A 6.3-h superhump in the cataclysmic variable TV Columbae: the longest yet seen

We present results from a two week multi-longitude photometric campaign on TV Col held in 2001 January. The data confirm the presence of a permanent positive superhump found in re-examination of extensive archive photometric data of TV Col. The 6.3-h period is 15 per cent longer than the orbital period and obeys the well known relation between superhump period excess and binary period. At 5.5-h, TV Col has an orbital period longer than any known superhumping cataclysmic variable and, therefore, a mass ratio which might be outside the range at which superhumps can occur according to the current theory. We suggest several solutions for this problem.Comment: 8 pages, 1 Latex file, 7 eps figures, MNRAS, accepte

The Watonga formation and tacking point gabbro, Port Macquarie, Australia: insights into crustal growth mechanisms on the eastern margin of Gondwana

A diverse assemblage of accretionary complex, island-arc, ophiolitic and high-pressure, low-temperature metamorphic rocks occurs within the serpentinite mélange at Port Macquarie on the eastern extremity of the New England Orogen of eastern Australia. New field observations, U-Pb zircon dating, petrography and geochemistry presented here establish a more robust chronology and interpretation of these rocks. Previously, all basalt, chert and volcaniclastic sandstones at Port Macquarie were grouped into the Watonga Formation. Ordovician to middle Devonian radiolarians and conodonts from \u27Watonga\u27 chert-basalt associations shows that they are older than, and unrelated to, \u27Watonga\u27 volcaniclastic rocks like those at Green Mound which contain volcanic/detrital zircons as young as 335 Ma that were derived from a Carboniferous arc. Volcanic detritus with pillow lava forming a block within the serpentinite mélange yielded 452 ± 10 Ma igneous zircons, indicating an Ordovician age. The Tacking Point Gabbro has an age of 390 ± 7 Ma (Devonian) and geochemical affinities with intra-oceanic arc igneous suites. It was intruded into deformed cherts of the Watonga Formation giving a spatial link between an Ordovician-Devonian? Accretionary complex and adjacent Devonian island-arc. The MORB-like basalt-chert association of the Watonga Formation and the Devonian Tacking Point gabbro represents a mid-Paleozoic assemblage allochthonous to Gondwana, which possibly correlates with the Djungati and Gamilaroi terranes respectively located further west in the New England Orogen. Zircon dating shows that post-serpentinite mafic-felsic dykes were emplaced into the Port Macquarie serpentinite at 247 ± 20 Ma and further disrupted. Therefore, tectonism affecting the serpentinite continued into the Early Triassic, with final movement during the Hunter-Bowen Orogeny. Our results from Port Macquarie are compatible with a tectonic model for the New England Orogen that involves episodic island-arc collisional events (Gamilaroi and Gympie terranes) interspersed with periods of continental margin Andean-type magmatism and accretion along eastern Gondwana

Multisite, multiwavelength studies of the active cool binary CC Eri

New data acquired on the active, cool binary CC Eri ranged across the spectrum from Chandra X-ray to broadband photometry and microwave observations using the VLA and ATCA. Also, high-dispersion spectropolarimetry using the AAT enabled Zeeman-Doppler imaging to be performed. Our interpretations infer strong localised concentrations of the stellar magnetic field, manifested by surface activity and related large coronal plasma structures. Comprehensive matching of the modelling parameters awaits more detailed investigation. This brief interim review includes consideration of the ATCA data. Microwave radio emission is usually low level ('quiescent'), but occasionally flares of several mJy peak intensity are observed. We associate the emission, generally, with wave-like mechanisms, expanding through the outer atmosphere. Related characteristics of this emission are discussed

Multisite, Multiwavelength Studies of the Active Cool BinaryCC Eri

New data acquired on the active, cool binary CC Eri ranged across the spectrum from Chandra X-ray to broadband photometry and microwave observations using the VLA and ATCA. Also, high-dispersion spectropolarimetry using the AAT enabled Zeeman-Doppler imaging to be performed. Our interpretations infer strong localised concentrations of the stellar magnetic field, manifested by surface activity and related large coronal plasma structures. Comprehensive matching of the modelling parameters awaits more detailed investigation.This brief interim review includes consideration of the ATCA data. Microwave radio emission is usually low level ('quiescent'), but occasionally flares of several mJy peak intensity are observed. We associate the emission, generally, with wave-like mechanisms, expanding through the outer atmosphere. Related characteristics of this emission are discussed.</p

Mid to late Paleozoic shortening pulses in the Lachlan Orogen, southeastern Australia: a review

In the late Silurian, the Lachlan Orogen of southeastern Australia had a varied paleogeography with deep-marine, shallow-marine, subaerial environments and widespread igneous activity reflecting an extensional backarc setting. This changed to a compressional-extensional regime in the Devonian associated with episodic compressional events, including the Bindian, Tabberabberan and Kanimblan orogenies. The Early Devonian Bindian Orogeny was associated with SSE transport of the Wagga-Omeo Zone that was synchronous with thick sedimentation in the Cobar and Darling basins in central and western New South Wales. Shortening has been controlled by the margins of the Wagga-Omeo Zone with partitioning along strike-slip faults, such as along the Gilmore Fault, and inversion of pre-existing extensional basins including the Limestone Creek Graben and the Canbelego-Mineral Hill Volcanic Belt. Shortening was more widespread in the late Early Devonian to Middle Devonian Tabberabberan Orogeny, with major deformation in the Melbourne Zone, Cobar Basin and eastern Lachlan Orogen. In the eastern Melbourne Zone, structural trends have been controlled by the pre-existing structural grain in the adjacent Tabberabbera Zone. Elsewhere Tabberabberan deformation involved inversion of pre-existing rifts resulting in a variation in structural trends. In the Early Carboniferous, the Lachlan Orogen was in a compressional backarc setting west of the New England continental margin arc with Kanimblan deformation most evident in Upper Devonian units in the eastern Lachlan Orogen. Kanimblan structures include major thrusts and associated fault-propagation folds indicated by footwall synclines with a steeply dipping to overturned limb adjacent to the fault. Ongoing deformation and sedimentation have been documented in the Mt Howitt Province of eastern Victoria. Overall, structural trends reflect a combination of controls provided by reactivation of pre-existing contractional and extensional structures in dominantly E-W shortening operating intermittently from the earliest Devonian to Early Carboniferous