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https://www.readbyqxmd.com/read/29323328/exoplanet-science-2-0
#1
Caleb Scharf, Debra Fischer, Victoria Meadows
No abstract text is available yet for this article.
January 11, 2018: Nature
https://www.readbyqxmd.com/read/29284746/atmospheric-escape-from-the-trappist-1-planets-and-implications-for-habitability
#2
Chuanfei Dong, Meng Jin, Manasvi Lingam, Vladimir S Airapetian, Yingjuan Ma, Bart van der Holst
The presence of an atmosphere over sufficiently long timescales is widely perceived as one of the most prominent criteria associated with planetary surface habitability. We address the crucial question of whether the seven Earth-sized planets transiting the recently discovered ultracool dwarf star TRAPPIST-1 are capable of retaining their atmospheres. To this effect, we carry out numerical simulations to characterize the stellar wind of TRAPPIST-1 and the atmospheric ion escape rates for all of the seven planets...
December 28, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29258300/orbital-misalignment-of-the-neptune-mass-exoplanet-gj-436b-with-the-spin-of-its-cool-star
#3
Vincent Bourrier, Christophe Lovis, Hervé Beust, David Ehrenreich, Gregory W Henry, Nicola Astudillo-Defru, Romain Allart, Xavier Bonfils, Damien Ségransan, Xavier Delfosse, Heather M Cegla, Aurélien Wyttenbach, Kevin Heng, Baptiste Lavie, Francesco Pepe
The angle between the spin of a star and the orbital planes of its planets traces the history of the planetary system. Exoplanets orbiting close to cool stars are expected to be on circular, aligned orbits because of strong tidal interactions with the stellar convective envelope. Spin-orbit alignment can be measured when the planet transits its star, but such ground-based spectroscopic measurements are challenging for cool, slowly rotating stars. Here we report the three-dimensional characterization of the trajectory of an exoplanet around an M dwarf star, derived by mapping the spectrum of the stellar photosphere along the chord transited by the planet...
December 18, 2017: Nature
https://www.readbyqxmd.com/read/29250563/%C3%AE-2-4-5-%C3%AE-m-spectroscopy-with-the-jwst-nircam-instrument
#4
Thomas P Greene, Douglas M Kelly, John Stansberry, Jarron Leisenring, Eiichi Egami, Everett Schlawin, Laurie Chu, Klaus W Hodapp, Marcia Rieke
The James Webb Space Telescope near-infrared camera (JWST NIRCam) has two 2'. 2 × 2'.2 fields of view that can be observed with either imaging or spectroscopic modes. Either of two R ∼ 1500 grisms with orthogonal dispersion directions can be used for slitless spectroscopy over λ = 2.4 - 5.0 μm in each module, and shorter wavelength observations of the same fields can be obtained simultaneously. We describe the design drivers and parameters of the grisms and present the latest predicted spectroscopic sensitivities, saturation limits, resolving powers, and wavelength coverage values...
July 2017: Journal of Astronomical Telescopes, Instruments, and Systems
https://www.readbyqxmd.com/read/29189040/organic-haze-as-a-biosignature-in-anoxic-earth-like-atmospheres
#5
Giada Arney, Shawn D Domagal-Goldman, Victoria S Meadows
Early Earth may have hosted a biologically mediated global organic haze during the Archean eon (3.8-2.5 billion years ago). This haze would have significantly impacted multiple aspects of our planet, including its potential for habitability and its spectral appearance. Here, we model worlds with Archean-like levels of carbon dioxide orbiting the ancient Sun and an M4V dwarf (GJ 876) and show that organic haze formation requires methane fluxes consistent with estimated Earth-like biological production rates...
November 30, 2017: Astrobiology
https://www.readbyqxmd.com/read/29168837/exoplanet-hunters-rethink-search-for-alien-life
#6
Alexandra Witze
No abstract text is available yet for this article.
November 20, 2017: Nature
https://www.readbyqxmd.com/read/29168820/exoplanet-find-oil-pipeline-and-a-gene-editing-first
#7
(no author information available yet)
No abstract text is available yet for this article.
November 23, 2017: Nature
https://www.readbyqxmd.com/read/29148825/on-the-growth-and-detectability-of-land-plants-on-habitable-planets-around-m-dwarfs
#8
Duo Cui, Feng Tian, Yuwei Wang, Changshen Li, Chaoqing Yu, Le Yu
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 investigate the distribution of land plants on potentially habitable planets around M dwarfs driven by climate data produced in a general circulation model (GCM). When considering the effects of clouds, the observation time needed for VRE detection on nearby p = 1 exoplanets around nearby M dwarfs is on the order of days using a 25 m(2) telescope if a large continent faces Earth during observations...
November 17, 2017: Astrobiology
https://www.readbyqxmd.com/read/29142018/terahertz-dictating-the-frequency-of-life-do-macromolecular-vibrational-modes-impose-thermal-limitations-on-terrestrial-life
#9
Kieran Hand, Edwin Yates
Conditions on exoplanets include elevated temperatures and pressures. The response of carbon-based biological macromolecules to such conditions is then relevant to the viability of life. The capacity of proteins and ribozymes to catalyse reactions or bind receptors, and nucleic acids to convey information, depends on them sampling different conformational states. These are determined by macromolecular vibrational states, or phonon modes, accessible using terahertz (THz: 10(12)Hz) absorption spectroscopy. THz spectra of biological macromolecules exhibit broad absorption at approximately 6 THz (equating to approx...
November 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/29097693/atmospheric-beacons-of-life-from-exoplanets-around-g-and-k-stars
#10
Vladimir S Airapetian, Charles H Jackman, Martin Mlynczak, William Danchi, Linda Hunt
The current explosion in detection and characterization of thousands of extrasolar planets from the Kepler mission, the Hubble Space Telescope, and large ground-based telescopes opens a new era in searches for Earth-analog exoplanets with conditions suitable for sustaining life. As more Earth-sized exoplanets are detected in the near future, we will soon have an opportunity to identify habitale worlds. Which atmospheric biosignature gases from habitable planets can be detected with our current capabilities? The detection of the common biosignatures from nitrogen-oxygen rich terrestrial-type exoplanets including molecular oxygen (O2), ozone (O3), water vapor (H2O), carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) requires days of integration time with largest space telescopes, and thus are very challenging for current instruments...
November 2, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29041743/ultrafast-laser-inscription-in-zblan-integrated-optics-chips-for-mid-ir-beam-combination-in-astronomical-interferometry
#11
Jan Tepper, Lucas Labadie, Simon Gross, Alexander Arriola, Stefano Minardi, Romina Diener, Michael J Withford
Astronomical interferometry is a unique technique that allows observation with angular resolutions on the milliarcsec scale by combining the light of several apertures hundreds of meters apart. The PIONIER and GRAVITY instruments at the Very Large Telescope Interferometer have demonstrated that silica-based integrated optics (IO) provide a small-scale and highly stable solution for the interferometric beam combination process. Yet, important science cases such as exoplanet hunting or the spectroscopic characterization of exoplanetary atmospheres are favorable for observation in the mid-IR, namely the atmospheric windows L and L' band (3-4 µm), a wavelength range that is not covered by conventional silica-based IO...
August 21, 2017: Optics Express
https://www.readbyqxmd.com/read/29041252/large-format-platinum-silicide-microwave-kinetic-inductance-detectors-for-optical-to-near-ir-astronomy
#12
P Szypryt, S R Meeker, G Coiffard, N Fruitwala, B Bumble, G Ulbricht, A B Walter, M Daal, C Bockstiegel, G Collura, N Zobrist, I Lipartito, B A Mazin
We have fabricated and characterized 10,000 and 20,440 pixel Microwave Kinetic Inductance Detector (MKID) arrays for the Dark-speckle Near-IR Energy-resolved Superconducting Spectrophotometer (DARKNESS) and the MKID Exoplanet Camera (MEC). These instruments are designed to sit behind adaptive optics systems with the goal of directly imaging exoplanets in a 800-1400 nm band. Previous large optical and near-IR MKID arrays were fabricated using substoichiometric titanium nitride (TiN) on a silicon substrate. These arrays, however, suffered from severe non-uniformities in the TiN critical temperature, causing resonances to shift away from their designed values and lowering usable detector yield...
October 16, 2017: Optics Express
https://www.readbyqxmd.com/read/28905896/detection-of-titanium-oxide-in-the-atmosphere-of-a-hot-jupiter
#13
Elyar Sedaghati, Henri M J Boffin, Ryan J MacDonald, Siddharth Gandhi, Nikku Madhusudhan, Neale P Gibson, Mahmoudreza Oshagh, Antonio Claret, Heike Rauer
As an exoplanet transits its host star, some of the light from the star is absorbed by the atoms and molecules in the planet's atmosphere, causing the planet to seem bigger; plotting the planet's observed size as a function of the wavelength of the light produces a transmission spectrum. Measuring the tiny variations in the transmission spectrum, together with atmospheric modelling, then gives clues to the properties of the exoplanet's atmosphere. Chemical species composed of light elements-such as hydrogen, oxygen, carbon, sodium and potassium-have in this way been detected in the atmospheres of several hot giant exoplanets, but molecules composed of heavier elements have thus far proved elusive...
September 13, 2017: Nature
https://www.readbyqxmd.com/read/28790357/red-edge-position-of-habitable-exoplanets-around-m-dwarfs
#14
Kenji Takizawa, Jun Minagawa, Motohide Tamura, Nobuhiko Kusakabe, Norio Narita
One of the possible signs of life on distant habitable exoplanets is the red-edge, which is a rise in the reflectivity of planets between visible and near-infrared (NIR) wavelengths. Previous studies suggested the possibility that the red-edge position for habitable exoplanets around M-dwarfs may be shifted to a longer wavelength than that for Earth. We investigated plausible red-edge position in terms of the light environment during the course of the evolution of phototrophs. We show that phototrophs on M-dwarf habitable exoplanets may use visible light when they first evolve in the ocean and when they first colonize the land...
August 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28770846/an-ultrahot-gas-giant-exoplanet-with-a-stratosphere
#15
Thomas M Evans, David K Sing, Tiffany Kataria, Jayesh Goyal, Nikolay Nikolov, Hannah R Wakeford, Drake Deming, Mark S Marley, David S Amundsen, Gilda E Ballester, Joanna K Barstow, Lotfi Ben-Jaffel, Vincent Bourrier, Lars A Buchhave, Ofer Cohen, David Ehrenreich, Antonio García Muñoz, Gregory W Henry, Heather Knutson, Panayotis Lavvas, Alain Lecavelier des Etangs, Nikole K Lewis, Mercedes López-Morales, Avi M Mandell, Jorge Sanz-Forcada, Pascal Tremblin, Roxana Lupu
Infrared radiation emitted from a planet contains information about the chemical composition and vertical temperature profile of its atmosphere. If upper layers are cooler than lower layers, molecular gases will produce absorption features in the planetary thermal spectrum. Conversely, if there is a stratosphere-where temperature increases with altitude-these molecular features will be observed in emission. It has been suggested that stratospheres could form in highly irradiated exoplanets, but the extent to which this occurs is unresolved both theoretically and observationally...
August 2, 2017: Nature
https://www.readbyqxmd.com/read/28770834/astronomy-ozone-like-layer-in-an-exoplanet-atmosphere
#16
Kevin Heng
No abstract text is available yet for this article.
August 2, 2017: Nature
https://www.readbyqxmd.com/read/28692303/searching-for-biosignatures-in-exoplanetary-impact-ejecta
#17
Gianni Cataldi, Alexis Brandeker, Philippe Thébault, Kelsi Singer, Engy Ahmed, Bernard L de Vries, Anna Neubeck, Göran Olofsson
With the number of confirmed rocky exoplanets increasing steadily, their characterization and the search for exoplanetary biospheres are becoming increasingly urgent issues in astrobiology. To date, most efforts have concentrated on the study of exoplanetary atmospheres. Instead, we aim to investigate the possibility of characterizing an exoplanet (in terms of habitability, geology, presence of life, etc.) by studying material ejected from the surface during an impact event. For a number of impact scenarios, we estimate the escaping mass and assess its subsequent collisional evolution in a circumstellar orbit, assuming a Sun-like host star...
August 2017: Astrobiology
https://www.readbyqxmd.com/read/28611223/enhanced-interplanetary-panspermia-in-the-trappist-1-system
#18
Manasvi Lingam, Abraham Loeb
We present a simple model for estimating the probability of interplanetary panspermia in the recently discovered system of seven planets orbiting the ultracool dwarf star TRAPPIST-1 and find that panspermia is potentially orders of magnitude more likely to occur in the TRAPPIST-1 system compared with the Earth-to-Mars case. As a consequence, we argue that the probability of abiogenesis is enhanced on the TRAPPIST-1 planets compared with the solar system. By adopting models from theoretical ecology, we show that the number of species transferred and the number of life-bearing planets are also likely to be higher because of the increased rates of immigration...
June 27, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28495748/hat-p-26b-a-neptune-mass-exoplanet-with-a-well-constrained-heavy-element-abundance
#19
Hannah R Wakeford, David K Sing, Tiffany Kataria, Drake Deming, Nikolay Nikolov, Eric D Lopez, Pascal Tremblin, David S Amundsen, Nikole K Lewis, Avi M Mandell, Jonathan J Fortney, Heather Knutson, Björn Benneke, Thomas M Evans
A correlation between giant-planet mass and atmospheric heavy elemental abundance was first noted in the past century from observations of planets in our own Solar System and has served as a cornerstone of planet-formation theory. Using data from the Hubble and Spitzer Space Telescopes from 0.5 to 5 micrometers, we conducted a detailed atmospheric study of the transiting Neptune-mass exoplanet HAT-P-26b. We detected prominent H2O absorption bands with a maximum base-to-peak amplitude of 525 parts per million in the transmission spectrum...
May 12, 2017: Science
https://www.readbyqxmd.com/read/28495725/how-much-water-is-in-that-exoplanet
#20
EDITORIAL
Keith T Smith
No abstract text is available yet for this article.
May 12, 2017: Science
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