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 report the discovery that the star V474 Car is an extremely active, highvelocity halo RS CVn system. The star was originally identified as a possiblepre-main sequence star in Carina, given its enhanced stellar activity, rapidrotation (10.3 days), enhanced Li, and absolute magnitude that places it abovethe main sequence. However, its extreme radial velocity (264 km s$^{-1}$)suggested that this system was unlike any previously known pre-MS system. Ourdetailed spectroscopic analysis of echelle spectra taken with the CTIO 4-mfinds that V474 Car is both a spectroscopic binary with orbital period similarto the photometric rotation period, and metal poor ([Fe/H] $\simeq -$0.99). Thestar's Galactic orbit is extremely eccentric (e $\simeq$ 0.93) withperigalacticon of only $\sim$0.3 kpc of the Galactic center - and itseccentricity and smallness of its perigalacticon are only surpassed by$\sim$0.05%, of local F/G-type field stars. The observed characteristics areconsistent with V474 Car being a high velocity, metal poor, tidally-lockedchromospherically active binary (CAB), i.e.\ a halo RS CVn binary, and one ofonly a few such specimens known.

V474 Car: A Rare Halo RS CVn Binary in Retrograde Galactic Orbit