3,340 research outputs found
The UNSW Extrasolar Planet Search: Methods and First Results from a Field Centred on NGC 6633
We report on the current status of the University of New South Wales
Extrasolar Planet Search project, giving details of the methods we use to
obtain millimagnitude precision photometry using the 0.5m Automated Patrol
Telescope. We use a novel observing technique to optimally broaden the PSF and
thus largely eliminate photometric noise due to intra-pixel sensitivity
variations on the CCD. We have observed 8 crowded Galactic fields using this
technique during 2003 and 2004. Our analysis of the first of these fields
(centred on the open cluster NGC 6633) has yielded 49 variable stars and 4
shallow transit candidates. Follow-up observations of these candidates have
identified them as eclipsing binary systems. We use a detailed simulation of
our observations to estimate our sensitivity to short-period planets, and to
select a new observing strategy to maximise the number of planets detected.Comment: 16 pages, 9 figures, version published in MNRAS Updated figures,
references, and additional discussion in section
The first high-amplitude delta Scuti star in an eclipsing binary system
We report the discovery of the first high-amplitude delta Scuti star in an
eclipsing binary, which we have designated UNSW-V-500. The system is an
Algol-type semi-detached eclipsing binary of maximum brightness V = 12.52 mag.
A best-fitting solution to the binary light curve and two radial velocity
curves is derived using the Wilson-Devinney code. We identify a late A spectral
type primary component of mass 1.49+/-0.02 M_sun and a late K spectral type
secondary of mass 0.33+/-0.02 M_sun, with an inclination of 86.5+/-1.0 degrees,
and a period of 5.3504751+/-0.0000006 d. A Fourier analysis of the residuals
from this solution is performed using PERIOD04 to investigate the delta Scuti
pulsations. We detect a single pulsation frequency of f_1 = 13.621+/-0.015 c/d,
and it appears this is the first overtone radial mode frequency. This system
provides the first opportunity to measure the dynamical mass for a star of this
variable type; previously, masses have been derived from stellar evolution and
pulsation models.Comment: 7 pages, 6 figures, 2 tables, for submission to MNRAS, v2: paper size
change, small typographical changes to abstrac
Fluid-Enhanced Annealing in the Subcontinental Lithospheric Mantle Beneath the Westernmost Margin of the Carpathian-Pannonian Extensional Basin System
Mantle xenoliths from the Styrian Basin Volcanic Field (Western Pannonian Basin, Austria) are mostly coarse granular amphibole-bearing spinel lherzolites with microstructures attesting for extensive annealing. Olivine and pyroxene CPO (crystal-preferred orientation) preserve nevertheless the record of coeval deformation during a preannealing tectonic event. Olivine shows transitional CPO symmetry from [010]-fiber to orthogonal type. In most samples with [010]-fiber olivine CPO symmetry, the [001] axes of the pyroxenes are also dispersed in the foliation plane. This CPO patterns are consistent with lithospheric deformation accommodated by dislocation creep in a transpressional tectonic regime. The lithospheric mantle deformed most probably during the transpressional phase after the Penninic slab breakoff in the Eastern Alps. The calculated seismic properties of the xenoliths indicate that a significant portion of shear wave splitting delay times in the Styrian Basin (0.5 s out of approximately 1.3 s) may originate in a highly annealed subcontinental lithospheric mantle. Hydroxyl content in olivine is correlated to the degree of annealing, with higher concentrations in the more annealed textures. Based on the correlation between microstructures and hydroxyl content in olivine, we propose that annealing was triggered by percolation of hydrous fluids/melts in the shallow subcontinental lithospheric mantle. A possible source of these fluids/melts is the dehydration of the subducted Penninic slab beneath the Styrian Basin. The studied xenoliths did not record the latest large-scale geodynamic events in the regionthe Miocene extension then tectonic inversion of the Pannonian Basin.We acknowledge the constructive criticism and helpful comments of QâK. Xia, an anonymous reviewer, and the Editor, John Geissman. We are grateful to F. Barou for his assistance during EBSDâSEM analyses. L. E. Aradi is grateful to Bernardo Cesare, Levente PatkĂł, and RaĂșl Carampin for their help during the EPMA measurements. The FTIR analyses were carried out with the help of Judith MihĂĄly and Csaba NĂ©meth. This research was partially granted by the Hungarian Science Foundation (OTKA, 78425 to Cs. SzabĂł). K. H.'s work was funded by the European Union Seventh Framework Programme Marie Curie postdoctoral fellowship (grant PIEFGAâ2012â327226) and by the Juan de la Cierva Postdoctoral Fellowship (grant FPDIâ2013â16253) of the Spanish Ministry of Economic and Competitiveness (MINECO). This project has been implemented with the support provided to I. J. KovĂĄcs from the National Research, Development and Innovation Fund of Hungary, financed under the K119740 funding scheme. The data used in this paper are listed in the references, tables, and supporting information. The raw EBSD and geochemical data are available from the corresponding author upon request. The FTIR spectra are available at the PULI (Pannonian Uniform Lithospheric Infrared spectral database) website (http://puli.mfgi.hu/). This is the 86 publication of the Lithosphere Fluid Research Lab (LRG)
A new detached K7 dwarf eclipsing binary system
We present an analysis of a new, detached, double-lined eclipsing binary
system with K7 Ve components, discovered as part of the University of New South
Wales Extrasolar Planet Search. The object is significant in that only 6 other
binary systems are known with comparable or lower mass. Such systems offer
important tests of mass-radius theoretical models. Follow-up photometry and
spectroscopy were obtained with the 40-inch and 2.3m telescopes at SSO
respectively. An estimate of the radial velocity amplitude from spectral
absorption features, combined with the orbital inclination (83.5 deg) estimated
from lightcurve fitting, yielded a total mass of M=(1.041 +/- 0.06)M_sun and
component masses of M_A=(0.529 +/- 0.035)M_sun and M_B=(0.512 +/- 0.035)M_sun.
The radial velocity amplitude estimated from absorption features (167 +/-
3)kmps was found to be less than the estimate from the H_alpha emission lines
(175 +/- 1.5)kmps. The lightcurve fit produced radii of R_A=(0.641 +/-
0.05)R_sun and R_B=(0.608 +/- 0.06)R_sun, and a temperature ratio of
T_B/T_A=0.980 +/- 0.015. The apparent magnitude of the binary was estimated to
be V=13.9 +/- 0.2. Combined with the spectral type, this gave the distance to
the binary as 169 +/- 14 pc. The timing of the secondary eclipse gave a lower
limit on the eccentricity of the binary system of 0.0025 +/- 0.0005. This is
the most statistically significant non-zero eccentricity found for such a
system, possibly suggesting the presence of a third companion.Comment: 6 pages, published in MNRAS (08/2006
Lateral and vertical heterogeneity in the lithospheric mantle at the northern margin of the Pannonian Basin reconstructed from peridotite xenolith microstructures
International audienceThis study analyzes the microstructures and deformational characteristics of spinel peridotite xenoliths from the NĂłgrĂĄdâGömör Volcanic Field (NGVF), located on the northern margin of a young extensional basin presently affected by compression. The xenoliths show a wide range of microstructures, bearing the imprints of heterogeneous deformation and variable degrees of subsequent annealing. Olivine crystal preferred orientations (CPOs) have dominantly [010]âfiber and orthorhombic patterns. Orthopyroxene CPOs indicate coeval deformation with olivine. Olivine J indices correlate positively with equilibration temperatures, suggesting that the CPO strength increases with depth. In contrast, the intensity of intragranular deformation in olivine varies as a function of the sampling locality. We interpret the microstructures and CPO patterns as recording deformation by dislocation creep in a transpressional regime, which is consistent with recent tectonic evolution in the CarpathianâPannonian region due to the convergence between the Adria microplate and the European platform. Postkinematic annealing is probably linked to percolation of metasomatism by mafic melts through the upper mantle of the NGVF prior to the eruption of the host alkali basalt. Elevated equilibration temperatures in xenoliths from the central part of the volcanic field are interpreted to be associated with the last metasomatic event, which only shortly preceded the ascent of the host magma. Despite wellâdeveloped olivine CPOs in the xenoliths, which imply a strong seismic anisotropy, the lithospheric mantle alone cannot account for the shear wave splitting delay times measured in the NGVF, indicating that deformation in both the lithosphere and the asthenosphere contributes to the observed shear wave splitting
An ingress and a complete transit of HD 80606 b
We have used four telescopes at different longitudes to obtain
near-continuous lightcurve coverage of the star HD 80606 as it was transited by
its \sim 4-MJup planet. The observations were performed during the predicted
transit windows around the 25th of October 2008 and the 14th of February 2009.
Our data set is unique in that it simultaneously constrains the duration of the
transit and the planet's period. Our Markov-Chain Monte Carlo analysis of the
light curves, combined with constraints from radial-velocity data, yields
system parameters consistent with previously reported values. We find a
planet-to-star radius ratio marginally smaller than previously reported,
corresponding to a planet radius of Rp = 0.921 \pm 0.036RJup .Comment: 6 pages, 2 figures, MNRAS accepte
A Search for Propylene Oxide and Glycine in Sagittarius B2 (LMH) and Orion
We have used the Mopra Telescope to search for glycine and the simple chiral
molecule propylene oxide in the Sgr B2 (LMH) and Orion KL, in the 3-mm band. We
have not detected either species, but have been able to put sensitive upper
limits on the abundances of both molecules. The 3-sigma upper limits derived
for glycine conformer I are 3.7 x 10^{14} cm^{-2} in both Orion-KL and Sgr B2
(LMH), comparable to the reported detections of conformer I by Kuan et al.
However, as our values are 3-sigma upper limits rather than detections we
conclude that this weighs against confirming the detection of Kuan et al. We
find upper limits for the glycine II column density of 7.7 x 10^{12} cm^{-2} in
both Orion-KL and Sgr B2 (LMH), in agreement with the results of Combes et al.
The results presented here show that glycine conformer II is not present in the
extended gas at the levels detected by Kuan et al. for conformer I. Our ATCA
results (Jones et al.) have ruled out the detection of glycine (both conformers
I and II) in the compact hot core of the LMH at the levels reported, so we
conclude that it is unlikely that Kuan et al. have detected glycine in either
Sgr B2 or Orion-KL. We find upper limits for propylene oxide abundance of 3.0 x
10^{14} cm^{-2} in Orion-KL and 6.7 x 10^{14} cm^{-2} in Sgr B2 (LMH). We have
detected fourteen features in Sgr B2 and four features in Orion-KL which have
not previously been reported in the ISM, but have not be able to plausibly
assign these transitions to any carrier.Comment: 12 pages, 3 figures. Accepted by MNRAS 12th January 200
TrES-3: A Nearby, Massive, Transiting Hot Jupiter in a 31-Hour Orbit
We describe the discovery of a massive transiting hot Jupiter with a very
short orbital period (1.30619 d), which we name TrES-3. From spectroscopy of
the host star GSC 03089-00929, we measure T_eff = 5720 +- 150 K, logg=4.6 +-
0.3, and vsini < 2 km/s, and derive a stellar mass of 0.90 +- 0.15 M_sun. We
estimate a planetary mass of 1.92 +- 0.23 M_Jup, based on the sinusoidal
variation of our high-precision radial velocity measurements. This variation
has a period and phase consistent with our transit photometry. Our spectra show
no evidence of line bisector variations that would indicate a blended eclipsing
binary star. From detailed modeling of our B and z photometry of the 2.5%-deep
transits, we determine a stellar radius 0.802 +- 0.046 R_sun and a planetary
radius 1.295 +- 0.081 R_Jup. TrES-3 has one of the shortest orbital periods of
the known transiting exoplanets, facilitating studies of orbital decay and mass
loss due to evaporation, and making it an excellent target for future studies
of infrared emission and reflected starlight.Comment: v1. 14 pages, 2 figures, 3 tables. Submitted to ApJL 27 April 2007.
Accepted for publication in ApJL 14 May 200
The natural history of secondary muscle-invasive bladder cancer
BACKGROUND: The management of patients with high-grade non muscle invasive bladder cancer (NMIBC) brings diagnostic and therapeutic challenges. In the current study, we sought to study the natural history of progression to "secondary" muscle-invasive bladder cancer (MIBC)-cancer that developed during follow up of patients presenting with non-muscle invasive bladder cancer (NMIBC). METHODS: Between 1998 and 2008, 760 patients were treated for bladder cancer. Primary MIBC (>=T2) tumors (present upon presentation) were diagnosed in 114 patients. All patients with high-grade NMIBC were treated with intravesical BCG. Mean follow-up was 44âmonths. RESULTS: Forty patients (6.1%) developed secondary MIBC after a mean period of 21âmonths from initial diagnosis of bladder cancer. The 2- and 5-year disease-specific survival rates were better for patients with secondary MIBC (90% and 56% compared to 69% and 42% for patients with primary disease, p=0.03). The Kaplan-Meier curves of the two groups were parallel but displaced by approximately 2âyears. CONCLUSION: In the current series, MIBC progression occurred among initially presenting patients with NMIBC in 6.1%. In most patients, the initial diagnosis of NMIBC is correct and muscle invasion occurs after a mean period of about 2âyears. This supports a non-radical approach in patients with high-grade T1, Ta or Tis. Meticulous follow-up with liberal biopsy of any suspicious lesion may provide early diagnosis of invasive disease
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