[INGNEWS] First Announcement: Hot Subdwarf Stars and Related Objects

From: Danny Lennon (djl@ing.iac.es)
Date: Wed Dec 01 2004 - 01:51:55 PST

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                              First Announcement
                    Hot Subdwarf Stars and Related Objects
               6 - 10 June 2005, La Palma, Canary Islands, Spain
                   http://www.ing.iac.es/conferences/subdwarf/
                         Contact: subdwarf@ing.iac.es
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    A new meeting series on hot subdwarf stars was started at Keele
    University in 2003. The meeting is an offspring of the long running
    biannual series of White Dwarf workshops. The intention is that the
    Subdwarf meetings will also run biannually, in the odd years between
    the WD meetings. The aim of the workshop series is to disseminate recent
    results on the properties, formation, and evolution of the hot subdwarf
    stars and related objects, and to assess the impact of these results on
    other areas of astrophysics (see below for a full scientific background).
    The second meeting on hot subdwarf stars and related objects will be held
    in Santa Cruz de La Palma on the Canary Islands, and is organised in
    collaboration by the Isaac Newton Group of Telescopes and the Nordic
    Optical Telescope.

    A preliminary list of session topics:
        * Evolutionary models and the UV-upturn phenomenon
        * Hot subdwarfs and hot HB stars in the field, clusters and galaxies
        * Hot subdwarfs in binary systems
        * Atmospheric properties of hot subdwarf stars
        * Asteroseismology of sdB stars
        * Progenitors and progeny of sdB stars

    IMPORTANT: The registration deadline is April 1, 2005.
    Please reply to this email, or send a mail to subdwarf@ing.iac.es
    if you are interested in further information and would like to remain
    on our mailing list.

    The registration opens on the 1st of December, and you should make your
    registration as soon as possible. Titles and abstracts of talks and
    posters can be submitted at any time up to the registration deadline.
    The registration fee is 150 Euro, to be paid on arrival at the meeting.
    Students can apply for a registration fee waiver. To register, complete
    the on-line registration form on our web-pages:
             http://www.ing.iac.es/conferences/subdwarf/

    Please pass on this announcement to any of your colleagues who may like
    to attend the workshop but who we have missed from this mailing list.

    Scientific background
    ---------------------
    Hot subdwarf stars are extreme horizontal branch (EHB) stars and pre-white
    dwarf stars. The EHB stars are core helium-burning stars with extremely
    thin hydrogen envelopes, and form the majority of bright stars in surveys
    for extremely blue objects, where they are classified as subdwarf-B (sdB)
    stars. They also appear in the colour-magnitude diagrams of some globular
    clusters as an extension of the blue tail formed by classical horizontal
    branch (HB) stars, though it is not clear why some clusters show this
    feature and other do not. The pre-white dwarf stars are related to the
    sdBs, but have exhausted their capacity to burn helium in the core. Many
    of the brightest hot subdwarfs in the field are of this class, and they
    are classified as sdO stars.

    Hot subdwarf stars and their relatives are believed to be important
    contributors to the hitherto mysterious UV upturn phenomenon in early-type
    galaxies; and a comprehensive investigation on this issue is being
    performed by the Galaxy Evolution Explorer (GALEX). The formation of EHB
    stars remains, in general, a matter of debate. Recent results for
    Galactic EHB stars show that the majority are close binary stars, so mass
    transfer and mass loss due to interactions between the stars clearly play
    a role. EHB stars are an excellent tool for studying evolution in close
    binary stars. Some EHB stars shows p-mode pulsations with periods of a few
    minutes and some others show g-mode pulsations with periods on the order
    of hours. Asteroseismology can be used to measure fundamental parameters
    for these stars directly. Hot subdwarf stars are also a laboratory for
    studying the effects of diffusion, weak stellar winds, radiative
    levitation and gravitational settling. These processes are seen to affect
    the peculiar composition of their atmospheres and also play a role in the
    driving mechanism for pulsations and, perhaps, the subsequent evolution of
    the star.

    Scientific Organising Committee
    -------------------------------
    Uli Heber, Bamberg
    Simon Jeffery, Armagh
    Sabine Moehler, Kiel
    Pierre Maxted, Keele
    Ralf Napiwotzki, Leicester
    Roy Ostensen, La Palma
    Philipp Podsiadlowski, Oxford
    Jan-Erik Solheim, Oslo
    Francois Wesemael, Montreal
    Sukyoung Yi, Oxford

    On behalf of the Local Organising Committee,
                     Roy ĜOstensen
    =============================================================
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