J/AJ/152/16 Bolometric flux estimation for cool evolved stars (van Belle+, 2016)
Bolometric flux estimation for cool evolved stars.
van Belle G.T., Creech-Eakman M.J., Ruiz-Velasco A.E.
<Astron. J., 152, 16 (2016)>
=2016AJ....152...16V 2016AJ....152...16V (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Stars, variable ; Spectral types ;
Photometry, infrared
Keywords: infrared: stars - instrumentation: high angular resolution -
instrumentation: interferometers - stars: carbon - stars: distances -
stars: fundamental parameters
Abstract:
Estimation of bolometric fluxes (FBOL) is an essential component of
stellar effective temperature determination with optical and
near-infrared interferometry. Reliable estimation of FBOL simply
from broadband K-band photometry data is a useful tool in those cases
were contemporaneous and/or wide-range photometry is unavailable for a
detailed spectral energy distribution (SED) fit, as was demonstrated
in Dyck et al. Recalibrating the intrinsic FBOL versus observed
F2.2µm relationship of that study with modern SED fitting
routines, which incorporate the significantly non-blackbody, empirical
spectral templates of the INGS spectral library (an update of the
library in Pickles) and estimation of reddening, serves to greatly
improve the accuracy and observational utility of this relationship.
We find that FBOL values predicted are roughly 11% less than the
corresponding values predicted in Dyck et al., indicating the effects
of SED absorption features across bolometric flux curves.
Description:
The target data come from 84 observations of 60 objects found in Dyck
et al. (1974ApJ...189...89D 1974ApJ...189...89D), all of which are cool evolved stars at
spectral types M4.0III and later. Two objects have measurements at
four separate epochs, three objects have three epochs, and 11 have two
epochs. These 60 objects include contemporaneous flux measurements in
logFlambda (in W/cm/µm) across up to 12 bands from 0.55 to
10.2µm, along with epoch-specific spectral-type determinations for
70 of the 84 observations, and 34FBOL determinations. Broadband
filters representing the V, J, H, K, L, M, and N passbands were used,
along with narrowband filters at 0.78, 0.87, 0.88, 1.04, and
1.05µm.
The data from Dyck et al. (1974ApJ...189...89D 1974ApJ...189...89D) were "obtained with
the Kitt Peak National Observatory 0.9- and 1.3-meter telescopes
during 1971 using three different photometric systems. Infrared
observations at 1.25, 1.65, 2.2, and 3.4µ were made with a lead
sulfide detector, while observations at 2.2, 3.4, 5.0, and 10.2µ
employed a gallium-doped germanium bolometer. The broad-band filters
used duplicated as far as possible the standard J, H, K, L, M, and N
passbands. In the visible and near-infrared regions, data were
obtained with an S-1 photomultiplier and various photometers using a
broad-band filter combination at 0.55µ approximating the V
passband, and narrow-band filters at 0.78, 0.87, 0.88, 1.04, and
1.05µ. The latter were chosen to isolate TiO and VO molecular bands
and nearby relatively uncontaminated continuum regions in M stars so
that photometric spectral types can be determined from the band
strengths".
For the purposes of this study, we have taken the data in Dyck et al.
(1974ApJ...189...89D 1974ApJ...189...89D) and converted it into Janskys (Jy), which can be
found in Table2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 123 84 Fluxes for the program stars derived from
Dyck et al. (1974ApJ...189...89D 1974ApJ...189...89D)
table3.dat 88 84 SED fitting results, including estimates for
reddening (AV), angular size (θEST),
and bolometric flux (FBOL)
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See also:
J/ApJ/694/1085 : Radii of exoplanet host stars (van Belle+, 2009)
J/ApJS/176/276 : PTI calibrator catalog (van Belle+, 2008)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Program star name
11- 14 I4 --- JD [1049/1302] Julian Date (JD-2440000)
16- 19 A4 --- SpT1 Spectral type from Dyck et al.
(1974ApJ...189...89D 1974ApJ...189...89D) (1)
21- 26 F6.2 [W/cm2] logFb [-14.3/-12.2]? Bolometric flux from Dyck et al.
(1974ApJ...189...89D 1974ApJ...189...89D); in units of
log107erg/s/cm2
28- 34 F7.4 Jy F0.55 [0.0003/10.32]? Flux at 0.55µm (2)
36- 41 F6.3 Jy F0.78 [0.01/69]? Flux at 0.78µm (2)
43- 48 F6.2 Jy F0.87 [0.02/467.4]? Flux at 0.87µm (2)
50- 55 F6.2 Jy F0.88 [0.15/398.2]? Flux at 0.88µm (2)
57- 63 F7.2 Jy F1.04 [0.15/1632.5]? Flux at 1.04µm (2)
65- 71 F7.2 Jy F1.05 [0.2/1431.4]? Flux at 1.05µm (2)
73- 79 F7.2 Jy F1.25 [0.8/2671.2]? Flux at 1.25µm (2)
81- 88 F8.2 Jy F1.65 [5.3/15770.6]? Flux at 1.65µm (2)
90- 98 F9.2 Jy F2.2 [18.9/122384]? Flux at 2.2µm (2)
100-107 F8.2 Jy F3.4 [15.3/10135.3]? Flux at 3.4µm (2)
109-115 F7.2 Jy F5.0 [24.5/5634.1]? Flux at 5.0µm (2)
117-123 F7.2 Jy F10.2 [10/6499.5]? Flux at 10.2µm (2)
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Note (1): Spectral types determined contemporaneously by Dyck et al.
(1974ApJ...189...89D 1974ApJ...189...89D) using the TiO and VO-band strengths in the narrowband
photometry, using the T1, T2, V1, D color indices calibration and
technique found in Lockwood (1972ApJS...24..375L 1972ApJS...24..375L). The color indices found
in Lockwood (1972ApJS...24..375L 1972ApJS...24..375L) were used to type stars in integer
subtypes between M1 and M3, half-integer subtypes between M4.0 and M8.0,
and quarter-integer subtypes between M8.0 and M10.
Note (2):
Derived from Dyck et al. (1974ApJ...189...89D 1974ApJ...189...89D). Dyck et al.
(1974ApJ...189...89D 1974ApJ...189...89D) cite their photometry errors as "2%-3%" for their
narrowband data, "5% or less" for 1-4µm, and "10 percent or slightly
greater" for their 5 and 10.2µm data points; no error is given for
V-band data, except to note that their stars are "extremely faint" (and
imply that larger errors result). Passband equivalents for fluxes:
* F0.55 = Broad-band V Filter
* F0.78 = Narrow-band Lockwood & Wing (1971ApJ...169...63L 1971ApJ...169...63L); Central
wavelength=7817Å, width at half power=90Å, feature
measured=TiO;
* F0.87 = Narrow-band Lockwood & Wing (1971ApJ...169...63L 1971ApJ...169...63L); Central
wavelength=8778Å, width at half power=82Å, feature
measured=continuum (TiO after M5);
* F0.88 = Narrow-band Lockwood & Wing (1971ApJ...169...63L 1971ApJ...169...63L); Central
wavelength=8884Å, width at half power=114Å, feature
measured=TiO;
* F1.04 = Narrow-band Lockwood & Wing (1971ApJ...169...63L 1971ApJ...169...63L); Central
wavelength=10351Å, width at half power=125Å, feature
measured=continuum;
* F1.05 = Narrow-band Lockwood & Wing (1971ApJ...169...63L 1971ApJ...169...63L); Central
wavelength=10506Å, width at half power=100Å, feature
measured=VO;
* F1.25 = Broad-band J filter;
* F1.65 = Broad-band H filter;
* F2.2 = Broad-band K filter;
* F3.4 = Broad-band L filter;
* F5.0 = Broad-band M filter;
* F10.2 = Broad-band N filter.
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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- 9 A9 --- Name Program star name
11- 14 I4 --- JD ? Julian Date (JD-2440000)
16- 21 A6 --- SpT2 Spectral type (3)
23- 29 A7 --- SpT3 The sedFit spectral type (4)
31- 37 F7.2 --- Dchi2 [1.6/1170]? Reduced chi-square (χ2/DOF) (3)
39- 43 F5.2 --- schi2 [0.08/18.15]? The sedFit reduced chi-square
(χ2/DOF) (4)
45- 48 F4.2 mag Av [0/8.81]? The sedFit visual extinction (4)
50- 53 F4.2 mag e_Av [0.2/0.43]? Uncertainty in Av
55- 59 F5.2 mas Size [1.1/15.4]? The sedFit angular size
(θEST) (4)
61- 64 F4.2 mas e_Size [0.09/6.92]? Uncertainty in Size
66- 72 E7.2 mW/m2 Fbol2 ? The sedFit bolometric flux; in ergs/s/cm2 (4)
74- 80 E7.2 mW/m2 e_Fbol2 ? Uncertainty in Fbol2; in ergs/s/cm2
82- 88 E7.2 mW/m2 Fbol1 ? Bolometric flux; in ergs/s/cm2 (3)
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Note (3): From Dyck et al. (1974ApJ...189...89D 1974ApJ...189...89D).
Note (4): For SED fitting, we used the sedFit code that we have employed on
previous occasions (e.g., van Belle et al., 2007ApJ...657.1058V 2007ApJ...657.1058V; van Belle
et al. 2008, Cat. J/ApJS/176/276; van Belle & von Braun 2009,
Cat. J/ApJ/694/1085) for determination of bolometric flux and other
relevant stellar parameters. The flux data from Dyck et al.
(1974ApJ...189...89D 1974ApJ...189...89D) were matched against a grid of M-giant template
spectra; for comparison, the epoch-specific spectral types determined in
Dyck et al. (1974ApJ...189...89D 1974ApJ...189...89D) were also specifically evaluated. See the
Section 2.2 in the paper for additional details.
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 13-Sep-2016