The Coinage and History of Achaiion in the Troad

International audienceTwo issues of bronze coinage from the Troad with the monogram AX (late 4th/early 3rd c. BC) have traditionally been attributed to Achilleion. However, excavations of Achilleion show that it was never more than a small fort. These coins should therefore be attributed to Achaiion, known to us from Strabo as the chief town of the nearby Tenedian peraia. In addition to the issues with the AX monogram, Achaiion also produced bronze coinage in the 2nd c. BC. It is argued that these two periods of minting probably represent periods of independence from Tenedos and thus prompt questions about the significance of the peraia to the Tenedian economy and the importance of bronze coinage in reconstructing the political history of the Hellenistic Troad.La provenance de deux exemplaires de monnaie de bronze de Troade avec le monogramme AX (fin IVe-début IIIe s. a.C.) a été habituellement attribuée à Achilleion. Cependant, les fouilles menées sur le site d’Achilleion n’ont jamais révélé autre chose qu’un fort. Ces pièces devraient donc être attribuées à Achaion, connu par Strabon comme la cité principale à proximité de la pérée de Ténédos. Outre ces exemplaires, Achaion a aussi frappé un monnayage de bronze au IIe siècle a.C. Ces deux périodes de frappe correspondent probablement à deux moments d’indépendance d’Achaion par rapport à Ténédos, interrogeant du même coup l’importance de la pérée dans l’économie ténédienne et celle du monnayage de bronze dans la reconstruction de l’histoire politique de la Troade hellénistique

The Tyrants Dossier from Eresos

Das so genannte Tyrannen-Dossier aus Eresos (IG XII 2, 526) ist eine Sammlung von Beschlüssen der Stadt Eresos und von Königsbriefen, die in den letzten drei Jahrzehnten des 4. Jh. v.Chr. entstanden. Diese bestätigen insgesamt noch einmal das Recht des Demos von Eresos, sich nicht mit den aus der Polis Verbannten versöhnen zu müssen. Entgegen der Auffassung von A. Heisserer bilden die zwei Teile der Inschrift nicht zwei getrennte Monumente, sondern ein einziges, das nicht im Laufe von drei Jahrzehnten, sondern gleichzeitig um 306–301 v.Chr. publiziert wurde. Die Entscheidung des Demos von Eresos, diese Dokumente in einem monumentalen Format noch einmal Jahrzehnte nach den in diesen Texten thematisierten Ereignissen zu veröffentlichen, bietet wichtige Einblicke in die politische Kultur von Eresos während der frühhellenistischen Zeit. Die Inschrift gibt auch Anlass dazu, über die langfristige Auswirkung der Verbannung auf eine politische Gemeinschaft, über die Art der Beziehung zwischen Stadt und König, über den Gebrauch der königlichen Dokumente durch die Städte und über die Politik der epigraphischen Veröffentlichung nachzudenken.The so-called Tyrants Dossier from Eresos (IG XII 2, 526) is a collection of Eresian decrees and royal letters produced over the course of the last three decades of the 4th c. BC which collectively re-affirm the right of the Eresian demos not to reconcile with their exiles. Contrary to the arguments of A. Heisserer, the inscription’s two parts do not represent two separate monuments, but rather a single monument which was inscribed not over the course of three decades, but all at once ca. 306–301 BC. The decision of the Eresian demos to re-publish these documents in a monumental format several decades after the events these texts describe therefore provides important insights into the political culture of Eresos in the early Hellenistic period and invites reflection on the long-term impact of exile on a political community, the nature of the relationship between city and king, the uses which cities made of royal documents, and the politics of epigraphic publication.Le «dossier des tyrans» d’Érésos (IG XII 2, 526) est composé de décrets érésiens et de lettres royales écrits au court des trois dernières décennies du 4e s.a.C. qui réaffirment collectivement le droit du démos érésien de ne pas se réconcilier avec ses exilés. Contrairement à l’interprétation d’A. Heisserer, les deux parties de l’inscription ne représentent pas deux monuments séparés, mais plutôt un seul qui fut non pas inscrit au cours de ces trois décennies, mais en une seule fois vers 306–301 a.C. La décision du démos érésien de republier ces documents sous une forme monumentale plusieurs décennies après les événements décrits dans ces textes donne donc une idée de la culture politique d’Érésos au début de l’époque hellénistique et invite à la réflexion sur l’impact à long terme de l’exil sur une communauté politique, la nature des relations entre la cité et le roi, les usages que les cités faisaient des documents royaux et les politiques de publication épigraphique

In situ apparatus for the study of clathrate hydrates relevant to solar system bodies using synchrotron X-ray diffraction and Raman spectroscopy

Clathrate hydrates are believed to play a significant role in various solar system environments, e.g. comets, and the surfaces and interiors of icy satellites, however the structural factors governing their formation and dissociation are poorly understood. We demonstrate the use of a high pressure gas cell, combined with variable temperature cooling and time-resolved data collection, to the in situ study of clathrate hydrates under conditions relevant to solar system environments. Clathrates formed and processed within the cell are monitored in situ using synchrotron X-ray powder diffraction and Raman spectroscopy. X-ray diffraction allows the formation of clathrate hydrates to be observed as CO2 gas is applied to ice formed within the cell. Complete conversion is obtained by annealing at temperatures just below the ice melting point. A subsequent rise in the quantity of clathrate is observed as the cell is thermally cycled. Four regions between 100-5000cm-1 are present in the Raman spectra that carry features characteristic of both ice and clathrate formation. This novel experimental arrangement is well suited to studying clathrate hydrates over a range of temperature (80-500K) and pressure (1-100bar) conditions and can be used with a variety of different gases and starting aqueous compositions. We propose the increase in clathrate formation observed during thermal cycling may be due to the formation of a quasi liquid-like phase that forms at temperatures below the ice melting point, but which allows easier formation of new clathrate cages, or the retention and delocalisation of previously formed clathrate structures, possibly as amorphous clathrate. The structural similarities between hexagonal ice, the quasi liquid-like phase, and crystalline CO2 hydrate mean that differences in the Raman spectrum are subtle; however, all features out to 5000cm-1 are diagnostic of clathrate structure.Comment: Astronomy & Astrophysics, in press. 6 page

Non-aqueous formation of the calcium carbonate polymorph vaterite: astrophysical implications

We study the formation of calcium carbonate, through the solid-gas interaction of amorphous Ca-silicate with gaseous CO2, at elevated pressures, and link this to the possible presence of calcium carbonate in a number of circumstellar and planetary environments. We use in-situ synchrotron X-Ray powder diffraction to obtain detailed structural data pertaining to the formation of the crystalline calcium carbonate phase vaterite and its evolution with temperature. We found that the metastable calcium carbonate phase vaterite was formed alongside calcite, at elevated CO2 pressure, at room temperature and subsequently remained stable over a large range of temperature and pressure. We report the formation of the calcium carbonate mineral vaterite whilst attempting to simulate carbonate dust grain formation in astrophysical environments. This suggests that vaterite could be a mineral component of carbonate dust and also presents a possible method of formation for vaterite and its polymorphs on planetary surfaces.Comment: Astronomy and Astrophysics, in pres

V445 Puppis: Dustier than a Thousand Novae

V445 Puppis, the only known Galactic helium nova, is a unique test bed to verify supernova (SN) theories in the single-degenerate channel that involve a white dwarf (WD) accreting matter from a helium-rich donor. An estimate of the mass of the helium shell on the WD is crucial to deciding whether or not it will undergo an SN detonation. In this context, this study estimates the dust and ejecta masses in the 2000 November eruption of V445 Pup. Subsequent to its outburst, the star became cocooned in a dust envelope. An analysis of the spectral energy distribution (SED) of the dust using infrared data shows that V445 Pup produced at least 10−3 M ⊙ of dust, which is unprecedented for a classical or recurrent nova. The SED can be explained by a combination of a cold dust component at 105 ± 10 K, mass (1.9 ± 0.8) × 10−3 M ⊙, and a warm dust component at 255 ± 10 K, mass (2.2 ± 1.2) × 10−5 M ⊙. For a conservative choice of the gas-to-dust mass ratio in the range 10–100, the mass of the ejecta is 0.01–0.1 M ⊙. Such a high mass range raises the question: why did V445 Pup not detonate as a Type Ia SN as is predicted in certain double-detonation sub-Chandrasekhar supernovae formalisms? We reexamine the nature of V445 Pup and discuss its role as a potential SN progenitor

X-ray powder diffraction study of the stability of clathrate hydrates in the presence of salts with relevance to the Martian cryosphere

Water on the present day Martian surface is thought to exist in two thermally distinct sub-surface reservoirs: as ice in the cryosphere and as groundwater located deeper in the crust. These sub-surface environments are thought to contain saline, rather than pure, water and laboratory studies on whether or not clathrate hydrates can form in such environments are lacking. We fill this gap by performing synchrotron radiation X-ray powder diffraction to investigate the formation and evolution of clathrate hydrates in weak chloride solutions at CO2 pressures, and over temperature ranges, that are similar to those found in the Martian regolith. We have found that clathrate hydrates can form under conditions relevant to the Martian cryosphere, despite the presence of chloride salts. We find that the dissociation temperatures for CO2 clathrate hydrates formed in saline solutions are depressed by 10–20 K relative to those formed in pure water, depending on the nature of the salt and the CO2 pressure. We suggest that the inhibiting effect that salts such as MgCl2, CaCl2 and NaCl have on clathrate hydrate formation could also be related to the salts’ effect on the formation of the low temperature phase

Elemental Abundances in the Ejecta of Old Classical Novae from Late-Epoch Spitzer Spectra

We present Spitzer Space Telescope mid-infrared IRS spectra, supplemented by ground-based optical observations, of the classical novae V1974 Cyg, V382 Vel, and V1494 Aql more than 11, 8, and 4 years after outburst respectively. The spectra are dominated by forbidden emission from neon and oxygen, though in some cases, there are weak signatures of magnesium, sulfur, and argon. We investigate the geometry and distribution of the late time ejecta by examination of the emission line profiles. Using nebular analysis in the low density regime, we estimate lower limits on the abundances in these novae. In V1974 Cyg and V382 Vel, our observations confirm the abundance estimates presented by other authors and support the claims that these eruptions occurred on ONe white dwarfs. We report the first detection of neon emission in V1494 Aql and show that the system most likely contains a CO white dwarf.Comment: 22 pages, 12 figure