J/ApJ/813/29 Classical and type II Cepheids IR excesses (Schmidt, 2015)
Excess mid-infrared flux: an indicator of mass loss in Cepheids?
Schmidt E.G.
<Astrophys. J., 813, 29 (2015)>
=2015ApJ...813...29S 2015ApJ...813...29S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Infrared sources
Keywords: stars: Population II; stars: variables: Cepheids
Abstract:
Spectral energy distributions for 132 classical and type II Cepheids
were searched for evidence of excess flux above the photospheric level
in the mid-infrared. Eight of them were found to have unambiguously
strong excess emission while a further 13 showed evidence of weak
emission. The presence of emission appears to be unrelated to either
the pulsational amplitude or the effective temperature while strong
emission is limited to stars with periods longer than 11 days, with a
single exception. For the stars with strong emission we attempted to
fit the energy distribution with a stellar wind model. No acceptable
fit could be found for silicate grains. With graphite or iron grains
we could only obtain an acceptable fit if the maximum dust temperature
was significantly lower than the condensation temperature. We conclude
that the excess emission is not evidence of mass loss.
Description:
In this paper we have used the optical V and R magnitudes from our
previous papers, the near-infrared J, H, and Ks magnitudes from the
Two Micron All Sky Survey (2MASS, II/246) and the mid-infrared W1, W2,
W3, and W4 magnitudes from ALLWISE (II/328).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 51 137 The program stars
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
II/328 : AllWISE Data Release (Cutri+ 2013)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/AJ/150/13 : Cepheid Radial Velocities (CRaV) project (Evans+, 2015)
J/A+A/576/A30 : NIR light-curve templates for classical Cepheids (Inno+, 2015)
J/AJ/146/61 : Type II Cepheid candidates. IV. NSVS sources (Schmidt+, 2013)
J/MNRAS/429/385 : Short-period variables near GC (Matsunaga+, 2013)
J/AJ/142/187 : HST observations of 7 Pop.II variable stars (Benedict+, 2011)
J/AJ/141/53 : Lick indices of type II Cepheid candidates (Schmidt+, 2011)
J/AcA/60/91 : VI light curves of SMC type II Cepheids (Soszynski+, 2010)
J/AJ/139/2300 : BVIc light curves of 3 type II Cepheids (Rabidoux+, 2010)
J/MNRAS/397/933 : LMC type II Cepheids JHKs magnitudes (Matsunaga+, 2009)
J/AJ/137/4598 : VR light curve of ASAS-North Cepheids (Schmidt+, 2009)
J/AJ/133/665 : Photometry of type II Cepheid candidates (Schmidt+, 2007)
J/A+A/453/155 : Extended envelopes around Galactic Cepheids II. (Merand+, 2006)
J/AJ/130/832 : VR photometry of type II Cepheids. III (Schmidt+, 2005)
J/AJ/129/2007 : Photometry of type II Cepheids. II (Schmidt+, 2005)
J/AJ/128/1748 : VR photometry of type II Cepheids (Schmidt+, 2004)
http://www.aavso.org/vsx/ : International Variable Star Index (VSX) home page
http://www.astro.utoronto.ca/DDO/research/cepheids/cepheids.html : DDO database
of Galactic classical Cepheids
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Name of star (1)
11- 14 A4 --- Star Preliminary designation of star (2)
16- 22 A7 --- ZType Cepheid type from Schmidt 2013, J/AJ/146/611,
("Class"=classical or "Type II")
24- 30 A7 --- VSXType Variable star type from the VSX (B/vsx) (3)
32- 37 F6.3 d Per [0.8/96] Pulsation period
39- 43 F5.3 mag E(B-V) [0/1.8] Adopted color excess
45 I1 --- r_E(B-V) Reference code for E(B-V) (4)
47 A1 --- Em [A-D] Emission category
(A=unambiguous excess IR emission) (5)
49- 51 A3 --- Notes Notes (6)
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Note (1): Designations from the General Catalog of Variable Stars or
the Catalog of Suspected Variables (GCVS and NSV;
with corrections and additions from the online version:
http://www.aavso.org/vsx/; see also B/gcvs and B/vsx).
Note (2): Since not all of the stars are yet in GCVS or NSV catalogs, the
preliminary designations from Schmidt et al. (2007, J/AJ/133/665;
2009, J/AJ/137/4598) and Schmidt (2013, J/AJ/146/611) are given.
Note (3): The AAVSO International Variable Star Index (the VSX) gives
classifications based on a variety of criteria and can provide a
check on our classifications. For a majority of the stars the VSX
types are consistent with their being classical Cepheids
(VSX type DCEP), type II Cepheids (VSX types CWA, CWB, AHB1 or RVA),
or Cepheids of uncertain type (VSX type CEP). However, five of them
are listed in the VSX as EA/D/WD, BY, RS or UG.
See section 2 for further explanations.
Note (4): Reference for E(B-V) as follows:
1 = Schmidt et al. (2011, J/AJ/141/53) or
Schmidt (2013, J/AJ/146/611);
2 = DDO Database or Fernie (1990ApJS...72..153F 1990ApJS...72..153F);
3 = Schlafly & Finkbeiner (2011ApJ...737..103S 2011ApJ...737..103S).
Note (5): Emission category as follows:
A = Cepheids with strong, unambigious excess infrared emission
B = Stars with weak mid-infrared excesses
C = Stars with anomalous mid-infrared fluxes
D = Stars that lack detectable mid-infrared excesses.
See section 3 for further details.
Note (6): Notes as follows:
1 = No W4 magnitude;
2 = No W3 or W4 magnitude;
3 = Companion may contribute to flux;
4 = Poor fit to VRJHKS fluxes;
5 = Rise beyond 10 microns;
6 = Infrared emission appears to overlap with the KS band;
7 = No W3 magnitude and W4 is very high. Probably no excess.
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Acknowledgements:
Edward G. Schmidt [University of Nebraska-Lincoln] for the coordinates.
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 11-Feb-2016