• Title/Summary/Keyword: Stars

Search Result 1,611, Processing Time 0.029 seconds

ASSOCIATION OF INFRARED DARK CLOUD CORES WITH YSOS: STARLESS OR STARRED IRDC CORES

  • Kim, Gwan-Jeong;Lee, Chang-Won;Kim, Jong-Soo;Lee, Youn-Gung;Ballesteros-Paredes, Javier;Myers, Philip C.;Kurtz, S.
    • Journal of The Korean Astronomical Society
    • /
    • v.43 no.1
    • /
    • pp.9-23
    • /
    • 2010
  • In this paper we examined the association of Infrared Dark Cloud (IRDC) cores with YSOs and the geometric properties of the IRDC cores. For this study a total of 13,650 IRDC cores were collected mainly from the catalogs of the IRDC cores published from other studies and partially from our catalog of IRDC cores containing new 789 IRDC core candidates. The YSO candidates were searched for using the GLIMPSE, MSX, and IRAS point sources by the shape of their SED or using activity of water or methanol maser. The association of the IRDC cores with these YSOs was checked by their line-of-sight coincidence within the dimension of the IRDC core. This work found that a total of 4,110 IRDC cores have YSO candidates while 9,540 IRDC cores have no indication of the existence of YSOs. Considering the 12,200 IRDC cores within the GLIMPSE survey region for which the YSO candidates were determined with better sensitivity, we found that 4,098 IRDC cores (34%) have at least one YSO candidate and 1,072 cores among them seem to have embedded YSOs, while the rest 8,102 (66%) have no YSO candidate. Therefore, the ratio of [N(IRDC core with protostars)]/[N(IRDC core without YSO)] for 12,200 IRDC cores is about 0.13. Taking into account this ratio and typical lifetime of high-mass embedded YSOs, we suggest that the IRDC cores would spend about $10^4\sim10^5$ years to form high-mass stars. However, we should note that the GLIMPSE point sources have a minimum detectable luminosity of about $1.2 L_{\odot}$ at a typical IRDC core's distance of ~4 kpc. Therefore, the ratio given here should be a 100ver limit and the estimated lifetime of starless IRDC cores can be an upper limit. The physical parameters of the IRDC cores somewhat vary depending on how many YSO candidates the IRDC cores contain. The IRDC cores with more YSOs tend to be larger, more elongated, and have better darkness contrast than the IRDC cores with fewer or no YSOs.

AKARI FAR-INFRARED ALL-SKY SURVEY MAPS

  • Doi, Yasuo;Komugi, Shinya;Kawada, Mitsunobu;Takita, Satoshi;Arimatsu, Ko;Ikeda, Norio;Kato, Daisuke;Kitamura, Yoshimi;Nakagawa, Takao;Ootsubo, Takafumi;Morishima, Takahiro;Hattori, Makoto;Tanaka, Masahiro;White, Glenn J.;Etxaluze, Mireya;Shibai, Hiroshi
    • Publications of The Korean Astronomical Society
    • /
    • v.27 no.4
    • /
    • pp.111-116
    • /
    • 2012
  • Far-infrared observations provide crucial data for the investigation and characterisation of the properties of dusty material in the Interstellar Medium (ISM), since most of its energy is emitted between ~ 100 and $200{\mu}m$. We present the first all-sky image from a sensitive all-sky survey using the Japanese AKARI satellite, in the wavelength range $50-180{\mu}m$. Covering > 99% of the sky in four photometric bands with four filters centred at $65{\mu}m$, $90{\mu}m$, $140{\mu}m$, and $160{\mu}m$ wavelengths, this achieved spatial resolutions from 1 to 2 arcmin and a detection limit of < 10 MJy $sr^{-1}$, with absolute and relative photometric accuracies of < 20%. All-sky images of the Galactic dust continuum emission enable astronomers to map the large-scale distribution of the diffuse ISM cirrus, to study its thermal dust temperature, emissivity and column density, and to measure the interaction of the Galactic radiation field and embedded objects with the surrounding ISM. In addition to the point source population of stars, protostars, star-forming regions, and galaxies, the high Galactic latitude sky is shown to be covered with a diffuse filamentary-web of dusty emission that traces the potential sites of high latitude star formation. We show that the temperature of dust particles in thermal equilibrium with the ambient interstellar radiation field can be estimated by using $90{\mu}m$, $140{\mu}m$, and $160{\mu}m$ data. The FIR AKARI full-sky maps provide a rich new data set within which astronomers can investigate the distribution of interstellar matter throughout our Galaxy, and beyond.

The Literature Study about Zodiac 28 fixed Star, and Nakshatra (천궁도 28수(宿)와 낙샤트라에 대한 문헌적 고찰)

  • Cho, Man-Seob;Kim, Ki-Seung
    • Industry Promotion Research
    • /
    • v.5 no.3
    • /
    • pp.105-122
    • /
    • 2020
  • The purpose of this thesis is to contemplate Astrology, 28 Fixed star, and Naksatra. The goal of this study was to look through the birth process of Astrology in the classical literature, and to examine how it can be applied to each individual's life by looking into the meaning of 28 Fixed star and Nakshatra. From the literary review, Astrology existed among the Babylonians 1000 BC and it originated from the start of calling by naming the animal. Assyrians called it "the zodiac is the Way of the Moon" which was written on Molapin in the Enuma Anu Enil, the clay plate recorded by Assyrians. Therefore, it was found that the zodiac, called Astrology, was made through the movement of the moon. There are also 28 stars in 배도, which is the way the moon passes, and it is called 28 Fixed star. 28 Fixed Star is called Nakshatra in India and can read the natural destiny of an individual through Nakshatra., Knowing the lunar month and date, you can find the individual Nakshatra and choose the best life in the framework of your natural destiny. Therefore, this researcher reviewed the literature on Astrology, 28 Fixed Star and Nakshatra and suggested the utilization plan. I hope this study will help the related field in the future.

The Effects of the 'Solar system and Stars' Unit Using Backward Design 2.0 on Science Academic Achievement, Performance Evaluation, and Science Class Satisfaction (백워드 설계 2.0을 활용한 '태양계와 별' 단원 수업이 과학 학업성취도와 수행평가 및 과학 수업 만족도에 미치는 효과)

  • Son, Junho;Kim, Hyunry
    • Journal of the Korean Society of Earth Science Education
    • /
    • v.13 no.2
    • /
    • pp.147-161
    • /
    • 2020
  • In order to help elementary students understand the astronomical unit in depth, this study applied backward design 2.0 to check the effect on students' science academic achievement, performance evaluation, and science class satisfaction. As a result of the study, there was no statistically significant difference in the science achievement test, but the average score of the experimental group has improved. As a result of the performance evaluation test, there was a statistically significant difference because the feedback was well provided through the process-focused assessment and it helped in-depth understanding. As a result of the science class satisfaction test, there was a statistically significant difference in the areas of science curriculum and peer relation except for the science teacher area. This is because a differentiated science curriculum was designed through analysis of achievement standards, and various teaching methods of student-centered were implemented to reach achievement standards. We hope this study will focus on the impact of backward design 2.0 on learners in elementary science classes and help find ways to effectively apply backward design 2.0 in the field.

Global Entrepreneurial Strategy of Korean Cuisine for Advancing into US Dine out Market (미국외식시장에서의 한식 글로벌 창업전략)

  • Park, Jaewhan;Kim, Jae Hong
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
    • /
    • v.11 no.3
    • /
    • pp.169-176
    • /
    • 2016
  • Our Korean cuisine, due to growing interests in Korean culture along with outstanding performance of K-pop stars, is attracting worldly attention. As the worldly food pursuit tendency is changing from"fast food" to "slow food", preference for our Korean cuisine, which is well-known for its healthiness, is growing. However, our Korean cuisine, in terms of the world citizen's preference, as receiving evaluation for being lacking behind of Sushi of Japan, Dimsum of China, pizza and pasta of Italy, rice noodle of Vietnam, even to Indonesian and Middle-East foods, has not been achieving drastic advancements despite the cosmopolitan's attention. The previous studies were suggesting that, failure of a localization strategy that changes our traditional taste and aroma adaptive to foreigners' preference, is a cause for this. This study, through case studies of Korean food businesses in the US which have achieved a success through localization strategy, attempts to propose the following global entrepreneurial strategy of Koran food at the US dining out market. As a global entrepreneurial strategy for success, we propose, first a sales strategy not for Koreans but for local people as main customers, second a customization strategy which is not our traditional way but that meets local standard, and finally a committed entrepreneurship.

  • PDF

Platinum complex oxide electrode catalyst for the solubilization of sewage sludge (하수슬러지 가용화 위한 백금족 복합 산화물 촉매 전극 개발)

  • Yoo, Jaemin;Kim, Hyunsook;pak, Daewon
    • Journal of the Korean Applied Science and Technology
    • /
    • v.33 no.2
    • /
    • pp.352-360
    • /
    • 2016
  • The purpose of this study was to determine the electrochemical properties develop DSA electrode for sewage sludge solubilization. Using Ir as a main catalyst, the catalyst selected for the sewage sludge solubilization durability and proceeds to functional electrode suitable for sewage sludge electrolysis experiment were obtained the following results. Less mass reduction of the sintering temperature of the main catalyst, Ir coated electrodes, the endothermic reaction zone $300^{\circ}C$ to $500^{\circ}C$, which was selected from a range of experiments. The efficiency of the catalyst results came up to $350^{\circ}C$ best. Each Binder stars (Ta, Sn, W) in this experiment was the biggest catalyst efficiency at $350^{\circ}C$. Used as a binder, $TaCl_5$, $SnCl_4$, $WCl_6$ of the Ta and without affecting the other characteristics of the main catalyst than Sn, W. For the 50% $IrO_2$ electrode is 1.4 V (vs. Ag / AgCl) in a current of about $29mA/cm^2$ was caused to evaluate the effectiveness of the electrode.

Tenth Graders' Ideas concerned with Earth's Rotation according to Interest and Learning style (흥미와 학습양식에 따른 고등학교 1학년 학생들의 지구의 자전 관련 개념)

  • Jeong, Jin-Woo;Jung, Jae-Gu;Moon, Sang-Yeon;Moon, Byoung-Chan
    • Journal of the Korean earth science society
    • /
    • v.25 no.7
    • /
    • pp.532-544
    • /
    • 2004
  • The purpose of this study is to analyze the concept concerned with Earth's rotation as passed by tenth graders whose interest in earth's rotation and learning styles were varied. To examine student's interest in the Earth's rotation, 4students (visual-verbal learning style student with much interest, visual learning style student with much interest, visual learning style student with little interest, and verbal learning style student with little interest) were chosen for study. Personal interview was used for this study. To probe students' conception in varied ways, they were allowed to make gesture and draw pictures through data collection process, except for interviews. And the data were analyzed one by one. The result of this study were as follows: First, the student with much interest was faster to answer the questions about Earth's rotation than the one with little interest. Also he comprehended better and was able to explain reasons coherently. Second, there was little difference according to student's learning style. Third, one of the repeated misconception was direction. For thinking that is the right side is the east side, students have misconception that the sun goes from right to left and stars in north sky move clock-wise.

UBVRI CCD PHOTOMETRY OF THE TYPE Ic SUPERNOVA SN 1994I IN M51: THE FIRST TWO MONTHS

  • LEE MYUNG GYOON;KIM EUNHYEUK;KIM SANG CHUL;KIM SEUNG LEE;PARK WON KEE;PYO TAE SOO
    • Journal of The Korean Astronomical Society
    • /
    • v.28 no.1
    • /
    • pp.31-43
    • /
    • 1995
  • We present UBVRI CCD photometry of the Type Ie supernova SN 19941 in M51 which was discovered on April 2, 1994 (UT). UBVRI CCD photometry of SN 1994 I were obtained for the period of the first two months from April 4, 1994, using the Seoul National University Observatory 60 cm telescope. The light curves of SN 19941 show several interesting features: (a) SN 19941 reaches the maximum brightness at B-band on April 8.23 (B = 13.68 mag), at V-band on April 9.10 (V = 12.89 mag), and at I-band on April 10.32 (I = 12.48 mag); (b) The light curves around the maximum brightness are much narrower than those of other types of supernovae; (c) The light curves after the peak decline more steeply than those of other types of supernovae; and (d) The colors get redder from $(V-R){\approx}0.2 mag ((V - I){\approx} 0.3 mag, (B - V){\approx}0.7 mag)$ on April 4 to $(V-R){\approx}0.6 mag ((V-1){\approx}0.9 mag, (B-V){\approx}1.3 mag)$ on April 18. Afterwards (V - R) colors get bluer slightly $(by\~0.005 mag/day)$, while (V-I) colors stay almost constant around $(V-1){\approx}1.0 mag$. The color at the maximum brightness is (B-V)=0.9 mag, which is $\~1$mag redder than the mean color of typical Type la supernovae at the maximum brightness. The light curves of SN 1994I are similar to those of the Type Ie supernova SN 1962L in NGC 1073. Adopting the distance modulus of $(m-M)_0 = 29.2 mag$ and the reddening of E(B - V) = 0.45 mag [Iwamoto et al. 1994, preprint for ApJ], we derive absolute magnitudes at the maximum brightness of SN 1994I, Mv(max) = -17.7 mag and MB(max) = -17.4 mag. This result shows that SN 1994I was $\~2$mag fainter at the maximum brightness compared with typical Type Ia supernovae. A narrower peak and faster decline after the maximum in the light curve of SN 1994I compared with other types of supernovae indicate that the progenitor of SN 1994I might be a lower mass star compared with those of other types of supernovae.

  • PDF

Children Wear's Shopping Orientation of Parents According to Watching Childcare-entertainment Reality TV Programs (육아 예능 TV 프로그램 시청에 따른 유아동복 쇼핑 성향)

  • Kim, Yuna;Kim, Yeri;Kim, Jisu;Na, Youngjoo
    • Science of Emotion and Sensibility
    • /
    • v.19 no.3
    • /
    • pp.59-70
    • /
    • 2016
  • Qualitative consumption is a trend in the children clothing market and watching TV of childcare-entertainment reality programs are becoming popular. This study examines the watching degree of childcare-entertainment reality TV programs of parent buyer (30s) and potential buyer (20s) and we investigate their shopping orientation of children wear. We did the survey research of 200 consumers with SPSS statistical analysis including the review of internet news, paper, and books on children wear shopping orientation. The results are following: first, the longer the watching time of childcare-entertainment reality TV programs, the higher shopping orientation, such as following the fashion of child stars, and the higher the watching preferences on childcare-entertainment reality programs, the greater shopping orientation in following childcare-entertainment reality programs star when they are purchasing children's clothing. Second, potential consumers as well as parent consumers were affected by watching the childcare-entertainment reality programs. Watching childcare-entertainment reality TV programs could give the impact when they were shopping children's clothing because they wanted to follow the fashion of childcare-entertainment reality programs TV star. Accordingly, the exposure of the childcare-entertainment reality programs for children clothing is found to be positive to the both current and future consumers.

The Characteristics of Ornamental Technique and Motifs in Folk Furniture of Chosun Dynasty-In Reference to a Comparison between Danish and Korean Folk Furniture- (조선조 가구의 장식적 표현기법과 무늬의 특징-덴마크와 한국의 민속가구 비교를 중심으로-)

  • 최정신
    • Korean Institute of Interior Design Journal
    • /
    • no.12
    • /
    • pp.57-66
    • /
    • 1997
  • This study was carried out to find out some similarities and differences of the ornamental technique and motifs in folk furniture between Denmark and Korea which had quite different background of development of folk furniture as one of a cross-cultural study. Furniture made and used in the 18th and 19th century was investigated in order to eliminate the influence of internationalism in the design area in the 20th century. This study was fulfilled by many study trips all over the districts in Denmark to identify Danish folk furniture as well as literature study. Study trips to folk museums. Insa-dong, Janghanpyung furniture market were done for Korean folk furniture. Characteristics of ornament in Danish folk furniture were as followings; Main materials of the Danish folk furniture were conifers, especially pine tree, as pine was very common and easy to get from their surroundings. The most popular and unique types of decoration in Danish folk furniture was painting. Colors used in painted furniture were very bright and vivid. This might be a reaction to the long and dark winter of Scandinavian countries. Motifs used in Danish folk furniture had been chosen to reflect their surroundings. Flowers, six-angular stars, animals, human figures and Biblical motifs were popular sources of decoration for Danish folk furniture. Characteristics of Korean folk furniture were as followings; Main materials of Korean folk furniture were broad-leaved trees as well as conifers, because of their beautiful wood grain. The Korean ways of decoration were different from Danish ones. The method of painting with bright from Danish ones. The method of painting with bright colors was hardly ever used in Korea, except only in lacquering. The most popular decoration method for Korean folk furniture was revealing the natural wood grain with transparent vegetable oil finish, instead of painting. Metal ornament was unique to Korean folk furniture. therefore a lot of metal ornaments were attached on the furniture. Motifs used in Korean folk furniture were more like symbolic than Danish ones. Korean people tried to express their longings and norms through the motifs, such as longevity, prosperity, good luck, and many sons, etc. Therefore, it was natural for Korean motifs to have special symbolic meanings.

  • PDF