J/ApJ/831/L6 Eclipsing binary parallaxes with Gaia data (Stassun+, 2016)
Evidence for a systematic offset of -0.25mas in the Gaia DR1 parallaxes.
Stassun K.G., Torres G.
<Astrophys. J., 831, L6-L6 (2016)>
=2016ApJ...831L...6S 2016ApJ...831L...6S (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Parallaxes, trigonometric ;
Effective temperatures
Keywords: binaries: eclipsing; parallaxes; stars: distances
Abstract:
We test the parallaxes reported in the Gaia first data release using
the sample of eclipsing binaries with accurate, empirical distances
from Stassun & Torres (2016, arXiv:1609.02579). We find an average
offset of -0.25±0.05mas in the sense of the Gaia parallaxes being
too small (i.e., the distances too long). The offset does not depend
strongly on obvious parameters such as color or brightness. However,
we find with high confidence that the offset may depend on ecliptic
latitude: the mean offset is -0.38±0.06mas in the ecliptic north and
-0.05±0.09mas in the ecliptic south. The ecliptic latitude
dependence may also be represented by the linear relation,
Δπ~-0.22(±0.05)-0.003(±0.001)xβmas (β in
degrees). Finally, there is a possible dependence of the parallax
offset on distance, with the offset becoming negligible for
π≲1mas; we discuss whether this could be caused by a systematic
error in the eclipsing binary distance scale, and reject this
interpretation as unlikely.
Description:
We adopted the predicted parallaxes for the 158 eclipsing binaries (EBs)
included in the study of Stassun & Torres (2016, arXiv:1609.02579). Of
these, 116 had parallaxes available in the Gaia first data release
(see I/337). We excluded from our analysis any EBs identified as
potentially problematic in Stassun & Torres (2016). This left 111 EBs
with good parallaxes from both the EB analysis and from Gaia.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 107 116 Eclipsing binary and Gaia data
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See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/324 : The Initial Gaia Source List (IGSL) (Smart, 2013)
III/254 : 2nd Cat. of RVs with Astrometric Data (Kharchenko+, 2007)
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
I/250 : The Tycho Reference Catalogue (Hog+ 1998)
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
J/A+A/530/A138 : Geneva-Copenhagen survey re-analysis (Casagrande+, 2011)
J/A+A/523/A48 : Gaia photometry (Jordi+, 2010)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Binary identifier
17 A1 --- f_Name [cd] Flag on Name (1)
19- 29 A11 --- TYC Tycho catalog identifier
31- 35 I5 K Teff [4330/38000] Effective temperature of
primary component
37- 40 I4 K e_Teff [45/2500] The 1σ uncertainty in Teff
42- 46 F5.2 mag Vmag [5.6/12.5] The V band magnitude
48- 52 F5.2 --- chi2 [0.2/86] The Χ2 of SED fit (2)
54- 58 F5.2 mas plxEB [0.1/30.7] Eclipsing binary parallax
60- 63 F4.2 mas E_plxEB [0.02/1.9] The 1σ upper boundary on plxEB
65- 68 F4.2 mas e_plxEB [0.02/1.8] The 1σ lower boundary on plxEB
70- 75 F6.3 mas plxG [0.2/32.3] Gaia parallax
77- 81 F5.3 mas e_plxG [0.2/1] The 1σ uncertainty in plxG
83- 94 F12.8 deg RAdeg Right Ascension in decimal degrees (J2000)
96-107 F12.8 deg DEdeg Declination in decimal degrees (J2000)
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Note (1): Flag as follows:
c = Flagged in Stassun & Torres (2016, arXiv:1609.02579) as a large
outlier relative to Hipparcos and excluded from analysis in this paper.
d = Identified in Stassun & Torres (2016, arXiv:1609.02579) as a
known triple system; these are retained in the analysis in this paper
(see the text).
Note (2): From Stassun & Torres (2016, arXiv:1609.02579).
Stars with Χ2ν>20 were considered unacceptable and are
excluded from analysis in this paper also.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 15-Feb-2017