bluuebunny/crossref_metadata_2025_split huggingface dataset:
KARAKTERISTIK SIFAT TARIK DAN MODE PATAHAN KOMPOSIT POLYESTER BERPENGUAT SERAT TAPIS KELAPA
Authors: Astika I Made , Komang Dwijana I Gusti 
Published: January 2018

The purpose of this study is to investigate the mechanical properties i.e. tensile strength of composites coconut filter fiber. In the future this material can be used to replace the wood, bamboo and gipsun which are high price and lower water resistance.The research material made with coconut filter fiber as reinforcement and matrix resin unsaturated polyester (UPRs) type Yukalac BQTN 157, with 1% hardener types MEKPO (Methyl Ethyl Ketone Peroxide) and fiber treatment by 0.5% KMnO4. Production methods are poltrusion and the variations of fiber volume fraction are 20, 25 and 30% and fiber length are 5, 10 and 15 mm. Testing of mechanical properties is tensile test (ASTM D3039-76) The results of research show that the longer of fiber and the bigger of fiber volume fraction, the higher of tensile strength are obtained. The fracture mode are overload, debonding, pullout and crack deflection
ANALISA NILAI KALOR DAN LAJU PEMBAKARAN PADA BRIKET CAMPURAN BIJI NYAMPLUNG (Calophyllm Inophyllum) DAN ABU SEKAM PADI
Authors: Almu M. Afif , Syahrul S. , Padang Yesung Allo 
Published: January 2018

The fuel is a source of energy with greatest consumption today. Where that stock is become less until 2025th. That’s way, it must to find some new energy to replacement, that one of alternative that is a fuel of solid phase that become from briquette. The briquette that use is compound between nyamplung’s fruit and rice husk. In this case because in NTB nyamplung’s fruit and rice husk is overabundance.This research conducted three testing that are testing of heat value, testing of combustion rate, and testing of dry measure. In case where to testing of heat value using bomb calorimeter. Independent variable both of this research is combine. Between nyamplung’s fruit and rice husk with comparison 1:1, 2:1, 3:1, 1:2, and 1:3. The highest heating value is obtained from sample 3:1 as big as 4792,40 cal/gr, the lowest rate of combustion from sample 3:1 as big as 0,00156 gr/s and the lowest of dry measure lowest from sample 1:1 that is 21,52%.
PENGARUH SUSUNAN PIPA LALUAN TERHADAP PEMANFAATAN KALOR PADA KOLEKTOR SURYA PELAT DATAR ABSORBER GRANITE
Authors: Wirawan Made , Mirmanto M. , Bawa Susana I Gede , Sutanto Rudy 
Published: January 2018

The collector of solar energy can be used for heating fluidssuch as liquid or gas. The optimize absorbtion of solar energy depends on the collectordimention and component, e.g.the width, body of collector, tube formation, cover and isolation system. This research usesa granite absorber with a variation of tube formations and water flow rates. The aim of the research is tofind out the optimal tube formation. To achieve the aim of the research,theexperiments of water heating usingthree collectorswith a granite absorber 80 Cm x 100 Cm and three way tube formatians have been done.The variation of water flow rates had beenperformed toinvestigate the maximal performance. The water flow rates used were200, 250 and 300 cc/minute.The result of research achieved value of heat utilization of solar collector influenced by: arrangement inlet tube, flow rates of water and time. The maksimal heat utilization occur at parallel 7 for each flow rate. The flow rate 300 cc/minute show maximal heat utilization.
PENERAPAN MODEL PEMBELAJARAN KOOPERATIF TIPE SNOWBALL THROWING PADA PEMBELAJARAN SEGIEMPAT UNTUK MENINGKATKAN AKTIVITAS DAN PRESTASI BELAJAR SISWA SMPN 1 LINGSAR KELAS VII-1 TAHUN PELAJARAN 2012/2013
Authors: Hirzi Ristu Haiban , Sripatmi Sripatmi , Hapipi Hapipi 
Published: January 2018

Abstrak: Penelitian ini bertujuan untuk meningkatkan aktivitas dan hasil belajar siswa SMPN 1 Lingsar kelas VII-1 pada materi segi empat melalui penerapan model pembelajaran Kooperatif tipe Snowball Thowing. Penelitian ini merupakan penelitian tindakan kelas yang dilaksnakaan dalam 2 siklus. Hasil penelitian menunjukkan bahwa penerapan model pembelajaran tersebut dapat memperbaiki aktivitas dan hasil belajar siswa. Hal ini ditunjukkan oleh skor aktivitas siswa tergolong tinggi pada siklus I dan sangat tinggi pada siklus II. Sedangkan skor rata-rata hasil evaluasi belajar siswa mengalami ÃÂ peningkatan ÃÂ padaÃÂ tiap ÃÂ siklus ÃÂ yaitu ÃÂ padaÃÂ siklus ÃÂ I rata-rata ÃÂ skor ÃÂ hasil evaluasi belajar 58,2 dengan ketuntasan klasikal 50% dan pada siklus II skor rata-rata hasil evaluasi belajarnya mencapai 85,74 dengan ketuntasan klasikal 89%. Capaian tersebut menunjukkan bahwa penerapan Model Pembelajaran Kooperatif tipe Snowball Throwing pada pembelajaran segiempat dapat meningkatkan aktivitas dan prestasi belajar siswa SMP Negeri 1 Lingsar kelas VII-1 tahun pelajaran 2012/2013.ÃÂ Kata kunci: Kooperatif tipe snow ball throwing, aktivitas belajar, hasil belajar.ÃÂ ÃÂ ÃÂ ÃÂ ÃÂ Abstract: This research aims to improve the activity and student learning outcomes SMPN 1 Lingsar class VII-1 on the rectangular material through the implementation of cooperative learning model type thowing Snowball. This research is a classroom action research conducted in two cycles. The results showed that the application of the learning model can improve the activity and student learning outcomes. This is demonstrated by the student activity score relatively high on theÃÂ first cycle and veryÃÂ highÃÂ in theÃÂ second cycle. While the average score on the evaluation of student learningÃÂ has increasedÃÂ inÃÂ eachÃÂ cycle,ÃÂ namelyÃÂ inÃÂ theÃÂ firstÃÂ cycleÃÂ anÃÂ averageÃÂ scoreÃÂ ofÃÂ 58.2ÃÂ onÃÂ theÃÂ evaluationÃÂ studyÃÂ withÃÂ classical completenessÃÂ 50%ÃÂ andÃÂ theÃÂ secondÃÂ cycleÃÂ theÃÂ averageÃÂ scoreÃÂ onÃÂ theÃÂ evaluationÃÂ studyÃÂ reachedÃÂ 85.74ÃÂ withÃÂ classical completenessÃÂ 89%.ÃÂ TheseÃÂ achievementsÃÂ showÃÂ thatÃÂ theÃÂ applicationÃÂ ofÃÂ cooperativeÃÂ learningÃÂ modelÃÂ typeÃÂ Snowball ThrowingÃÂ onÃÂ theÃÂ rectangularÃÂ materialÃÂ canÃÂ increaseÃÂ theÃÂ activityÃÂ ofÃÂ learningÃÂ andÃÂ studentÃÂ achievementÃÂ SMPÃÂ NegeriÃÂ 1 Lingsar class VII-1 of the school year 2012/2013.ÃÂ Keywords: snowball throwing cooperative type, learning activity, learning outcomes
ALAT DESTILASI SEDERHANA SEBAGAI MEDIA EDUKASI UNTUK MENINGKATKAN MINAT WIRAUSAHA SISWA-SISWI SMA IT AL KAMAL NW NARMADA
Authors: Asnawati Dina , Hamdiani Saprini , Sudarma I Made , Ismilayli Nurul 
Published: January 2018

Abstrak: Peningkatan Sumber Daya Manusia dalam pelaksanaannya menghadapi banyak kendala terutamaÃÂ dalamÃÂ halÃÂ saranaÃÂ danÃÂ prasaranaÃÂ terutamaÃÂ bagiÃÂ sekolah-sekolahÃÂ swastaÃÂ diÃÂ pedesaan LombokÃÂ Barat.ÃÂ SalahÃÂ satunyaÃÂ adalahÃÂ SMAÃÂ ITÃÂ AlÃÂ KamalÃÂ NWÃÂ NarmadaÃÂ yangÃÂ terletakÃÂ diÃÂ Desa Golong Kecamatan Narmada, Lombok Barat. Sekolah yang berdiri tahunÃÂ 2008 ini belum memiliki fasilitasÃÂ ruangÃÂ danÃÂ alatÃÂ laboratorium.ÃÂ HalÃÂ iniÃÂ sangatÃÂ menyulitkanÃÂ siswaÃÂ untukÃÂ dapatÃÂ memahami konsep-konsepÃÂ IPAÃÂ secaraÃÂ lebihÃÂ mendalamÃÂ tanpaÃÂ disertaiÃÂ praktikum.ÃÂ SehinggaÃÂ perluÃÂ dilakukan inovasiÃÂ denganÃÂ memanfaatkanÃÂ barang-barangÃÂ bekasÃÂ yangÃÂ mudahÃÂ diperolehÃÂ untukÃÂ dijadikanÃÂ alat peragaÃÂ sederhana.ÃÂ SalahÃÂ satuÃÂ inovasiÃÂ yangÃÂ telahÃÂ dilakukanÃÂ adalahÃÂ perancanganÃÂ danÃÂ pembuatan sendiriÃÂ alatÃÂ praktikumÃÂ destilasiÃÂ sederhana,ÃÂ untukÃÂ membantuÃÂ siswaÃÂ memahamiÃÂ konsepÃÂ destilasi serta penerapannya dalam industri. Diharapkan pengabdian ini akan meningkatkan kreatifitas dan minatÃÂ paraÃÂ siswa/siswiÃÂ SMAÃÂ ITÃÂ AlÃÂ KamalÃÂ untukÃÂ mengembangkanÃÂ penggunaanÃÂ alatÃÂ destilasi sederhana tersebut dalam bidang praktis seperti pertanian sehingga dapat juga menigkatkan jiwa kewirausahaan siswa.Kata kunci : alat destilasi sederhana, praktikum, wirausahaAbstract: ImprovementÃÂ ofÃÂ humanÃÂ resourcesÃÂ facesÃÂ manyÃÂ challenges,ÃÂ especiallyÃÂ inÃÂ termsÃÂ of facilities and infrastructure, especially for private schools in rural, West Lombok. One of the high schools that face the same problem is the High School IT Al Kamal NW Narmada located in the villageÃÂ ofGolongÃÂ DistrictÃÂ ofÃÂ Narmada,ÃÂ LombokÃÂ Barat.ÃÂ SchoolÃÂ wasÃÂ establishedÃÂ inÃÂ 2008ÃÂ butÃÂ have no adequateÃÂ classroomÃÂ facilitiesÃÂ andÃÂ laboratoryÃÂ equipment.ÃÂ ItÃÂ isÃÂ veryÃÂ difficultÃÂ forÃÂ studentsÃÂ to understandÃÂ scienceÃÂ conceptsÃÂ inÃÂ moreÃÂ depthÃÂ withoutÃÂ laboratoryÃÂ workÃÂ activity. ThereforeÃÂ itÃÂ needs innovationÃÂ forÃÂ simpleÃÂ laboratoryÃÂ workÃÂ activityÃÂ byÃÂ utilizingÃÂ second-handÃÂ goodsÃÂ thatÃÂ readilyavailable.ÃÂ TheÃÂ simpleÃÂ innovationÃÂ thatÃÂ hasÃÂ beenÃÂ introducedÃÂ isÃÂ toÃÂ designÃÂ andÃÂ manufactureÃÂ simple distillationÃÂ apparatusÃÂ inÃÂ orderÃÂ toÃÂ helpÃÂ studentsÃÂ understandÃÂ theÃÂ conceptÃÂ ofÃÂ distillationÃÂ andÃÂ its applicationÃÂ inÃÂ theÃÂ industry.ÃÂ ThisÃÂ approachÃÂ isÃÂ expectedÃÂ toÃÂ increaseÃÂ creativityÃÂ andÃÂ interestÃÂ ofÃÂ the student especially from SMA IT Al Kamal to develop simple destilation apparatus for practical purposes (e.g in agriculture) so that it is espected that student has entrepreneurs skills.ÃÂ Keywords :simple distillation device,ÃÂ laboratory work, entrepreneur
PERUMUMAN LEMMA SNAKE DAN LEMMA LIMA
Authors: Sripatmi Sripatmi , Septriana Anwar Yunita 
Published: January 2018

Abstrak. Barisan -eksak merupakan perumuman dari barisan eksak yang diperkenalkan oleh Davvaz dan Parnian-Garamaleky. Dalam tulisan ini akan dikaji perumuman dari Lemma Snake dan Lemma Lima yang memanfaatkan sifat-sifat dari barisan -eksak.ÃÂ Kata Kunci : Barisan -eksak, Lemma Snake, Lemma LimaÃÂ Abstract. -exact sequences was introduced byÃÂ Davvaz dan Parnian-Garamaleky as a generalization of exact sequences. In this paper, we give some characterizations and properties of -exact sequences. We use these result to find a generalization of Snake Lemma and Five Lemma.ÃÂ Key words Kunci : -exact sequences, Snake Lemma, Five Lemma
PENGARUH MODEL PEMBELAJARAN KOOPERATIF STAD BERBASIS MULTI MEDIA INTERAKTIF TERHADAP PENGUASAAN KONSEP SISWA PADA MATERI TERMODINAMIKA
Authors: - Jamuri , - Kosim , Doyan Aris 
Published: January 2018

The objective of this study is : To know The influence of learning cooperative STAD model based on interactive multi media toward the student’s mastery concept of thermodynamics. Type of study done ,is experimental research by pretest-post test control group design. Population study is XI grade of Science students in SMAN 5 Mataram. The sample was chosen two classes which taken 73 students with random sampling which consisted of 37 students for experiment and 36 students for control. In this research taken through pretest and posttest by using the ability of problem solving student test toward experiment class and control class. The data analyzed by using N- gain to know the increase percentage of problem solving of student’s ability in each class. And ANAVA analysis to know cooperative learning model of STAD type based on interactive multi media toward the mastery of student concept in thermodynamics. Analysis result of N-gain shows that value reaches 70% with high category in mastery of student concept in experiment class. Whereas, the mastery of student concept in control class reaches 50% with average category. ANAVA analysis in significant level 5% shows significant score gotten 0,000 0,05 from significant level used. Based on the result of ANAVA analysis could be concluded that the use of cooperative learning model of STAD type based on interactive multimedia in learning thermodynamics influence toward the student’s mastery concept, Keywords: Learning Cooperative, Interactive Multi Media learning, Mastery Concept and problem solving ability
PEMBELAJARAN FISIKA BERBASIS INKUIRI TERBIMBING DENGAN MENGGUNAKAN LKS UNTUK MENINGKATKAN KETERAMPILAN BERPIKIR KRITIS DITINJAU DARI SIKAP ILMIAH SISWA MADRASAH ALIYAH QAMARUL HUDA BAGU LOMBOK TENGAH
Authors: Sudarmini Yuyu , - Kosim , Hadiwijaya Aos Santosa 
Published: January 2018

This research aimed at 1). Developing learning design of guided inquiry based physics learning using student worksheet. 2). Knowing the difference of improvement of the critical thinking between students those who learned using guided inquiry based physics learning and those who learned physics conventionally. 3). Knowing the difference of improvement of the critical thinking between students with a highly scientific attitude and those with a low one. 4) Knowing the interaction between learning physics and scientific attitude toward the improvement of students’ critical thinking skill. The research was conducted through two steps, namely: 1) Development research using Dick’s and Carey’s development model, 2) Experimental research using 2x2 factorial design. The population of this research was the students of MA Qamarul Huda Bagu, central Lombok, year eleven. The sample of the research consisted of 2 classes taken by simple random sampling technique. Data collection using questioner to know the students’ scientific attitude, and test to know the students’ critical thinking skill score. Hypothetical test for experimental research used two path ANAVA by using SPSS. The result of development research was yielded a good learning equipment of the guided inquiry based physics learning using student worksheet. The experimental research showed that: 1) There was difference of improvement of critical thinking skill between the students who got a guided inquiry physics learning using student worksheet and those who got conventional learning. This was shown by value of Ftest=42,480, was higher than that of Ftable=4,11, and the value of sig=000 was lower than 0,05; 2) There was difference of improvement of critical thinking skill between the students with a high scientific attitude and those with a low one. This was shown by value of Ftest=13,150, was higher than that of Ftable=4,11, and the value of sig=0,001 was lower than 0,05; 3). There was no interaction between the physics learning (guided inquiry based using student worksheet and that of conventionally) and scientific attitude towards the improvement of critical thinking skill. This was shown by value of Ftest=1,277 was lower than that of Ftable=4,11 and value of sig=0,265 was higher than 0,05. It was expected that the guided inquiry based physics learning using student worksheet was combined with other learning models to enhance critical thinking skill more optimal mainly for the abstract materials of physics.Key word: guided inquiry, student worksheet, scientific attitude, critical thinking skill,
EFEKTIFITAS PENGGUNAAN MEDIA VIDEO BERBASIS LINGKUNGAN (MVBL) DALAMMENINGKATKAN PERILAKU POSITIF ANAK TERHADAP LINGKUNGAN
Authors: Anantasari Widowati , Jufri A. Wahab , Hadiwijaya Aos Santosa 
Published: January 2018

The positive attitude of students toward environment is the manifestation of a positive attitude of students toward the environment. The development of student positive attitude toward environment can be gotten through the aplication of daily attitude and the model that student s catch and feel from the environment where student s live. The students need to get the experiences and learn by themselves with a possitive attitude in order that they are accepted by the environment and they do not do harm their environment. The experiences given to the student should be prepared to help them to share, cooperate, respect, love renponsible, and having self confidance. This research aim at knowing the difference of children’s possitive attitude toward environment at students who lern by using video media based environment (VMBE). Will those who do not learn by using video media based environment (VMBE). Research was aquasi experimental research with pretest and posttest control design. The data of students positive attitude toward environment were gotten by using observation technique ( the observation of students positive attitude improvement ) The data of this research were analyzed by using the analysis of independent sample t-test tecnique.The result of analysis can be concluded as follows : with df : 16 at significant level 0.05 showed that there was difference of students possitive attitude who learn by using MVBL than those who did not learn by using MVBL (t=3.120)Keywords : VMBE, Possitive attitude toward environment.
The K2-138 System: A Near-resonant Chain of Five Sub-Neptune Planets Discovered by Citizen Scientists
Authors: Christiansen Jessie L. , Crossfield Ian J. M. , Barentsen Geert , Lintott Chris J. , Barclay Thomas , Simmons Brooke . D. , Petigura Erik , Schlieder Joshua E. , Dressing Courtney D. , Vanderburg Andrew , Allen Campbell , McMaster Adam , Miller Grant , Veldthuis Martin , Allen Sarah , Wolfenbarger Zach , Cox Brian , Zemiro Julia , Howard Andrew W. , Livingston John , Sinukoff Evan , Catron Timothy , Grey Andrew , Kusch Joshua J. E. , Terentev Ivan , Vales Martin , Kristiansen Martti H. 
Published: January 2018

Abstract
K2-138 is a moderately bright (V = 12.2, K = 10.3) main-sequence K star observed in Campaign 12 of the NASA K2 mission. It hosts five small (1.6–3.3

) transiting planets in a compact architecture. The periods of the five planets are 2.35, 3.56, 5.40, 8.26, and 12.76 days, forming an unbroken chain of near 3:2 resonances. Although we do not detect the predicted 2–5 minute transit timing variations (TTVs) with the K2 timing precision, they may be observable by higher-cadence observations with, for example, Spitzer or CHEOPS. The planets are amenable to mass measurement by precision radial velocity measurements, and therefore K2-138 could represent a new benchmark system for comparing radial velocity and TTV masses. K2-138 is the first exoplanet discovery by citizen scientists participating in the Exoplanet Explorers project on the Zooniverse platform.
Magnetic Reconnection in Strongly Magnetized Regions of the Low Solar Chromosphere
Authors: Ni Lei , Lukin Vyacheslav S. , Murphy Nicholas A. , Lin Jun 
Published: January 2018

Abstract
Magnetic reconnection in strongly magnetized regions around the temperature minimum region of the low solar atmosphere is studied by employing MHD-based simulations of a partially ionized plasma within a reactive 2.5D multi-fluid model. It is shown that in the absence of magnetic nulls in a low β plasma, the ionized and neutral fluid flows are well-coupled throughout the reconnection region. However, non-equilibrium ionization–recombination dynamics play a critical role in determining the structure of the reconnection region, leading to much lower temperature increases and a faster magnetic reconnection rate as compared to simulations that assume plasma to be in ionization–recombination equilibrium. The rate of ionization of the neutral component of the plasma is always faster than recombination within the current sheet region even when the initial plasma β is as high as

. When the reconnecting magnetic field is in excess of a kilogauss and the plasma β is lower than 0.0145, the initially weakly ionized plasmas can become fully ionized within the reconnection region and the current sheet can be strongly heated to above

K, even as most of the collisionally dissipated magnetic energy is radiated away. The Hall effect increases the reconnection rate slightly, but in the absence of magnetic nulls it does not result in significant asymmetries or change the characteristics of the reconnection current sheet down to meter scales.
Measurements of the Temperature and E-mode Polarization of the CMB from 500 Square Degrees of SPTpol Data
Authors: Henning J. W. , Sayre J. T. , Reichardt C. L. , Ade P. A. R. , Anderson A. J. , Austermann J. E. , Beall J. A. , Bender A. N. , Benson B. A. , Bleem L. E. , Carlstrom J. E. , Chang C. L. , Chiang H. C. , Cho H-M. , Citron R. , Moran C. Corbett , Crawford T. M. , Crites A. T. , Haan T. de , Dobbs M. A. , Everett W. , Gallicchio J. , George E. M. , Gilbert A. , Halverson N. W. , Harrington N. , Hilton G. C. , Holder G. P. , Holzapfel W. L. , Hoover S. , Hou Z. , Hrubes J. D. , Huang N. , Hubmayr J. , Irwin K. D. , Keisler R. , Knox L. , Lee A. T. , Leitch E. M. , Li D. , Lowitz A. , Manzotti A. , McMahon J. J. , Meyer S. S. , Mocanu L. , Montgomery J. , Nadolski A. , Natoli T. , Nibarger J. P. , Novosad V. , Padin S. , Pryke C. , Ruhl J. E. , Saliwanchik B. R. , Schaffer K. K. , Sievers C. , Smecher G. , Stark A. A. , Story K. T. , Tucker C. , Vanderlinde K. , Veach T. , Vieira J. D. , Wang G. , Whitehorn N. , Wu W. L. K. , Yefremenko V. 
Published: January 2018

Abstract
We present measurements of the E-mode polarization angular auto-power spectrum (EE) and temperature–E-mode cross-power spectrum (TE) of the cosmic microwave background (CMB) using 150 GHz data from three seasons of SPTpol observations. We report the power spectra over the spherical harmonic multipole range

and detect nine acoustic peaks in the EE spectrum with high signal-to-noise ratio. These measurements are the most sensitive to date of the EE and TE power spectra at

and

, respectively. The observations cover 500

, a fivefold increase in area compared to previous SPTpol analyses, which increases our sensitivity to the photon diffusion damping tail of the CMB power spectra enabling tighter constraints on ΛCDM model extensions. After masking all sources with unpolarized flux

mJy, we place a 95% confidence upper limit on residual polarized point-source power of

at

, suggesting that the EE damping tail dominates foregrounds to at least

with modest source masking. We find that the SPTpol data set is in mild tension with the ΛCDM model (

), and different data splits prefer parameter values that differ at the

level. When fitting SPTpol data at

, we find cosmological parameter constraints consistent with those for Planck temperature. Including SPTpol data at

results in a preference for a higher value of the expansion rate (

) and a lower value for present-day density fluctuations (

).
Chemical Abundance Analysis of Three α-poor, Metal-poor Stars in the Ultrafaint Dwarf Galaxy Horologium I*
Authors: Nagasawa D. Q. , Marshall J. L. , Li T. S. , Hansen T. T. , Simon J. D. , Bernstein R. A. , Balbinot E. , Drlica-Wagner A. , Pace A. B. , Strigari L. E. , Pellegrino C. M. , DePoy D. L. , Suntzeff N. B. , Bechtol K. , Walker A. R. , Abbott T. M. C. , Abdalla F. B. , Allam S. , Annis J. , Benoit-Lévy A. , Bertin E. , Brooks D. , Rosell A. Carnero , Kind M. Carrasco , Carretero J. , Cunha C. E. , D’Andrea C. B. , da Costa L. N. , Davis C. , Desai S. , Doel P. , Eifler T. F. , Flaugher B. , Fosalba P. , Frieman J. , García-Bellido J. , Gaztanaga E. , Gerdes D. W. , Gruen D. , Gruendl R. A. , Gschwend J. , Gutierrez G. , Hartley W. G. , Honscheid K. , James D. J. , Jeltema T. , Krause E. , Kuehn K. , Kuhlmann S. , Kuropatkin N. , March M. , Miquel R. , Nord B. , Roodman A. , Sanchez E. , Santiago B. , Scarpine V. , Schindler R. , Schubnell M. , Sevilla-Noarbe I. , Smith M. , Smith R. C. , Soares-Santos M. , Sobreira F. , Suchyta E. , Tarle G. , Thomas D. , Tucker D. L. , Wechsler R. H. , Wolf R. C. , Yanny B. 
Published: January 2018

Abstract
We present chemical abundance measurements of three stars in the ultrafaint dwarf galaxy Horologium I, a Milky Way satellite discovered by the Dark Energy Survey. Using high-resolution spectroscopic observations, we measure the metallicity of the three stars, as well as abundance ratios of several α-elements, iron-peak elements, and neutron-capture elements. The abundance pattern is relatively consistent among all three stars, which have a low average metallicity of [Fe/H] ∼ −2.6 and are not α-enhanced ([α/Fe] ∼ 0.0). This result is unexpected when compared to other low-metallicity stars in the Galactic halo and other ultrafaint dwarfs and suggests the possibility of a different mechanism for the enrichment of Hor I compared to other satellites. We discuss possible scenarios that could lead to this observed nucleosynthetic signature, including extended star formation, enrichment by a Population III supernova, and or an association with the Large Magellanic Cloud.