http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Evans, D. F.,Southworth, J.,Smalley, B.,Jørgensen, U. G.,Dominik, M.,Andersen, M. I.,Bozza, V.,Bramich, D. M.,Burgdorf, M. J.,Ciceri, S.,D’Ago, G.,Figuera Jaimes, R.,Gu, S.-H.,Hinse, T. C.,Henning, Th Springer-Verlag 2018 Astronomy and astrophysics Vol.610 No.-
<P><I>Context.</I> The formation and dynamical history of hot Jupiters is currently debated, with wide stellar binaries having been suggested as a potential formation pathway. Additionally, contaminating light from both binary companions and unassociated stars can significantly bias the results of planet characterisation studies, but can be corrected for if the properties of the contaminating star are known.</P><P><I>Aim.</I> We search for binary companions to known transiting exoplanet host stars, in order to determine the multiplicity properties of hot Jupiter host stars. We also search for and characterise unassociated stars along the line of sight, allowing photometric and spectroscopic observations of the planetary system to be corrected for contaminating light.</P><P><I>Methods.</I> We analyse lucky imaging observations of 97 Southern hemisphere exoplanet host stars, using the Two Colour Instrument on the Danish 1.54 m telescope. For each detected companion star, we determine flux ratios relative to the planet host star in two passbands, and measure the relative position of the companion. The probability of each companion being physically associated was determined using our two-colour photometry.</P><P><I>Results.</I> A catalogue of close companion stars is presented, including flux ratios, position measurements, and estimated companion star temperature. For companions that are potential binary companions, we review archival and catalogue data for further evidence. For WASP-77AB and WASP-85AB, we combine our data with historical measurements to determine the binary orbits, showing them to be moderately eccentric and inclined to the line of sight (and hence planetary orbital axis). Combining our survey with the similar Friends of Hot Jupiters survey, we conclude that known hot Jupiter host stars show a deficit of high mass stellar companions compared to the field star population; however, this may be a result of the biases in detection and target selection by ground-based surveys.</P>
RED NOISE VERSUS PLANETARY INTERPRETATIONS IN THE MICROLENSING EVENT OGLE-2013-BLG-446
Bachelet, E.,Bramich, D. M.,Han, C.,Greenhill, J.,Street, R. A.,Gould, A.,D’Ago, G.,AlSubai, K.,Dominik, M.,Jaimes, R. Figuera,Horne, K.,Hundertmark, M.,Kains, N.,Snodgrass, C.,Steele, I. A.,Tsapras, IOP Publishing 2015 The Astrophysical journal Vol.812 No.2
<P>For all exoplanet candidates, the reliability of a claimed detection needs to be assessed through a careful study of systematic errors in the data to minimize the false positives rate. We present a method to investigate such systematics in microlensing data sets using the microlensing event OGLE-2013-BLG-0446 as a case study. The event was observed from multiple sites around the world and its high magnification (A(max) similar to 3000) allowed us to investigate the effects of terrestrial and annual parallax. Real-time modeling of the event while it was still ongoing suggested the presence of an extremely low-mass companion (similar to 3M(circle plus)) to the lensing star, leading to substantial follow-up coverage of the light curve. We test and compare different models for the light curve and conclude that the data do not favor the planetary interpretation when systematic errors are taken into account.</P>
Physical properties of the HAT-P-23 and WASP-48 planetary systems from multi-colour photometry
Ciceri, S.,Mancini, L.,Southworth, J.,Bruni, I.,Nikolov, N.,D’Ago, G.,Schrö,der, T.,Bozza, V.,Tregloan-Reed, J.,Henning, Th. Springer-Verlag 2015 Astronomy and astrophysics Vol.577 No.-
<P>Context. Accurate and repeated photometric follow-up observations of planetary transit events are important to precisely characterize the physical properties of exoplanets. A good knowledge of the main characteristics of the exoplanets is fundamental in order to trace their origin and evolution. Multi-band photometric observations play an important role in this process. Aims. By using new photometric data, we computed precise estimates of the physical properties of two transiting planetary systems at equilibrium temperatures of ~2000 K. Methods. We present new broadband, multi-colour photometric observations obtained using three small class telescopes and the telescope-defocussing technique. In particular we obtained 11 and 10 light curves covering 8 and 7 transits of HAT-P-23 and WASP48, respectively. For each of the two targets, one transit event was simultaneously observed through four optical filters. One transit of WASP-48b was monitored with two telescopes from the same observatory. The physical parameters of the systems were obtained by fitting the transit light curves with JKTEBOP and from published spectroscopic measurements. Results. We have revised the physical parameters of the two planetary systems, finding a smaller radius for both HAT-P-23?b and WASP48?b, Rb = 1.224 ± 0.037 RJup and Rb = 1.396 ±0.051 RJup, respectively, than those measured in the discovery papers (Rb = 1.368 ± 0.090 RJup and Rb = 1.67 ±0.10 RJup). The density of the two planets are higher than those previously published (ρb ~ 1.1 and ~0.3 ρjup for HAT-P-23 and WASP48, respectively) hence the two hot Jupiters are no longer located in a parameter space region of highly inflated planets. An analysis of the variation of the planet’s measured radius as a function of optical wavelength reveals flat transmission spectra within the experimental uncertainties. We also confirm the presence of the eclipsing contact binary NSVS3071474 in the same field of view of WASP48, for which we refine the value of the period to be 0.459?d.</P>
Physical properties of the WASP-67 planetary system from multi-colour photometry
Mancini, L.,Southworth, J.,Ciceri, S.,Calchi Novati, S.,Dominik, M.,Henning, Th.,Jørgensen, U. G.,Korhonen, H.,Nikolov, N.,Alsubai, K. A.,Bozza, V.,Bramich, D. M.,D’Ago, G.,Figuera Jaimes, R.,Galianni EDP Sciences 2014 Astronomy and astrophysics Vol.568 No.2
Han, C.,Udalski, A.,Bozza, V.,Szymań,ski, M. K.,Soszyń,ski, I.,Skowron, J.,Mró,z, P.,Poleski, R.,Pietrukowicz, P.,Kozłowski, S.,Ulaczyk, K.,Wyrzykowski, Ł.,Novati, S. Calchi,D’Ago, G. American Astronomical Society 2017 The Astrophysical journal Vol.843 No.2
<P>Due to the nature of the gravitational field, microlensing, in principle, provides an important tool for detecting faint and even dark brown dwarfs. However, the number of identified brown dwarfs is limited due to the difficulty of the lens mass measurement that is needed to check the substellar nature of the lensing object. In this work, we report a microlensing brown dwarf discovered from an analysis of the gravitational binary-lens event OGLE-2014-BLG1112. We identify the brown dwarf nature of the lens companion by measuring the lens mass from the detections of both microlens-parallax and finite-source effects. We find that the companion has a mass of. ' ( 3.03 +/- 0.78) 10(-2) M-circle dot and it is orbiting a solar-type primary star with a mass of 1.07 +/- 0.28 M-circle dot. The estimated projected separation between the lens components is 9.63 +/- 1.33 au and the distance to the lens is 4.84 +/- 0.67 kpc. We discuss the usefulness of space-based microlensing observations for detecting brown dwarfs through the channel of binary-lens events.</P>