Minimality of planes in normed spaces

We prove that a region in a two-dimensional affine subspace of a normed space $V$ has the least 2-dimensional Hausdorff measure among all compact surfaces with the same boundary. Furthermore, the 2-dimensional Hausdorff area density admits a convex extension to $\Lambda^2 V$. The proof is based on a (probably) new inequality for the Euclidean area of a convex centrally-symmetric polygon.Comment: 10 pages, v2: minor changes according to referees' comments, to appear in GAF

Solar noble gases in Vigarano bulk minerals – First results of the new 'BENGEL' in-vacuo etching facility

Extract from introduction: Regolith breccias are breccias that contain solar-gas-bearing grains [1,2]. It is generally accepted that the exposure to the solar wind took place rather recently on the surface of a parent body. However, it appears possible that grains were exposed early (or obtained their solar gas load by other mechanisms) prior to accretion. Some of the solar gases in chondrites may indeed be 'primordial' [3,4]. In the CI chondrite Orgueil, the presence of solar gases is restricted to magnetite, whereas the silicates appear solar-gas-free [3]. This is difficult to reconcile in a planetary environment. The observation that solar-like gases in the unbrecciated E chondrite St. Mark's were released only upon severe etching provides further evidence for the presence of primordial solar gas [5]

Plutonium-Xenon systematics of Angrites

Introduction: Angrites are igneous meteorites that crystallized very early in the solar system, ~10 Ma after CAIs, as also implied by the presence of now extinct short-lived radionuclides such as 53Mn, 146Sm and 244Pu [1]. Fission Xe was used to calculate 244Pu-136Xeretention ages of eucrites, relative to that of Angra dos Reis (AdoR) [2]. AdoR has an absolute Pb-Pb age of 4557.8 Ma [see 1 for ref.]. Most eucrites, being as old as angrites, experienced various parent body processes leading to ages ranging from ~20 Ma before, to ~100 Ma after AdoR [2]. Angrites, however, remained largely unaltered after differentiation. Here, we examine whether Xe isotopic characteristics allow determining an age sequence for angrites

The trapped heavy noble gases in recently found Martian meteorites

The composition of the trapped Ar, Kr, and Xe in the Martian meteorites Los Angeles, Say Al Uhaymir 005/008, and 094 is discussed and found to be consistent with a mixture of Martian mantle and atmosphere noble gases and terrestrial contamination

Solar noble bases in enstatite chondrites and implications for the formation of the terrestrial planets

We report evidence for tiny amounts of - most likely primordial - noble gases with solar-like elemental and isotopic composition admixed to Q-type primordial noble gases in an E chondrite. We will discuss possible implications of this finding for terrestrial planet formation

Helium isotopic ratios in carbonaceous chondrites: Significant for the early solar nebula and circumstellar diamonds?

Stepwise etching of acid-resistant residues from carbonaceous chondrites yields a new, extraordinarily low He isotopic ratio for phase Q that might represent early solar nebula composition. A much lower ratio possibly characterizes He-P3 from circumstellar diamonds

Phase Q - A carrier for subsolar noble gases

We discuss noble gases in the E-chondrite St. Mark's indicating that the subsolar component does not exclusively reside in enstatite. Element and isotope abundances including He are presented. Fractionation probably took place prior to incorporation

Subsolar noble gases in an acid-resistant residue of the EH5 chondrite St Mark's

Extract from the introduction: Enstatite chondrites have remarkable properties: they were formed in a reducing environment, they are putatively similar to precursor material of Earth, Venus, or Mercury, have a terrestrial oxygen isotopic composition and an uncommon noble gas signature [1-5]. Trapped noble gases in Echondrites are intermediate between solar and chondritic composition and consist of two components: Subsolar, enriched in Ar and Kr relative to Xe and Q-gas, possibly residing in enstatite, micro-vesicles or graphite within enstatite [6,7] and Q-gases [5,8]

On line etching of bulk EH5 St. Mark's – Radiogenic and subsolar noble gases

Introduction: On line etching is very useful to analyse noble gas components such as 'Q' or the solar wind [1, 2]. A bulk meteorite sample, however, has never been analysed by on line etching in order to characterise its complete noble gas inventory

Ancient volcanic xenon in single glass grains from the D'Orbigny angrite

We present high-sensitivity xenon data for single glass grains from the D'Orbigny angrite. These grains contain the first sample of volcanic gas from a planetary body other than the Earth and excess Xe-129 detected for the first time in angrites