Validation of Gaia DR3 orbital and acceleration solutions with hierarchical triples

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Auteurs principaux: Nagarajan, Pranav, El-Badry, Kareem
Format: Preprint
Publié: 2024
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author Nagarajan, Pranav
El-Badry, Kareem
author_facet Nagarajan, Pranav
El-Badry, Kareem
contents Using data from Gaia DR3, we construct a sample of 14,791 gravitationally bound wide pairs in which one of the components is an unresolved binary with an astrometric orbital or acceleration solution. These systems are hierarchical triples, with inner binary separations of order $1$ au, and outer separations of $100$-$100,000$ au. Leveraging the fact that the inner binary and outer tertiary should have nearly identical parallaxes, we use the sample to calibrate the parallax uncertainties for orbital and acceleration binary solutions. We find that the parallax uncertainties of orbital solutions are typically underestimated by a factor of $1.3$ at $G>14$, and by a factor of $1.7$ at $G = 8$-$14$. The true parallax uncertainties are nevertheless a factor of $\sim 10$ smaller than those of the single-star astrometric solutions for the same sources. The parallax uncertainties of acceleration solutions are underestimated by larger factors of $2$-$3$ but still represent a significant improvement compared to the sources' single-star solutions. We provide tabulated uncertainty inflation factors for astrometric binary solutions and make the catalog of hierarchical triples publicly available.
format Preprint
id arxiv_https___arxiv_org_abs_2407_16760
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Validation of Gaia DR3 orbital and acceleration solutions with hierarchical triples
Nagarajan, Pranav
El-Badry, Kareem
Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
Astrophysics of Galaxies
Using data from Gaia DR3, we construct a sample of 14,791 gravitationally bound wide pairs in which one of the components is an unresolved binary with an astrometric orbital or acceleration solution. These systems are hierarchical triples, with inner binary separations of order $1$ au, and outer separations of $100$-$100,000$ au. Leveraging the fact that the inner binary and outer tertiary should have nearly identical parallaxes, we use the sample to calibrate the parallax uncertainties for orbital and acceleration binary solutions. We find that the parallax uncertainties of orbital solutions are typically underestimated by a factor of $1.3$ at $G>14$, and by a factor of $1.7$ at $G = 8$-$14$. The true parallax uncertainties are nevertheless a factor of $\sim 10$ smaller than those of the single-star astrometric solutions for the same sources. The parallax uncertainties of acceleration solutions are underestimated by larger factors of $2$-$3$ but still represent a significant improvement compared to the sources' single-star solutions. We provide tabulated uncertainty inflation factors for astrometric binary solutions and make the catalog of hierarchical triples publicly available.
title Validation of Gaia DR3 orbital and acceleration solutions with hierarchical triples
topic Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2407.16760