• 천문학회보
• /
• 제36권1호
• /
• pp.82.2-82.2
• /
• 2011

Infra-Red Dark Clouds (IRDCs) seen silhouette against the bright Galactic background in mid-IR are a class of interstellar clouds that are dense and cold with very high column densities. While IRDCs are believed to be the precursors to massive stars and star clusters, individual IRDCs show diverse star forming activities within them. We report a remarkable example of such cloud, the IRDC at ${\Gamma}53.2^{\circ}$, and star formation activity in this cloud. The IRDC was previously identified in part as three separate, arcmin-size clouds in the catalogue of MSX IRDC candidates, but we found that the IRDC is associated with a long, filamentary CO cloud at 2 kpc from the Galactic Ring Survey data of $^{13}CO$ J = 1-0 emission, and that its total extent reaches ~ 30pc. The Spitzer MIPSGAL 24mm data show a number of reddened mid-IR sources distributed along the IRDC which are probably young stellar objects (YSOs), and the UWISH2 $H_2$ data (2.122mm) reveal ubiquitous out flows around them. These observations indicate that the IRDC is a site of active star formation with YSOs in various evolutionary stages. In order to investigate the nature of mid-IR sources, we have performed photometry of MIPSGAL data, and we present a catalogue of YSOs combining other available point source catalogues from optical to IR. We discuss the evolutionary stages and characteristics of YSOs from their IR colors and spectral energy distributions.

• 천문학회보
• /
• 제46권2호
• /
• pp.67.4-68
• /
• 2021

In studying the dynamical evolution of galaxy clusters, one intriguing approach is to compare the spatial distributions of various components, such as the dark matter, the member galaxies, the gas, and the intracluster light (ICL; the diffuse light from stars, which are not bound any individual cluster galaxy). If we find a visible component whose spatial distribution coincides with the dark matter distribution, then we could draw a dark matter map without requiring laborious weak lensing analysis. Furthermore, if the component traces the dark matter distribution better for more relaxed galaxy cluster, we could use the similarity as a dynamical stage estimator of the galaxy cluster. We present a novel new methodology to quantify the similarity of two or more 2-dimensional spatial distributions. We apply the method to a sample of galaxy clusters at different dynamical stages simulated within N-cluster Run, which is an N-body simulation using the galaxy replacement technique. Among the various components (stellar particles, galaxies, ICL), the velocity defined ICL+ brightest cluster galaxy (BCG) component traces the dark matter best. Between the sample galaxy clusters, the relaxed clusters show stronger similarity of the spatial distribution between the dark matter and ICL+BCG than the dynamically young clusters.

• 천문학회지
• /
• 제56권1호
• /
• pp.35-40
• /
• 2023

We have been conducting a exoplanet search survey using Bohyunsan Observatory Echelle Spectrograph (BOES) for the last 18 years. We present the detection of exoplanet candidate in orbit around HD 18438 from high-precision radial velocity (RV) mesurements. The target was already reported in 2018 (Bang et al. 2018). They conclude that the RV variations with a period of 719 days are likely to be caused by the pulsations because the Lomb-Scargle periodogram of HIPPARCOS photometric and H_α EW variations for HD 18438 show peaks with periods close to that of RV variations and there were no correlations between bisectors and RV measurements. However, the data were not sufficient to reach a firm conclusion. We obtained more RV data for four years. The longer time baseline yields a more accurate determination with a revised period of 803 ± 5 days and the planetary origin of RV variations with a minimum planetary companion mass of 21 ± 1 M_Jup. Our current estimate of the stellar parameters for HD 18438 makes it currently the largest star with a planetary companion.

• 천문학회보
• /
• 제38권2호
• /
• pp.71.1-71.1
• /
• 2013

Among quadruples or higher multiplicity stars, only a few binary systems have been discovered. They are important targets to understand the formation and evolution of multiple stellar systems because we can obtain accurate stellar parameters from photometric and spectroscopic studies. We present the observational results of this kind of rare object 1SWASP J093010.78+533859.5, for which the doubly eclipsing feature had been detected previously from the SuperWASP photometric archive. Individual PSF photometry for two objects with a separation of about 1.9 arcsec was performed for the first time in this study. Our time-series photometric data show that the brighter object A is an Algol-type detached eclipsing binary with an orbital period of 1.3 days and the fainter B is a W UMa-type contact eclipsing binary with a period of 0.23 days. Using the high-resolution optical spectra, we obtained well-defined radial velocity variations of the system A. Furthermore, stationary spectral lines were detected and should have originated from the other stellar component, which was confirmed by the third object contribution from the light curve analysis. No spectral feature of the system B was detected, probably due to its faintness. We obtained the binary parameters and the absolute dimensions from each light curve synthesis. The primary and secondary components of the system A have a spectral type of K1 and K5 main sequences, respectively. Two components of system B have nearly the same type of K3 main sequence. Light variations at out of eclipses were appeared in both systems, interpreting as the effect of stellar spots on these late spectral type stars. We estimated the distances to the systems A and B individually. They may have similar distances of about 70 pc and seem to be gravitationally bound with a separation of about 130 AU. In conclusion, we suggest that 1SWASP J093010.78+533859.5 is a quintuple stellar system with a hierarchical structure of a triple system A(ab)c and a binary system B(ab).

• 한국지구과학회지
• /
• 제32권4호
• /
• pp.402-410
• /
• 2011

본 논문에서는 IRAS 07280-1829 적외선원과 이를 둘러싸고 있는 분자운에 대해 수행된 $^{12}CO$와 $^{13}CO$ 1-0 분자선 관측결과와 기존의 적외선 자료를 이용하여 이 적외선원의 생성환경에 관해 연구하였다. 관측자료로부터 얻어진 적외선원의 파장별 에너지분포의 기울기(${\alpha}$=1.16)와 복사온도(145 K), 그리고 광도(${\sim}2.9{\times}10^4L_{\odot}$)는 이 적외선 천체가 CLASS I형의 중량급원시성임을 의미한다. 이 적외선원방향에서 관측된 두 CO 분자선에서 보이는 넓은 속도 성분은 분자분출류의 존재를 암시한다. 적외선원을 감싸고 있으리라 짐작되는 분자운A에서 측정된 여기온도는 9-22 K, 질량은 약 ~180 $M_{\odot}$인 것으로 보아 이 분자운이 전형적인 적외선 암흑분자운(Infrared-dark clouds)의 물리적 특성을 가짐을 보았다. 이 분자운의 질량은 비리알 질량보다 10배 이상 작은 값으로 계산되었는데 이것은 여기에 어린 원시성이 이미 생성되고 있다는 관측사실에 모순된다. 이는 아마도 분자운A가 교란운동(turbulence) 혹은 강한 자기장에 의해 지배되는 환경 가운데에 중량급원시성 IRAS 07280-1829을 생성하고 있음을 의미하는 것 일수도 있는 것으로 해석하였다.

• 복식
• /
• 제31권
• /
• pp.145-164
• /
• 1997

Cinema costume can stimulate the public to synchronize with and replicate what they see in the movies. Especially when the public thinks the stars in the movies . Especially when the public thinks the stars in the movies are beautiful or dramatic the styles of cinema costumes powerfully affect them. Thus cinema costume designers quickey become fashion designers. Edith Head who strongly believed cinema costumes to be an effective means of portraying the Character's personality and psychological make-up was an innovative designer whose costumes manifested this belief. She enhanced the character's individual image and distinction for the public through her artistic design in costumes. She adapted a realistic approach but her costumes invariably produced aesthetic ef-fects. Since the Academy Awards added the category of costume design she led the field with 35 nominations and eight oscars during 33 years of her productive work. Edith head was a dominant figure in costume design; her creations were highly renowned as an art form while they gained popularity. The purpose of this study was to reveal the ef-fects of Edith Head's cinema costume designs on fashion. This study was also to emphasize the powerful influence on ashion of cinema costume and cinema costume designers in general. The study was done through literature movies for which she created costumes fashion magazines and Edith Head's original sketches. The influence of Edith Head's costume de-sign on fashion is as follows: 1. She introduced and lead the casual fashion in the 1950's combining simplicity and sophistication. 2. She altered uniforms and reconstructed public clothing for multiple functions. 3. She rearranged high school prom dresses through the movie 'A Place in the Sun" to en-hance characteristic of each gender and the Dandy Look of the 1930's into men's apparel in the 1970's through the movie "The Sting" 4. She expanded the traditional style in the 1940's and became a leader in ecological style. 5. She adapted glitter from astronaut's ap-parel into public clothing. 6. She resturctured Sabrina Pants in the 1960's to accentuate the individuals strength by overcoming one's weakness without minimi-zing it's aesthetic appeal and reintroduced the pants in the 1990's. 7. She introduced elegant negligees to gen-eral public and maintained it in the public do-main. As it is revealed Edith Head's costume de-sign not only impacted the field of fashion dur-ing her time but also is presently influencing modern fashion throughout the world as it is witnessed by repeated reintroduction of her fashion styles. Reviewing her cinema costumes it is concluded that cinema costumes it is concluded that cinema costumes powerfully af-fect the public through a visual channel more than any other routes. Cinema costumes can become the origin of fashion by stimulating the public to synchronize with and replicate what they see in the movies. Since cinema costumes can launch fashion trend it requires further research. Based on what is revealed in this study. it would be beneficial to examine how cinema costumes affect people socially and culturally and how they could provide resources for re-search in fashion trends. It is also the writers opinion that there should be more designers such as Edith head who could lead the field of costume design into the twenty-first century.

• 천문학회지
• /
• 제49권5호
• /
• pp.199-208
• /
• 2016

We present photometric results of the δ Sct star V1162 Ori, which is extensively monitored for a total of 49 nights from mid-December 2014 to early-March 2015. The observations are made with three KMTNet (Korea Microlensing Telescope Network) 1.6 m telescopes installed in Chile, South Africa, and Australia. Multiple frequency analysis is applied to the data and resulted in clear detection of seven frequencies without an alias problem: five known frequencies and two new ones with small amplitudes of 1.2-1.7 mmag. The amplitudes of all but one frequency are significantly different from previous results, confirming the existence of long-term amplitude changes. We examine the variations in pulsation timings of V1162 Ori for about 30 years by using the times of maximum light obtained from our data and collected from the literatures. The O − C (Observed minus Calculated) timing diagram shows a combination of a downward parabolic variation with a period decreasing rate of (1/P)dP/dt = −4.22 × 10⁻⁶ year⁻¹ and a cyclic change with a period of about 2780 days. The most probable explanation for this cyclic variation is the light-travel-time effect caused by an unknown binary companion, which has a minimum mass of 0.69 M_⊙. V1162 Ori is the first δ Sct-type pulsating star of which the observed fast period decrease can be interpreted as an evolutionary effect of a pre-main sequence star, considering its membership of the Orion OB 1c association.

• 산업진흥연구
• /
• 제5권3호
• /
• pp.105-122
• /
• 2020

본 연구의 목적은 천궁도 28수(宿)와 낙샤트라에 대하여 고찰해보는 것이다. 천궁도가 어떤 과정을 거쳐서 만들어졌는지 고전 문헌에 기록된 자료들을 살펴보고 28수와 낙샤트라가 어떤 의미를 지니는지 살펴봄으로써 각 개인의 삶에 어떻게 적용될 수 있는지 알아보고자 하였다. 천궁도의 문헌적 고찰을 통해 천궁도가 기원전 1000년 전 바빌로니아인들 사이에 존재했으며 동물의 이름을 붙여서 부르기 시작한 데서 유래된 것으로 알려지고 있다. 아시리아인들이 기록한 점토판인 에누마 아누 엔릴(Enuma Anu Enlil)중 몰아핀(Molapin)에 "황도대는 달의 길"이라고 칭하고 있다. 따라서 천궁도라고 불리는 황도대는 달의 움직임을 통해서 만들어졌다는 것을 알 수 있었다. 또한 달이 지나는 길인 백도(白道)에 28개의 항성이 존재하며 이를 28수(宿)라 한다. 28수(宿)는 인도에서 낙샤트라라고 하며 낙샤트라를 통해서 개인의 타고난 운명을 읽을 수 있는 것이다. 음력의 태어난 달과 날짜를 알면 개인의 낙샤트라를 찾아 타고난 운명의 틀 안에서 가장 나은 삶을 선택할 수 있다. 그러므로 본 연구자는 천궁도와 28수(宿) 그리고 낙샤트라에 대한 문헌을 고찰하고 활용방안을 제시해 보았다. 이 연구 결과가 향후 관련 연구에 도움이 되기를 기대한다.

• 천문학논총
• /
• 제27권4호
• /
• pp.243-248
• /
• 2012

Nearby spiral galaxies M101 and M81 are considered to have undergone a galaxy-galaxy interaction. M101 has experienced HI gas infall due to the interaction. With AKARI far-infrared (IR) photometric observations, we found regions with enhanced star forming activity, which are spatially close to regions affected by the interaction. In addition, the relation between the star formation rate (SFR) and the gas content for such regions shows a significant difference from typical spiral arm regions. We discuss possible explanations for star formation processes on a kiloparsec scale and the association with interaction-triggered star formation. We also observed the compact group of galaxies Stephan's Quintet (SQ) with the AKARI Far-infrared Surveyor (FIS). The SQ shows diffuse intergalactic medium (IGM) due to multiple collisions between the member galaxies and the IGM. The intruder galaxy NGC 7318b is currently colliding with the IGM and causes a large-scale shock. The 160 micron image clearly shows the structure along the shock ridge as seen in warm molecular hydrogen line emission and X-ray emission. The far-IR emission from the shocked region comes from the luminous [CII]$158{\mu}m$ line and cold dust (~ 20 K) that coexist with molecular hydrogen gas. Survival of dust grains is indispensable to form molecular hydrogen gas within the collision age (~ 5 Myr). At the stage of the dusty IGM environment, [CII] and $H_2$ lines rather than X-ray emission are powerful cooling channels to release the collision energy.

• 천문학회지
• /
• 제34권3호
• /
• pp.167-179
• /
• 2001

A molecular line survey towards the UC H II region G34.3+0.15 from 155.3 to 165.3GHz has been conducted with the TRAO 14-m radio telescope. Combined with our previous observations from 84.7 to 115.6GHz and 123.5 to 155.3GHz (Paper I), the spectral coverage of this survey in G34.3+0.15 now runs from 85 to 165 GHz. From these latest observations, a total of 18 lines from 6 species were detected. These include four new lines corresponding to ${\Delta}$J = 0, ${\Delta}$K = 1 transitions of the $CH_3OH$ E-type species, and two new lines corresponding to transitions from $SO_2$ and $HC_3N$. These 6 new lines are $CH_3OH$[1(1) - 1(0)E], $CH_3OH$[2(1) - 2(0)E], $CH_3OH$[3(1) - 3(0)E], $CH_3OH$[4(1) - 4(0)E], $SO_2$[14(1, 13) -14(0, 14)] and $HC_3N$[18 -17]. We applied a rotation diagram analysis to derive rotation temperatures and column densities from the methanol transitions detected, and combined with NRAO 12-m data from Slysh et al. 1999. Applying a two-component fit, we find a cold component with temperature 13-16K and column density $3.3-3.4 {\times} 10^{14} cm^{-2}$, and a hot component with temperature 64 - 83K and column density $9.3{\times}10^{14} - 9.7 {\times} 10^{14} cm^{-2}$. On the other hand, applying just a one-component fit yields temperatures in the 47 -62 K range and column densities from $7.5-1.1 {\times} 10^{15} cm^{-2}$.