This lecture begins with the fundamental reasons for a nation to undertake planetary exploration. Expected benefits to Korea is discussed. Then the current status of Korea\\\\\\\\/s readiness for planetary exploration is described. The case for Korean lunar mission and Mars mission are made. The recently-signed agreement between KAIST and NASA on lunar exploration is elaborated on. Finally, what was done to Korean Mars mission concept, and what could be actually done in the future, are discussed.

Magnetospheric substorms are considered to be one of the major energy release processes as a consequence of the interaction between the solar wind and the Earth’s magnetosphere. The interaction is known to sensitively depend on the direction and magnitude of the north-south component of the interplanetary magnetic field that the solar wind brings together. Substorms are manifested by sudden auroral brightening due to particle precipitation along magnetic field, energetic charged particle generation, ULF magnetic pulsation excitation, abrupt changes of the magnetospheric magnetic field, and magnetic reconnection. One of the intriguing features of substorms is that they sometimes occur quasi-periodically with a period of ~1-3 hrs. This is commonly observed when corotating high-speed solar streams lasting several days impinge upon the magnetosphere. The high-speed streams accompany large amplitude Alfvenic fluctuations of the interplanetary magnetic field, leading to alternating polarities between north and south, which may be responsible for the repetitive substorms. Interestingly, we have recently found that quasi-periodic substorms do also occur even when the interplanetary magnetic field is purely northward for which the magnetic reconnection at the dayside magnetopause is hardly expected to occur. Also, substorm features are seen for sawtooth-type quasi-periodic oscillations of energetic particle injections under prolonged southward conditions of the accompanied interplanetary magnetic field. The fact that such diverse interplanetary conditions lead to quasi-periodic substorms poses a real mystery to substorm scientists. This talk will introduce our recent effort to follow up a clue to the mystery.

We have measured the annual parallax of the Mira-type variable star UX Cygni to be (pi) = 0.54 +/- 0.06 mas from phase-referencing VLBI observations of its circumsteller water masers with the VLBA. This is the first parallax from water maser observations. These are also the pilot observations for VERA (VLBI Exploration for Radio Astrometry) project in Japan, which measure the parallaxes and proper motions of galactic maser sources to reveal the three-dimensional structure of the Galaxy. Four epoch monitoring observations of water masers around the Mira-type star UX Cygni are carried out. The motions of maser spots referred to the position of phase-referencing source show the common annual parallax and proper motions of each spots. From the least-square fitting, the annual parallax is 0.54 +/- 0.06 mas. The corresponding distance is 1.85 (+0.25/-0.19) kpc. This result is consistent with the period-luminosity relation (PLR) of Mira-type variables in P > 420 days. From this result and the PLR of Large Magellanic Cloud, we can derive the distance to the Large Magellanic Cloud to be 55.0 (+9.0/-7.2) kpc, which is consistent to the values from other methods. We can also get the three-dimensional position and velocity in the Galaxy. These results show the possibility of astrometric observations with phase-referencing VLBI and research into galactic kinematics which is one of the big target of the VERA.

see attached file, please

Magnetic energy release via field line reconnections is believed to be a major fundamental process in space and astrophysical environments, ranging from accretion disks, flare stars, the sun to the heliosphere and the earth magnetosphere. It is, however, only through solar flare images that we can see direct signatures for the magnetic reconnection. This talk will review recent progresses toward quantitative measurements of the reconnection efficiency using solar images as carried out by NJIT solar group. In most cases, we could utilize the standard two-dimensional reconnection model to derive the reconnection electric field, electric potential and electromagnetic Poynting flux, and thus ultimately the energy release rate during solar flares. In a few exceptional cases, however, we found shortcomings of the two-dimensional model due to the complexity of magnetic topologies, for which we suggest a simple three-dimensional generalization.

We describe a multidimensional relativistic hydrodynamic code which solves the special relativistic hydrodynamic equations as a hyperbolic system of conservation laws based on the total variation diminishing scheme. Three-dimensional hydrodynamic interactions of relativistic extragalactic jets with two-phase ambient media are presented.

Within the last decade, our notions of the cosmos have been radically altered by precision observations of the light from distant Type Ia supernovae and, separately, the power spectrum of the cosmic microwave background radiation [CMBR]. These show that the expansion of the universe is actually accelerating, and that the Universe is overwhelmingly composed of dark energy (75%) and dark matter (21%), with only 4% of the total being baryonic (“normal”) matter. Determining the amount and characteristics of dark matter, dark energy, and normal matter is one of the most compelling problems in astrophysics today. A complementary and independent approach to determine the baryonic matter density is to compare the predictions of the abundances of “primordial” light elements (H, He, Li) formed three minutes after the Big Bang with observations of these elements in the interstellar medium and on the surface of very old stars. “Big Bang Nucleosynthesis” (BBN) calculations require, as input, thermonuclear reaction rates at the high temperatures characteristic of the early universe. BBN estimates of the 2H, 4He, and 7Li abundances imply a baryonic matter density that, respectively, agrees, marginally agrees, and disagrees with the density from other approaches. The precision of the BBN constraint on the baryonic matter density depends on the uncertainties in observational determinations of primordial 2H, 4He, and 7Li abundances, as well as on uncertainties in BBN abundance predictions derived from input nuclear physics uncertainties [1]. We have performed new Monte Carlo BBN simulations wherein all input reaction rate uncertainties are reduced to their smallest reasonable limit in order to determine the “ultimate” precision of the BBN baryonic matter constraint given current observational uncertainties: 21%, 41%, and 39%, using (respectively) 2H, 4He, and 7Li. The uncertainties in abundance determinations must be significantly reduced to give the BBN constraint a precision approaching that of the 3.5% precision derived from WMAP observations of the CMBR [2]. Comparisons of the constraints from these two complementary methods are important because they can indicate, and constrain, potential new physics. We have also performed simulations where individual rate uncertainties are systematically reduced to determine the impact that future nuclear physics measurements would have on the abundance uncertainties and the baryonic matter constraint. We find that the neutron lifetime and the rates of a number of reactions all deserve further scrutiny. Results of the simulations and their implications for cosmology and for future nuclear physics measurements will be presented. These calculations were all performed with the new online suite of codes freely available at bigbangonline.org. [1] M.S. Smith, L.H. Kawano, R.A. Malaney, Astrophys. J. Suppl. 85 (1993) 219. [2] D.N. Spergel et al., Astrophys. J. Suppl. 170 (2007) 377. * Managed by UT-Battelle, LLC, for the U.S.D.O.E. under contract DE-AC05-00OR22725

First Pop III stars are believed to form inside minihalos (T<10^4 K) with the help of hydrogen molecule (H_2) cooling. H_2, however, is easily dissociated by H_2 Lyman-Werner band photons, which can originate from sources in cosmological distance. We calculate the build-up of this H_2 dissociating background during the epoch of reionization, based upon the recent cosmic reionization simulation results. We show that (1) H_2 dissociating background builds up long before the end of cosmic reionization and (2) due to the clustering of sources of reionization, the resultant background shows a significant spatial fluctuation. This would lead to a spatial variation of the formation of Pop III objects. The observational perspective (e.g. JWST observation) of our result is also presented.

운석은 태양계의 물질로서 지구나 화성등과 같이 완전한 행성진화과정을 겪지 않은 물질이다. 따라서, 운석중에 나타나는 화학성분들은 태양계 초기의 기록에 가까우며 이중 특히 분화를 거의 겪지 않은 원시운석들은 태양계의 나이, 원소분포 등에 대한 귀중한 정보를 갖고 있다. 또한, 운석은 다양한 종류의 운석과 월석, 화성운석에서 나타나는 여러 가지 다른 기원을 갖는 가스 성분들은 태양계 초기의 기록뿐 아니라 지구와 같은 행성의 진화과정에 대한 단서를 제공한다.

Prof. K.C. Freeman will shortly visit KASI in the morning of November 16th to talk about what can be done with the Wide-Field Multi-Object Spectrograph (WFMOS) possibly on Gemini/ Subaru/AAT. In addition, as ANU is currently a partner in GMT, he will also talk about what they are planning with the GMT project.

고대로부터 현재에 이르기까지 우리 문화생활과 가장 밀접한 관련성이 있는 것이 시간과 공간에 대한 생각이다. 이는 철학적인 연구의 대상일 뿐만 아니라 20세기 들어서 과학적적으로도 많은 논쟁의 대상으로 연구를 해온 대상이다. 조선시대에는 시간의 흐름과 공간상의 위치를 대단히 중요시 여겨서 모든 우리의 생활 속에서 중요한 요소로 자리를 잡았다. 이러한 시간과 공간에 대한 기본 관념이 조선시대 국가 기관인 관상감에서 매년 간행된 책력에 잘 나타나있다. 책력에는 천체 운행의 천문학적 계산을 바탕으로 하는 역산(曆算)과 전통 문화 속에 숨겨진 미신적 요소인 역주(曆注)라는 두 종류가 포함되어 있다. 본 내용에서는 책력 속에서 이 두 요소가 어떻게 시간과 공간 문제와 관련을 짓고 어떻게 표현 했는지 알아보기로 한다. 책력에서 제시하고 있는 천체의 운행은 시간과 공간을 서로 독립적인 관계로서 설명하지 않고, 서로 끊임없이 인간 생활과 관련을 짓고 있는 것으로 보고 있다. 그 중에서 태양, 달 및 오행성(五行星) 등 칠정(七政)의 운행은 시간과 계절을 결정하는 중요한 천체들이다. 본 내용에서는 주로 천체의 위치와 운동과 관련한 천문학적 계산을 중심으로 설명하고자 한다. 우선 시간과 공간과 관련된 시각과 계절의 결정 방법, 공간 속에서의 방위와 위치를 계산하는 원리, 계산의 실제 등에 대하여 알아보기로 한다.

Firstly, I will simply introduce the different accretion processes in both supermassive black holes and X-ray binaries. Then I would like to talk about my recent work on the accretion and jet physics in radio galaxy FR Is and its possible relation to large scale surroundings.