We have observed 60 Weak-line T Tauri stars (WTTSs) toward the Chamaeleon star forming region using the AKARI Far-Infrared Surveyor (FIS) All-Sky maps. We could not detect any signicant emission from each source even at the most sensitive WIDE-S band. Then, we have performed stacking analysis of these WTTSs using the WIDE-S band images to improve the sensitivity. However, we could not detect any signicant emission in the resultant image with a noise level of 0.05 MJy sr-1, or 3 mJy for a point source. The three-sigma upper limit of 9 mJy leads to the disk dust mass of 0.01 M⊕. This result suggests that the disks around Chamaeleon WTTSs are already evolved to debris disks.

Like Hipparcos, Gaia is designed to give absolute parallaxes, independent of any astrophysical reference system. And indeed, Gaia’s internal zero-point error for parallaxes is likely to be smaller than any individual parallax error. Nevertheless, due in part to mechanical issues of unknown origin, there are many astrophysical questions for which the parallax zero-point error σ(π0) will be the fundamentally limiting constraint. These include the distance to the Large Magellanic Cloud and the Galactic Center. We show that by using the photometric parallax estimates for RR Lyrae stars (RRL) within 8kpc, via the ultra-precise infrared period-luminosity relation, one can independently determine a hyper-precise value for π0. Despite their paucity relative to bright quasars, we show that RRL are competitive due to their order-of-magnitude improved parallax precision for each individual object relative to bright quasars. We show that this method is mathematically robust and well-approximated by analytic formulae over a wide range of relevant distances.

We present the results of BV time-series photometry of the globular cluster NGC 288. Ob- servations were carried out to search for variable stars using the Korea Microlensing Telescope Network (KMTNet) 1.6-m telescopes and a 4k pre-science CCD camera during a test observation from August to December, 2014. We found a new SX Phe star and confirmed twelve previously known variable stars in NGC 288. For the semi-regular variable star V1, we newly determined a period of 37.3 days from light curves spanning 137 days. The light-curve solution of the eclipsing binary V10 indicates that the system is probably a detached system. The pulsation properties of nine SX Phe stars were examined by applying multiple frequency analysis to their light curves. We derived a new Period-Luminosity (P-L) relation, hMV i = −2.476(±0.300) logP − 0.354(±0.385), from six SX Phe stars showing the fundamental mode. Additionally, the period ratios of three SX Phe stars that probably have a double-radial mode were investigated; PFO/PF = 0.779 for V5, PTO/PFO = 0.685 for V9, PSO/PFO = 0.811 for V11. This paper is the first contribution in a series assessing the detections and properties of variable stars in six southern globular clusters with the KMTNet system.

We present the results of simultaneous monitoring observations of H2O 61,6–52,3 (22GHz) and SiO J=1–0, 2–1, 3–2 maser lines (43, 86, 129GHz) toward five post-AGB (candidate) stars, using the 21-m single-dish telescopes of the Korean VLBI Network. Depending on the target objects, 7 – 11 epochs of data were obtained. We detected both H2O and SiO maser lines from four sources: OH16.1−0.3, OH38.10−0.13, OH65.5+1.3, and IRAS 19312+1950. We could not detect H2O maser emission toward OH13.1+5.1 between the late OH/IR and post-AGB stage. The detected H2O masers show typical double- peaked line profiles. The SiO masers from four sources, except IRAS 19312+1950, show the peaks around the stellar velocity as a single peak, whereas the SiO masers from IRAS 19312+1950 occur above the red peak of the H2O maser. We analyzed the properties of detected maser lines, and investigated their evolutionary state through comparison with the full widths at zero power. The distribution of observed target sources was also investigated in the IRAS two-color diagram in relation with the evolutionary stage of post-AGB stars. From our analyses, the evolutionary sequence of observed sources is suggested as OH65.5+1.3! OH13.1+5.1! OH16.1−0.3! OH38.10−0.13, except for IRAS 19312+1950. In addition, OH13.1+5.1 from which the H2O maser has not been detected is suggested to be on the gateway toward the post-AGB stage. With respect to the enigmatic object, IRAS 19312+1950, we could not clearly figure out its nature. To properly explain the unusual phenomena of SiO and H2O masers, it is essential to establish the relative locations and spatial distributions of two masers using VLBI technique. We also include the 1.2 – 160 μm spectral energy distribution using photometric data from the following surveys: 2MASS, WISE, MSX, IRAS, and AKARI (IRC and FIS). In addition, from the IRAS LRS spectra, we found that the depth of silicate absorption features shows significant variations depending on the evolutionary sequence, associated with the termination of AGB phase mass-loss.

Through time-series BV CCD photometry of the open cluster NGC 225 region, we have detected 30 variable stars including 22 new ones. They are five δ Scuti-type variable stars, a slowly pulsating B star, six eclipsing binary stars and 18 semi-long periodic or slow irregular variables, respectively. We have performed multiple-frequency analysis to determine pulsation frequencies of the δ Scuti-type stars and a slowly pulsating B star, using the discrete Fourier transform and linear least-square fitting methods. We also have derived the periods and amplitudes of 6 eclipsing binaries and a long-period variable star from the phase tting method, and presented the light curves of all variable stars. A slowly pulsating B star is a member of NGC 225, but δ Scuti-type stars are not members from the positions in the color-magnitude diagram and the radial distancies from the center of the cluster. From Dias et al. (2014, A&A, 564, 79), only three variable stars including the slowly pulsating B star are members of clusters: two are in NGC 225 and one is in Stock 24. But a variable star in Stock 24 is not a member of the cluster because of its position of color-magnitude diagarm.

본 연구는 기존의 부산국제광고제의 정체된 문제점을 보완하기 위해서 디지털 영상 부문 도입 에 따른 부산국제광고제 수익창출 및 활성화 방안에 대해서 알아보았다. 최근 급속한 매체 환경 변화에 적합한 해외 사례를 바탕으로 부산국제광고제 디지털 영상부문 신설 안을 제시하고, 전문 가 심층인터뷰를 통해 현실적인 방안을 모색하였다. 연구결과는 다음과 같다. 우선, 디지털 영상 부문 도입 방안으로 전문가들은 글로벌 광고주가 미션을 부여하여 전 세계 크리에이터가 영상을 제작하는 방식을 가장 선호하였다. 하지만 현실적 인 방안으로 해외 영상제에서 실행하고 있는 웹, 모바일 UCC 영상분야를 신설하여 다양한 작품 을 확보하는 것이 중요하다고 제안하였다. 두 번째로 수익창출 방안으로는 출품료를 위한 수익창 출과 광고주 후원을 통한 수익창출 방안을 제시하였다. 결과적으로 전문가들은 부산국제광고제 디지털 영상부문을 크게 브랜디드 콘텐츠(Branded Contents) 부문과 솔루션 콘텐츠(Solution Contents) 부문으로 나누었고, 그에 따른 내용은 세부 연구결과를 통해 살펴볼 수 있다.

We investigate optical properties of amorphous alumina (Al2O3) dust grains in the envelopes around O-rich asymptotic giant branch (AGB) stars using laboratory measured optical data. We derive the optical constants of amorphous alumina over a wide wavelength range that satisfy the Kramers- Kronig relation and reproduce the laboratory data. Using the amorphous alumina and silicate dust, we compare the radiative transfer model results with the observed spectral energy distributions. Comparing the theoretical models with observations on various IR two-color diagrams for a large sample of O-rich AGB stars, we find that the amorphous alumina dust (about 10-40%) mixed with amorphous silicate better models the observed points for the O-rich AGB stars with thin dust envelopes.

본 논문은 예이츠가 “오점”이라고 칭한 『아무도 없는 곳』(1902년)의 어 려운 저술과정, 『별나라에서 온 외뿔달린 백마』(1907년)으로의 개작, 1899년과 1907년 사이의 그의 공동저술의 역사 등을 다룬다. 공동저술가로서 조지 무어와 레이디 그레 고리의 도움으로, 그들의 보다 사실주의적 접근에 의지하여, 미묘한 상상력과 일상사의 관심, 활력, 언어와 결합함으로써 자신의 시적 방법의 최상의 결합을 하고자 희망 했다. 그는 이것을 “한 몸에 디킨즈와 셸리”를 결합하는 형식이라고 여겼다. 『별나라에서 온 외뿔달린 백마』는 이런 형식에 대한 희망이 좌절되는 과정을 보여준다. 예이츠는 의도적으로 자신과 그레고리 사이의 증대되는 창조적 긴장을 모색하는 데 이 작품을 사용한 것 같다. 이 작업의 실패와 의견의 차이는 그가 “농부의 극”을 쓰려는 노력을 끝내게 되고, 수년간의 그레고리와의 긴밀한 협력도 끝나게 되고, 자신의 창조적 결함 을 상쇄할 자신과는 다른 창조적 반자아를 모색할 마음을 잃게 된다.