Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave, 2020
Although astronomers have confirmed the existence of 4,000 exoplanets to date, it is still diffic... more Although astronomers have confirmed the existence of 4,000 exoplanets to date, it is still difficult to directly compare exoplanets with the planets in our solar system because most of the known transiting exoplanets have an orbital period shorter than 1 year. Recent analyses of the 4-year data from the Kepler spacecraft revealed dozens of long-period transiting exoplanets and showed that their abundance is of order unity around Sun-like stars. However, the stars targeted by Kepler are too faint to conduct follow-up observations. The on-going all-sky survey mission TESS, with four 10.5 cm cameras with a field of view of 24 deg x 24 deg, is finding nearby transiting planets; however, the nominal observation period (1 month{1 year) is too short to find long-period planets with au-scale orbits. Herein, we propose using the LOng-period Transiting exoplanet sUrvey Satellite (LOTUS) mission, which employs a 7.5 cm wide-field (33 deg x 33 deg) camera placed on a nanosatellite, to continuously monitor the same sky region and find long-period planets transiting nearby bright stars. We present a conceptual design for the optics and bus system of LOTUS. Our optical system has a uniform point spread function over the entire field of view and a wide wavelength range (0.5{1.0 um). The bus system is designed to ensure that the pointing precision is sufficient to achieve the sub-percent photometry required for the detection of transiting exoplanets.
Detailed analysis of high-resolution Subaru telescope mid-IR imaging observation data of the Deep... more Detailed analysis of high-resolution Subaru telescope mid-IR imaging observation data of the Deep Impact collision with comet 9/P Tempel 1 reveals that the surface dust mantle of the comet may have been made before its first perihelion passage.
1970), which is now a commonly accepted scenario for the early evolution of terrestrial planets a... more 1970), which is now a commonly accepted scenario for the early evolution of terrestrial planets and other sufficiently large rocky bodies. Likewise, the lunar crater chronology, based on a well-known correlation between the number density of craters and radiometric ages of lunar terrains, has been applied to other inner solar system bodies (e.g., Hartmann, 1970). Particles obtained from the comet 81P/Wild2 in the Stardust mission (since 1999) showed that the comet is a mixture of materials formed in "hot" and "cold" environments. Most of the particles show oxygen isotopic compositions similar to the solar system composition, and some particles were fragments of Ca-and Al-rich inclusions (CAIs) and chondrules (e.g.,
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave, 2020
Although astronomers have confirmed the existence of 4,000 exoplanets to date, it is still diffic... more Although astronomers have confirmed the existence of 4,000 exoplanets to date, it is still difficult to directly compare exoplanets with the planets in our solar system because most of the known transiting exoplanets have an orbital period shorter than 1 year. Recent analyses of the 4-year data from the Kepler spacecraft revealed dozens of long-period transiting exoplanets and showed that their abundance is of order unity around Sun-like stars. However, the stars targeted by Kepler are too faint to conduct follow-up observations. The on-going all-sky survey mission TESS, with four 10.5 cm cameras with a field of view of 24 deg x 24 deg, is finding nearby transiting planets; however, the nominal observation period (1 month{1 year) is too short to find long-period planets with au-scale orbits. Herein, we propose using the LOng-period Transiting exoplanet sUrvey Satellite (LOTUS) mission, which employs a 7.5 cm wide-field (33 deg x 33 deg) camera placed on a nanosatellite, to continuously monitor the same sky region and find long-period planets transiting nearby bright stars. We present a conceptual design for the optics and bus system of LOTUS. Our optical system has a uniform point spread function over the entire field of view and a wide wavelength range (0.5{1.0 um). The bus system is designed to ensure that the pointing precision is sufficient to achieve the sub-percent photometry required for the detection of transiting exoplanets.
Detailed analysis of high-resolution Subaru telescope mid-IR imaging observation data of the Deep... more Detailed analysis of high-resolution Subaru telescope mid-IR imaging observation data of the Deep Impact collision with comet 9/P Tempel 1 reveals that the surface dust mantle of the comet may have been made before its first perihelion passage.
1970), which is now a commonly accepted scenario for the early evolution of terrestrial planets a... more 1970), which is now a commonly accepted scenario for the early evolution of terrestrial planets and other sufficiently large rocky bodies. Likewise, the lunar crater chronology, based on a well-known correlation between the number density of craters and radiometric ages of lunar terrains, has been applied to other inner solar system bodies (e.g., Hartmann, 1970). Particles obtained from the comet 81P/Wild2 in the Stardust mission (since 1999) showed that the comet is a mixture of materials formed in "hot" and "cold" environments. Most of the particles show oxygen isotopic compositions similar to the solar system composition, and some particles were fragments of Ca-and Al-rich inclusions (CAIs) and chondrules (e.g.,
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Uploads
Papers by Seiji Sugita