English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present the direct-imaging discovery of a substellar companion in orbitaround a Sun-like star member of the Hyades open cluster. So far, no othersubstellar companions have been unambiguously confirmed via direct imagingaround main-sequence stars in Hyades. The star HIP 21152 is an acceleratingstar as identified by the astrometry from the Gaia and Hipparcos satellites. Wehave detected the companion, HIP 21152 B, in multi-epoch using thehigh-contrast imaging from SCExAO/CHARIS and Keck/NIRC2. We have also obtainedthe stellar radial-velocity data from the Okayama 188cm telescope. The CHARISspectroscopy reveals that HIP 21152 B's spectrum is consistent with the L/Ttransition, best fit by an early T dwarf. Our orbit modeling determines thesemi-major axis and the dynamical mass of HIP 21152 B to be17.5$^{+7.2}_{-3.8}$ au and 27.8$^{+8.4}_{-5.4}$ $M_{\rm{Jup}}$, respectively.The mass ratio of HIP 21152 B relative to its host is $\approx$2\%, near theplanet/brown dwarf boundary suggested from recent surveys. Mass estimatesinferred from luminosity evolution models are slightly higher (33--42$M_{\rm{Jup}}$). With a dynamical mass and a well-constrained age due to thesystem's Hyades membership, HIP 21152 B will become a critical benchmark inunderstanding the formation, evolution, and atmosphere of a substellar objectas a function of mass and age. Our discovery is yet another keyproof-of-concept for using precision astrometry to select direct imagingtargets.

Direct Imaging Discovery and Dynamical Mass of a Substellar Companion Orbiting an Accelerating Hyades Sun-like Star with SCExAO/CHARIS