• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.142.1-142.1
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• 2011

UBVI and $H{\alpha}$ CCD photometry of IC 1848, one of active star-forming regions in Cas OB6, is carried out as a part of Sejong Open cluster Survey (SOS) project. An OB association is an ideal laboratory for studying the triggered star formation and star formation history. Our purposes are to provide deep photometric data up to 21 mag in V and physical parameters of IC 1848. We classify 79 early-type stars and 186 pre-main sequence (PMS) stars as being the members of the cluster using photometric criteria. The IR excess emission PMS stars by Koenig et al. (2008) are also included as members of IC 1848. Total number of members is 414. We derive the interstellar reddening (=$0.659{\pm}0.058$ mag), reddening law ($R_V=4.0{\pm}0.1$), distance modulus ($V_0-M_V=12.0{\pm}0.1$ mag) using the early-type members of IC 1848. We also determine the age of the cluster ($3.5{\pm}1.5$ Myr) by placing the theoretical isochrones on the HR diagram.

• The Bulletin of The Korean Astronomical Society
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• v.25 no.1
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• pp.28-28
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• 2000

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.58.2-58.2
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• 2016

FU Orionis 형 별들은 폭발 현상(outburst)을 일으키며 급작스럽게 변광 하는 전주계열(PMS) 변광성의 한 부류(class)이다. 원형(prototype)인 FU Orioins를 비롯하여 이와 비슷한 분광 특성을 갖는 이 그룹은 FUors로 알려져 왔다. 이와 같은 유형의 별들이라도 주변 환경 및 원반의 활동에 따라서 광학 분광선들의 모양이나 특징은 다르게 나타난다. 2013년 2월부터 2016년 3월까지 보현산 천문대의 BOES 분광기로 6개의 FUors (FU Ori, V1057 Cyg, V1515 Cyg, HBC 722, V582 Aur, 2MASS J06593158-0405277)에 대한 고분산 스펙트럼을 얻었다. 발머선을 포함한 여러 파장대의 선들을 비교 분석 하였으며 주요 분광선의 변화 양상을 나타내고 그 변화 원인을 유추하고자 한다.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.71.3-71.3
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• 2015

Deep UBVI and $H{\alpha}$ photometry of the ${\eta}$ Carina nebula, one of the brightest nebulae on the sky, was obtained with the CTIO 4m telescope and MOSAIC II CCD Camera to determine the initial mass function down to low-mass (~1 M¤) stars. We modified the spatial variation coefficients in transformation relations of the MOSAIC II CCD. From the cross-identification of optical sources with previous surveys in X-ray, near-infrared, and mid-infrared, a clear PMS sequence is revealed in the optical color-magnitude diagrams down to V=23 mag. Our previous SSO 1m UBVI data for Trumpler 14 (Tr 14) and Trumpler 16 (Tr 16) region, and additional SSO 1m UBVI data for Trumpler 15 (Tr 15) region were combined with the CTIO 4m data to re-examine the reddening law and distance of the young open clusters in the ${\eta}$ Carina nebula. From the new photometric data for Tr 15 region, we report that RV[=AV/E(B-V)], the total-to-selective extinction ratio, decreases from southern part of the nebula (Tr 14 and Tr 16) to northern part (Tr 15) in our field of view.