Discovery of an Edge-on Circumstellar Debris Disk around BD+45° 598: A Newly Identified Member of the β Pictoris Moving Group

Abstract

We report the discovery of a circumstellar debris disk viewed nearly edge-on and associated with the young, K1 star BD+45° 598 using high-contrast imaging at 2.2 μm obtained at the W.M. Keck Observatory. We detect the disk in scattered light with a peak significance of ~5σ over three epochs, and our best-fit model of the disk is an almost edge-on ~70 au ring, with inclination angle ~87°. Using the NOEMA interferometer at the Plateau de Bure Observatory operating at 1.3 mm, we find resolved continuum emission aligned with the ring structure seen in the 2.2 μm images. We estimate a fractional infrared luminosity of L_(IR)/L_(tot) ≃6⁺²₋₁ × 10⁻⁴, higher than that of the debris disk around AU Mic. Several characteristics of BD+45° 598, such as its galactic space motion, placement in a color–magnitude diagram, and strong presence of lithium, are all consistent with its membership in the β Pictoris Moving Group with an age of 23 ± 3 Myr. However, the galactic position for BD+45° 598 is slightly discrepant from previously known members of the β Pictoris Moving Group, possibly indicating an extension of members of this moving group to distances of at least 70 pc. BD+45° 598 appears to be an example from a population of young circumstellar debris systems associated with newly identified members of young moving groups that can be imaged in scattered light, key objects for mapping out the early evolution of planetary systems from ~10–100 Myr. This target will also be ideal for northern-hemisphere, high-contrast imaging platforms to search for self-luminous, planetary mass companions residing in this system.

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