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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20200521T103000
DTEND;TZID=Atlantic/Canary:20200521T113000
UID:iactalks-1404
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/1404
CREATED:2020-05-21T10:30:00+01:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:Barium stars as tracers of binary evolution in the Gaia era
DESCRIPTION:Barium stars as tracers of binary evolution in the Gaia era\nDr
 . Ana Escorza Santos\n\nAbout half of the stars in our Galaxy are born in 
 binary systems meaning that their evolution might be affected by the prese
 nce of a companion. Many aspects of binary interaction are still unknown s
 o understanding the products that result from interacting systems is cruci
 al to unravel the physical mechanisms involved. A prototypical example of 
 such post-interaction binary systems in the low- and intermediate-mass reg
 ime are Barium (Ba) stars. Ba stars are main-sequence or giant stars which
  show an enhancement of chemical elements that should not yet be overabund
 ant at these evolutionary stages. Currently, it is widely accepted that th
 ese chemicals were transferred from a more evolved companion during a phas
 e of mass transfer and that this companion evolved into a cool white dwarf
 . Understanding the orbital properties of these systems, as well as the st
 ellar properties of the Ba star and its polluter, is the key to the system
 ’s interaction history.In the last years, the synergy between Gaia d
 ata, of unprecedented quality, high-resolution spectroscopy, long-term rad
 ial-velocity monitoring programmes, and state-of-the-art stellar and binar
 y evolution models has contributed to a better understanding of the proper
 ties of Ba stars and provided new observational constraints to theoretical
  studies. The new Hertzsprung-Russell diagrams of Ba stars allowed us to a
 ccurately determine their evolutionary status and their masses. Additional
 ly, we have recently determined the orbital properties of many main-sequen
 ce Ba stars, much less studied until now than their giant counterparts, wh
 ich led to a thorough comparison of the properties of the two samples. The
  comparison between the distributions of masses, periods and eccentricitie
 s that resulted from this analysis allowed us to investigate the evolution
  of Ba-star systems between these two phases. Our models show that a secon
 d stage of binary interaction, this time between the main-sequence Ba star
  and its white-dwarf companion, also takes place in some systems, affectin
 g the distribution of orbits observed among Ba giants.\nZoom link:   
 https://rediris.zoom.us/j/96557655189
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