The Astronomical Journal (Jan 2024)

Gaia22dkvLb: A Microlensing Planet Potentially Accessible to Radial-velocity Characterization

  • Zexuan Wu,
  • Subo Dong,
  • Tuan Yi,
  • Zhuokai Liu,
  • Kareem El-Badry,
  • Andrew Gould,
  • L. Wyrzykowski,
  • K. A. Rybicki,
  • Etienne Bachelet,
  • Grant W. Christie,
  • L. de Almeida,
  • L. A. G. Monard,
  • J. McCormick,
  • Tim Natusch,
  • P. Zieliński,
  • Huiling Chen,
  • Yang Huang,
  • Chang Liu,
  • A. Mérand,
  • Przemek Mróz,
  • Jinyi Shangguan,
  • Andrzej Udalski,
  • J. Woillez,
  • Huawei Zhang,
  • Franz-Josef Hambsch,
  • P. J. Mikołajczyk,
  • M. Gromadzki,
  • M. Ratajczak,
  • Katarzyna Kruszyńska,
  • N. Ihanec,
  • Uliana Pylypenko,
  • M. Sitek,
  • K. Howil,
  • Staszek Zola,
  • Olga Michniewicz,
  • Michal Zejmo,
  • Fraser Lewis,
  • Mateusz Bronikowski,
  • Stephen Potter,
  • Jan Andrzejewski,
  • Jaroslav Merc,
  • Rachel Street,
  • Akihiko Fukui,
  • R. Figuera Jaimes,
  • V. Bozza,
  • P. Rota,
  • A. Cassan,
  • M. Dominik,
  • Y. Tsapras,
  • M. Hundertmark,
  • J. Wambsganss,
  • K. Bąkowska,
  • A. Słowikowska

DOI
https://doi.org/10.3847/1538-3881/ad5203
Journal volume & issue
Vol. 168, no. 2
p. 62

Abstract

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We report discovering an exoplanet from following up a microlensing event alerted by Gaia. The event Gaia22dkv is toward a disk source rather than the traditional bulge microlensing fields. Our primary analysis yields a Jovian planet with ${M}_{{\rm{p}}}={0.59}_{-0.05}^{+0.15}\,{M}_{{\rm{J}}}$ at a projected orbital separation ${r}_{\perp }={1.4}_{-0.3}^{+0.8}$ au, and the host is a ∼1.1 M _⊙ turnoff star at ∼1.3 kpc. At $r^{\prime} \approx 14$ , the host is far brighter than any previously discovered microlensing planet host, opening up the opportunity to test the microlensing model with radial velocity (RV) observations. RV data can be used to measure the planet’s orbital period and eccentricity, and they also enable searching for inner planets of the microlensing cold Jupiter, as expected from the “inner–outer correlation” inferred from Kepler and RV discoveries. Furthermore, we show that Gaia astrometric microlensing will not only allow precise measurements of its angular Einstein radius θ _E but also directly measure the microlens parallax vector and unambiguously break a geometric light-curve degeneracy, leading to the definitive characterization of the lens system.

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