Comparison of Gaia DR2 Parallaxes of Stars with VLBI Astrometry

Xu, Shuangjing; Zhang, B.; Reid, M. J.; Zheng, Xingwu; Wang, Guangli

doi:10.3847/1538-4357/ab0e83

Cited by 60 publications

(51 citation statements)

References 70 publications

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“…IC1396A is a bright-rimmed globule complex, also known as "the Elephant Trunk Nebula," illuminated by HD206267, a Trapezium-like O star system (O6.5V + O9V), which is a part of the Cepheus OB2 association and is at a distance of 945 73 Collaboration 2018; Sicilia-Aguilar et al 2019). This value is consistent within the errors with the result from main-sequence fitting of the intermediate-mass (∼A-type) stars, 870±80 pc (Contreras et al 2002), particularly given a possible small bias in the Gaia results toward large distances (Xu et al 2019). IC1396A is at the western edge of the Tr37 cluster (Marschall & van Altena 1987;Platais et al 1998).…”

Section: Introductionsupporting

confidence: 81%

“…The nominal errors in the Gaia-estimated distance (Sicilia-Aguilar et al 2019) are too small to explain these shifts. However, there is evidence for a small bias toward underestimating parallaxes in Gaia (see summary in Xu et al 2019). A weighted average of all the measurements (Xu et al 2019) yields −53±3 μas, but this value is strongly influenced by the single input with the smallest quoted error.…”

Section: K-band Luminosity Function and Cmd Comparisonmentioning

confidence: 99%

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Near-infrared Variability of Low-mass Stars in IC 1396A and Tr 37

Meng

Rieke

Kim

et al. 2019

ApJ

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We have monitored nearly a square degree in IC 1396A/Tr 37 over 21 epochs extending over 2014-2016 for sources variable in the JHK bands. In our data, 65%±8% of previously identified cluster members show variations, compared with 0.3% of field stars. We identify 119 members of Tr 37 on the basis of variability, forming an unbiased sample down to the brown dwarf regime. The K-band luminosity function in Tr 37 is similar to that of IC 348 but shifted to somewhat brighter values, implying that the K-and M-type members of Tr 37 are younger than those in IC 348. We introduce methods to classify the causes of variability, based on behavior in the color-color and color-magnitude diagrams. Accretion hot spots cause larger variations at J than at K with substantial scatter in the diagrams; there are at least a dozen, with the most active resembling EXors. Eleven sources are probably dominated by intervention of dust clumps in their circumstellar disks, with color behavior indicating the presence of grains larger than for interstellar dust, presumably due to grain growth in their disks. Thirteen sources have larger variations at K than at J or H. For 11 of them, the temperature fitted to the variable component is very close to 2000 K, suggesting that the changes in output are caused by turbulence at the inner rim of the circumstellar disk exposing previously protected populations of grains.

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Section: Introductionsupporting

confidence: 81%

Section: K-band Luminosity Function and Cmd Comparisonmentioning

confidence: 99%

Near-infrared Variability of Low-mass Stars in IC 1396A and Tr 37

Meng

Rieke

Kim

et al. 2019

ApJ

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“…Working with empirical eclipsing binary surface brightness-color relations, Graczyk et al (2019) estimated a zero-point offset of 31µas ± 11µas. Other results confirm this picture: using a statistical approach based on the effect of parallax errors on tangential velocities, Schönrich et al (2019) determined a zero-point offset of 54µas ± 6.0µas; applying a machine learning distance classifier using APOGEE spectroscopy, Leung & Bovy (2019) found a zero-point offset of 52.3µas ± 2.0µas; and Xu et al (2019) inferred an offset of 75µas ± 29µas with very long baseline interferometry astrometry. Most recently, Khan et al (2019) and Hall et al (2019) found offsets of 51.7µas ± 0.8µas (± ≈ 10µas when including spatially-correlated parallax errors) and 38.38 +13.54 −13.83 µas, by computing asteroseismic 1 The angle between the two fields of view of Gaia that allows an absolute measure of parallax.…”

Section: Introductionmentioning

confidence: 90%

Confirmation of the Gaia DR2 Parallax Zero-point Offset Using Asteroseismology and Spectroscopy in the Kepler Field

Zinn

Pinsonneault

Huber

et al. 2019

ApJ

192

131

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We present an independent confirmation of the zero-point offset of Gaia Data Release 2 (DR2) parallaxes using asteroseismic data of evolved stars in the Kepler field. Using well-characterized red giant branch (RGB) stars from the APOKASC-2 catalogue we identify a Gaia astrometric pseudo-color (ν eff )-and Gaia G-band magnitude-dependent zero-point offset of seis − Gaia = 52.8±2.4 (rand.)±8.6 (syst.)−(150.7±22.7)(ν eff −1.5)−(4.21±0.77)(G−12.2)µas, in the sense that Gaia parallaxes are too small. The offset is found in high and low-extinction samples, as well as among both shell H-burning red giant stars and core He-burning red clump stars. We show that errors in the asteroseismic radius and temperature scales may be distinguished from errors in the Gaia parallax scale. We estimate systematic effects on the inferred global Gaia parallax offset, c, due to radius and temperature systematics, as well as choices in bolometric correction and the adopted form for Gaia parallax spatial correlations. Because of possible spatiallycorrelated parallax errors, as discussed by the Gaia team, our Gaia parallax offset model is specific to the Kepler field, but broadly compatible with the magnitude-and color-dependent offset inferred by the Gaia team and several subsequent investigations using independent methods.

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“…reported a parallax offset of 0.082±0.033 mas using a sample of eclipsing binaries. In 2019, many more studies dealt with the Gaia parallax zero point and the value varies between 0.030 and 0.1 mas (0.031±0.11mas,Graczyk et al (2019); 0.054±0.006mas,Schönrich et al (2019); 0.0523±0.002 mas,Leung & Bovy (2019); 0.075±0.029mas,Xu et al (2019); 0.0517±0.0008mas,Khan et al (2019); 0.03838 +0.01354 −0.01383 mas,Hall et al (2019); and 0.0528±0.0024 mas,Zinn et al (2019)).…”

mentioning

confidence: 99%

Distance mapping applied to four well-known planetary nebulae and a nova shell

Gómez-Gordillo

Akras

Gonçalves

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Accurate distance estimates of astrophysical objects such as planetary nebulae (PNe), and nova and supernova remnants, among others, allow us to constrain their physical characteristics, such as size, mass, luminosity, and age. An innovative technique based on the expansion parallax method, the so-called distance mapping technique (DMT), provides distance maps of expanding nebulae as well as an estimation of their distances. The DMT combines the tangential velocity vectors obtained from 3D morpho-kinematic models and the observed proper motion vectors to estimate the distance. We applied the DMT to four PNe (NGC 6702, NGC 6543, NGC 6302, and BD+30 3639) and one nova remnant (GK Persei) and derived new distances in good agreement with previous studies. New simple morpho-kinematic shape models were generated for NGC 6543, NGC 6302, and NGC 6702, whereas for BD+30 3639 and GK Persei published models were used. We demonstrate that the DMT is a useful tool to obtain distance values of PNe, in addition to revealing kinematically peculiar regions within the nebulae. Distances are also derived from the trigonometric Gaia parallaxes. The effect of the non-negligible parallax offset in the second Gaia data release is also discussed.

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Comparison of Gaia DR2 Parallaxes of Stars with VLBI Astrometry

Cited by 60 publications

References 70 publications

Near-infrared Variability of Low-mass Stars in IC 1396A and Tr 37

Near-infrared Variability of Low-mass Stars in IC 1396A and Tr 37

Confirmation of the Gaia DR2 Parallax Zero-point Offset Using Asteroseismology and Spectroscopy in the Kepler Field

Distance mapping applied to four well-known planetary nebulae and a nova shell

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