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 discovery and spectroscopy of HIP 75056Ab, a companiondirectly imaged at a very small separation of 0.125 arcsec to an A2V star inthe Scorpius-Centaurus OB2 association. Our observations utilized VLT/SPHEREbetween 2015$-$2019, enabling low-resolution spectroscopy (0.95$-$1.65 $\mum$), dual-band imaging (2.1$-$2.25 $\mu m$), and relative astrometry over afour-year baseline. HIP 75056Ab is consistent with spectral types in the rangeof M6$-$L2 and $T_{\rm eff}\sim$ 2000$-$2600 K. A comparison of the companion'sbrightness to evolutionary tracks suggests a mass of $\sim$20$-$30 M$_{Jup}$.The astrometric measurements are consistent with an orbital semi-major axis of$\sim$15$-$45 au and an inclination close to face-on (i$\lesssim$35$^o$). Inthis range of mass and orbital separation, HIP 75056Ab is likely at thelow-mass end of the distribution of companions formed via disk instability,although a formation of the companion via core accretion cannot be excluded.The orbital constraints are consistent with the modest eccentricity valuespredicted by disk instability, a scenario that can be confirmed by furtherastrometric monitoring. HIP 75056Ab may be utilized as a low-mass atmosphericcomparison to older, higher-mass brown dwarfs, and also to young giant planets.Finally, the detection of HIP 75056Ab at 0.125 arcsec represents a milestone indetecting low-mass companions at separations corresponding to the habitablezones of nearby Sun-like stars.

Direct Imaging Discovery of a Young Brown Dwarf Companion to an A2V Star