OGLE-2017-BLG-0482Lb: A Microlensing Super-Earth Orbiting a Low-mass Host Star

Han, C.,Hirao, Y.,Udalski, A.,Lee, C.-U.,Bozza, V.,Gould, A.,Abe, F.,Barry, R.,Bond, I. A.,Bennett, D. P.,Bhattacharya, A.,Donachie, M.,Evans, P.,Fukui, A.,Itow, Y.,Kawasaki, K.,Koshimoto, N.,Li, M. C American Astronomical Society 2018 The Astronomical journal Vol.155 No.5

Mesoarchaean collision of Kapisilik terrane 3070Ma juvenile arc rocks and >3600Ma Isukasia terrane continental crust (Greenland)

Nutman, A.P.,Bennett, V.C.,Friend, C.R.L.,Yi, K.,Lee, S.R. Elsevier Scientific Pub. Co., etc.] 2015 Precambrian research Vol.258 No.-

<P>The Mesoarchaean Kapisilik and Eoarchaean Isukasia terranes in the Nuuk region of southern West Greenland were tectonically juxtaposed in the Archaean. The north of the Isukasia terrane is distal from the Kapisilik terrane and has only rare growth of similar to 2690 Ma metamorphic zircon and no 2980-2950 Ma metamorphic zircon. The southern part of the Isukasia terrane lies between two similar to 2690 Ma shear zones, and has locally preserved high pressure granulite fades assemblages and widespread growth of 2980-2950 Ma metamorphic zircon and also sporadic growth of similar to 2690 Ma metamorphic zircon. Within this southern part of the Isukasia terrane there is a folded klippe of mylonitised Mesoarchaean detrital meta-sedimentary rocks (carrying >3600 and similar to 3070 Ma detrital zircons), mafic and ultramafic rocks, with similar to 2970 Ma metamorphic zircon overgrowths. South of the Isukasia terrane is the Kapisilik terrane, containing similar to 3070 Ma arc-related volcanic rocks, gabbro-anorthosites and meta-tonalites, intruded by 2970-2960 Ma granites. Zircons of an Ivisartoq supracrustal belt similar to 3075 Ma intermediate volcanic rock have initial elif values of +2 to +5 thus are juvenile crustal additions. similar to 3070 Ma tonalites along the northern edge of the Kapisilik terrane have whole rock positive initial epsilon(Nd) values and thus are also juvenile crustal additions. In contrast, igneous zircons in 2960 Ma granites intruded into juvenile similar to 3075 Ma supracrustal rocks of the Kapisilik terrane have initial epsilon(Hf) values of -5 to -10, and must have involved the partial melting of >3600 Ma Isukasia terrane rocks. The integrated structural and zircon U-Th-Pb-Hf isotopic data show that at 2980-2950 Ma the Kapisilik terrane juvenile arc components collided with, and over-rid, the Isukasia terrane. The southern edge of the Isukasia terrane came to lie in the deep crust under the Ivisartoq supracrustal belt and melted at 2970-2960 Ma to produce granites. These granites derived from ancient crust rose into the upper crust, where they intruded the overlying allochthonous juvenile similar to 3075 Ma Ivisartoq supracrustal belt arc assemblages. The southern edge of the Isukasia terrane is interpreted as an interior nappe of Eoarchaean basement rocks interfolded with a klippe of Mesoarchaean metasedimentary and mafic/ultramafic rocks, both of which are affected by 2980-2950 Ma metamorphism. The mixed Eoarchaean-Mesoarchaean detrital provenance suggests that the klippe could be dismembered components of an accretionary prism or forearc crust. The northern part of the Isukasia terrane is interpreted as foreland, free of 2980-2950 Ma high-grade metamorphic overprint. This shows that the Isukasia terrane is not a coherent block, but contains ancient rocks that are parautochthonous or allochthonous to each other, with contrasting later metamorphic history. At similar to 2690 Ma the crustal architecture arisen from Mesoarchaean collision between an older continental block and an island arc was reworked along intra-crustal shear zones, coeval with amphibolite facies metamorphism. This reworking followed on from major terrane assembly at 2710-2700 Ma in the southern part of the Nuuk region, when the Eoarchaean Faeringehavn terrane was juxtaposed with 2840-2825 Ma arc rocks. Thus the 2980-2950 Ma assembly of the Isukasia and Kapisilik terranes is distinct from the later 2710-2700 Ma terrane assembly further south in the Nuuk region. (C) 2015 Elsevier B.V. All rights reserved.</P>

MOA-2007-BLG-197: Exploring the brown dwarf desert

Ranc, C.,Cassan, A.,Albrow, M. D.,Kubas, D.,Bond, I. A.,Batista, V.,Beaulieu, J.-P.,Bennett, D. P.,Dominik, M.,Dong, Subo,Fouqué,, P.,Gould, A.,Greenhill, J.,Jørgensen, U. G.,Kains, N.,Menzies, EDP Sciences 2015 Astronomy and astrophysics Vol.580 No.-

Tracing Archaean terranes under Greenland's Icecap: U-Th-Pb-Hf isotopic study of zircons from melt-water rivers in the Isua area

Yi, K.,Bennett, V.C.,Nutman, A.P.,Lee, S.R. Elsevier Scientific Pub. Co., etc.] 2014 Precambrian research Vol.255 No.3

The Archaean gneisses of the Nuuk area (southern West Greenland) are partitioned into tectonostratigraphic terranes - blocks of arc-like crust that evolved independently until they coalesced by collisional orogeny. To 'map' terranes to the east under the Inland Ice, sand samples were taken from rivers issuing from the edge of the Icecap; three from the Isua area and one from ~20km to the south. Bedrock along this part of the ice front consists of ~3820-3600Ma amphibolite facies rocks. 40km south of Isua (Kapisilik terrane in the Ivisaartoq area) and also from ~10km to the north there are Mesoarchaean amphibolite facies gneisses (3070-2950Ma) exposed at the ice front. In the moraine fields in the Isua area there are erratic blocks of granulite facies gneisses. These were sourced from a hidden terrane to the east under the ice because no such rocks are exposed in the Isua area. The majority of the zircons from the sand samples yielded close to concordant U-Pb ages. Apart from one 2414Ma grain, all are Archaean. The Isua sands show ~2695, 2710 and 2730Ma; then 2790, 2805 and 2840Ma clusters with a few grains back to 2950Ma and then a complex 3440-3960Ma spectrum. Less than 1% of the grains have ages between 3000 and 3400Ma. In the Isua sands, Neoarchaean and late Mesoarchaean zircons form >50% of the population. The sand 20km to the south shows a similar span of zircon ages, but there is a 2960Ma peak not seen in the Isua sands. As the Eoarchaean and late Mesoarchaean-Neoarchaean cycles progress, the spread of Th/U and @?<SUB>Hf</SUB> values seen in each zircon age population increases. This is interpreted as repeated addition of juvenile material to the crust, but also with increasing amounts of high temperature tectonothermal recycling of older materials within a package. However, there is no isotopic evidence for any contribution of Eoarchaean crust to the later ≥2750Ma Archaean cycle(s), showing evolution in disparate terranes. Furthermore, no evidence for Hadean material beneath the ice is seen in either the U-Pb ages or Hf isotopic compositions of the detrital zircons. On the other hand, 2750-2500Ma metamorphic zircons show a spread of initial @?<SUB>Hf</SUB> values of zero to -25, with the most negative indicating zircon growth in Eoarchaean rocks. Overall these results closely mirror those obtained from direct sampling of rocks of the Archaean terranes exposed beyond the Icecap. The zircon data indicate that Mesoarchaean rocks equivalent to the Kapisilik terrane are absent under the ice. Instead, zircons were sourced from a late Mesoarchaean to Neoarchaean terrane affected by high grade metamorphism, whose age spectra perfectly matches the Tasiusarsuaq terrane to the southeast of Nuuk. Guided by the zircon results and aeromagnetic signatures, a terrane map is presented that extrapolates the Tasiusarsuaq terrane northwards under the Inland Ice towards the Tuno terrane in the north of the craton. Implications for different syntheses on the evolution of Archaean crust in southern West Greenland are discussed.

Tracing Archaean terranes under Greenland`s Icecap

Keewook Yi,V.C. Bennett,Allen P. Nutman,Seung Ryeol Lee 대한지질학회 2015 대한지질학회 학술대회 Vol.2015 No.10

A COLD NEPTUNE-MASS PLANET OGLE-2007-BLG-368Lb: Cold neptunes are common

Sumi, T.,Bennett, D. P.,Bond, I. A.,Udalski, A.,Batista, V.,Dominik, M.,Fouqué,, P.,Kubas, D.,Gould, A.,Macintosh, B.,Cook, K.,Dong, S.,Skuljan, L.,Cassan, A.,Abe, F.,Botzler, C. S.,Fukui, A.,Fu IOP Publishing 2010 The Astrophysical journal Vol.710 No.2

<P>We present the discovery of a Neptune-mass planet OGLE-2007-BLG-368Lb with a planet-star mass ratio of q = [9.5 +/- 2.1] x 10(-5) via gravitational microlensing. The planetary deviation was detected in real-time thanks to the high cadence of the Microlensing Observations in Astrophysics survey, real-time light-curve monitoring and intensive follow-up observations. A Bayesian analysis returns the stellar mass and distance at M(l) = 0.64(-0.26)(+0.21) M(circle dot) and D(l) = 5.9(-1.4)(+ 0.9) kpc, respectively, so the mass and separation of the planet are M(p) = 20(-8)(+7) M(circle plus) and a = 3.3(-0.8)(+1.4) AU, respectively. This discovery adds another cold Neptune-mass planet to the planetary sample discovered by microlensing, which now comprises four cold Neptune/super-Earths, five gas giant planets, and another sub-Saturn mass planet whose nature is unclear. The discovery of these 10 cold exoplanets by the microlensing method implies that the mass ratio function of cold exoplanets scales as dN(pl)/d log q alpha q(-0.7+/-0.2) with a 95% confidence level upper limit of n < -0.35 ( where dN(pl)/d log q alpha q(n)). As microlensing is most sensitive to planets beyond the snow-line, this implies that Neptune-mass planets are at least three times more common than Jupiters in this region at the 95% confidence level.</P>

REVISITING THE MICROLENSING EVENT OGLE 2012-BLG-0026: A SOLAR MASS STAR WITH TWO COLD GIANT PLANETS

Beaulieu, J.-P.,Bennett, D. P.,Batista, V.,Fukui, A.,Marquette, J.-B.,Brillant, S.,Cole, A. A.,Rogers, L. A.,Sumi, T.,Abe, F.,Bhattacharya, A.,Koshimoto, N.,Suzuki, D.,Tristram, P. J.,Han, C.,Gould, A American Astronomical Society 2016 The Astrophysical Journal Vol.824 No.2

<P>Two cold gas giant planets orbiting a G-type main-sequence star in the galactic disk were previously discovered in the high-magnification microlensing event OGLE-2012-BLG-0026. Here, we present revised host star flux measurements and a refined model for the two-planet system using additional light curve data. We performed high angular resolution adaptive optics imaging with the Keck and Subaru telescopes at two epochs while the source star was still amplified. We detected the lens flux, H = 16.39 +/- 0.08. The lens, a disk star, is brighter than predicted from the modeling in the original study. We revisited the light curve modeling using additional photometric data from the B&C telescope in New Zealand and CTIO 1.3 m H-band light curve. We then include the Keck and Subaru adaptive optic observation constraints. The system is composed of a similar to 4-9 Gyr lens star of M-lens = 1.06 +/- 0.05 M circle dot at a distance of D-lens = 4.0 +/- 0.3 kpc, orbited by two giant planets of 0.145 +/- 0.008 M-Jup and 0.86 +/- 0.06 M-Jup, with projected separations of 4.0 +/- 0.5 au and 4.8 +/- 0.7 au, respectively. Because the lens is brighter than the source star by 16 +/- 8% in H, with no other blend within one arcsec, it will be possible to estimate its metallicity using subsequent IR spectroscopy with 8-10 m class telescopes. By adding a constraint on the metallicity it will be possible to refine the age of the system.</P>

Search for Ω(2012)→KΞ(1530)→KπΞ at Belle

Jia, S.,Shen, C. P.,Adachi, I.,Ahn, J. K.,Aihara, H.,Al Said, S.,Asner, D. M.,Aushev, T.,Ayad, R.,Babu, V.,Bahinipati, S.,Bakich, A. M.,Behera, P.,Beleñ,o, C.,Bennett, J.,Berger, M.,Bhardwaj, V. American Physical Society 2019 Physical review. D Vol.100 No.3

MICROLENSING DISCOVERY OF A POPULATION OF VERY TIGHT, VERY LOW MASS BINARY BROWN DWARFS

Choi, J.-Y.,Han, C.,Udalski, A.,Sumi, T.,Gaudi, B. S.,Gould, A.,Bennett, D. P.,Dominik, M.,Beaulieu, J.-P.,Tsapras, Y.,Bozza, V.,Abe, F.,Bond, I. A.,Botzler, C. S.,Chote, P.,Freeman, M.,Fukui, A.,Furu IOP Publishing 2013 The Astrophysical journal Vol.768 No.2

<P>Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs (BDs) are poorly understood. The multiplicity properties and minimum mass of the BD mass function provide critical empirical diagnostics of these mechanisms. We present the discovery via gravitational microlensing of two very low mass, very tight binary systems. These binaries have directly and precisely measured total system masses of 0.025 M-circle dot and 0.034 M-circle dot, and projected separations of 0.31 AU and 0.19 AU, making them the lowest-mass and tightest field BD binaries known. The discovery of a population of such binaries indicates that BD binaries can robustly form at least down to masses of similar to 0.02 M-circle dot. Future microlensing surveys will measure a mass-selected sample of BD binary systems, which can then be directly compared to similar samples of stellar binaries.</P>

OGLE-2012-BLG-0563Lb: A SATURN-MASS PLANET AROUND AN M DWARF WITH THE MASS CONSTRAINED BY<i>SUBARU</i>AO IMAGING

Fukui, A.,Gould, A.,Sumi, T.,Bennett, D. P.,Bond, I. A.,Han, C.,Suzuki, D.,Beaulieu, J.-P.,Batista, V.,Udalski, A.,Street, R. A.,Tsapras, Y.,Hundertmark, M.,Abe, F.,Bhattacharya, A.,Freeman, M.,Itow, IOP Publishing 2015 The Astrophysical journal Vol.809 No.1

<P>We report the discovery of a microlensing exoplanet OGLE-2012-BLG-0563Lb with the planet-star mass ratio of similar to 1 x 10(-3). Intensive photometric observations of a high-magnification microlensing event allow us to detect a clear signal of the planet. Although no parallax signal is detected in the light curve, we instead succeed at detecting the flux from the host star in high-resolution JHK'-band images obtained by the Subaru/AO188 and Infrared Camera and Spectrograph instruments, allowing us to constrain the absolute physical parameters of the planetary system. With the help of spectroscopic information about the source star obtained during the high-magnification state by Bensby et al., we find that the lens system is located at 1.3(-0.8)(+0.6) kpc from us, and consists of an M dwarf (0.34(-0.20)(+0.12)M(circle dot)) orbited by a Saturn-mass planet (0.39(-0.23)(+0.14)M(Jup)) at the projected separation of 0.74(-0.42)(+0.26)AU (close model) or 4.3(-2.5)(+1.5)AU (wide model). The probability of contamination in the host star's flux, which would reduce the masses by a factor of up to three, is estimated to be 17%. This possibility can be tested by future high-resolution imaging. We also estimate the (J - K-s) and (H - K-s) colors of the host star, which are marginally consistent with a low metallicity mid-to-early M dwarf, although further observations are required for the metallicity to be conclusive. This is the fifth sub-Jupiter-mass (0.2 < m(p)/M-Jup < 1) microlensing planet around an M dwarf with the mass well constrained. The relatively rich harvest of sub-Jupiters around M dwarfs is contrasted with a possible paucity of similar to 1-2 Jupiter-mass planets around the same type of star, which can be explained by the planetary formation process in the core-accretion scheme.</P>