天文学家，勒维特 (Leavitt,Henrietta Swan)(1868 - 1921)
美国天文学家。当她在哈佛大学天文台工作时，她对造父变星进行研究，发现愈光亮的造父变星的光度变化周期也愈长。
一九一三年，丹麦天文学家赫茨普龙 (Hertzsprung) 准确地估量了数颗造父变星跟地球间的距离，而利用勒维特所发现的造父变星周期和光度间的关系，天文学家可推算出所有造父变星的距离，从而进一步增进人类对宇宙科学的了解。
基本资料编辑本段回目录
Henrietta Swan Leavitt
Henrietta Swan Leavitt
Born July 4, 1868
Died December 12, 1921 (aged 53)
Nationality United States
Fields Astronomy
Institutions Harvard University
Alma mater Radcliffe College
Known for period-luminosity relationship of Cepheid stars
最著名的人肉计算机Henrietta Swan Leavitt编辑本段回目录
Henrietta Swan Leavitt (1868 - 1921)，天文学家，聋哑人。19世纪90年代，哈佛大学天文学家皮克林招募了一些聋哑女性对天文台拍摄的照相底片进行测量和分类 工作，实际 上就是以人力来做今天计算机的工作，因此她们也被称为哈佛计算机。1893年开始，Leavitt参加了这项工作，每周的薪水是10.5美元。她在枯燥的工作中发现了著名的造父变星周光关系，革命性地改变了现代天文学理论。1893年，新西兰成为第一个给妇女投票权的国家。同年，日本首次改用公历。这一年是光绪十九年，年初宋庆龄出生，年底毛泽东出生。次年，甲午海战爆发。
亨丽爱塔·勒维特编辑本段回目录
亨丽爱塔·勒维特（Henrietta Swan Leavitt，1868年7月4日－1921年12月12日），美国女天文学家，聋哑人，造父变星周光关系的发现者。
勒维特1868年出生于美国马萨诸塞州的兰开斯特。19世纪90年代，哈佛大学天文台的天文学家皮克林招募了一些聋哑女性对天文台拍摄的照相底片进行测量和分类工作，1893年勒维特作为其中之一参加了工作。她在工作中注意到，小麦哲伦云中的一些变星光变周期越长，亮度变化越大。1908年她把初步结果发在哈佛大学天文台年报上。经过进一步研究，最终于1912年确认了造父变星的周光关系。
勒维特在哈佛大学天文台工作期间经常被健康问题和家庭事务所困扰。1921年，美国天文学家哈罗·沙普利成为这个天文台的主任，勒维特随之开始领导哈佛大学天文台的恒星测光工作。同年年底，勒维特因癌症逝世。
造父变星周光关系的发现在天文学上具有重要意义。1913年丹麦天文学家埃希纳·赫茨普龙就利用视差法测定了银河系中几颗较近的造父变星的距离，距离尺度得到标定。1915年，沙普利成功解决了造父变星的零点标定问题。随后美国著名天文学家埃德温·哈勃利用造父变星测量了仙女座大星云的距离，确认了它是一个河外星系。
为纪念这位女天文学家，第5383号小行星以及月球表面的一座环形山以她的名字“勒维特”命名。
介绍编辑本段回目录
Henrietta Swan Leavitt (July 4, 1868 – December 12, 1921) was an American astronomer. A graduate of Radcliffe College, Leavitt went to work in 1893 at the Harvard College Observatory in a menial capacity as a "computer", assigned to count images on photographic plates. Study of the plates led Leavitt to propound a groundbreaking theory, worked out while she labored as a $10.50-a-week assistant, that was the basis for the pivotal work of astronomer Edwin Hubble. Leavitt's discovery of the period-luminosity relation of Cepheid variables radically changed the theory of modern astronomy, an accomplishment for which she received almost no recognition during her lifetime.
Early years and education
Henrietta Swan Leavitt, the daughter of Congregational church minister George Roswell Leavitt[1] and his wife Henrietta Swan (Kendrick), was born in Lancaster, Massachusetts, a descendant of Deacon John Leavitt, an English Puritan tailor, who settled in the Massachusetts Bay Colony in the early seventeenth century. (The family name was spelled Levett in early Massachusetts records.) She attended Oberlin College, and graduated from Radcliffe College, then called the Society for the Collegiate Instruction for Women, with a bachelors degree in 1892. It wasn't until her fourth year of college that Leavitt took a course in astronomy, in which she earned an A–.
Career
Leavitt began work in 1893 at Harvard College Observatory as one of the women human "computers" brought in by Edward Charles Pickering to measure and catalog the brightness of stars in the observatory's photographic plate collection. (In the early 1900s, women were not allowed to operate telescopes). She noted thousands of variable stars in images of the Magellanic Clouds. In 1908 she published her results in the Annals of the Astronomical Observatory of Harvard College, noting that a few of the variables showed a pattern: brighter ones appeared to have longer periods. After further study, she confirmed in 1912 that the variable stars of greater intrinsic luminosity – actually Cepheid variables – did indeed have longer periods, and the relationship was quite close and predictable.
Leavitt's discovery is known as the 'period-luminosity relationship'. "A straight line can be readily drawn among each of the two series of points corresponding to maxima and minima," Leavitt wrote of her study of 1,777 variable stars recorded on Harvard's photographic plates, "thus showing that there is a simple relation between the brightness of the variable and their periods."
This relationship provided an important yardstick for measuring distances in the Universe, if it could be calibrated. One year after Leavitt reported her results, Ejnar Hertzsprung determined the distance of several Cepheids in the Milky Way, and with this calibration the distance to any Cepheid could be determined.
At the time, it was not clear that millions of (what we now call) galaxies were actually outside of the Milky Way galaxy. Their distance could not be measured until a tool existed. Cepheids were soon detected in other galaxies such as the Andromeda Galaxy (notably by Edwin Hubble in 1923–24). Cepheids were an important part of the evidence that galaxies are far outside of the Milky Way. Our picture of the universe was changed forever, largely because of Leavitt's discovery.
The accomplishments of Edwin Hubble, renowned American astronomer, were made possible by Leavitt's groundbreaking research and Leavitt's Law. "If Henrietta Leavitt had provided the key to determine the size of the cosmos, then it was Edwin Powell Hubble who inserted it in the lock and provided the observations that allowed it to be turned," write David H. and Matthew D.H. Clark in their book Measuring the Cosmos. Hubble himself often said that Leavitt deserved the Nobel for her work.[citation needed]
Henrietta Swan Leavitt – one of several women working in "Pickering's Harem" who made fundamental contributions to astronomy Leavitt worked sporadically during her time at Harvard, often sidelined by health problems and family obligations. An illness contracted after her graduation from Radcliffe College rendered her increasingly deaf. By 1921, when Harlow Shapley took over as director of the observatory, Leavitt was made head of stellar photometry. By the end of that year she had succumbed to cancer, and was buried in the Leavitt family plot at Cambridge Cemetery in Cambridge, Massachusetts.
"Sitting at the top of a gentle hill," writes George Johnson in his biography of Leavitt, "the spot is marked by a tall hexagonal monument, on top of which (cradled on a draped marble pedestal) sits a globe. Her uncle Erasmus Darwin Leavitt and his family are also buried there, along with other Leavitts. A plaque memorializing Henrietta and her two siblings who died so young, Mira and Roswell, is mounted directly below the continent of Australia. Off to one side, and more often visited, are the graves of Henry and William James."
Leavitt was a member of Phi Beta Kappa, the American Association of University Women, the American Astronomical and Astrophysical Society, the American Association for the Advancement of Science, and an honorary member of the American Association of Variable Star Observers. Her early passing was seen as a tragedy by her colleagues for reasons that went beyond her scientific achievements. As Solon I. Bailey noted:
She had the happy faculty of appreciating all that was worthy and lovable in others, and was possessed of a nature so full of sunshine that, to her, all of life became beautiful and full of meaning.
Awards and honors
The asteroid 5383 Leavitt and the crater Leavitt on the Moon are named in her honor.
Unaware of her death four years prior, the Swedish mathematician Gösta Mittag-Leffler considered nominating her for the 1926 Nobel prize in physics, and wrote to Shapley requesting more information on her work on Cepheid variables, offering to send her his monograph on Sofia Kovalevskaya. Shapley replied, let Mittag-Leffler know that Leavitt had died, and suggested that the true credit belonged to his (Shapley's) interpretation of her findings. She was never nominated, because the Nobel Prize is not awarded posthumously.
纪念美国天文学家亨丽爱塔·勒维特诞辰140周年编辑本段回目录
勒维特1868年出生于美国马萨诸塞州的兰开斯特。19世纪90年代，哈佛大学天文台的天文学家皮克林招募了一些聋哑女性对天文台拍摄的照相底片进行测量和分类工作，1893年勒维特作为其中之一参加了工作。她在工作中注意到，小麦哲伦云中的一些变星光变周期越长，亮度变化越大。1908年她把初步结果发在哈佛大学天文台年报上。经过进一步研究，最终于1912年确认了造父变星的周光关系（注）。勒维特在哈佛大学天文台工作期间经常被健康问题和家庭事务所困扰。1921年，美国天文学家沙普利成为这个天文台的主任，勒维特随之开始领导哈佛大学天文台的恒星测光工作。同年年底，勒维特因癌症逝世。
造父变星周光关系的发现在天文学上具有重要意义。1913年丹麦天文学家赫茨普龙就利用视差法测定了银河系中几颗较近的造父变星的距离，距离尺度得到标定。1915年，沙普利成功解决了造父变星的零点标定问题。随后美国著名天文学家哈勃利用造父变星测量了仙女座大星云的距离，确认了它是一个河外星系。为纪念这位女天文学家，第5383号小行星以及月球表面的一座环形山以她的名字“勒维特”命名。
（注）周光关系period-luminosity relation
亨丽爱塔·斯琬·莉维特最先发现的造父变星的周期和绝对星等之间的关系。周光关系实际上有两个，一个适用于星族Ⅰ造父变星(又称为经典造父变星)，另一个适用于星族Ⅱ造父变星(又称为室女座W型星)。
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