Annual parallax and a dimming event of a Mira variable star, FV Bootis

Kamezaki, Tatsuya; Nakagawa, Akiharu; Omodaká, Toshihiro; Inoue, Kenji; Chibueze, James O.; Nagayama, Tomonori; Ueno, Yuji; Matsunaga, Noriyuki

doi:10.1093/pasj/psw068

Cited by 9 publications

(3 citation statements)

References 38 publications

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“…This implies that additional assumptions must be made about the origin of the radio synchrotron or molecular maser emission that is used as a beacon, where Gaia usually (but not always!) [6,8,7], VERA results for water and SiO results from [9,10,11,12,13,14,15], VLBA OH masers from [16,17], and VLBA water masers from [18,19], pulsar results from references in [20] Figure 2: The residuals for Gaia versus VLBI parallaxes, allowing for a Gaia parallax zero point of −46µas. The distribution has been normalised by the quadratically summed errors, including the Gaia estimate of "excess noise".…”

Section: Introductionmentioning

confidence: 99%

“…Figure 1: A direct comparison of parallaxes obtained in the radio with VLBI techniques and in the optical as published in the Gaia DR2. Continuum sources are pre-main sequence sources from[6,8,7], VERA results for water and SiO results from[9,10,11,12,13,14,15], VLBA OH masers from[16,17], and VLBA water masers from[18,19], pulsar results from references in[20] …”

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confidence: 99%

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The Synergy between VLBI and Gaia astrometry

Langevelde¹,

Quiroga-Nuñez²,

Vlemmings³

et al. 2019

Proceedings of 14th European VLBI Network Symposium &Amp; Users Meeting — PoS(EVN2018)

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With the publication of Gaia DR2, 1.3 billion stars now have public parallax and proper motion measurements. In this contribution, we compare the results for sources that have both optical and radio measurements, focusing on circumstellar masers. For these large, variable and bright AGB stars, the VLBI astrometry results can be more robust. Moreover, there are a number of applications where VLBI astrometry provides unique data for studying stellar populations and Galactic structure. The BeSSel project not only provides parallax and proper motions at much larger distances than Gaia can reach, but it also uniquely samples the spiral arms of the Galaxy. The evolved stars in the BAaDE sample can potentially constrain the dynamics and stellar content of the inner bulge and bar of the Milky Way, not reachable in the optical.

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

The Synergy between VLBI and Gaia astrometry

Langevelde¹,

Quiroga-Nuñez²,

Vlemmings³

et al. 2019

Proceedings of 14th European VLBI Network Symposium &Amp; Users Meeting — PoS(EVN2018)

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“…Lewis (2002a,b) described FV Boo as a dying OH/IR star, with a mass loss that abruptly switches on and off. Monitoring of FV Boo in the IR over a 20-year span by Kamezaki et al (2016b) showed that it suffered a temporary but significant dip in its luminosity in 2005. The star UX Cyg stood out in the sample of Mira variables investigated by Etoka & Le Squeren (2000) due to rapid, large changes in the amplitude of the variations of its maser lines, likely linked to an unusually turbulent envelope.…”

Section: A New Pl Relation For Mirasmentioning

confidence: 99%

Distance estimates for AGB stars from parallax measurements

Andriantsaralaza

Ramstedt

Vlemmings

et al. 2022

A&A

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Context. Estimating the distances to asymptotic giant branch (AGB) stars using optical measurements of their parallaxes is not straightforward because of the large uncertainties introduced by their dusty envelopes, their large angular sizes, and their surface brightness variability. Aims. This paper aims to assess the reliability of the distances derived with Gaia DR3 parallaxes for AGB stars, and provide a new distance catalogue for a sample of ∼ 200 nearby AGB stars Methods. We compared the parallaxes from Gaia DR3 with parallaxes measured with maser observations with very long baseline interferometry (VLBI) to determine a statistical correction factor for the DR3 parallaxes using a sub-sample of 33 maser-emitting oxygen-rich nearby AGB stars. We then calculated the distances of a total of ∼ 200 AGB stars in the DEATHSTAR project using a Bayesian statistical approach on the corrected DR3 parallaxes and a prior based on the previously determined Galactic distribution of AGB stars. We performed radiative transfer modelling of the stellar and dust emission to determine the luminosity of the sources in the VLBI sub-sample based on the distances derived from maser parallaxes, and derived a new bolometric period-luminosity relation for Galactic oxygen-rich Mira variables. Results. We find that the errors on the Gaia DR3 parallaxes given in the Gaia DR3 catalogue are underestimated by a factor of 5.44 for the brightest sources (G < 8 mag). Fainter sources (8 ≤ G < 12) require a lower parallax error inflation factor of 2.74. We obtain a Gaia DR3 parallax zero-point offset of −0.077 mas for bright AGB stars. The offset becomes more negative for fainter AGB stars. After correcting the DR3 parallaxes, we find that the derived distances are associated with significant, asymmetrical errors for more than 40 % of the sources in our sample. We obtain a PL relation of the form M bol = (−3.31 ± 0.24) [log P − 2.5] + (−4.317 ± 0.060) for the oxygen-rich Mira variables in the Milky Way. A new distance catalogue based on these results is provided for the sources in the DEATHSTAR sample. Conclusions. The corrected Gaia DR3 parallaxes can be used to estimate distances for AGB stars using the AGB prior, but we confirm that one needs to be careful when the uncertainties on parallax measurements are larger than 20 %, which can result in model-dependent distances and source-dependent offsets. We find that a RUWE (re-normalised unit weight error) below 1.4 does not guarantee reliable distance estimates and we advise against the use of only the RUWE to measure the quality of Gaia DR3 astrometric data for individual AGB stars.

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