several surveys.
The mid-IR data come from the SAGE survey of the LMC (Meixner et al.
2006, J/AJ/132/2268) and the SAGE-SMC survey for the SMC (Gordon et
al. 2011AJ....142..102G 2011AJ....142..102G)). The SAGE-VAR survey adds four epochs from
the Warm Spitzer Mission at 3.6 and 4.5um for portions of the LMC and
SMC (Riebel et al. 2015ApJ...807....1R 2015ApJ...807....1R). We also used additional
epochs at 3.4 and 4.6um from the Wide-field Infrared Survey Experiment
(WISE; Wright et al. 2010AJ....140.1868W 2010AJ....140.1868W) and the NEOWISE reactivation
mission (Mainzer et al. 2014ApJ...792...30M 2014ApJ...792...30M). Near-IR photometry comes
from the 2MASS survey, and the deeper 2MASS-6X survey provides a
second epoch at J, H, and Ks (Cutri et al. 2012, II/281; Skrutskie et
al. 2006, VII/233). Additional epochs come from the Deep Near-IR
Survey of the Southern Sky (DENIS) at J and Ks (Cioni et al. 2000,
II/228) and the IR Survey Facility (IRSF) at J, H, and Ks (Kato et al.
2007, II/288). In the optical, we relied on the Magellanic Clouds
Photometric Survey (MCPS) at U, B, V, and I (Zaritsky et al. 2002,
J/AJ/123/855; 2004, J/AJ/128/1606). DENIS adds data at I. Additional
mean magnitudes at V and I in the LMC come from the OGLE-III Shallow
Survey (Ulaczyk et al. 2013, J/AcA/63/1). Where possible, we replaced
the V and I data with mean magnitudes from the OGLE-III surveys of the
Magellanic Clouds, which also give pulsation periods and amplitudes
(Soszynski et al. 2009, J/AcA/59/335; 2011, J/AcA/61/217).
We also consider a Galactic control sample using spectra from the
Short-Wavelength Spectrometer (SWS) on the Infrared Space Observatory
(ISO); see section 2.5.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 77 184 The Spitzer sample of Magellanic carbon stars
table3.dat 107 184 Optical and near-infrared photometry
table4.dat 87 184 Mid-infrared photometry and bolometric magnitudes
table5.dat 87 184 Spectroscopic data - Spitzer/IRS sample
table6.dat 97 42 Spectroscopic data - ISO/SWS control sample
table9.dat 26 251 *Multi-epoch K-band photometry for 9 carbon stars
table10.dat 74 1380 *Multi-epoch 3-5 micron photometry
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Note on table9.dat: This table gives the multi-epoch K-band photometry for the
nine new periods determined from K-band monitoring; see Appendix B for
further details.
Note on table10.dat: All the carbon stars in this study have been observed
multiple times at 3.6 and 4.5um by Spitzer and at 3.4 and 4.6um by WISE
(see Section 2.4). We examined if sufficient epochs were available from the
two spacecraft to generate mid-IR light curves and from these determine
pulsation periods. This table presents the multi-epoch photometry at 3.6 and
4.5um, including the converted WISE photometry, for all of the Magellanic
carbon stars in our sample. We were able to fit the light curves of 42
objects. Of these objects, 37 had periods previously determined from more
extensive light curves available at shorter wavelengths, such as those
from OGLE. See Appendix C for further explanations.
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See also:
B/denis : The DENIS database (DENIS Consortium, 2005)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
II/305 : SAGE LMC and SMC IRAC Source Catalog (IPAC 2009)
II/288 : IRSF Magellanic Clouds Point Source Catalog (Kato+ 2007)
II/281 : 2MASS 6X Point Source Working Database / Catalog (Cutri+ 2006)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
II/228 : DENIS Catalogue toward Magellanic Clouds (DCMC) (Cioni+ 2000)
J/ApJ/811/145 : LMC + SMC evolved stars detected with Herschel (Jones+, 2015)
J/MNRAS/451/3504 : Classification of IRS sources in the SMC (Ruffle+, 2015)
J/MNRAS/449/639 : VMC survey. XIV. SFR in SMC (Rubele+, 2015)
J/AJ/149/11 : Spectra of candidate standard stars in mid-IR (Sloan+, 2015)
J/A+A/564/A88 : L2 Pup JHKL images (Kervella+, 2014)
J/AcA/63/1 : OGLE-IV Magellanic Bridge Data supernovae (Kozlowski+, 2013)
J/ApJ/753/71 : Mass-loss return from LMC evolved stars. VI. (Riebel+, 2012)
J/A+A/537/A105 : Modelisation of AGB stars in the LMC (Gullieuszik+, 2012)
J/AcA/61/217 : VI LCs of SMC long-period variables (Soszynski+, 2011)
J/PASP/122/683 : SAGE-Spec Spitzer legacy program (Kemper+, 2010)
J/AcA/59/335 : VI light curves of LMC R CBr stars (Soszynski+, 2009)
J/A+A/506/1277 : Modelisation of Magellanic Cloud C/O stars
(Groenewegen+, 2009)
J/AJ/136/1703 : Ridgelines of 6 intermediate-age SMC clusters (Glatt+, 2008)
J/MNRAS/376/313 : Carbon star in Magellanic Cloud (Groenewegen+, 2007)
J/ApJ/655/212 : S3MC IRAC and MIPS photometry (Bolatto+, 2007)
J/AJ/132/2268 : SAGE calibration stars (Meixner+, 2006)
J/MNRAS/369/751 : Near-infrared photometry of carbon stars (Whitelock+, 2006)
J/A+A/438/521 : SMC C stars B and R light curves (Raimondo+, 2005)
J/A+A/425/595 : OGLE+2MASS+DENIS LPV in Magellanic Clouds (Groenewegen, 2004)
J/MNRAS/355/1196 : MS bands of SiC2 in LMC carbon stars (Morgan+, 2004)
J/MNRAS/353/705 : OGLE Variables in Magellanic Clouds (Ita+, 2004)
J/AJ/128/1606 : Magellanic Clouds Photometric Survey: LMC (Zaritsky+, 2004)
J/AJ/123/855 : Magellanic Clouds Photometric Survey: SMC (Zaritsky+, 2002)
J/A+A/369/932 : RI photometry of LMC carbon stars (Kontizas+, 2001)
J/A+AS/122/507 : Kinematics of SMC carbon stars (Hatzidimitriou+ 1997)
J/A+AS/122/463 : Carbon stars in Magellanic Clouds (Kunkel+ 1997)
J/A+AS/113/539 : A survey of carbon stars in the SMC (Morgan+, 1995)
J/A+AS/97/603 : C stars in SMC (Rebeirot+ 1993)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- Name Target identifier
18- 33 A16 --- Alias Target alias
35- 43 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
45- 54 F10.6 deg DEdeg Declination in decimal degrees (J2000)
56- 60 A5 --- Ref Position reference (2MASS or IRAC)
62- 64 I3 d Per [133/976]? Period
66- 71 A6 --- r_Per Reference for Per (1)
73- 77 I5 --- PID Program identifier (2)
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Note (1): Reference as follows:
OGLE = Optical Gravitational Lensing Experiment,
Soszynski et al. (2009, J/AcA/59/335; 2011, J/AcA/61/217)
GO7 = Groenewegen et al (2007, J/MNRAS/376/313);
G09 = Groenewegen et al (2009, J/A+A/506/1277);
K10 = Kamath et al. (2010MNRAS.408..522K 2010MNRAS.408..522K);
N00 = Nishida et al. (2000MNRAS.313..136N 2000MNRAS.313..136N);
R05 = Raimondo et al (2005, J/A+A/438/521);
S06 = Sloan et al. (2006ApJ...645.1118S 2006ApJ...645.1118S);
W89 = Whitelock et al. (1989MNRAS.238..769W 1989MNRAS.238..769W);
W03 = Whitelock et al. (2003MNRAS.342...86W 2003MNRAS.342...86W);
Z06 = Zijlstra et al. (2006MNRAS.370.1961Z 2006MNRAS.370.1961Z);
App. B = This article's appendix B (9 sources; see table 9);
App. C = This article's appendix C (5 sources; see table 10).
Note (2): Spectroscopic Spitzer programs that observed Magellanic carbon
stars (table 2):
---------------------------------------------------------------------
PID Project leaders Description
---------------------------------------------------------------------
200 Houck & Sloan Evolved stars in the LMC and SMC
1094 F. Kemper AGB evolution in the LMC (and Galaxy)
3277 Egan & Sloan MSX-based sample in the SMC
3426 Kastner & Buchanan Bright infrared sources in the LMC
3505 Wood & Zijlstra AGB stars in the LMC and SMC
3591 F. Kemper AGB evolution in the LMC
37088 R. Sahai Embedded carbon stars in the LMC
40650 Looney & Gruendl YSOs and red sources in the LMC
40519 Tielens & Kemper Extended the IRS sample in the LMC
50240 Sloan & Kraemer Extended the IRS sample in the SMC
50338 M. Matsuura Carbon-rich post-AGB candidates in the LMC
---------------------------------------------------------------------
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Target identifier
18- 23 F6.3 mag Umag [15.7/21.7]? U band magnitude
25- 29 F5.3 mag e_Umag [0.04/0.6]? Uncertainty in Umag
31- 36 F6.3 mag Bmag [16.1/23.1]? B band magnitude
38- 42 F5.3 mag e_Bmag [0.02/1]? Uncertainty in Bmag
44- 49 F6.3 mag Vmag [15.1/22.4]? V band magnitude
51- 55 F5.3 mag e_Vmag [0.02/1.3]? Uncertainty in Vmag
57- 62 F6.3 mag Imag [12.5/20.6]? I band magnitude
64- 68 F5.3 mag e_Imag [0.007/2.4]? Uncertainty in Imag
70- 75 F6.3 mag Jmag [11.4/19.5]? Johnson J band magnitude
77- 81 F5.3 mag e_Jmag [0.02/3]? Uncertainty in Jmag
83- 88 F6.3 mag Hmag [10.2/18.1]? Johnson H band magnitude
90- 94 F5.3 mag e_Hmag [0.001/2]? Uncertainty in Hmag
96-101 F6.3 mag Kmag [9.1/17.5]? Johnson K band magnitude
103-107 F5.3 mag e_Kmag [0.01/1.2]? Uncertainty in Kmag
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Target identifier
18- 23 F6.3 mag 3.6mag [7.6/16.6] Spitzer/IRAC 3.6um band magnitude
25- 29 F5.3 mag e_3.6mag [0.02/0.9] Uncertainty in 3.6mag
31- 36 F6.3 mag 4.5mag [6.9/14] Spitzer/IRAC 4.5 micron band magnitude
38- 42 F5.3 mag e_4.5mag [0.03/0.8] Uncertainty in 4.5mag
44- 49 F6.3 mag 5.8mag [5.7/11]? Spitzer/IRAC 5.8 micron band magnitude
51- 55 F5.3 mag e_5.8mag [0.005/0.8]? Uncertainty in 5.8mag
57- 62 F6.3 mag 8.0mag [4.8/10.7]? Spitzer/IRAC 8.0um band magnitude
64- 68 F5.3 mag e_8.0mag [0.003/0.6]? Uncertainty in 8.0mag
70- 75 F6.3 mag 24mag [2.7/10]? Spitzer/MIPS 24 micron band magnitude
77- 81 F5.3 mag e_24mag [0.001/0.5]? Uncertainty in 24mag
83- 87 F5.2 mag Mbol [-6.5/-3] Bolometric magnitude
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Byte-by-byte Description of file: table[56].dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- Name Target identifier
18- 23 F6.3 um EW [-0.08/0.4] Equivalent width of C2H2 at 7.5um
25- 29 F5.3 um e_EW [0.001/0.05] Uncertainty in EW
31- 36 F6.3 --- FSiC [-0.2/0.6] SiC flux relative to the continuum
38- 42 F5.3 --- e_FSiC [0.001/0.04] Uncertainty in FSiC
44- 49 F6.3 mag Color1 [-0.16/3.1] The ([6.4]-[9.3]) color index
51- 55 F5.3 mag e_Color1 [0/0.09] Uncertainty in Color1
57 A1 --- f_Color1 [a] Flag on Color1 (3)
59- 64 F6.3 mag Color2 [-0.5/1.5]? The ([16.5]-[21.5]) color index
66- 70 F5.3 mag e_Color2 [0.001/0.3]? Uncertainty in Color2
72- 77 F6.3 --- FMgS [-0.14/1.4]? MgS flux relative to the continuum
79- 83 F5.3 --- e_FMgS [0.001/0.2]? Uncertainty in FMgS
85- 87 A3 --- Class IR spectral classification (4)
89- 97 A9 --- Alias Target alias (only for table 6)
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Note (3):
a = The [6.4]-[9.3] color replaced with an estimate based on [5.8]-[8].
Note (4): The CE0-CE5 sequence depends solely on the [6.4]-[9.3] color, with
the breaks at a color of 0.05 and at intervals of 0.30 from there
to 1.25 (i.e. CE1 sources = 0.05<[6.4]-[9.3]<0.35).
See sections 3.2 and 4.5 for further explanations.
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Target identifier
17- 20 I4 d JD Julian Date of observation; JD-2450000
22- 26 F5.2 mag Kmag [11/15] K band magnitude
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Byte-by-byte Description of file: table10.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Target identifier
18- 26 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
28- 37 F10.6 deg DEdeg Declination in decimal degrees (J2000)
39- 43 I5 d MJD Modified Julian Date
45- 50 F6.3 mag 3.6mag [7.2/16.6]? The 3.6 micron band magnitude
52- 56 F5.3 mag e_3.6mag [0.01/0.3]? Uncertainty in 3.6mag
58- 63 F6.3 mag 4.5mag [6.5/14.3]? The 4.5 micron band magnitude
65- 69 F5.3 mag e_4.5mag [0.009/0.2]? Uncertainty in 4.5mag
71- 74 A4 --- Ref Data source (IRAC or WISE) (1)
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Note (1): WISE data are corrected as described in Appendix A.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 21-Sep-2016