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Nightside condensation of iron in an ultrahot giant exoplanet 期刊论文
NATURE, 2020, 580 (7805) : 597-+
作者:  Lu, Zhihao;  Zou, Jianling;  Li, Shuang;  Topper, Michael J.;  Tao, Yong;  Zhang, Hao;  Jiao, Xi;  Xie, Wenbing;  Kong, Xiangqian;  Vaz, Michelle;  Li, Huili;  Cai, Yi;  Xia, Limin;  Huang, Peng;  Rodgers, Kristen;  Lee, Beverly;  Riemer, Joanne B.;  Day, Chi-Ping;  Yen, Ray-Whay Chiu;  Cui, Ying;  Wang, Yujiao;  Wang, Yanni;  Zhang, Weiqiang;  Easwaran, Hariharan;  Hulbert, Alicia;  Kim, KiBem;  Juergens, Rosalyn A.;  Yang, Stephen C.;  Battafarano, Richard J.;  Bush, Errol L.;  Broderick, Stephen R.;  Cattaneo, Stephen M.;  Brahmer, Julie R.;  Rudin, Charles M.;  Wrangle, John;  Mei, Yuping;  Kim, Young J.;  Zhang, Bin;  Wang, Ken Kang-Hsin;  Forde, Patrick M.;  Margolick, Joseph B.;  Nelkin, Barry D.;  Zahnow, Cynthia A.;  Pardoll, Drew M.;  Housseau, Franck;  Baylin, Stephen B.;  Shen, Lin;  Brock, Malcolm V.
收藏  |  浏览/下载:59/0  |  提交时间:2020/07/03

Ultrahot giant exoplanets receive thousands of times Earth'  s insolation(1,2). Their high-temperature atmospheres (greater than 2,000 kelvin) are ideal laboratories for studying extreme planetary climates and chemistry(3-5). Daysides are predicted to be cloud-free, dominated by atomic species(6) and much hotter than nightsides(5,7,8). Atoms are expected to recombine into molecules over the nightside(9), resulting in different day and night chemistries. Although metallic elements and a large temperature contrast have been observed(10-14), no chemical gradient has been measured across the surface of such an exoplanet. Different atmospheric chemistry between the day-to-night ('  evening'  ) and night-to-day ('  morning'  ) terminators could, however, be revealed as an asymmetric absorption signature during transit(4,7,15). Here we report the detection of an asymmetric atmospheric signature in the ultrahot exoplanet WASP-76b. We spectrally and temporally resolve this signature using a combination of high-dispersion spectroscopy with a large photon-collecting area. The absorption signal, attributed to neutral iron, is blueshifted by -11 +/- 0.7 kilometres per second on the trailing limb, which can be explained by a combination of planetary rotation and wind blowing from the hot dayside(16). In contrast, no signal arises from the nightside close to the morning terminator, showing that atomic iron is not absorbing starlight there. We conclude that iron must therefore condense during its journey across the nightside.


Absorption lines of iron in the dayside atmosphere of an ultrahot giant exoplanet disappear after travelling across the nightside, showing that the iron has condensed during its travel.


  
'No one is allowed to go out': your stories from the coronavirus outbreak 期刊论文
NATURE, 2020, 578 (7796) : 499-499
作者:  Ferrante, Lucas;  Fearnside, Philip M.
收藏  |  浏览/下载:7/0  |  提交时间:2020/07/03

The outbreak of a new coronavirus is wreaking havoc worldwide. In China, the epicentre of the epidemic, the virus has infected tens of thousands of people and killed some 2,600. Unprecedented measures meant to contain the spread have brought millions of lives to a halt, and the effects have touched economies and global supply chains. The restrictions have also brought challenges to scientists. Some have suspended their usual research to study the coronavirus. Others have had their work or personal lives disrupted by laboratory closures and travel restrictions. In a Nature reader poll, more than 600 of you told us that the coronavirus had affected your lives. These are some of your stories.


  
Catchment Travel Times From Composite StorAge Selection Functions Representing the Superposition of Streamflow Generation Processes 期刊论文
WATER RESOURCES RESEARCH, 2019
作者:  Rodriguez, Nicolas B.;  Klaus, Julian
收藏  |  浏览/下载:7/0  |  提交时间:2020/02/16
stable isotopes  superposition of processes  catchment travel time  StorAge Selection functions  runoff generation  multimodal distribution  
From walking buffers to active places: An activity-based approach to measure human-scale urban form 期刊论文
LANDSCAPE AND URBAN PLANNING, 2019, 191
作者:  Xu, JieLan
收藏  |  浏览/下载:9/0  |  提交时间:2019/11/27
Urban form  Activity space  Travel behavior  Walkability  Landuse planning  Older adults  
The environmental footprint of academic and student mobility in a large research-oriented university 期刊论文
ENVIRONMENTAL RESEARCH LETTERS, 2019, 14 (9)
作者:  Arsenault, Julien;  Talbot, Julie;  Boustani, Lama;  Gonzales, Rodolphe;  Manaugh, Kevin
收藏  |  浏览/下载:10/0  |  提交时间:2019/11/27
academic mobility  student mobility  nitrogen footprint  carbon footprint  air travel  
Climate change and air pollution: the connection between traffic intervention policies and public acceptance in a local context 期刊论文
ENVIRONMENTAL RESEARCH LETTERS, 2019, 14 (8)
作者:  Weiand, Laura;  Schmitz, Sean;  Becker, Sophia;  Niehoff, Norman;  Schwartzbach, Frank;  von Schneidemesser, Erika
收藏  |  浏览/下载:8/0  |  提交时间:2019/11/27
air quality  climate change  policy attitudes  travel behaviour  sustainable urban transport  cluster analysis  transdisciplinary  
From supply to demand factors: What are the determinants of attractiveness for outdoor recreation? 期刊论文
ECOLOGICAL ECONOMICS, 2019, 161: 163-175
作者:  Tardieu, Lea;  Tuffery, Laetitia
收藏  |  浏览/下载:10/0  |  提交时间:2019/11/27
Forest recreational attractiveness  Supply and demand factors  Travel cost method  Function benefit transfer  Regional park strategy  
Recreational beach use values with multiple activities 期刊论文
ECOLOGICAL ECONOMICS, 2019, 160: 137-144
作者:  Pascoe, Sean
收藏  |  浏览/下载:1/0  |  提交时间:2019/11/26
Beach use  Travel cost model  Consumer surplus  Multi-purpose activity  
Analysis of factors affecting urban park service area in Beijing: Perspectives from multi-source geographic data 期刊论文
LANDSCAPE AND URBAN PLANNING, 2019, 181: 103-117
作者:  Guo, Sihui;  Yang, Gege;  Pei, Tao;  Ma, Ting;  Song, Ci;  Shu, Hua;  Du, Yunyan;  Zhou, Chenghu
收藏  |  浏览/下载:9/0  |  提交时间:2019/04/09
Urban parks  Service area  Travel behavior  Influencing factors  Multi-source data  
Transport policies, induced traffic and their influence on vehicle emissions in developed and developing countries 期刊论文
ENERGY POLICY, 2018, 121: 264-274
作者:  Lee, Shin
收藏  |  浏览/下载:4/0  |  提交时间:2019/04/09
Vehicle emission reductions  Road capacity expansion  Travel demand management  Induced traffic  Policy effectiveness  Developed and developing countries