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Pesquisa : G01.060.075.750 [Categoria DeCS]
Referências encontradas : 122 [refinar]
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[PMID]:28426003
[Au] Autor:Dittmann JA; Irwin JM; Charbonneau D; Bonfils X; Astudillo-Defru N; Haywood RD; Berta-Thompson ZK; Newton ER; Rodriguez JE; Winters JG; Tan TG; Almenara JM; Bouchy F; Delfosse X; Forveille T; Lovis C; Murgas F; Pepe F; Santos NC; Udry S; Wünsche A; Esquerdo GA; Latham DW; Dressing CD
[Ad] Endereço:Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA.
[Ti] Título:A temperate rocky super-Earth transiting a nearby cool star.
[So] Source:Nature;544(7650):333-336, 2017 04 19.
[Is] ISSN:1476-4687
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:M dwarf stars, which have masses less than 60 per cent that of the Sun, make up 75 per cent of the population of the stars in the Galaxy. The atmospheres of orbiting Earth-sized planets are observationally accessible via transmission spectroscopy when the planets pass in front of these stars. Statistical results suggest that the nearest transiting Earth-sized planet in the liquid-water, habitable zone of an M dwarf star is probably around 10.5 parsecs away. A temperate planet has been discovered orbiting Proxima Centauri, the closest M dwarf, but it probably does not transit and its true mass is unknown. Seven Earth-sized planets transit the very low-mass star TRAPPIST-1, which is 12 parsecs away, but their masses and, particularly, their densities are poorly constrained. Here we report observations of LHS 1140b, a planet with a radius of 1.4 Earth radii transiting a small, cool star (LHS 1140) 12 parsecs away. We measure the mass of the planet to be 6.6 times that of Earth, consistent with a rocky bulk composition. LHS 1140b receives an insolation of 0.46 times that of Earth, placing it within the liquid-water, habitable zone. With 90 per cent confidence, we place an upper limit on the orbital eccentricity of 0.29. The circular orbit is unlikely to be the result of tides and therefore was probably present at formation. Given its large surface gravity and cool insolation, the planet may have retained its atmosphere despite the greater luminosity (compared to the present-day) of its host star in its youth. Because LHS 1140 is nearby, telescopes currently under construction might be able to search for specific atmospheric gases in the future.
[Mh] Termos MeSH primário: Meio Ambiente Extraterreno/química
Planetas
Astros Celestes
Temperatura Ambiente
[Mh] Termos MeSH secundário: Exobiologia
Água/análise
Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
059QF0KO0R (Water)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170824
[Lr] Data última revisão:
170824
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170421
[St] Status:MEDLINE
[do] DOI:10.1038/nature22055


  2 / 122 MEDLINE  
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[PMID]:28230125
[Au] Autor:Gillon M; Triaud AH; Demory BO; Jehin E; Agol E; Deck KM; Lederer SM; de Wit J; Burdanov A; Ingalls JG; Bolmont E; Leconte J; Raymond SN; Selsis F; Turbet M; Barkaoui K; Burgasser A; Burleigh MR; Carey SJ; Chaushev A; Copperwheat CM; Delrez L; Fernandes CS; Holdsworth DL; Kotze EJ; Van Grootel V; Almleaky Y; Benkhaldoun Z; Magain P; Queloz D
[Ad] Endereço:Space Sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège, Allée du 6 Août 19C, Bat. B5C, 4000 Liège, Belgium.
[Ti] Título:Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1.
[So] Source:Nature;542(7642):456-460, 2017 02 22.
[Is] ISSN:1476-4687
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:One aim of modern astronomy is to detect temperate, Earth-like exoplanets that are well suited for atmospheric characterization. Recently, three Earth-sized planets were detected that transit (that is, pass in front of) a star with a mass just eight per cent that of the Sun, located 12 parsecs away. The transiting configuration of these planets, combined with the Jupiter-like size of their host star-named TRAPPIST-1-makes possible in-depth studies of their atmospheric properties with present-day and future astronomical facilities. Here we report the results of a photometric monitoring campaign of that star from the ground and space. Our observations reveal that at least seven planets with sizes and masses similar to those of Earth revolve around TRAPPIST-1. The six inner planets form a near-resonant chain, such that their orbital periods (1.51, 2.42, 4.04, 6.06, 9.1 and 12.35 days) are near-ratios of small integers. This architecture suggests that the planets formed farther from the star and migrated inwards. Moreover, the seven planets have equilibrium temperatures low enough to make possible the presence of liquid water on their surfaces.
[Mh] Termos MeSH primário: Planetas
Astros Celestes
[Mh] Termos MeSH secundário: Exobiologia
Meio Ambiente Extraterreno/química
Temperatura Ambiente
Água/análise
Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
059QF0KO0R (Water)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:171010
[Lr] Data última revisão:
171010
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170224
[St] Status:MEDLINE
[do] DOI:10.1038/nature21360


  3 / 122 MEDLINE  
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[PMID]:28150784
[Au] Autor:Popkin G
[Ti] Título:What it would take to reach the stars.
[So] Source:Nature;542(7639):20-22, 2017 02 01.
[Is] ISSN:1476-4687
[Cp] País de publicação:England
[La] Idioma:eng
[Mh] Termos MeSH primário: Meio Ambiente Extraterreno
Astros Celestes
[Mh] Termos MeSH secundário: Seres Humanos
[Pt] Tipo de publicação:JOURNAL ARTICLE; COMMENT
[Em] Mês de entrada:1702
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170203
[St] Status:MEDLINE
[do] DOI:10.1038/542020a


  4 / 122 MEDLINE  
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[PMID]:28103107
[Au] Autor:Waltham D
[Ad] Endereço:Department of Earth Sciences, Royal Holloway University of London , Egham, UK .
[Ti] Título:Star Masses and Star-Planet Distances for Earth-like Habitability.
[So] Source:Astrobiology;17(1):61-77, 2017 Jan.
[Is] ISSN:1557-8070
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:This paper presents statistical estimates for the location and duration of habitable zones (HZs) around stars of different mass. The approach is based upon the assumption that Earth's location, and the Sun's mass, should not be highly atypical of inhabited planets. The results support climate-model-based estimates for the location of the Sun's HZ except models giving a present-day outer-edge beyond 1.64 AU. The statistical approach also demonstrates that there is a habitability issue for stars smaller than 0.65 solar masses since, otherwise, Earth would be an extremely atypical inhabited world. It is difficult to remove this anomaly using the assumption that poor habitability of planets orbiting low-mass stars results from unfavorable radiation regimes either before, or after, their stars enter the main sequence. However, the anomaly is well explained if poor habitability results from tidal locking of planets in the HZs of small stars. The expected host-star mass for planets with intelligent life then has a 95% confidence range of 0.78 M < M < 1.04 M , and the range for planets with at least simple life is 0.57 M < M < 1.64 M . Key Words: Habitability-Habitable zone-Anthropic-Red dwarfs-Initial mass function. Astrobiology 17, 61-77.
[Mh] Termos MeSH primário: Terra (Planeta)
Exobiologia
Meio Ambiente Extraterreno
Astros Celestes
[Mh] Termos MeSH secundário: Probabilidade
Rotação
Sistema Solar
Fatores de Tempo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171009
[Lr] Data última revisão:
171009
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170120
[St] Status:MEDLINE
[do] DOI:10.1089/ast.2016.1518


  5 / 122 MEDLINE  
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[PMID]:28004669
[Au] Autor:d'Huy J
[Ti] Título:The Evolution of Myths.
[So] Source:Sci Am;315(6):62-69, 2016 Nov 15.
[Is] ISSN:0036-8733
[Cp] País de publicação:United States
[La] Idioma:eng
[Mh] Termos MeSH primário: Migração Humana
Mitologia
[Mh] Termos MeSH secundário: Cultura
História Antiga
Migração Humana/história
Seres Humanos
Mitologia/psicologia
Filogenia
Astros Celestes
[Pt] Tipo de publicação:HISTORICAL ARTICLE; JOURNAL ARTICLE
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170720
[Lr] Data última revisão:
170720
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161223
[St] Status:MEDLINE
[do] DOI:10.1038/scientificamerican1216-62


  6 / 122 MEDLINE  
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[PMID]:28001448
[Au] Autor:Ziurys LM; Halfen DT; Geppert W; Aikawa Y
[Ad] Endereço:1 Department of Chemistry and Biochemistry, Department of Astronomy, and Arizona Radio Observatory, University of Arizona , Tucson, Arizona, USA .
[Ti] Título:Following the Interstellar History of Carbon: From the Interiors of Stars to the Surfaces of Planets.
[So] Source:Astrobiology;16(12):997-1012, 2016 Dec.
[Is] ISSN:1557-8070
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The chemical history of carbon is traced from its origin in stellar nucleosynthesis to its delivery to planet surfaces. The molecular carriers of this element are examined at each stage in the cycling of interstellar organic material and their eventual incorporation into solar system bodies. The connection between the various interstellar carbon reservoirs is also examined. Carbon has two stellar sources: supernova explosions and mass loss from evolved stars. In the latter case, the carbon is dredged up from the interior and then ejected into a circumstellar envelope, where a rich and unusual C-based chemistry occurs. This molecular material is eventually released into the general interstellar medium through planetary nebulae. It is first incorporated into diffuse clouds, where carbon is found in polyatomic molecules such as H CO, HCN, HNC, c-C H , and even C . These objects then collapse into dense clouds, the sites of star and planet formation. Such clouds foster an active organic chemistry, producing compounds with a wide range of functional groups with both gas-phase and surface mechanisms. As stars and planets form, the chemical composition is altered by increasing stellar radiation, as well as possibly by reactions in the presolar nebula. Some molecular, carbon-rich material remains pristine, however, encapsulated in comets, meteorites, and interplanetary dust particles, and is delivered to planet surfaces. Key Words: Carbon isotopes-Prebiotic evolution-Interstellar molecules-Comets-Meteorites. Astrobiology 16, 997-1012.
[Mh] Termos MeSH primário: Carbono/análise
Planetas
Astros Celestes/química
[Mh] Termos MeSH secundário: Poeira Cósmica/análise
Meteoroides
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Cosmic Dust); 7440-44-0 (Carbon)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170929
[Lr] Data última revisão:
170929
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161222
[St] Status:MEDLINE
[do] DOI:10.1089/ast.2016.1484


  7 / 122 MEDLINE  
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[PMID]:27558064
[Au] Autor:Anglada-Escudé G; Amado PJ; Barnes J; Berdiñas ZM; Butler RP; Coleman GA; de la Cueva I; Dreizler S; Endl M; Giesers B; Jeffers SV; Jenkins JS; Jones HR; Kiraga M; Kürster M; López-González MJ; Marvin CJ; Morales N; Morin J; Nelson RP; Ortiz JL; Ofir A; Paardekooper SJ; Reiners A; Rodríguez E; Rodrίguez-López C; Sarmiento LF; Strachan JP; Tsapras Y; Tuomi M; Zechmeister M
[Ad] Endereço:School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Road, London E1 4NS, UK.
[Ti] Título:A terrestrial planet candidate in a temperate orbit around Proxima Centauri.
[So] Source:Nature;536(7617):437-40, 2016 08 25.
[Is] ISSN:1476-4687
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:At a distance of 1.295 parsecs, the red dwarf Proxima Centauri (α Centauri C, GL 551, HIP 70890 or simply Proxima) is the Sun's closest stellar neighbour and one of the best-studied low-mass stars. It has an effective temperature of only around 3,050 kelvin, a luminosity of 0.15 per cent of that of the Sun, a measured radius of 14 per cent of the radius of the Sun and a mass of about 12 per cent of the mass of the Sun. Although Proxima is considered a moderately active star, its rotation period is about 83 days (ref. 3) and its quiescent activity levels and X-ray luminosity are comparable to those of the Sun. Here we report observations that reveal the presence of a small planet with a minimum mass of about 1.3 Earth masses orbiting Proxima with a period of approximately 11.2 days at a semi-major-axis distance of around 0.05 astronomical units. Its equilibrium temperature is within the range where water could be liquid on its surface.
[Mh] Termos MeSH primário: Planetas
Astros Celestes
[Mh] Termos MeSH secundário: Meio Ambiente Extraterreno/química
Rotação
Temperatura Ambiente
Água/análise
Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
059QF0KO0R (Water)
[Em] Mês de entrada:1609
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160826
[St] Status:MEDLINE
[do] DOI:10.1038/nature19106


  8 / 122 MEDLINE  
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[PMID]:27558041
[Au] Autor:Witze A
[Ti] Título:Earth-sized planet around nearby star is astronomy dream come true.
[So] Source:Nature;536(7617):381-2, 2016 08 25.
[Is] ISSN:1476-4687
[Cp] País de publicação:England
[La] Idioma:eng
[Mh] Termos MeSH primário: Astronomia
Planetas
Astros Celestes
[Mh] Termos MeSH secundário: Exobiologia/tendências
Meio Ambiente Extraterreno/química
Voo Espacial/métodos
Voo Espacial/tendências
Água/análise
[Pt] Tipo de publicação:NEWS
[Nm] Nome de substância:
059QF0KO0R (Water)
[Em] Mês de entrada:1609
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160826
[St] Status:MEDLINE
[do] DOI:10.1038/nature.2016.20445


  9 / 122 MEDLINE  
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[PMID]:27522832
[Au] Autor:Hohtola E
[Ti] Título:[Birds' sense of direction].
[Ti] Título:Lintujen suuntavaisto..
[So] Source:Duodecim;132(13-14):1239-45, 2016.
[Is] ISSN:0012-7183
[Cp] País de publicação:Finland
[La] Idioma:fin
[Ab] Resumo:Birds utilize several distinct sensory systems in a flexible manner in their navigation. When navigating with the help of landmarks, location of the sun and stars, or polarization image of the dome of the sky, they resort to vision. The significance of olfaction in long-range navigation has been under debate, even though its significance in local orientation is well documented. The hearing in birds extends to the infrasound region. It has been assumed that they are able to hear the infrasounds generated in the mountains and seaside and navigate by using them. Of the senses of birds, the most exotic one is the ability to sense magnetic fields of the earth.
[Mh] Termos MeSH primário: Aves/fisiologia
Sinais (Psicologia)
Orientação/fisiologia
[Mh] Termos MeSH secundário: Migração Animal
Animais
Audição/fisiologia
Campos Magnéticos
Olfato/fisiologia
Astros Celestes
Luz Solar
Visão Ocular/fisiologia
[Pt] Tipo de publicação:ENGLISH ABSTRACT; JOURNAL ARTICLE; REVIEW
[Em] Mês de entrada:1609
[Cu] Atualização por classe:160815
[Lr] Data última revisão:
160815
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160816
[St] Status:MEDLINE


  10 / 122 MEDLINE  
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[PMID]:27311962
[Au] Autor:Adibekyan V; Figueira P; Santos NC
[Ad] Endereço:Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas, 4150-762, Porto, Portugal. Vardan.Adibekyan@astro.up.pt.
[Ti] Título:Which Type of Planets do We Expect to Observe in the Habitable Zone?
[So] Source:Orig Life Evol Biosph;46(4):351-359, 2016 Nov.
[Is] ISSN:1573-0875
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:We used a sample of super-Earth-like planets detected by the Doppler spectroscopy and transit techniques to explore the dependence of orbital parameters of the planets on the metallicity of their host stars. We confirm the previous results (although still based on small samples of planets) that super-Earths orbiting around metal-rich stars are not observed to be as distant from their host stars as we observe their metal-poor counterparts to be. The orbits of these super-Earths with metal-rich hosts usually do not reach into the Habitable Zone (HZ), keeping them very hot and inhabitable. We found that most of the known planets in the HZ are orbiting their GK-type hosts which are metal-poor. The metal-poor nature of planets in the HZ suggests a high Mg abundance relative to Si and high Si abundance relative to Fe. These results lead us to speculate that HZ planets might be more frequent in the ancient Galaxy and had compositions different from that of our Earth.
[Mh] Termos MeSH primário: Meio Ambiente Extraterreno
Planetas
Astros Celestes
[Mh] Termos MeSH secundário: Exobiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1704
[Cu] Atualização por classe:171031
[Lr] Data última revisão:
171031
[Sb] Subgrupo de revista:IM; S
[Da] Data de entrada para processamento:160618
[St] Status:MEDLINE



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