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ESPRESSO (Echelle SPectrograph for Rocky Exoplanet- and Stable Spectroscopic Observations)〔(【引用サイトリンク】title=ESO - Espresso )〕 is a new third-generation, high-resolution, fiber-fed and cross-dispersed echelle spectrograph (R = 140,000) for the visible wavelength range (350 nm – 720 nm), for the European Southern Observatory's Very Large Telescope (VLT). Its main feature is the spectroscopic stability and the radial velocity precision. With its very high spectroscopic precision, it will be able to detect Earth-like planets. For example, our Earth induces a radial-velocity variation of 9 cm/s on our Sun. ESPRESSO will build on the foundations laid by the hugely successful High Accuracy Radial Velocity Planet Searcher (HARPS) instrument at the 3.6-metre telescope at ESO’s La Silla Observatory. ESPRESSO will benefit not only from the much larger combined light-collecting capacity of the four 8.2-metre VLT Unit Telescopes, but also from improvements in the stability and calibration accuracy that are now possible (for example, laser frequency comb technology). The requirement is to reach 10 cm/s,〔 but the aimed goal is to obtain a precision level of a few cm/s. This would mean a large step forward over current radial-velocity spectrographs like ESO's HARPS. The highly successful HARPS instrument can attain a precision of 97 cm/s (3.5 km/h), with an effective precision of the order of 30 cm/s, making it one of only two instruments worldwide with such accuracy. The ESPRESSO would greatly exceed this capability making detection of earth-like planets from ground based instruments possible. Installation and commissioning of ESPRESSO at the VLT is foreseen in 2016.〔 The instrument is capable of operating in 1-UT mode (using one of the telescopes) and in 4-UT mode. In 4-UT mode, in which all the four 8-m telescopes are connected incoherently to form a 16-m equivalent telescope, the spectrograph will reach extremely faint objects.〔 == Sensitivity == For example (for G2V type stars): * Rocky planets around stars as faint as V ~ 9 in (in 1-UT mode) * Neptune mass planets around stars as faint as V ~ 12 (in 4-UT mode ) * Earth-like planets around stars as faint as V ~ 9 (CODEX on the E-ELT) (2025) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ESPRESSO」の詳細全文を読む スポンサード リンク
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