10,305 research outputs found
Nulling interferometry: impact of exozodiacal clouds on the performance of future life-finding space missions
Earth-sized planets around nearby stars are being detected for the first time
by ground-based radial velocity and space-based transit surveys. This milestone
is opening the path towards the definition of missions able to directly detect
the light from these planets, with the identification of bio-signatures as one
of the main objectives. In that respect, both ESA and NASA have identified
nulling interferometry as one of the most promising techniques. The ability to
study distant planets will however depend on exozodiacal dust clouds
surrounding the target stars. In this paper, we assess the impact of
exozodiacal dust clouds on the performance of an infrared nulling
interferometer in the Emma X-array configuration. For the nominal mission
architecture with 2-m aperture telescopes, we found that point-symmetric
exozodiacal dust discs about 100 times denser than the solar zodiacal cloud can
be tolerated in order to survey at least 150 targets during the mission
lifetime. Considering modeled resonant structures created by an Earth-like
planet orbiting at 1 AU around a Sun-like star, we show that the tolerable dust
density for planet detection goes down to about 15 times the solar zodiacal
density for face-on systems and decreases with the disc inclination. The upper
limits on the tolerable exozodiacal dust density derived in this study must be
considered as rather pessimistic, but still give a realistic estimation of the
typical sensitivity that we will need to reach on exozodiacal discs in order to
prepare the scientific programme of future Earth-like planet characterisation
missions.Comment: 17 pages, accepted for publication in A&
The Search for Other Planets and Life
This Les Houches School offers students a wide ranging view of the field of exoplanets and the search for life beyond the solar system. Observational and theoretical opportunities abound in a new field of astronomy that will be growing for decades to come. I give a brief introduction and overview to the many detailed talks that will be presented in this volume
New Frontiers for Terrestrial-sized to Neptune-sized Exoplanets In the Era of Extremely Large Telescopes
Surveys reveal that terrestrial- to Neptune-sized planets (1 4
R) are the most common type of planets in our galaxy. Detecting
and characterizing such small planets around nearby stars holds the key to
understanding the diversity of exoplanets and will ultimately address the
ubiquitousness of life in the universe. The following fundamental questions
will drive research in the next decade and beyond: (1) how common are
terrestrial to Neptune-sized planets within a few AU of their host star, as a
function of stellar mass? (2) How does planet composition depend on planet
mass, orbital radius, and host star properties? (3) What are the energy
budgets, atmospheric dynamics, and climates of the nearest worlds? Addressing
these questions requires: a) diffraction-limited spatial resolution; b)
stability and achievable contrast delivered by adaptive optics; and c) the
light-gathering power of extremely large telescopes (ELTs), as well as
multi-wavelength observations and all-sky coverage enabled by a comprehensive
US ELT Program. Here we provide an overview of the challenge, and promise of
success, in detecting and comprehensively characterizing small worlds around
the very nearest stars to the Sun with ELTs. This white paper extends and
complements the material presented in the findings and recommendations
published in the National Academy reports on Exoplanet Science Strategy and
Astrobiology Strategy for the Search for Life in the Universe.Comment: Astro2020 Science White Pape
Report from solar physics
A discussion of the nature of solar physics is followed by a brief review of recent advances in the field. These advances include: the first direct experimental confirmation of the central role played by thermonuclear processes in stars; the discovery that the 5-minute oscillations of the Sun are a global seismic phenomenon that can be used as a probe of the structure and dynamical behavior of the solar interior; the discovery that the solar magnetic field is subdivided into individual flux tubes with field strength exceeding 1000 gauss. Also covered was a science strategy for pure solar physics. Brief discussions are given of solar-terrestrial physics, solar/stellar relationships, and suggested space missions
Workshop on Innovative Instrumentation for the In Situ Study of Atmosphere-Surface Interactions on Mars
The speakers in the first session of the workshop addressed some of the continuing enigmas regarding the atmospheric composition, surface composition, and atmosphere-surface interactions on Mars; provided a description of a database of proposed payloads and instruments for SEI missions that is scheduled to be accessible in 1993; discussed potential uses of atmospheric imaging from landed stations on Mars; and advocated the collection and employment of high-spectral-resolution reflectance and emission data
Raman Spectroscopic Analysis of Geological and Biogeological Specimens of Relevance to the ExoMars Mission
H.G.M.E., I.H., and R.I. acknowledge the support of the STFC Research Council in the UK ExoMars programme. J.J. and P.V. acknowledge the support of the Grant Agency of the Czech Republic (210/10/0467) and of the Ministry of Education of the Czech Republic (MSM0021620855).Peer reviewedPublisher PD
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