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several recent studies show that constraints can be put on primordial black holes (pbhs) as a candidate for dark matter by considering their capture by neutron stars (nss). if a pbh is captured by a ns, the ns is accreted onto the pbh and eventually collapses. a related scenario arises from asymmetric dark matter parti... | interactions of primordial black hole with neutron star |
very few mysteries in our current picture of the universe are more intriguing than the puzzle of dark matter. the qcd axion, a weakly interacting, sub-ev particle is a compelling cold dark matter candidate and was originally postulated as a solution to the strong cp problem. this talk will give an overview of direct de... | first results from the generation-2 axion dark matter experiment (admx) |
astrophysical and cosmological observations of the last 40 years provide strong evidence for the existence of non-baryonic dark matter. among possible candidates are dark axions, hypothetical particles suggested to solve the cp problem in quantum chromodynamics. it is known that magnetically doped topological insulator... | a proposal to detect dark matter using axionic topological antiferromagnets |
the minimal dark matter framework classifies viable dark matter (dm) candidates that are obtained by simply augmenting the standard model of particle interactions with a new multiplet, without adding new ad hoc symmetries to make the dm stable. the model has no free parameters and is therefore extremely predictive; mor... | generalizing minimal dark matter: millicharge or decay |
we request hst/acs imaging to obtain a deep color-magnitude diagram of the newly discovered candidate milky way satellite virgo i. with an estimated absolute magnitude of only m_v -0.8 and a galactocentric radius of 90 kpc, virgo i is one of the faintest and most distant dwarfs ever observed, and could be identified as... | unveiling the extreme nature of the hyper faint galaxy virgo i |
the nonbaryonic dark matter of the universe is assumed to consist of new stable particles. stable particle candidates for cosmological dark matter are usually considered as neutral and weakly interacting. however stable charged leptons and quarks can also exist hidden in elusive dark atoms and can play a role of dark m... | search for double charged particles as direct test for dark atom constituents |
a series of brief reviews collected in the present issue present various candidates for cosmological dark matter (dm) predicted by models of particle physics. the range from superlight axions to extended objects is covered. though the possible list of candidates is far from complete it gives the flavor of the extensive... | particle dark matter candidates |
galactic dark matter subhalos are promising targets for dark matter searches in the gamma-ray band. unlike other more conventional targets, like dwarf spheroidal galaxies, galaxy clusters, or the galactic center and halo, the locations of these hypothetical sources remain unknown. under the assumption of a self-annihil... | scrutinizing the gamma-ray sky for dark matter subhalos |
quarks were introduced 50 years ago opening the road towards our understanding of the elementary constituents of matter and their fundamental interactions. since then, a spectacular progress has been made with important discoveries that led to the establishment of the standard theory that describes accurately the basic... | quarks and a unified theory of nature fundamental forces |
a z2 parity odd real scalar is a good candidate for dark matter in the present universe. we consider models contain two higgs doublet fields and one real scalar dark matter particle with mass in the range of 31 - 40 gev and annihilating into a bb¯ pair, or with about 10 gev mass and annihilating into tau lepton pair. t... | galactic center excess by higgs portal dark matter |
the sterile neutrino is a particle dark matter candidate with a host of observable signatures that is close to being fully tested. i will first review the implications for structure formation, comparing predictions of sterile neutrino cosmologies against observations. i will then review analyses of x-rays from dark mat... | the status of sterile neutrino dark matter |
the compelling astrophysical evidence for dark matter on one hand and the experimental evidence for neutrino masses on the other, demands modifications beyond the standard model. therefore, building new models by extending the symmetries and particle content of the standard model is being pursued to remedy these proble... | extensions of the standard model with dark matter in some explicit examples |
there is as yet no confirmed and statistically significant evidence for direct, indirect, or collider-based detection of dark matter. however, several indirect searches, including ams-02, fermi-lat, and pamela, have shown an intriguing excess of positrons when compared to expectations. here we predict a higgs-related b... | dark matter candidate with well-defined mass and couplings |
the deep space climate observatory (dscovr) spacecraft resides at the first lagrangian point about one million miles from earth. a polychromatic imaging camera onboard delivers nearly hourly observations of the entire sunlit face of the earth. many images contain unexpected bright flashes of light over both ocean and l... | terrestrial glint seen from deep space: oriented ice crystals detected from the lagrangian point |
for rocky exoplanets, knowledge of their geologic characteristics such as composition and mineralogy, surface recycling mechanisms, and volcanic behavior are key to determining their suitability to host life. thus, determining exoplanet habitability requires an understanding of surface chemistry, and understanding the ... | experimental determination of mantle solidi and melt compositions for two likely rocky exoplanet compositions |
stellar magnetic fields are poorly understood, but are known to be important for stellar evolution and exoplanet habitability. they drive stellar activity, which is the main observational constraint on theoretical models for magnetic field generation and evolution. starspots are the main manifestation of the magnetic f... | butterfly diagram of a sun-like star observed using asteroseismology |
highly sensitive and fast imaging at short-wavelength infrared (swir) is one of the key enabling technologies for the direct-imaging of habitable exoplanets. swir imaging systems currently available in the market are dominated by imagers based on ingaas pin photodiodes. the sensitivity of these cameras is limited by th... | ingaas based heterojunction phototransistors: viable solution for high-speed and low-noise short wave infrared imaging |
it is generally believed that the presence of a ${{{n}}2}{-} {{{o}}2}$-dominant atmosphere is an indication of biological and geological activity on terrestrial exoplanets that are in the habitable region. one of indicators of such an atmosphere is the nitric oxide (no) molecule. it is known from satellite observations... | on the possibility of observing nitric oxide on terrestrial exoplanets using the wso-uv observatory |
in recent years, exoplanet detection has become the technological frontier in the field of astronomy, because it provides evidence of the origin of life and the future human habitable exoplanet. deploying several satellites to form an aperture-synthetic interferometer system in space may help discover “another earth” v... | mission design of an aperture-synthetic interferometer system for space-based exoplanet exploration |
mapping the large-scale magnetic field in late f-type stars is important for understanding the nature of the stellar dynamo and the dynamics of thin outer convection zones. we use zeeman doppler imaging to produce multi-epoch maps of the surface magnetic field for two mature late f-type stars: β virginis (f9v) and θ dr... | the magnetic fields and stellar winds of the mature late f-stars: β virginis and θ draconis |
m-dwarf stars provide very favourable conditions for finding habitable worlds beyond our solar system. the estimation of the fundamental parameters of the transiting exoplanets relies on the accuracy of the theoretical predictions for radius and effective temperature of the host m dwarf, therefore it is important to co... | effective temperature - radius relationship of m dwarfs |
we propose a cosmic accelerometer, designed for velocity precision of ≤1 cm/s over years to decades. this astro2020 “small” program will be ideal for radial velocity measurements of terrestrial exoplanets in the habitable zone of sun-like stars. it will also be the technical pathfinder for a future facility to measure ... | the cosmic accelerometer |
the mid-infrared imager, spectrometer, coronagraph (misc) is one of the instruments studied both for the origins space telescope (ost) mission concept 1 and 2. the misc for ost mission concept 1 consists of the misc imager and spectrometer module (misc i and s), the misc coronagraph module (misc cor) and the misc trans... | the mid-infrared imager, spectrometer, coronagraph (misc) for the origins space telescope (ost) |
can high-energy transient events affect life on a planet? we provide a review of the works that have tried to answer this question. it is argued that that gamma ray bursts, specifically those of the long class, are among the most dangerous astrophysical sources for biotic life and may exert evolutionary pressure on pos... | the impact of grbs on exoplanetary habitability |
in the near future we will have ground- and space-based telescopes that are designed to observe and characterize earth-like planets. while attention is focused on exoplanets orbiting main-sequence stars, more than 150 exoplanets have already been detected orbiting red giants, opening the intriguing question of what roc... | high-resolution spectra of earth-like planets orbiting red giant host stars |
context. terrestrial-type exoplanets in or near stellar habitable zones appear to be ubiquitous. it is, however, unknown which of these planets have temperate, earth-like climates or for example, extreme venus-like climates.aims: technical tools to distinguish different kinds of terrestrial-type planets are crucial for... | from exo-earths to exo-venuses: flux and polarization signatures of reflected light |
development of a high-contrast imaging system, especially toward direct detection of habitable earth-like exoplanets, would be one of the most challenging themes in modern astronomy. for direct detection of exo-earth, coronagraphic devices are required for suppressing bright diffracted light from a parent star. in addi... | construction of exist (exoplanet imaging system testbed) toward future space coronagraphs |
the recent announcement of a neptune-sized exomoon candidate orbiting the jupiter-sized object kepler-1625b has forced us to rethink our assumptions regarding both exomoons and their host exoplanets. in this paper, i describe calculations of the habitable zone for earth-like exomoons in the orbit of kepler-1625b under ... | the habitable zone for earth-like exomoons orbiting kepler-1625b |
speculoos (search for habitable planets eclipsing ultra-cool stars) aims to perform a transit search on the nearest (< 40 pc) ultracool (< 3000k) dwarf stars. the project's main motivation is to discover potentially habitable planets well-suited for detailed atmospheric characterisation with upcoming giant telesc... | development of the speculoos exoplanet search project |
understanding planetary habitability is one of the major challenges of the current scientific era, and is a vast inter-disciplinary undertaking that combines planetary science, climate science, and stellar astrophysics. this book provides an overview of the many processes that influence the energy balance of planetary ... | planetary habitability |
a planet may be defined as habitable if it has an atmosphere and is warm enough to support the existence of liquid water on its surface. such a world has the basic set of conditions that allow it to develop life similar to ours, which is carbon-based and has water as its universal solvent. while this definition is suit... | evolutionary exobiology: towards the qualitative assessment of biological potential on exoplanets |
the goal of this paper is to take steps towards estimating the frequency of terrestrial planets in the habitable zones of their host stars, using planet counts from the kepler mission. the method is to assume that an analytical form for the underlying distribution function, numerically simulate the observing procedure,... | steps towards eta-earth, from kepler data |
finding life on other worlds is a fascinating area of astrobiology and planetary sciences. presently, over 3800 exoplanets, representing a very wide range of physical and chemical environments, are known. scientists are not only looking for traces of life outside earth, but they are also trying to find out which of ear... | tardigrade indexing approach on exoplanets |
coronagraph instruments rely on predictable and stable deformable mirror (dm) surface displacement to achieve the contrast required to detect earth-sized exoplanets in the habitable zone of their host star. anomalous dm behavior, such as unstable or pinned actuators, can limit contrast in coronagraphs. simulating how t... | deriving deformable mirror performance requirements in simulation |
our present-day atmosphere is often used as analog for potentially habitable exoplanets, but earth's atmosphere has changed dramatically throughout its 4.5-billion-year history. for example, molecular oxygen is abundant in the atmosphere today but was absent on the early earth. meanwhile, the physical and chemical evol... | earth: atmospheric evolution of a habitable planet |
previous studies have shown that planets that rotate retrograde (backward with respect to their orbital motion) generally experience less severe obliquity variations than those that rotate prograde (the same direction as their orbital motion). here, we examine retrograde-rotating planets on eccentric orbits and find a ... | retrograde-rotating exoplanets experience obliquity excitations in an eccentricity-enabled resonance |
a primary goal of general education introductory astronomy courses often is to provide students with examples of how science is actually done. low to nonexistent mathematical prerequisites in some courses can make useful exercises difficult to find, and sometimes very difficult for students, especially if the exercises... | using real data from the kepler mission to find potentially habitable planets: an introductory astronomy exercise |
the current exoplanet database includes 5454 confirmed and candidate planets observed with the kepler mission. we find 932 planet pairs from which we extract distance and orbital period ratios. while earlier studies used a logarithmic spacing, which lacks a physical model, we employ here the theory of harmonic orbit re... | exoplanet predictions based on harmonic orbit resonances |
an analysis of the currently known exoplanets in the habitable zones (hzs) of their host stars is of interest both in the wake of the nasa kepler mission and with prospects for expanding the known planet population through future ground- and space-based projects. in this paper, we compare the empirical distributions of... | using kepler candidates to examine the properties of habitable zone exoplanets |
the circumstellar habitable zone and its various refinements serves as a useful entry point for discussing the potential for a planet to generate and sustain life. but little attention is paid to the quality of available energy in the form of stellar photons for phototrophic (e.g., photosynthetic) life. this short pape... | exoplanet exergy: why useful work matters for planetary habitabilty |
astrophysical observations reveal a large diversity of radii and masses of exoplanets. it is important to characterize the interiors of exoplanets to understand planetary diversity and further determine how unique, or not, earth is. assessing interior structure is challenging because there are few data and large uncert... | assessing the interior structure of terrestrial exoplanets with implications for habitability |
nowadays, we know thousands of exoplanets, some of them potentially habitable. next technological facilities (jwst, for example) have exoplanet atmosphere analysis capabilities, but they also have limits in terms of how many targets can be studied. therefore, there is a need to rank and prioritize these exoplanets with... | a fuzzy multi-criteria decision making approach for exo-planetary habitability |
the planetary system of the star trappist-1 hosts seven exoplanets, three of which are in the habitable zone. based on published data, we have analyzed the properties of cool dwarfs that could be considered as an analog of this object. using the data available in the literature (seli et al. 2021) for ultracool dwarfs s... | activity of trappist-1 analogs |
roughly 40 billion m dwarfs in our galaxy host at least one small planet in the habitable zone (hz). the stellar ultraviolet (uv) radiation from m dwarfs is strong and highly variable, and impacts planetary atmospheric loss, composition and habitability. these effects are amplified by the extreme proximity of their hzs... | monitoring the high-energy radiation environment of exoplanets around low-mass stars with sparcs (star-planet activity research cubesat) |
a starshade enables direct imaging of earth-like exoplanets in the habitable zone of nearby stars by suppressing light from a target star so that orbiting planets are revealed. the perimeter of a starshade, known as the optical edge, has two critical functions. first, it must meet a precise in-plane profile specificati... | advancements in precision edges for a starshade external occulter |
based on data on stars with planets located in the habitable zone, a study is made of manifestations of their activity. light curves obtained during observations in the q3 set with the kepler space telescope for them were studied and the amplitudes of the brightness variability were studied in order to determine the pr... | activity of stars with planets in the habitable zone |
the rate at which interstellar habitable planets are being discovered would naturally warrant consideration and exploration of a number of related issues. while the physical conditions that can support persistent contact demand structural similarity of an extra-solar planet (exoplanet) to earth, and the necessary bio-c... | expert habitat: a colonization conjecture for exoplanetary habitability via penalized multi-objective optimization-based candidate validation |
many rocky exoplanets are heavier and larger than earth, so-called "super-earths". some of these may be habitable, and a few may be inhabited by super-earthlings. due to the higher surface gravity on these worlds, space-flight is much more challenging. we find that chemical rockets still allow for escape velocities on ... | super-earths in need for extremly big rockets |
for the large ultraviolet/optical/infrared surveyor (luvoir) to perform high-contrast direct imaging of habitable exoplanets using a coronagraph instrument, the system must maintain extremely low system dynamic wavefront error (on the order of 10 picometers rms over the spatial frequencies corresponding to the dark-hol... | dynamic wavefront error and line-of-sight performance predictions for the 15-meter segmented large ultraviolet/optical/infrared surveyor (luvoir) with non-contact vibration isolation |
direct imaging and spectroscopy of terrestrial exoplanets requires the control of vector electromagnetic fields to approximately one part in ten to the fifth over a few milliarc second fov to achieve the necessary 10-10 intensity contrast levels. observations using space telescopes are necessary to achieve these levels... | terrestrial exoplanet coronagraph image quality polarization aberrations in habex♦,# |
the discovery of kepler 452b is a milestone in searching for habitable exoplanets. while it has been suggested that kepler 452b is the first earth-like exoplanet discovered in the habitable zone of a sun-like star, its climate states and habitability require quantitative studies. here, we first use a three-dimensional ... | climate and habitability of kepler 452b simulated with a fully coupled atmosphere-ocean general circulation model |
the first discovery of an extra-solar planet (exoplanet) around a main-sequence star, 51 peg b, discovered using doppler spectroscopy, opened up the field of exoplanets. for more than a decade, the dominant way for finding exoplanets was using precise doppler spectroscopy to measure the radial velocity (rv) changes of ... | on detecting new worlds: the art of doppler spectroscopy with iodine cells |
we analyze the potential transit light curve effects due to a clarke belt of satellites around an exoplanet. building on code and analysis from korpela et al., we refine the transit analysis of socas-navarro by incorporating limb-darkening and taking an observer-centered approach to examining residuals. these considera... | improved analysis of clarke exobelt detectability |
understanding the surface and atmospheric conditions of earth-size, rocky planets in the habitable zones (hzs) of low-mass stars is currently one of the greatest astronomical endeavors. knowledge of the planetary effective surface temperature alone is insufficient to accurately interpret biosignature gases when they ar... | characterizing the habitable zones of exoplanetary systems with a large ultraviolet/visible/near-ir space observatory |
the habex (habitable exoplanet) space telescope mission concept carries two complementary optical systems as part of its baseline design, a coronagraph and a starshade, that are designed to detect and characterize planetary systems around nearby stars. the starshade is an external occulter which would be 72 m in diamet... | habex space telescope exoplanet instruments |
current post-processing techniques in high contrast imaging depend on some source of diversity between the exoplanet signal and the residual star light at that location. the two main techniques are angular differential imaging (adi), which makes use of parallactic sky rotation to separate planet from star light, and sp... | orbital differential imaging: a new high-contrast post-processing technique for direct imaging of exoplanets |
the habex and luvoir mission concepts reported science yields for mission scenarios in which the instruments must search for potentially habitable planets, determine their orbits, and, if worthwhile, invest the integration time for a spectral characterization. we evaluate the impact of prior knowledge of planet existen... | faster exo-earth yield for habex and luvoir via extreme precision radial velocity prior knowledge |
we investigate the atmospheric responses of modeled hypothetical earth-like planets in the habitable zone of the m-dwarf ad leonis to reduced oxygen (o2), removed biomass ("dead" earth), and varying carbon dioxide (co2) and surface relative humidity (srh). results suggest large o2 differences between the reduced-o2 and... | influence of biomass emissions on habitability, biosignatures, and detectability in earth-like atmospheres |
context. detailed characterizations of exoplanets are clearly moving to the forefront of planetary science. temperature is a key marker for understanding atmospheric physics and chemistry.aims: we aim to retrieve temperatures of n2-o2 dominated atmospheres from secondary eclipse spectroscopic observations of the therma... | sveeeeties: singular vector expansion to estimate earth-like exoplanet temperatures from infrared emission spectra |
the near-infrared planet searcher (nirps) is a new ultra-stable near-infrared spectrograph installed on eso 3.6-m telescope in la silla, chile. aiming to achieve a precision of 1 m/s, nirps is operating together with harps. nirps has been designed to explore the exciting prospects offered by the m dwarfs, focusing on t... | the new near-infrared adaptive-optics assisted high-resolution nirps spectrograph on the eso 3.6m |
small planets orbiting faint red stars less than half the size of the sun are numerous and could be the best places to search for signatures of life (1). however, the detailed compositions of these planets—and the implications for how they formed and evolved—have been difficult to study because of how far away they are... | three types of planets orbit red dwarfs |
precipitation and its response to forcing is an important aspect of planetary climate system. in this study, we examine the strength of precipitation in the experiments with different atmospheric masses and their response to surface warming, using three global atmospheric general circulation models and one regional clo... | smaller sensitivity of precipitation to surface temperature under massive atmospheres |
as part of a comprehensive effort to characterize the nearest stars, the chiron echelle spectrograph on the ctio/smarts 1.5 m telescope is being used to acquire high-resolution (r = 80,000) spectra of k dwarfs within 50 pc. this paper provides spectral details about 35 k dwarfs from five benchmark sets with estimated a... | the solar neighborhood l: spectroscopic discovery of k dwarfs younger than 1 gyr and new binaries within 30 pc |
a major science goal of future, large-aperture, optical space telescopes is to directly image and spectroscopically analyze reflected light from potentially habitable exoplanets. to accomplish this, the optical system must suppress diffracted light from the star to reveal point sources approximately ten orders of magni... | characterization of microdot apodizers for imaging exoplanets with next-generation space telescopes |
to directly image and characterize exoplanets, starlight suppression systems rely on coronagraphs to optically remove starlight while preserving planet light for spectroscopy. the phase-induced amplitude apodization complex mask coronagraph (piaacmc) is an attractive coronagraph option for the next generation of large ... | design and performance analysis of a piaacmc coronagraph on a segmented aperture |
earth as an evolving planetary system, fourth edition discusses key topics dealing with the evolution and interaction through time of earth's crust, mantle, core, atmosphere, hydrosphere, and biosphere. it addresses the questions of why earth is unique among planets of the solar system, and how the various subsystems i... | earth as an evolving planetary system |
the recent discovery that billions of planets in the milky way galaxy may be in circumstellar habitable zones has renewed speculation over the possibility of extraterrestrial life. the drake equation is a probabilistic framework for estimating the number of technological advanced civilizations in our galaxy; however, m... | bernoulli, darwin, and sagan: the probability of life on other planets |
exoplanet detection in the past decade by efforts including nasa's kepler and tess missions has discovered many worlds that differ substantially from planets in our own solar system, including more than 400 exoplanets orbiting binary or multi-star systems. this not only broadens our understanding of the diversity of ex... | analyzing the stability of non-coplanar circumbinary planets using machine learning |
we propose a novel space observatory designed to find and characterize habitable, earth-like planets around all sun-like stars within 10 parsecs, using technology that could conceivably be available in the near future. at 10pc, the diffraction limit requires a telescope more than 20m in diameter to resolve the earth fr... | diffractive interfero coronagraph exoplanet resolver (dicer): detecting and characterizing all earth-like exoplanets orbiting sun-like stars within 10 pc |
approximately 60 % of all stars in the solar neighbourhood (up to 80 % in our milky way) are members of binary or multiple star systems. this fact led to the speculations that many more planets may exist in binary systems than are currently known. to estimate the habitability of exoplanetary systems, we have to define ... | on the possibility of habitable trojan planets in binary star systems |
uv-scope is a mission concept to determine the causes of atmospheric mass loss in exoplanets, investigate the mechanisms driving aerosol formation in hot jupiters, and study the influence of the stellar environment on atmospheric evolution and habitability. as part of these investigations, the mission will generate a b... | the uv-scope mission: ultraviolet spectroscopic characterization of planets and their environments |
missions to directly detect exoplanets with a coronagraph, such as the potential habitable exoplanet (habex) mission, require an optical telescope with extreme wavefront stability. the key systems engineering question is: `how stable?' the poetic answer is 10 picometers per 10 minutes. but, what is the actual spatial d... | deriving telescope wavefront error (wfe) stability error budget from coronagraph performance |
identifying rocky planets in or near the habitable zones of their stars (near-earth analogs) is one of the key motivations of many past and present planet-search missions. the census of near-earth analogs is important because it informs calculations of the occurrence rate of earth-like planets, which in turn feed into ... | revising properties of planet-host binary systems. ii. apparent near-earth-analog planets in binaries are often sub-neptunes |
we propose to search for biosignatures in the spectra of reflected light from about 100 earth-sized planets that are already known to be orbiting in their habitable zones (hz). for a sample of g and k type hosts, most of these planets will be between 25 and 50 milli-arcsec (mas) from their host star and 1 billion to 10... | supersharp - segmented unfolding primary for exoplanet research via spectroscopic high angular resolution photography |
the remarkable optical properties of the solar gravitational lens (sgl) include major brightness amplification (∼1011 on the optical axis, at a wavelength of 1μm) and extreme angular resolution (∼10-10arcsec). a deep space mission equipped with a modest telescope and coronagraph, traveling to the focal area of the sgl ... | putting gravity to work: imaging of exoplanets with the solar gravitational lens |
the genesis potential index (gpi) of tropical cyclones (tc) on ocean planets in the habitable zones of m dwarfs is analyzed based on 3d gcm simulations. we found that gpi on these planets are smaller than those in tc basins on the earth mainly because of slow rotation of such planets. gpi's on exoplanets with eccentric... | low probability of tropical cyclones on ocean planets in the habitable zones of m dwarfs |
the need for high payload dynamic stability and ultra-stable mechanical systems is an overarching technology need for large space telescopes such as the large ultraviolet / optical / infrared (luvoir) surveyor. wavefront error stability of less than 10 picometers rms of uncorrected system wfe per wavefront control step... | dynamic stability with the disturbance-free payload architecture as applied to the large uv/optical/infrared (luvoir) mission |
to study the distribution of earth-like planets and to locate the habitable zone around extrasolar planets and their known satellites, we have emphasized in this paper the consideration of earth similarity index (esi) as a multi parameter quick assessment of earth-likeness with a value between zero and one. weight expo... | a relook on using the earth similarity index for searching habitable zones around solar and extrasolar planets |
detection of radio emission from jupiter was identified quickly as being due to its planetary-scale magnetic field. subsequent spacecraft investigations have revealed that many of the planets, and even some moons, either have or have had a planetary-scale magnetic field. in the case of the earth, jupiter, saturn, uranu... | radio observations as an exoplanet discovery method |
the nancy grace roman space telescope will enable advances in astrophysics by providing a large-scale survey capability in infrared wavelengths. the observatory is designed to provide data that will allow astronomers to unlock mysteries of the universe, answering high-priority scientific questions related to the evolut... | roman space telescope wide field instrument design evolution |
an external occulter for starlight suppression - a starshade - flying in formation with the habitable exoplanet imaging mission concept (habex) space telescope could enable the direct imaging and spectrographic characterization of earthlike exoplanets in the habitable zone. this starshade is flown between the telescope... | starshade mechanical design for the habitable exoplanet imaging mission concept (habex) |
one signature of life on earth is the vegetation red edge (vre) feature of land plants, a dramatic change of reflectivity at wavelength near 0.7 μm. potentially habitable planets around m dwarfs are tidally locked, which can limit the distribution of land plants. in this study, we used a biogeochemical model to investi... | on the growth and detectability of land plants on habitable planets around m dwarfs |
plato is the m3 (medium-class) mission in the esa cosmic vision 2015-2025 program, with a planned launch date in 2026. plato will carry out transit surveys to detect and characterize planets around bright stars, with special emphasis on small planets orbiting in the habitable zone of solar-like stars. plato will allow ... | space missions for exoplanet science: plato |
the science return of detecting temperate exoplanets as large as 2 re should be considered as one of the primary evaluation criteria to assess exoplanet missions. given the implications on the size of space telescopes, this evaluation criteria should be applied independently from the assessment of capability to find a ... | the super-earth opportunity — search for habitable exoplanets in the 2020s |
the fermi paradox is the discrepancy between the strong likelihood of alien intelligent life emerging (under a wide variety of assumptions) and the absence of any visible evidence for such emergence. we use this intriguing unlikeness to derive an upper limit on the fraction of living intelligent species that develop co... | is there anybody out there? |
the observed value λobs of the cosmological constant λ is extremely smaller than theoretical expectations, and the anthropic argument has been proposed as a solution to this problem because galaxies do not form when λ ≫ λobs. however, the contemporary galaxy formation theory predicts that stars form even with a high va... | lethal radiation from nearby supernovae helps explain the small cosmological constant |
anglada-escudé and tuomi question the statistical rigor of our analysis while ignoring the stellar activity aspects that we present. although we agree that improvements in multiparametric radial velocity (rv) modeling are necessary for the detection of earth-mass planets, the key physical points we raised were not chal... | response to comment on “stellar activity masquerading as planets in the habitable zone of the m dwarf gliese 581” |
recent advances in the physical vapor deposition (pvd) of protective fluoride films have raised the far-ultraviolet (fuv: 912-1600 å) reflectivity of aluminum-based mirrors closer to the theoretical limit. the greatest gains, at more than 20%, have come for lithium fluoride-protected aluminum, which has the shortest wa... | advanced environmentally resistant lithium fluoride mirror coatings for the next-generation of broadband space observatories |
with the growing number of discovered exoplanets, the gaia concept finds its second wind. the gaia concept defines that the biosphere of an inhabited planet regulates a planetary climate through feedback loops such that the planet remains habitable. crunching the "gaia" puzzle has been a focus of intense empirical rese... | stability of a planetary climate system with the biosphere species competing for resources |
we have investigated the possible evolutional history of the water ocean on venus, adopting the one dimensional radiative-convective model,including the parameters as albedo and relative humidity. under this model, it has the possibility that the habitable zone could include venus. it could continue for $\sim 1$ gy in ... | on the possible evolutionary history of the water ocean on venus |
in this paper it is analysed which of the thousands of stars in the wow! signal region could have the highest chance of being the real source of the signal, providing that it came from a star system similar to ours. a total of 66 g and k-type stars are sampled, but only one of them is identified as a potential sun-like... | an approximation to determine the source of the wow! signal |
we propose a suite of telescopes be deployed as part of the artemis iii human-crewed expedition to the lunar south pole, able to collect wide-field simultaneous far-ultraviolet (uv), near-uv, and optical band images with a fast cadence (10 seconds) of a single part of the sky for several hours continuously. wide-field,... | a high-cadence uv-optical telescope suite on the lunar south pole |
nitrogen is a biosignature gas that cannot be maintained in its earth-like ratio with co2 under abiotic conditions. it has also been proven to be notoriously hard to detect at optical and infrared wavelengths. fortunately, the ultraviolet region, which has only recently started being explored for terrestrial exoplanets... | observability of ultraviolet ni lines in the atmosphere of transiting earth-like planets |
having a massive moon has been considered as a primary mechanism for stabilized planetary obliquity, an example of which being our earth. this is, however, not always consistent with the exoplanetary cases. this article details the discovery of an alternative mechanism, namely that planets orbiting around binary stars ... | low spin-axis variations of circumbinary planets |
this work seeks to summarize some special aspects of a type of exoplanets known as super-earths (se), and the direct influence of these aspects in their habitability. physical processes like the internal thermal evolution and the generation of a protective planetary magnetic field (pmf) are directly related with habita... | planetary magnetic fields and habitability in super earths |
the precision thermal control (ptc) project was a multiyear effort initiated in fiscal year 2017 to mature the technology readiness level (trl) of technologies required to enable ultra-thermally stable ultraviolet/optical/infrared space telescope primary-mirror assemblies for ultra-high-contrast observations of exoplan... | precision thermal control technology to enable thermally stable telescopes |
the presence of volcanism is often anecdotally used to define a "living planet". since dome-building volcanism on earth occurs primarily at plate boundaries, the identification of such domes could inform on exoplanetary development. lava domes form when extruded magma is too viscous to flow from a vent, and their morph... | a toolbox for identifying the expression of dome-forming volcanism on exoplanets |
the habitable-zone exoplanet observatory mission (habex) is one of four large missions under review for the 2020 astrophysics decadal survey. its goal is to directly image and spectroscopically characterize planetary systems in the habitable zone around nearby sun-like stars. in addition, habex will perform a broad ran... | habitable-zone exoplanet observatory baseline 4-m telescope: systems-engineering design process and predicted structural thermal optical performance |
we present a new spitzer transit observation of k2-28b, a sub-neptune (r p = 2.45 ± 0.28 r ⊕) orbiting a relatively bright (v mag = 16.06, k mag = 10.75) metal-rich m4 dwarf (epic 206318379). this star is one of only seven with masses less than 0.2 {m}⊙known to host transiting planets, and the planet appears to be a sl... | an improved transit measurement for a 2.4 r ⊕ planet orbiting a bright mid-m dwarf k2-28 |
using a paraboloid model of an earth-like exoplanetary magnetospheric magnetic field, developed from a model of the earth, we investigate the magnetospheric structure of planets located in the habitable zone around g-type stars. different directions of the stellar wind magnetic field are considered and the correspondin... | modeling of magnetospheres of terrestrial exoplanets in the habitable zone around g-type stars |
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