J/ApJ/663/320 IR-through-UV extinction curve (Fitzpatrick+, 2007)
An analysis of the shapes of interstellar extinction curves.
V. The IR-through-UV curve morphology.
Fitzpatrick E.L., Massa D.
<Astrophys. J., 663, 320-341 (2007)>
=2007ApJ...663..320F 2007ApJ...663..320F
ADC_Keywords: Models ; Extinction
Keywords: dust, extinction - methods: data analysis
Abstract:
We study the IR-through-UV wavelength dependence of 328 Galactic
interstellar extinction curves affecting normal, near-main-sequence B
and late O stars. We derive the curves using a new technique that
employs stellar atmosphere models in lieu of unreddened "standard"
stars. Under ideal conditions, this technique is capable of virtually
eliminating spectral mismatch errors in the curves. In general, it
lends itself to a quantitative assessment of the errors and enables a
rigorous testing of the significance of relationships between various
curve parameters, regardless of whether their uncertainties are
correlated.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 67 328 Basic Data for Survey Stars
table3.dat 87 328 Best-Fit Parameters for Survey Stars
table4.dat 138 328 Best-Fit Extinction Curve Parameters for
Survey Stars
refs.dat 64 83 References
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Name Star name (1)
24- 38 A15 --- SpType MK Spectral type (2)
40- 44 F5.2 mag Vmag The V band magnitude
46- 49 I4 pc Dist ? Heliocentric distance (3)
51- 57 F7.3 deg GLON Galactic longitude
59- 64 F6.2 deg GLAT Galactic latitude
66- 67 I2 --- Ref ? Reference, in refs.dat file
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Note (1): The stars are listed in order of increasing Right Ascension using
the most commonly adopted forms of their names. The first preference
was ``HDnnn'', followed by ``BDnnn'', etc. There are 185 survey stars
which are members of open clusters or associations. The identity of
the cluster or association is either contained in the star name itself
(e.g., NGC 457 Pesch 34) or is given in parentheses after the star's
name.
Note (2): Spectral types were selected from those given in the SIMBAD
database, and the source of the adopted types is shown in the "Ref".
When multiple types were available for a particular star, we selected
one based on our own preferred ranking of the sources.
Note (3): Distances are:
NGC 2244 = distance is from Perez et al. (1987PASP...99.1050P 1987PASP...99.1050P);
NGC 3293 = distance is from Balona & Crampton (1974MNRAS.166..203B 1974MNRAS.166..203B);
Trumpler 14 and 16 = distances are from Massey & Johnson
(1993, Cat. J/AJ/105/980);
Cep OB3 = distance is from Crawford & Barnes (1970AJ.....75..952C 1970AJ.....75..952C).
The distances to all other clusters or associations are from the Open
Clusters and Galactic Structure database maintained by Wilton S. Dias,
Jacques Lepine, Bruno S. Alessi, and Andre Moitinho, Cat. B/ocl, and
http://www.astro.iag.usp.br/~wilton/ .
For the non-cluster stars, distances were calculated using the E(B-V)
values from this study and the absolute magnitudes from Turner
(1980ApJ...240..137T 1980ApJ...240..137T) (for mid-B and earlier types) and Blaauw 1963
(in Basic Astronomical Data, ed. K. A. Strand (Chicago:
Univ. Chicago Press), chap. 20) (for mid-B and later types).
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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- 22 A22 --- Name Star name
24- 28 I5 K Teff Model effective temperature (2)
30- 33 I4 K e_Teff 1σ uncertainty in Teff
35- 38 F4.2 [cm/s2] log(g) Log of model surface gravity (3)
40- 43 F4.2 [cm/s2] e_log(g) 1σ uncertainty in log(g)
45- 49 F5.2 [Sun] [m/H] Log of model metallicity (4)
51- 54 F4.2 [Sun] e_[m/H] ? 1σ uncertainty in [m/H]
56- 59 F4.1 km/s Vturb Model turbulent velocity (5)
61- 63 F3.1 km/s e_Vturb ? 1σ uncertainty in Vturb
65- 70 F6.4 mas theta Model angular radius
72- 77 F6.4 mas e_theta 1σ uncertainty in theta
79- 82 F4.2 mag E(B-V) Model reddening
84- 87 F4.2 mag e_E(B-V) 1σ uncertainty in E(B-V)
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Note (2): For the O stars analyzed using the TLUSTY atmosphere models, the
values of Teff were adopted from the Spectral Type vs. Teff relation
given in Table 2. These stars can be identified by their 1-σ
uncertainties, which are ±1000K.
Table 2: Adopted Temperature Scale for Main-Sequence O Stars
-------------------
SpType Teff (K)
-------------------
O6 40000
O6.5 38500
O7 37000
O7.5 36500
O8 36000
O8.5 34750
O9 33500
O9.5 32750
B0 32000
-------------------
Note (3): For stars in clusters, the surface gravities are determined as
discussed in Sect. 3.1 and rely on stellar evolution models and
cluster distance determinations. Surface gravities for non-cluster
stars are not always well-determined, because of a lack of specific
spectroscopic indicators. In some cases, the best-fit solutions for
these stars indicated physically unlikely results (i.e., log(g)≳4.3
or log(g)≲3.0). For these stars, a value of log(g)=3.9 was assumed
(which is the mean log(g) of the rest of the sample) and a 1-σ
uncertainty of ±0.2 was incorporated in the error analysis. These
cases can be identified by log(g) entries of "3.9±0.2".
Note (4): For the O stars in the sample, our fitting procedure utilized
solar abundance TLUSTY models. For these stars the values of [m/H]
are indicated by entries of "0" without uncertainties.
Note (5): For the O stars, the adopted TLUSTY models incorporate
Vturb=10km/s. For these stars the values of Vturb are indicated by
entries of "10" without uncertainties.
For the B stars, which were modeled using ATLAS9 models, the values of
Vturb were determined by the fitting procedure, but were constrained
to lie between 0 and 10km/s.
Stars whose best-fit SED models required these limiting values are
indicated by Vturb entries of "0" or "10", without error bars. The
uncertainties for stars with best-fit Vturb values close to these
limits may be underestimated due to this truncation.
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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- 22 A22 --- Name Star name
24- 28 F5.3 --- x0 The UV x0 coefficient (2)
30- 34 F5.3 --- e_x0 1-σ uncertainty in x0
36- 39 F4.2 --- gamma UV γ coefficient (2)
41- 44 F4.2 --- e_gamma 1-σ uncertainty in γ
46- 50 F5.2 --- c1 UV c1 coefficient (2)
52- 55 F4.2 --- e_c1 ? 1-σ uncertainty in c1
57- 61 F5.2 --- c2 UV c2 coefficient (2)
63- 66 F4.2 --- e_c2 1-σ uncertainty in c2
68- 72 F5.2 --- c3 UV c3 coefficient (2)
74- 77 F4.2 --- e_c3 1-σ uncertainty in c3
79- 82 F4.2 --- c4 UV c4 coefficient (2)
84- 87 F4.2 --- e_c4 1-σ uncertainty in c4
89- 92 F4.2 --- c5 UV c5 coefficient (2)
94- 97 F4.2 --- e_c5 1-σ uncertainty in c5
99-102 F4.2 --- O1 ? Optical spline O1 point (3)
104-107 F4.2 --- e_O1 ? 1-σ uncertainty in O1
109-112 F4.2 --- O2 Optical spline O2 point (3)
114-118 F5.2 --- O3 Optical spline O3 point (3)
120-123 F4.2 --- R(V) IR R(V) coefficient (4)
125-128 F4.2 --- e_R(V) ? 1-σ uncertainty in R(V)
130-133 F4.2 --- kIR IR kIR coefficient (4)
135-138 F4.2 --- e_kIR ? 1-σ uncertainty in kIR
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Note (2): Extinction curve is defined by
k(λ-V) = c1+c2x+c3.D(x,x0,γ) for x≤c5 and
= c1+c2x+c3.D(x,x0,γ) = c4(x-c5)2 for x>c5.
where x=λ-1, in units of inverse microns (um-1) and
D(x,x0,γ)=x2/[(x2-x02)+x2γ2]
For the stars HD237019, HD18352, and HD25443 the long wavelength IUE
spectra are incomplete. For these cases we constrained the UV linear
extinction component to follow the relation c1=2.18-2.91*c2 from
Fitzpatrick (2004, in ASP Conf. Ser. 309, 33). For these stars we
list uncertainties for the c2 values but not for the c1 values.
Note (3): The uncertainties in the O2 and O3 optical spline points (at
wavelengths of 4000 and 5530 Angstroms, respectively) are typically
0.01 or less and are not listed. For several stars, those without U
band photometry, we did not solve for the O1 point at 3300 Angstroms.
Note (4): R(V) is the ratio of reddening to extinction at V. For field
stars without IR photometry, we assumed R(V)=3.1 and kIR=1.11, with
the latter based on the relation kIR=0.63*R(V)-0.84 from Fitzpatrick
(2004, in ASP Conf. Ser. 309, 33) clusters, we adopted the mean R(V)
of the other cluster members and a value of kIR based on the
aforementioned relation. These assumed values are listed in the Table
without uncertainties. Several survey stars have apparently noisy JHK
data and yielded very uncertain values of kIR. For these, we
ultimately derived the extinction curve by solving for the best-fit
value of R(V) with kIR constrained to follow the Fitzpatrick (2004, in
ASP Conf. Ser. 309, 33) relation. The resultant R(V) values are listed
with their uncertainties while the kIR values are listed without
uncertainties.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 45 A22 --- Aut Author's name
46- 64 A19 --- Com Comments
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History:
From electronic version of the journal
References:
Fitzpatrick & Massa, Paper I 1986ApJ...307..286F 1986ApJ...307..286F
Fitzpatrick & Massa, Paper II 1988ApJ...328..734F 1988ApJ...328..734F
Fitzpatrick & Massa, Paper III 1990ApJS...72..163F 1990ApJS...72..163F
Fitzpatrick & Massa, Paper IV 2005AJ....130.1127F 2005AJ....130.1127F
Fitzpatrick & Massa, Paper VI 2009ApJ...699.1209F 2009ApJ...699.1209F
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 14-Aug-2009