| 作品信息 |
| 作品名: | ssc2007-05c.jpg |
| 文件名称: | 北回归线 / 哈勃望远镜天空壁纸 |
| 评分 (30 次投票): |  |
| 作品尺寸: | 141 KiB |
| 加入日期: | 四月 04, 2009 |
| 尺寸: | 3000 x 2000 像素 |
| 显示: | 440 次 |
| Exif 作品宽度: | 3000 pixels |
| Exif 作品高度: | 2000 pixels |
| Exif 偏移量: | 3004 |
| Exif 版本: | version 2.2 |
| FNumber: | f/11 |
| X 分辨率: | 300 |
| Y 分辨率: | 300 |
| 作品简介: | Our solitary sunsets here on Earth might not be all that common in the grand scheme of things. New observations from NASA's Spitzer Space Telescope have revealed that mature planetary systems â dusty disks of asteroids, comets and possibly planets â are more frequent around close-knit twin, or binary, stars than single stars like our sun. That means sunsets like the one portrayed in this artist's photo concept, and more famously in the movie "Star Wars," might be quite commonplace in the universe.
Binary and multiple-star systems are about twice as abundant as single-star systems in our galaxy, and, in theory, other galaxies. In a typical binary system, two stars of roughly similar masses twirl around each other like pair-figure skaters. In some systems, the two stars are very far apart and barely interact with each other. In other cases, the stellar twins are intricately linked, whipping around each other quickly due to the force of gravity.
Astronomers have discovered dozens of planets that orbit around a single member of a very wide stellar duo. Sunsets from these worlds would look like our own, and the second sun would just look like a bright star in the night sky.
But do planets exist in the tighter systems, where two suns would dip below a planet's horizon one by one? Unveiling planets in these systems is tricky, so astronomers used Spitzer to look for disks of swirling planetary debris instead. These disks are made of asteroids, comets and possibly planets. The rocky material in them bangs together and kicks up dust that Spitzer's infrared eyes can see. Our own solar system is swaddled in a similar type of disk.
Surprisingly, Spitzer found more debris disks around the tightest binaries it studied (about 20 stars) than in a comparable sample of single stars. About 60 percent of the tight binaries had disks, while the single stars only had about 20 percent. These snug binary systems are as close or closer than just three times the distance between Earth and the sun. And the disks in these systems were found to circumnavigate both members of the star pair, rather than just one.
Though follow-up studies are needed, the results could mean that planet formation is more common around extra-tight binary stars than single stars. Since these types of systems would experience double sunsets, the artistic view portrayed here might not be fiction.
The original sunset photo used in this artist's concept was taken by Robert Hurt of the Spitzer Science Center at the California Institute of Technology, Pasadena, Calif. |
| 光圈最大值: | f/4 |
| 光源: | Unknown or Auto |
| 分辨率: | Inch |
| 压缩量/像素: | 4 |
| 原本日期: | 2002:12:01 17:41:16 |
| 品牌: | Nikon Corporation |
| 场景拍摄模式: | 0 |
| 场景类型: | Directly Photographed |
| 型号: | NIKON D100 |
| 定位: | 1: Normal (0 deg) |
| 对比: | 0 |
| 尖锐度: | 0 |
| 文件来源: | Digital Still Camera |
| 曝光时间: | 1/500 sec |
| 曝光模式: | 0 |
| 曝光补光: | 0 EV |
| 曝光软件: | Program |
| 浸透度: | 0 |
| 焦点尺寸: | 85 mm |
| 电子变焦比率: | 1 |
| 电子日期: | 2002:12:01 17:41:16 |
| 白色平衡: | 0 |
| 获得控制: | 0 |
| 计量模式: | Multi-Segment |
| 软件: | Adobe Photoshop CS3 Macintosh |
| 闪光: | No Flash |
| 闪光版本: | version 1 |
| 零件设定: | YCbCr |
| 顾客处理: | 1 |
| 颜色空间: | sRGB |
| IPTC 版权: | http://www.spitzer.caltech.edu/Media/mediaimages/copyright.shtml |
| URL: | http://album.skylook.org/displayimage.php?pid=5242 |
| 我的最爱: | 加到我的最爱 |
