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SUMMARY:With a grain of salt: Variably fractionated volatile lithophile al
 kali metals and alkali earths in (exo)planetary contexts
DTSTART:20260514T093000Z
DTEND:20260514T103000Z
DTSTAMP:20260511T070100Z
UID:indico-event-1825@indico.dfa.unipd.it
CONTACT:lorenzo.spina@inaf.it
DESCRIPTION:Speakers: Stephen J. Mojzsis (Bayerisches Geoinstitut (BGI) Un
 iversität Bayreuth)\n\n\n\nCompared to Earth\, moderately volatile lithop
 hile elements (MVLEs) are strongly depleted and fractionated in the Moon. 
 Observed and model bulk compositions of Mars\, Venus and Mercury show broa
 d similarities in MVLE to the Earth trend and plot within a ‘planetary
 ’ field of carbonaceous (CC) and non-carbonaceous (NC) chondrites and ac
 hondrites. To understand what this means in the solar system context\, I c
 ompare the ‘planetary’ trends in MVLE and refractory lithophile elemen
 t (RLE) with those for the Sun (baseline)\, NC and CC iron meteorites\, an
 d the measured comets (Halley\, 67P\, Wild2). The solar-corrected log10 [K
 /Na] and log10 [Ca/Na] of Earth is +0.1958 and +0.7416\, respectively. The
  Moon’s values are very different from the ‘planetary’ trend (-0.031
 2 and +1.6697\, respectively)\, consistent its special history. The angrit
 e meteorites also plot in this ‘lunar’ field. Vestoid meteorites (HEDs
 ) plot between the ‘planetary’ and ‘lunar’ field. Extending this t
 o exoplanets\, I document the variations of the major MVLEs K+Na/Ca report
 ed for the extended atmosphere of a hot (>2100K) jovian exoplanet (WASP-76
 b) orbiting an F7 star. Based on comparison with its host F7 star\, jovian
  planets such as WASP-76B are probably stellar abundance mirrors. Thus in 
 MVLEs and RLEs in hot exo-jupiters helps us to understand our own gas gian
 t compositions. I reassess interpretations of the pollutants on the surfac
 es of some dense stellar remnants (white dwarfs). Many white dwarf polluta
 nts are often assumed to originate from infall of rocky bodies including a
 steroids and disrupted planetary crusts. I show from analysis of data from
  the Planetary Enriched White Dwarf Database that instead many of these co
 mpositions comport with Kuiper Belt and Trans-neptunian type objects. This
  outcome reconciles the dynamical problem of late accretion to WDs being s
 ourced from anywhere except the outer edges of an otherwise extinct planet
 ary system owing to the absence of a mechanism to donate angular momentum.
   \n \n\nJoin Zoom Meeting  \n \nhttps://unipd.zoom.us/j/82482883288?
 pwd=MVvmMWSGaiVrGMyAFOdyQG61OAcI7D.1\nMeeting ID: 824 8288 3288 Passcode:
  072472\n\n\nhttps://indico.dfa.unipd.it/event/1825/
LOCATION:Sala Jappelli (Osservatorio astronomico di Padova)
URL:https://indico.dfa.unipd.it/event/1825/
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