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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The first three hyper-velocity stars (HVS) unbound to the Galaxy wereserendipitously discovered in 2005. The only suggested origin of hyper-velocitystars is the Galactic Centre as it hosts a super-massive black hole capable ofaccelerating stars to such high velocities. Only one HVS, the sdO star US 708,is known to be an old low mass star, while HE 0437$-$5439 is an apparentlynormal early-type B-star, too short-lived to originate from the GalacticCentre, but could possibly come from the LMC. A systematic survey has led tothe discovery of seven new HVS of late B-type (similar to the prototype HVS1),which can either be massive stars 3 M(sun) or horizontal branch stars,sufficiently long-lived to have travelled from the Galactic Centre. We presentnew spectral analyses of five known HVS as well as of a newly discoveredcandidate. It is possible that the late B-type HVS are a mix of main sequenceand evolved BHB stars. In view of the time scale problem we revisit HE0437$-$5439 and discuss a possible subluminous nature of this star.

Hypervelocity Stars: Young and Heavy or Old and Light?