Looking for astrometric signals below 20 m/s: A Jupiter-mass planet signature in $\epsilon$ Eri

Valeri V. Makarov; Norbert Zacharias; Charles T. Finch

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arXiv · 2107.01090

Looking for astrometric signals below 20 m/s: A Jupiter-mass planet signature in $\epsilon$ Eri

Valeri V. Makarov·Norbert Zacharias·Charles T. Finch

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Abstract

The USNO ground-based astrometric program URAT-Bright in combination with the Hipparcos mission epoch astrometry provides precise proper motions of a thousand bright stars in the southern hemisphere on a time basis of about 25 years. Small but statistically significant differences between these proper motions and Gaia EDR3 data can reveal long-period exoplanets similar to Jupiter in the nearest star systems. The presence of such a planet orbiting the magnetically active dwarf $\epsilon$ Eri is confirmed from both URAT--Hipparcos--EDR3 data and Hipparcos--EDR3 data with a corresponding projected velocity of $(+5,+8)$ and $(+6,+13)$ m s$^{-1}$, respectively. These signals are formally significant at a 0.989 and 1.0 confidence. We conclude that the newest astrometric results confirm the existence of a long-period exoplanet orbiting $\epsilon$ Eri, which was marginally detected from precision radial velocity measurements some 20 years ago.

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Valeri V. Makarov, Norbert Zacharias, Charles T. Finch. 2021-07-02. Looking for astrometric signals below 20 m/s: A Jupiter-mass planet signature in $\epsilon$ Eri. https://arxiv.org/abs/2107.01090

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