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Thread: Astrobiological papers from Arvix and everywhere

  1. #61
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    Living near the galactic core is very very VERY bad for you. It is a reasonable assumption, based on this paper, that no one lives there anymore, if anyone ever did.


    https://arxiv.org/abs/1902.07950

    Comparative analysis of the influence of Sgr A* and nearby active galactic nuclei on the mass loss of known exoplanets

    Agata M. Wisłocka, Andjelka B. Kovačević, Amedeo Balbi (Submitted on 21 Feb 2019)

    The detailed evolution of exoplanetary atmospheres has been the subject of decade-long studies. Only recently, investigations began on the possible atmospheric mass loss caused by the activity of galactic central engines. This question has so far been explored without using available exoplanet data. The goal of this paper is to improve our knowledge of the erosion of exoplanetary atmospheres through radiation from supermassive black holes (SMBHs) undergoing an active galactic nucleus (AGN) phase. To this end, we extended the well-known energy-limited mass-loss model to include the case of radiation from AGNs. We set the fraction of incident power ϵ available to heat the atmosphere as either constant (ϵ=0.1 ) or flux dependent (ϵ=ϵ(F XUV ) ). We calculated the possible atmospheric mass loss for 54 known exoplanets (of which 16 are hot Jupiters residing in the Galactic bulge and 38 are Earth-like planets (EPs)) due to radiation from the Milky Way's (MW) central SMBH, Sagittarius A* (Sgr A*), and from a set of 107,220 AGNs generated using the 33,350 AGNs at z<0.5 of the Sloan Digital Sky Survey database. We found that planets in the Galactic bulge might have lost up to several Earth atmospheres in mass during the AGN phase of Sgr A*, while the EPs are at a safe distance from Sgr A* (>7 kpc) and have not undergone any atmospheric erosion in their lifetimes. We also found that the MW EPs might experience a mass loss up to ∼15 times the Mars atmosphere over a period of 50 Myr as the result of exposure to the cumulative extreme-UV flux F XUV from the AGNs up to z=0.5 . In both cases we found that an incorrect choice of ϵ can lead to significant mass loss overestimates.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  2. #62
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    Binary stars might not be such bad places for habitable planets after all. Well, 1-2 times in 352, that is.

    https://arxiv.org/abs/1903.01995

    Enlarging habitable zones around binary stars in hostile environments

    Bethany A. Wootton, Richard J. Parker (Submitted on 5 Mar 2019)

    Habitable zones are regions around stars where large bodies of liquid water can be sustained on a planet or satellite. As many stars form in binary systems with non-zero eccentricity, the habitable zones around the component stars of the binary can overlap and be enlarged when the two stars are at periastron (and less often when the stars are at apastron). We perform N-body simulations of the evolution of dense star-forming regions and show that binary systems where the component stars originally have distinct habitable zones can undergo interactions that push the stars closer together, causing the habitable zones to merge and become enlarged. Occasionally, overlapping habitable zones can occur if the component stars move further apart, but the binary becomes more eccentric. Enlargement of habitable zones happens to 1-2 binaries from an average initial total of 352 in each simulated star-forming region, and demonstrates that dense star-forming regions are not always hostile environments for planet formation and evolution.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  3. #63
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    Maybe aliens use black holes to power their starships. Seriously.

    https://phys.org/news/2019-03-gamma-...s-powered.html

    Gamma ray telescopes could detect starships powered by black hole
    March 7, 2019, Universe Today

    In the course of looking for possible signs of extra-terrestrial intelligence (ETI), scientists have had to do some really outside-of-the-box thinking. Since it is a foregone conclusion that many ETIs would be older and more technologically advanced than humanity, those engaged in the Search for Extra-Terrestrial Intelligence (SETI) have to consider what a more advanced species would be doing. A particularly radical idea is that spacefaring civilizations could harness radiation emitted from black holes (Hawking radiation) to generate power. Building on this, Louis Crane, a mathematician from Kansas State University (KSU), recently authored a study that suggests how surveys using gamma telescopes could find evidence of spacecraft powered by tiny artificial black holes. The study, "Searching for Extraterrestrial Civilizations Using gamma Ray Telescopes," recently appeared online. This is the second paper published by Dr. Crane on the subject, the first of which was co-authored by Shawn Moreland (a physics grad student with KSU) and published in 2009 – titled "Are Black Hole Spacecraft Possible?"
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  4. #64
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    Are A-stars good prospects for habitable planets? This papers suggests they might be.

    https://arxiv.org/abs/1903.03706

    Habitable zone predictions and how to test them

    Dorian S. Abbot, et al. (Submitted on 9 Mar 2019)

    The habitable zone (HZ) is the region around a star(s) where standing bodies of water could exist on the surface of a rocky planet. The classical HZ definition makes a number of assumptions common to the Earth, including assuming that the most important greenhouse gases for habitable planets are CO2 and H2O, habitable planets orbit main-sequence stars, and that the carbonate-silicate cycle is a universal process on potentially habitable planets. Here, we discuss these and other predictions for the habitable zone and the observations that are needed to test them. We also, for the first time, argue why A-stars may be interesting HZ prospects. Instead of relying on unverified extrapolations from our Earth, we argue that future habitability studies require first principles approaches where temporal, spatial, physical, chemical, and biological systems are dynamically coupled. We also suggest that next-generation missions are only the beginning of a much more data-filled era in the not-too-distant future, when possibly hundreds to thousands of HZ planets will yield the statistical data we need to go beyond just finding habitable zone planets to actually determining which ones are most likely to exhibit life.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  5. #65
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    A contrarian view on whether high levels of UV radiation from a red dwarf is a bad thing for its planets' biospheres.

    https://arxiv.org/abs/1904.03956

    Lessons from early Earth: UV surface radiation should not limit the habitability of active M star systems

    Jack T. O'Malley-James, Lisa Kaltenegger (Submitted on 8 Apr 2019)

    The closest potentially habitable worlds outside our Solar system orbit a different kind of star than our Sun: smaller red dwarf stars. Such stars can flare frequently, bombarding their planets with biologically damaging high-energy UV radiation, placing planetary atmospheres at risk of erosion and bringing the habitability of these worlds into question. However, the surface UV flux on these worlds is unknown. Here we show the first models of the surface UV environments of the four closest potentially habitable exoplanets: Proxima-b, TRAPPIST-1e, Ross-128b, and LHS-1140b assuming different atmospheric compositions, spanning Earth-analogue to eroded and anoxic atmospheres and compare them to levels for Earth throughout its geological evolution. Even for planet models with eroded and anoxic atmospheres, surface UV radiation remains below early Earth levels, even during flares. Given that the early Earth was inhabited, we show that UV radiation should not be a limiting factor for the habitability of planets orbiting M stars. Our closest neighbouring worlds remain intriguing targets for the search for life beyond our Solar system.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  6. #66
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    Think outside the box when it comes to aliens... like this Earth critter with 45 arms. The artwork is... oh boy.

    https://bgr.com/2019/04/10/cthulhu-f...ature-45-arms/

    Researchers find fossil of ancient creature with 45 arms
    Mike Wehner, April 10th, 2019 at 10:05 PM

    Today’s oceans are full of interesting and bizarre creatures, many of which would seem utterly unfathomable to us if we hadn’t learned of their existence from a young age. Take a starfish, for example. If you hadn’t been taught about them as a child they’d seem otherworldly once you finally saw one. The same is true for long-extinct species that populated ancient Earth. Now, a new discovery reveals the existence of a very, very peculiar creature from Earth’s past, and it’s drawing comparisons to an evil entity from the mind of H.P. Lovecraft.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  7. #67
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    https://www.forbes.com/sites/jamieca.../#76a1b0e362ba

    Alien Life Could Thrive On Four Earth-Like Planets Close To The Solar System, Says Study
    Jamie Carter Apr 11, 2019, 03:00am

    Alien life could be evolving right now on some of the nearest exoplanets to our solar system [Proxima-b, TRAPPIST-1e, Ross-128b, LHS-1140b--REM], claim scientists at Cornell University in Ithaca, New York. Their proof is you.

    (see article link above, "Lessons from early Earth: UV surface radiation should not limit the habitability of active M star systems")
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  8. #68
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    This is confusing me. Numerous papers are arguing that life can/cannot develop on planets around young active stars. Which is it?

    https://phys.org/news/2019-04-rapid-...res-young.html

    Rapid destruction of Earth-like atmospheres by young stars
    by University of Vienna, 4/24/2019

    The discoveries of thousands of planets orbiting stars outside our solar system has made questions about the potential for life to form on these planets fundamentally important in modern science. Fundamentally important for the habitability of a planet is whether or not it can hold onto an atmosphere, which requires that the atmosphere is not completely lost early in the lifetime of the planet. A new study by researchers based at the University of Vienna and at the Space Research Institute of the ÖAW in Graz has shown that young stars can rapidly destroy the atmospheres of potentially-habitable Earth-like planets, which is a significant additional difficulty for the formation of life outside our solar system. The results will appear soon in the journal Astronomy & Astrophysics Letters.

    ...Researchers based at the University of Vienna and the Space Research Institute of the ÖAW in Graz have calculated for the first time how rapidly an Earth-like atmosphere would be lost from a planet orbiting a very active young star. Their calculations have shown that extreme hydrodynamic losses of the atmosphere would take place, leading to an Earth-like atmosphere being entirely lost, in less than one million years, which for the evolution of a planet is almost instantaneous.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  9. #69
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    Here's a biological twist from the Pacific Ocean.

    https://phys.org/news/2019-05-arseni...fic-ocean.html

    Arsenic-breathing life discovered in the tropical Pacific Ocean
    by Hannah Hickey, University of Washington

    Arsenic is a deadly poison for most living things, but new research shows that microorganisms are breathing arsenic in a large area of the Pacific Ocean. A University of Washington team has discovered that an ancient survival strategy is still being used in low-oxygen parts of the marine environment.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  10. #70
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    A great resource for anyone interested in SETI.

    https://arxiv.org/abs/1905.03225

    SETI in Russia, USSR and the post-Soviet space: a century of research

    Lev M. Gindilis, Leonid I. Gurvits (Submitted on 7 May 2019)

    Studies on extraterrestrial civilisations in Russia date back to the end of the 19th century. The modern period of SETI studies began in the USSR in the early 1960s. The first edition of the I.S. Shklovsky's book {\it Universe, Life, Intelligence} published in 1962 was a founding stone of SETI research in the USSR. A number of observational projects in radio and optical domains were conducted in the 1960s - 1990s. Theoretical studies focused on defining optimal spectral domains for search of artificial electromagnetic signals, selection of celestial targets in search for ETI, optimal methods for encoding and decoding of interstellar messages, estimating the magnitude of astro-engineering activity of ETI, and developing philosophical background of the SETI problem. Later, in the 1990s and in the first two decades of the 21st century, in spite of acute underfunding and other problems facing the scientific community in Russia and other countries of the former Soviet Union, SETI-oriented research continued. In particular, SETI collaborations conducted a number of surveys of Sun-like stars in the Milky Way, searched for Dyson spheres and artificial optical signals. Several space broadcasting programs were conducted too, including a radio transmission toward selected stars. Serious rethinking was given to incentives for passive and active participation of space civilisations in SETI and CETI. This paper gives an overview of past SETI activities. It also gives a comprehensive list of publications by authors from Russia, the Soviet Union and the post-Soviet space, as well as some SETI publications by other authors. The rich heritage of SETI research presented in the paper might offer a potentially useful background and starting point for developing strategy and specific research programs of the near future.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  11. #71
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    Could another civilization signal to us using a neutrino "laser"?

    https://arxiv.org/abs/1905.05184

    A Neutrino Beacon

    A.A. Jackson (Submitted on 13 May 2019)

    Observational SETI has concentrated on using electromagnetism as the carrier, namely radio waves and laser radiation. Michael Hippke [2] has pointed out that it may be possible to use neutrinos or gravitational waves as signals. Gravitational waves demand the command of the generation of very large scale amounts of energy, Jackson and Benford [3]. This paper describes a beacon that uses beamed neutrinos as the signal. Neutrinos, like gravitational waves, have the advantage of extremely low extinction in the interstellar medium. To make use of neutrinos an advanced civilization can use a gravitational lens as a focus and amplifier. The lens can be a neutron star or a black hole. Using wave optics one can calculate the advantage of gravitational lensing for amplification of a beam and along the optical axis it is exceptionally large. Even though the amplification is very large the dimeter of the beam is quite small, less that a centimeter. This implies that a large constellation of neutrino transmitters would have to enclose the local neutron star or black hole to cover the sky. This means that such a beacon would have to be built by a Kardashev Type II civilization.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  12. #72
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    Does Titan have life on it? Forbes magazine takes a closer look. Nice illos.

    https://www.forbes.com/sites/jamieca.../#b0f1664f1a6a
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  13. #73
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    Yet another paper that says cool brown dwarfs might be teaming with life in their upper atmospheres. This stuff cries out for SF novels.

    https://arxiv.org/abs/1905.11410

    Brown Dwarf Atmospheres As The Potentially Most Detectable And Abundant Sites For Life

    Manasvi Lingam, Abraham Loeb (Submitted on 27 May 2019)

    We show that the total habitable volume in the atmospheres of cool brown dwarfs with effective temperatures of ∼250 -350 K is possibly larger by two orders of magnitude than that of Earth-like planets. We also study the role of aerosols, nutrients and photosynthesis in facilitating life in brown dwarf atmospheres. Our predictions might be testable through searches for spectral edges in the near-infrared and chemical disequilibrium in the atmospheres of nearby brown dwarfs that are either free-floating or within ∼10 AU of stars. For the latter category, we find that the James Webb Space Telescope (JWST) may be able to achieve a signal-to-noise ratio of ∼5 after a few hours integration per source for the detection of biogenic spectral features in ∼10 3 cool brown dwarfs.

    ===

    Two earlier papers on the same topic.

    https://arxiv.org/abs/1611.09074

    Atmospheric Habitable Zones in Cool Y Dwarf Atmospheres

    Jack S. Yates, Paul I. Palmer, Beth Biller, Charles S. Cockell (Submitted on 28 Nov 2016 (v1), last revised 20 Dec 2016 (this version, v2))

    We use a simple organism lifecycle model to explore the viability of an atmospheric habitable zone (AHZ), with temperatures that could support Earth-centric life, which sits above an environment that does not support life. To illustrate our model we use a cool Y dwarf atmosphere, such as WISE J085510.83−0714442.5 whose 4.5−5.2 micron spectrum shows absorption features consistent with water vapour and clouds. We allow organisms to adapt to their atmospheric environment (described by temperature, convection, and gravity) by adopting different growth strategies that maximize their chance of survival and proliferation. We assume a constant upward vertical velocity through the AHZ. We found that the organism growth strategy is most sensitive to the magnitude of the atmospheric convection. Stronger convection supports the evolution of more massive organisms. For a purely radiative environment we find that evolved organisms have a mass that is an order of magnitude smaller than terrestrial microbes, thereby defining a dynamical constraint on the dimensions of life that an AHZ can support. Based on a previously defined statistical approach we infer that there are of order 10^9 cool Y brown dwarfs in the Milky Way, and likely a few tens of these objects are within ten parsecs from Earth. Our work also has implications for exploring life in the atmospheres of temperate gas giants. Consideration of the habitable volumes in planetary atmospheres significantly increases the volume of habitable space in the galaxy.

    ===

    http://cdsads.u-strasbg.fr/abs/2002ESASP.518..525K
    Astrobiological potentials of brown dwarfs
    Kereszturi, A.

    ===============

    LATER: Another thread in this folder on the same topic, life in Jovian or brown-dwarf atmospheres.

    https://forum.cosmoquest.org/showthr...66#post2384166
    Last edited by Roger E. Moore; 2019-May-29 at 06:41 PM. Reason: adds
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  14. #74
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    You apparently cannot get habitable planets in bulk in dense, star-forming regions.

    https://arxiv.org/abs/1906.00201

    On the enlargement of habitable zones around binary stars in hostile environments

    Nikolaos Georgakarakos, Siegfried Eggl (Submitted on 1 Jun 2019)

    We investigate the hypothesis that the size of the habitable zone around hardened binaries in dense star-forming regions increases. Our results indicate that this hypothesis is essentially incorrect. Although certain binary star configurations permit extended habitable zones, such setups typically require all orbits in a system to be near circular. In all other cases planets can only remain habitable if they display an extraordinarily high climate inertia.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  15. #75
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    "Life will find a way." Apparently so, unless the cosmos is not cooperating. Applicable to life anywhere, I believe.

    https://arxiv.org/abs/1906.01112

    Typical Climate Perturbations Unlikely to Disrupt Gaia Hypothesis

    Olivia D. N. Alcabes, Stephanie Olson, Dorian S. Abbot (Submitted on 3 Jun 2019)

    The Gaia hypothesis postulates that life regulates its environment to be favorable for its own survival. Most planets experience numerous perturbations throughout their lifetimes such as asteroid impacts, volcanism, and the evolution of a star's luminosity. For the Gaia hypothesis to be viable, life must be able to keep the conditions of its host planet habitable, even in the face of these challenges. ExoGaia, a model created to investigate the Gaia hypothesis, has been previously used to demonstrate that a randomly mutating biosphere is in some cases capable of maintaining planetary habitability. However, those model scenarios assumed that all non-biological planetary parameters were static, neglecting the inevitable perturbations that real planets would experience. To see how life responds to climate perturbations to its host planet, we created three climate perturbations in ExoGaia: one rapid cooling of a planet and two heating events, one rapid and one gradual. The planets on which Gaian feedbacks emerge without climate perturbations are the same planets on which life is most likely to survive each of our perturbation scenarios. Biospheres experiencing gradual changes to the environment are able to survive changes of larger magnitude than those experiencing rapid perturbations, and the magnitude of change matters more than the sign. These findings suggest that if the Gaia hypothesis is correct, then typical perturbations that a planet would experience may be unlikely to disrupt it.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  16. #76
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    Is anyone lurking near Earth, spying on us? If they were, this might be one way they'd do it.

    https://arxiv.org/abs/1903.09582

    Looking for Lurkers

    James Benford (Submitted on 22 Mar 2019 (v1), last revised 13 Jun 2019 (this version, v2))

    A recently discovered group of nearby co-orbital objects is an attractive location for extraterrestrial intelligence (ETI) to locate a probe to observe Earth while not being easily seen. These near-Earth objects provide an ideal way to watch our world from a secure natural object. That provides resources an ETI might need: materials, a firm anchor, concealment. These have been little studied by astronomy and not at all by SETI or planetary radar observations. I describe these objects found thus far and propose both passive and active observations of them as possible sites for ET probes.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  17. #77
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    Stellar superflares reduce the possibility of their worlds hosting life. Not a good sign for M-dwarfs that blow up a lot.

    https://arxiv.org/abs/1906.06797

    Impact of Stellar Superflares on Planetary Habitability

    Yosuke A. Yamashiki, et al. (Submitted on 16 Jun 2019)

    High-energy radiation caused by exoplanetary space weather events from planet-hosting stars can play a crucial role in conditions promoting or destroying habitability in addition to the conventional factors. In this paper, we present the first quantitative impact evaluation system of stellar flares on the habitability factors with an emphasis on the impact of Stellar Proton Events. We derive the maximum flare energy from stellar starspot sizes and examine the impacts of flare associated ionizing radiation on CO 2 , H 2 , N 2 +O 2 --rich atmospheres of a number of well-characterized terrestrial type exoplanets. Our simulations based on the Particle and Heavy Ion Transport code System [PHITS] suggest that the estimated ground level dose for each planet in the case of terrestrial-level atmospheric pressure (1 bar) for each exoplanet does not exceed the critical dose for complex (multi-cellular) life to persist, even for the planetary surface of Proxima Centauri b, Ross-128 b and TRAPPIST-1 e. However, when we take into account the effects of the possible maximum flares from those host stars, the estimated dose reaches fatal levels at the terrestrial lowest atmospheric depth on TRAPPIST-1 e and Ross-128 b. Large fluxes of coronal XUV radiation from active stars induces high atmospheric escape rates from close-in exoplanets suggesting that the atmospheric depth can be substantially smaller than that on the Earth. In a scenario with the atmospheric thickness of 1/10 of Earth's, the radiation dose from close-in planets including Proxima Centauri b and TRAPPIST-1 e reach near fatal dose levels with annual frequency of flare occurrence from their host stars.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  18. #78
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    Teegarden's Star, a VERY close red dwarf, has two planets that might be habitable.

    https://www.nationalgeographic.com/s...egardens-star/
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  19. #79
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    Speaking of those Teegarden's Star planets, they might have water.

    https://arxiv.org/abs/1906.07704

    On the Habitability of Teegarden's Star planets

    Amri Wandel, Lev Tal-Or (Submitted on 18 Jun 2019)

    We study the habitability of the two 1-2 Earth-mass planets, recently detected by the CARMENES collaboration, around the ultra-cool nearby M dwarf Teegarden's Star. With orbital periods of 4.9 and 11.4 days, both planets are likely to be within the Habitable Zone and tidally locked. They are among the most Earth-like exoplanets yet discovered. Applying an analytical habitability model we find that surface liquid water could be present on both planets for a wide range of atmospheric properties, which makes them attractive targets for bio-signature searches. The prospects of the planets retaining such an atmosphere over their history are discussed.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  20. #80
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    Enceladus, best place for underground sea life? Read the article and see.

    https://www.geekwire.com/2019/astrob...er-free-lunch/
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

  21. #81
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    LHS 1140b, very close to us in our galaxy, is looking better as a possible home for alien life.

    https://arxiv.org/abs/1906.08783

    The high-energy radiation environment of the habitable-zone super-Earth LHS 1140b

    R. Spinelli, F. Borsa, G. Ghirlanda, G. Ghisellini, S. Campana, F. Haardt, E. Poretti (Submitted on 20 Jun 2019)

    In the last few years many exoplanets in the habitable zone (HZ) of M-dwarfs have been discovered, but the X-ray/UV activity of cool stars is very different from that of our Sun. The high-energy radiation environment influences the habitability, plays a crucial role for abiogenesis, and impacts planetary atmospheres. LHS 1140b is a super-Earth-size planet orbiting in the HZ of LHS 1140, an M4.5 dwarf at ~15 parsecs. We present the results of a Swift X-ray/UV observing campaign. We characterize for the first time the X-ray/UV radiation environment of LHS 1140b. We measure the variability of the near ultraviolet (NUV) flux and estimate the far ultraviolet (FUV) flux with a correlation between FUV and NUV flux of a sample of low-mass stars in the GALEX archive. We highlight the presence of a dominating X-ray source close to the J2000 coordinates of LHS 1140, characterize its spectrum, and derive an X-ray flux upper limit for LHS 1140. We find that this contaminant source could have influenced the previously estimated spectral energy distribution. No significant variation of the NUV flux of LHS 1140 is found over 3 months, and we do not observe any flare during the 38 ks on the target. LHS 1140 is in the 25th percentile of least variable M4-M5 dwarfs of the GALEX sample. Analyzing the UV flux experienced by the HZ planet LHS 1140b, we find that outside the atmosphere it receives a NUV flux <2% with respect to that of the present-day Earth, while the FUV/NUV ratio is ~100-200 times higher. This represents a lower limit to the true FUV/NUV ratio since the GALEX FUV band does not include Lyman-alpha, which dominates the FUV output of low-mass stars. This is a warning for future searches for biomarkers, which must take into account this high ratio. The relatively low level and stability of UV flux experienced by LHS 1140b should be favorable for its present-day habitability.
    There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
    — Mark Twain, Life on the Mississippi (1883)

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