Latest results on Jovian disk X-rays from XMM-Newton

We present the results of a spectral study of the soft X-ray emission (0.2-2.5 keV) from low-latitude (`disk') regions of Jupiter. The data were obtained during two observing campaigns with XMM-Newton in April and November 2003. While the level of the emission remained approximately the same between April and the first half of the November observation, the second part of the latter shows an enhancement by about 40% in the 0.2-2.5 keV flux. A very similar, and apparently correlated increase, in time and scale, was observed in the solar X-ray and EUV flux. The months of October and November 2003 saw a period of particularly intense solar activity, which appears reflected in the behaviour of the soft X-rays from Jupiter's disk. The X-ray spectra, from the XMM-Newton EPIC CCD cameras, are all well fitted by a coronal model with temperatures in the range 0.4-0.5 keV, with additional line emission from Mg XI (1.35 keV) and Si XIII (1.86 keV): these are characteristic lines of solar X-ray spectra at maximum activity and during flares. The XMM-Newton observations lend further support to the theory that Jupiter's disk X-ray emission is controlled by the Sun, and may be produced in large part by scattering, elastic and fluorescent, of solar X-rays in the upper atmosphere of the planet.Comment: 17 pages, 7 figures, accepted for publication in a special issue of Planetary and Space Scienc

Eksperimentasi Model Pembelajaran Kooperatif Teknik Make a Match pada Materi Persamaan dan Pertidaksamaan Linear Satu Variabel terhadap Prestasi Belajar Matematika Ditinjau dari Minat Belajar Matematika

Samirah. K1313065. EKSPERIMENTASI MODEL PEMBELAJARAN KOOPERATIF TEKNIK MAKE A MATCH PADA MATERI PERSAMAAN DAN PERTIDAKSAMAAN LINEAR SATU VARIABEL TERHADAP PRESTASI BELAJAR MATEMATIKA DITINJAU DARI MINAT BELAJAR MATEMATIKA. Skripsi, Surakarta: Fakultas Keguruan dan Ilmu Pendidikan Universitas Sebelas Maret Surakarta, Juli 2018. Penelitian ini bertujuan untuk mengetahui: (1) manakah yang menghasilkan prestasi belajar matematika lebih baik, pembelajaran matematika dengan model pembelajaran kooperatif teknik Make a Match atau model pembelajaran langsung, (2) manakah yang menghasilkan prestasi belajar matematika lebih baik, siswa dengan minat belajar matematika tinggi, sedang, atau rendah, (3) pada masing-masing model pembelajaran (Make a Match dan langsung), manakah yang menghasilkan prestasi belajar matematika lebih baik, siswa dengan minat belajar matematika tinggi, sedang, atau rendah, (4) pada masing-masing tingkat minat belajar matematika (tinggi, sedang, dan rendah), manakah yang menghasilkan prestasi belajar matematika lebih baik, model pembelajaran kooperatif teknik Make a Match atau model pembelajaran langsung. Penelitian ini termasuk jenis penelitian eksperimental semu. Populasi dalam penelitian ini adalah seluruh siswa kelas VII SMP Negeri 11 Surakarta tahun ajaran 2017/2018. Sampel yang terpilih adalah kelas VII E dan VII F dengan teknik pengambilan sampel cluster random sampling. Uji coba instrumen dilaksanakan di SMP Negeri 25 Surakarta. Pengumpulan data dilaksanakan dengan metode dokumentasi untuk mengumpulkan data kemampuan awal siswa yang berupa nilai ulangan tengah semester I, metode angket untuk data minat belajar matematika, dan metode tes untuk data prestasi belajar. Teknik analisis data menggunakan analisis variansi dua jalan dengan sel tak sama, kemudian dilanjutkan dengan uji komparasi ganda menggunakan metode Scheffe dengan taraf signifikansi 0,05. Berdasarkan hasil penelitian diperoleh simpulan sebagai berikut: (1) model pembelajaran kooperatif teknik Make a Match menghasilkan prestasi belajar matematika yang lebih baik daripada model pembelajaran langsung, (2) siswa dengan minat belajar matematika tinggi menghasilkan prestasi belajar matematika yang lebih baik daripada siswa dengan minat belajar matematika sedang maupun rendah, dan siswa dengan minat belajar matematika sedang menghasilkan prestasi belajar matematika yang sama baiknya dengan siswa dengan minat belajar matematika rendah, (3) pada masing-masing model pembelajaran, siswa dengan minat belajar matematika tinggi menghasilkan prestasi belajar matematika yang lebih baik daripada siswa dengan minat belajar matematika sedang dan rendah, dan siswa dengan minat belajar matematika sedang menghasilkan prestasi belajar matematika yang sama baiknya dengan siswa dengan minat belajar matematika rendah, dan (4) pada masing-masing tingkat minat belajar matematika, pembelajaran dengan menggunakan model pembelajaran kooperatif teknik Make a Match menghasilkan prestasi belajar yang lebih baik daripada pembelajaran dengan menggunakan model pembelajaran langsung. Kata Kunci: Make a Match, minat belajar, persamaan dan pertidaksamaan linear satu variabe

Jupiter’s colorful hair

Auroral emissions on Jupiter form intricate structures. They may be conveniently separated by transient and more permanent features. Transient features often appear in the poleward-most sector of the auroral polar region and are usually found to depend on the direction of the Sun. Interestingly, the brightness and morphology of these polar emissions, at least in the north, appear to depend both on local time, but also on the sub-solar longitude. On the other hand, the permanent or longer lifetime auroral emissions are frequently associated with the main and outer emissions and are found to move close to corotation with Jupiter. However, this distinction between transient auroral features that are poleward and fixed in local time, and permanent features that are equatorward and corotating is somewhat artificial and may not include other types of auroral emissions. The dawn storm and the polar bright spot are two examples of such auroral emissions not following this simple categorization. The global morphology of Jupiter’s aurora was largely constrained by observations with HST, which only sees Jupiter’s dayside hemisphere. Thanks to the polar orbit of Juno, we now have access to views of the aurora at all local times and in particular to the night side hemisphere. We have combined HST-STIS, Juno-UVS and Juno-JIRAM observations of Jupiter’s UV and IR aurora to bring forward a new type of auroral structure - Jupiter’s hair - forming long-term multiple arcs whose orientation and location are influenced by local time. They extend from the poleward boundary of the main emission to the polar region, in the afternoon sector. This structure presumably encompasses previously found auroral features like the poleward auroral filament, transpolar arcs, and the auroral bridge structure

The geology and geophysics of Kuiper Belt object (486958) Arrokoth

The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, are primitive objects preserving information about Solar System formation. The New Horizons spacecraft flew past one of these objects, the 36 km long contact binary (486958) Arrokoth (2014 MU69), in January 2019. Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters diameter) within a radius of 8000 km, and has a lightly-cratered smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism

The mystery of Jupiter's proton aurora

The terawatts of ever-changing ultraviolet auroral emissions that are always observed with HST at both poles of Jupiter demonstrate that Jupiter's planetary system is “alive.” The characteristics of the different components of Jupiter's UV aurora provide information on the evolution of the overall state of the portion of the Jovian magnetosphere to which they connect. During the present medium-size HST campaign (HST GO-15638, cycle 26), precession of the line of apsides of Juno's orbit makes it possible to probe different regions of the magnetosphere, compared to Juno orbits during previous HST cycles. Solar wind dynamics and internal processes are known to have strong influence on Jupiter's aurora, but their relative contributions and the way they couple with each other are still under debate. Cycle 26 falls during the expected minimum of the 11-year solar activity cycle. Current measurements suggest that the solar activity is already exceptionally low, with very few solar events, like CMEs, reaching Jupiter. This provides an unprecedented opportunity to observe Jupiter's aurora during a period when its magnetosphere is mainly controlled by internal processes, therefore revealing Jupiter's natural "breathing." The present HST campaign is meant to observe Jupiter's bright FUV auroral emissions in time-tag imaging mode during Juno orbits 18 to 22 (Feb-Sep 2019). We focus on the 5-day periods prior to and during Junos perijove, when Juno is sampling the current sheet region within 60 RJ, which is expected to contain the plasma source responsible for most bright auroral components, but is in a location where these aurorae cannot be observed with Juno-UVS. We sample Jupiter's emissions at a frequency of ~1 HST visit per Jovian rotation, with typically 10 HST visits for each of the 5 Juno orbits. Here we present preliminary results inferred from HST observations and concurrent Juno in situ data, obtained during Juno orbits 18, 19 and 20

Cassini-UVIS observation of dayglow FUV emissions of carbon in the thermosphere of Venus

We analyze FUV spatially-resolved dayglow spectra obtained at 0.37 nm resolution by the UVIS instrument during the Cassini flyby of Venus. The intensities of the ultraviolet multiplets of carbon at 126.1, 156.1 and 165.7 nm are determined using a least squares fit technique applied to all dayglow spectra recorded by UVIS along the Cassini track. These intensities are compared with the results of a full radiative transfer model of these emissions, that includes the known photochemical sources of photons and resonant scattering of sunlight. The carbon density profile of the Venus thermosphere has never been directly measured and is taken from a model. We find a serious disagreement between these observations and modeling that can be accounted for by applying a scaling factor to the carbon column. This needed scaling factor is found to increase monotonically with solar zenith angle, suggesting a possible photochemical origin to the disagreement, possibly involving the photochemistry of molecular oxygen to which the carbon density is highly sensitive

No indication of X-ray activity in Terzan 1 from a short Swift/XRT observation

Following the report of enhanced X-ray activity towards the direction of Terzan 1 by MAXI from May 19--30 (Atel #5096), we performed an observation with Swift/XRT on June 4th (Obs. ID: 00032852001) and found no evidence of X-ray activity in the vicinity of Terzan 1. The exposure of this observation after standard processing was 35 seconds, though the unfiltered data's exposure time is 897 seconds