• 제목/요약/키워드: asteroid

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미국 국내법령상 우주자원 소유권의 국제법상 의의 (International Legal Status of U.S. Citizens Property Right to Space Resources)

  • 신홍균
    • 항공우주정책ㆍ법학회지
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    • 제33권2호
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    • pp.419-442
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    • 2018
  • 우주조약 제2조는 우주공간의 비영유 원칙을 규정하고 있는데, 주권행사 및 여하한 수단에 의해서도 금지된다고 규정하고 있다. 여기서 여하한 수단의 의미와 범위도 모호한 표현 채택의 사례에 속한다. 사인의 소유도 금지됨을 의미하는지가 명확하지 않다. 또한 우주공간은 전 국가를 위하여 이용되어야 한다는 동 조약 제1조의 법적 구속력도 논쟁의 대상이 되어 왔기에, 사인의 소유 금지여부는 다양한 해석 논쟁의 대상이었다. 미국 의회는 지난 2015년도에 우주자원법을 제정하였다. 미국 기업의 우주개발 투자를 둘러싼 법적인 불확실성을 없앨 필요가 있다는 취지하에 우주자원에 대한 사적인 권리의 규정을 담고 있다. 당초 법안 H.R. 1508에서는 다음과 같이 자원에 대한 소유권 규정을 직접 명시하였었다. "우주공간에서 획득된 여하한 행성 자원은 해당 자원을 획득한 주체의 소유물이며, 해당 주체는 연방법 및 국제적 의무에 부합하는 모든 소유권을 갖는다." 여기서 '획득'이라는 표현이 우주조약 제2조에 따른 영유금지와 상충될 수 있다는 의견이 제시되면서, 천연 자원의 이동(remove)이라는 용어가 법안 토의 과정에서 사용되었다. 권리에 있어서, 우주자원법은 소유권이라는 용어를 택하지 않고, 행성 자원 또는 우주 자원을 상업적으로 회수(recovery)하는 업에 종사하는 자는 그러한 자원에 대한 권리를 갖는 바("shall be entitled to), 그러한 권리는 미국의 국제법상 의무를 포함하여 적용될 수 있는 법에 따라서 적법하게 획득된 행성 자원 또는 우주자원을 점유, 소유, 운송, 이용 및 판매할 권리를 포함한다고 규정하고 있다. 우주자원법 제51303조는 사적인 권리가 인정되는 객체는 미국의 국제적 의무를 포함해서 적용 법률에 맞추어서 획득된(obtained) 자원이라고 규정하고 있다. 이를 해석하여 보면, 앞에서 살펴 본 바와 같이, 획득에 의해서 소유권이 부여될 텐데, 그 획득은 미국의 국제적 의무가 고려되어서 적법성이 판단된다. 우주자원법은 미국 기업들의 불확실성을 확실히 해소하지는 않지만, 그러나, 우주자원의 획득을 위한 미국 기업들의 투자를 활성화할 수는 있다고 기대될 수 있고, 그렇다면 향후에 우주자원 획득이 본격화되면서, 그러한 활동이 국제법상 점진적으로 적법화될 가능성도 열려 있다고 판단된다.

The Solar Nebular on Fire: A Solution to the Carbon Deficit in the Inner Solar System

  • 이정은
    • 천문학회보
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    • 제35권1호
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    • pp.91.1-91.1
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    • 2010
  • Despite a surface dominated by carbon-based life, the bulk composition of the Earth is dramatically carbon poor when compared to the material available at formation. Bulk carbon deficiency extends into the asteroid belt representing a fossil record of the conditions under which planets are born. The initial steps of planet formation involve the growth of primitive sub-micron silicate and carbon grains in the Solar Nebula. We present a solution wherein primordial carbon grains are preferentially destroyed by oxygen atoms ignited by heating due to stellar accretion at radii < 5 AU. This solution can account for the bulk carbon deficiency in the Earth and meteorites, the compositional gradient within the asteroid belt, and for growing evidence for similar carbon deficiency in rocks surrounding other stars.

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Thermal Radiation Pressure Force on Atmosphereless Bodies

  • Bach, Yoonsoo P.;Ishiguro, Masateru
    • 천문학회보
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    • 제44권1호
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    • pp.64.1-64.1
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    • 2019
  • Thermal fracture and cracking near the perihelion are found to be a possible mechanism to produce the dust trail of the near-Earth asteroid, (3200) Phaethon (Jewitt and Li, 2013, ApJ 771, L36). It is, however, not well understood how the debris particles were escalated from the regolith against the asteroid's gravity. Thus, the scenario that these debris particles are responsible for the detected activities (Li and Jewitt, 2013, ApJ, 145, 154), is not complete yet. Here, we hypothesize that the thermal radiation pressure around the perihelion passage would exert substantial force outwards from the regolith on dust grains, and they can be lifted up and contributes the dust tail formation with further help of solar radiation pressure. Our modeling indicates that particles with sizes of roughly ~1-10 micron can be ejected from Phaethon by the mechanism, while a detailed model of gravitational field is required for accurate estimation of the particle size range. Our idea is not necessarily limited to Phaethon case, but is applicable to any atmosphereless bodies.

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PHOTOMETRIC STUDY OF NPA ROTATOR (5247) KRYLOV

  • Lee, Hee-Jae;Moon, Hong-Kyu;Kim, Myung-Jin;Kim, Chun-Hwey;Durech, Josef;Choi, Young-Jun;Oh, Young-Seok;Park, Jintae;Roh, Dong-Goo;Yim, Hong-Suh;Cha, Sang-Mok;Lee, Yongseok
    • 천문학회지
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    • 제50권3호
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    • pp.41-49
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    • 2017
  • We conduct BVRI and R band photometric observations of asteroid (5247) Krylov from January 2016 to April 2016 for 51 nights using the Korea Microlensing Telescope Network (KMTNet). The color indices of (5247) Krylov at the light curve maxima are determined as $B-V=0.841{\pm}0.035$, $V-R=0.418{\pm}0.031$, and $V-I=0.871{\pm}0.031$ where the phase angle is $14.1^{\circ}$. They are acquired after the standardization of BVRI instrumental measurements using the ensemble normalization technique. Based on the color indices, (5247) Krylov is classified as a S-type asteroid. Double periods, that is, a primary period $P_1=82.188{\pm}0.013h$ and a secondary period $P_2=67.13{\pm}0.20h$ are identified from period searches of its R band light curve. The light curve phases with $P_1$ and this indicate that it is a typical Non-Principal Axis (NPA) asteroid. We discuss the possible causes of its NPA rotation.

The Geometric Albedo of (4179) Toutatis

  • Bach, Yoonsoo P.;Ishiguro, Masateru;Jin, Sunho;Yang, Hongu;Moon, Hong-Kyu;Choi, Young-Jun;JeongAhn, Youngmin;Kim, Myung-Jin;Kwak, Sungwon
    • 천문학회보
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    • 제43권2호
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    • pp.44.4-45
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    • 2018
  • (4179) Toutatis (Toutatis hereafter) is one of the Near-Earth Asteroids which has been studied most rigorously not only via ground-based photometric, spectroscopic, polarimetric, and radar observations, but also via the in-situ observation by the Chinese Chang'e-2 spacecraft. However, one of the most fundamental physical properties, the geometric albedo, is less determined. In order to derive the reliable geometric albedo and further study the physical condition on the surface, we made photometric observations of Toutatis near the opposition (i.e., the opposite direction from the Sun). We thus observed it for four days on 2018 April 7-13 using three 1.6-m telescopes, which consist of the Korean Microlensing Telescope Network (KMTNet). Since the asteroid has a long rotational period (5.38 and 7.40 days from Chang'e-2, Zhao et al., 2015), the continuous observations with KMTNet matches the purpose of our photometric study of the asteroid. The observed data cover the phase angle (Sun-asteroid-observer's angle) of 0.65-2.79 degree. As a result, we found that the observed data exhibited the magnitude changes with an amplitude of ~0.8 mag. We calculated the time-variable geometrical cross-section using the radar shape model (Hudson & Ostro 1995), and corrected the effect from the observed data to derive the geometric albedo. In this presentation, we will present our photometric results. In addition, we will discuss about the regolith particles size together with the polarimetric properties based on the laboratory measurements of albedo-polarization maximum.

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Near-Infrared Photopolarimetry of Large Main Belt Asteroid - (4) Vesta

  • Bach, Yoonsoo P.;Ishiguro, Masateru;Takahashi, Jun;Naito, Hiroyuki;Kwon, Jungmi;Kuroda, Daisuke
    • 천문학회보
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    • 제46권1호
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    • pp.45.1-45.1
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    • 2021
  • The polarization degree as a function of phase angle (the Sun-target-observer's angle), so-called the polarimetric phase curves (PPC), have provided priceless information on asteroids' albedos since B. Lyot (1929). Succeeding experimental works in 1970s have confirmed the Umow law: There is a universal and strong correlation between the albedo and the PPC slope (slope of the tangential line at the zero of the PPC at phase angle ~ 20 degrees). Experiments in 1990s (ref [1]), on the other hand, have demonstrated that the negative branch of PPC is dependent on the size parameter (X ~ π * particle-size / wavelength), especially when X <~5. The change in particle size changed the minimum polarization degree, location of the minimum, and the width of the negative branch (called the inversion angle). From polarimetry[2] and spectroscopy[3], large asteroids are expected to be covered with fine (<~ 10 ㎛ size) particles due to the gravity. The size parameters are X ~ 30 at the optical wavelength (λ ~ 0.5 ㎛) and X ~ 10 in near-infrared (J, H, Ks bands; λ ~ 1.2-2.2 ㎛), if the representative particle size of 5 ㎛ is considered. Accordingly, the near-infrared polarimetry has a great potential to validate the idea in ref[1]. We conducted near-infrared photopolarimetry of the large asteroid (4) Vesta using the Nishiharima Infrared Camera (NIC) at Nishi-Harima Astronomical Observatory (NHAO). NIC allows simultaneous polarimetric measurements in J, H, and Ks bands, and thus the change of PPC is obtained for three different size parameters. As a result, we found a signature of the change in the negative branch in the PPC of asteroid (4) Vesta. We will introduce our observation and the results and give an interpretation of the regolith on Vesta.

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Photometric observations of the Baptistina asteroid family

  • Kim, Myung-Jin;Choi, Young-Jun;Moon, Hong-Kyu;Erece, Orhan;Ries, Judit Gyorgyey;Kaynar, Suleyman;Kaplan, Murat;Eker, Zeki
    • 천문학회보
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    • 제40권1호
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    • pp.84.1-84.1
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    • 2015
  • The Baptistina family is one of the typical young asteroid families with an age estimated to be about 140-320 Myrs old (Masiero et al. 2012); considered to have not enough time to experience a significant collisional and dynamical evolution since it was formed. Therefore, it may offer a unique insight into spin rate distribution of relatively fresh fragments and physical mechanism of a family break-up event. Observations of the Baptistina family asteroids were conducted during 111 nights from 2013 Oct. to 2015 Feb., using 0.5 m- to 2 m- class telescopes at 6 observatories in the northern hemisphere. We used CCD cameras on the Sobaeksan Optical Astronomy Observatory (SOAO) 0.6 m telescope on Mt. Sobaek, Korea, the Lemmonsan Optical Astronomy Observatory (LOAO) 1.0 m telescope on Mt. Lemmon, USA, the Tubitak Ulusal Gozlemevi (TUG) 1.0 m telescope in Bakirlitepe, Turkey, the Bohyunsan Optical Astronomy Observatory (BOAO) 1.8 m telescope on Mt. Bohyun, Korea, the McDonald Observatory 2.1 m Otto Struve Telescope on Mt. Locke, USA, and the National Astronomical Research Institute of Thailand (NARIT) Observatory 2.4 m telescope on Mt. Doi Inthanon, Thailand. Here, we will present our preliminary results for lightcurve analyses of Baptistina family members.

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