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Project #1: Famous Astronomers: Henrietta Swan Leavitt

 

Here's what I have for my final draft interview: Manya interview Henrietta Swan Leavitt(3).doc

 

Manya here is a few comments to consider.Manya interview Henrietta Swan Leavitt.doc

 

Here's my original: Manya Science paper Henrietta Swan Leavitt.doc

 

 

Here's a link to something on the radio about her:

 

http://www.npr.org/templates/story/story.php?storyId=4738071

 

 

 

http://www.pbs.org/wgbh/aso/databank/entries/baleav.html

Henrietta Leavitt

1868 - 1921

 

 

Henrietta Leavitt was born in Landcaster, Massachusetts, the daughter of a Congregational minister. She attended Oberlin College and the Society for Collegiate Instruction of Women (later Radcliffe College). As a senior in 1892, Leavitt discovered astronomy. After graduation she took another course in it, but then spent several years at home when she suffered a serious illness that left her severely deaf. She hadn't forgotten about astronomy, though. She volunteered at the Harvard College Observatory in 1895. Seven years later she was appointed to the permanent staff (at a salary of 30 cents an hour) by director Charles Pickering. She got little chance to do theoretical work, but did become head of the photographic photometry department. This group studied photo images of stars to determine their magnitude.

During her career, Leavitt discovered more than 2,400 variable stars, about half of the known total in her day. These stars change from bright to dim and back fairly regularly. Leavitt's work with variable stars led to her most important contribution to the field: the cepheid variable period-luminosity relationship. By intense observation of a certain class of variable star, the cepheids, Leavitt discovered a direct correlation between the time it took a star to go from bright to dim to how bright it actually was. Knowing this relationship helped other astronomers, such as Edwin Hubble, to make their own groundbreaking discoveries.

Leavitt also developed a standard of photographic measurements that was accepted by the International Committee on Photographic Magnitudes in 1913, and called the Harvard Standard. To do this she used 299 plates from 13 telescopes and used logarithmic equations to order stars over 17 magnitudes of brightness. She continued refining and enlarging upon this work throughout her life.

Leavitt was not allowed to pursue her own topics of study, but researched what the head of the observatory assigned. Because of the prejudices of the day, she didn't have the opportunity to use her intellect to the fullest, but a colleague remembered her as "possessing the best mind at the Observatory," and a modern astronomer calls her "the most brilliant woman at Harvard." She worked at the Harvard College Observatory until her death from cancer in 1921.

 

http://en.wikipedia.org/wiki/Henrietta_Swan_Leavitt

July 4, 1868 – December 12, 1921 was an American astronomer, as well as being the deaf[1]daughter of a Congregational church minister [2]. She was born in Lancaster, Massachusetts to an old Massachusetts Puritan family which had settled in the Massachusetts Bay Colony in the early part of the seventeenth century. She graduated from Radcliffe College (then called the Society for the Colligiate Instruction for Women) with an A.B. degree in 1892.

Leavitt began work in 1895 at Harvard College Observatory as one of the women "computers" brought in by Edward Charles Pickering to measure and catalog the brightness of stars in the observatory's photographic plate collection. 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, actually Cepheid variables, of greater intrinsic luminosity indeed had longer periods, with a fairly close and predictable relation between the two.

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. When Cepheids were detected in other galaxies such as the Andromeda Galaxy, the distance to those galaxies could also be determined. These distances settled the debate on whether the galaxies were external to the Milky Way or part of it.

Leavitt worked sporadically during her time at Harvard, often sidelined by health problems and family obligations. But by 1921, when Harlow Shapley took over as director of the observatory, she was head of stellar photometry. She succumbed to cancer by the end of that year.

 

 

 

http://www.windows.ucar.edu/tour/link=/people/leavitt.html&edu=high

Henrietta Swan Leavitt was born in Lancaster, Massachusetts in 1868. She became interested in science and astronomy in college. Unfortunately, she became quite ill after her graduation from college. She spent several years at home recovering from the illness which left her almost completely deaf. But she hadn't forgotten astronomy!

She volunteered at Harvard College's Observatory, until she was hired permanently at the salary of 30 cents an hour. At the observatory, she observed stars and watched how variable stars changed in brightness over time. Henrietta is known for her 1904 discovery of a type of variable stars named cepheid variables. Cepheid variables are stars that go through cycles of brightness and darkness. Henrietta found that when observing a cepheid variable in another galaxy, she could relate the length of the brightness cycle to the size of the star. With this discovery, she was able to determine the distances between stars and the Earth. Cepheid variables are referred to as "astronomical yardsticks" as they make it easier to measure distances within the universe.

She died of cancer in 1921 at age fifty-three. Her name was given to a crater of the moon to honor deaf men and women who have worked as astronomers and scientists.

 

http://www.womanastronomer.com/hleavitt.htm

“A straight line can readily be drawn among each of the two series of points corresponding to maxima and minima, thus showing that there is a simple relation between the brightness of the variables and their periods.” Henrietta Swan Leavitt describing her famous discovery. Henrietta Swan Leavitt - Lady of Luminosity Henrietta Swan Leavitt was born on July 4, 1868 in Lancaster, Massachusetts. As a young child, her family moved to Cleveland, Ohio. Leavitt attended Oberlin College and in 1892 graduated from the Society for the Collegiate Instruction for Women, now known as Radcliffe College. She then traveled in America and in Europe during which time she lost her hearing. Three years after graduation, she became a volunteer research assistant at Harvard College Observatory. Seven years later, in 1902, Pickering hired her on the permanent staff at $.30 per hour. Leavitt’s interest in astronomy began during her senior year in college when she took an astronomy class. She furthered her studies in astronomy with graduate work. As an assistant at Harvard College Observatory, though she had the ability, she was given little theoretical work. Pickering did not like his female staff to pursue such endeavors. Instead, she was given the position of chief of the photographic photometry department and was responsible for the care of telescopes. Leavitt also was required to perform research from the observatory’s photographic plates collection. Using the plates, she was to determine a star’s magnitude. There was no standard for ascertaining magnitudes at the time. Leavitt devised a system, using “the north polar sequence” as a gage of brightness for stars during her investigations. This was quickly recognized by the scientific community as an important standard and in 1913, was adopted by the International Committee on Photographic Magnitudes. Another area of research that Leavitt pursued was on variable stars and in 1908 she made her most important discovery. By studying Cepheid variables in the Small Magellanic Cloud, which are all about the same distance from Earth, Leavitt determined the absolute magnitudes of stars. Her study led to the period-luminosity relationship of these variables, which in turn led to the ability to determine distances of stars from a mere one hundred light years to ten million light years. Ejnar Hertzsprung used her discovery to plot the distance of stars; Harlow Shapley used it to measure the size of the Milky Way; and Edwin Hubble used her work to ascertain the age of the Universe. Leavitt died on December 12, 1921 from cancer. During her lifetime, she discovered over 1,200 variable stars, half the number of all such objects known at the time of her death. She was also a member of many organizations and a proponent for women in astronomy. She made monumental contributions to the advancement of astronomy and our understanding of our place in the Universe. There is no way of knowing what other contributions she would have made had she not died so young.

 

 

http://search.eb.com/women/article-9047538

Leavitt, Henrietta Swan

Henrietta Swan Leavitt born July 4, 1868, Lancaster, Mass., U.S.

 

died Dec. 12, 1921, Cambridge, Mass.

 

 

American astronomer known for her discovery of the relationship between period and luminosity in Cepheid variables, pulsating stars that vary regularly in brightness in periods ranging from a few days to several months.

Leavitt attended Oberlin College for two years (1886–88) and then transferred to the Society for the Collegiate Instruction of Women (later Radcliffe College), from which she graduated in 1892. Following an interest aroused in her senior year, she became a volunteer assistant in the Harvard Observatory in 1895. In 1902 she received a permanent staff appointment. From the outset she was employed in the observatory's great project, begun by Edward C. Pickering, of determining the brightnesses of all measurable stars. In this work she was associated with the older Williamina Fleming and the more nearly contemporary Annie Jump Cannon.

Leavitt soon advanced from routine work to a position as head of the photographic stellar photometry department. A new phase of the work began in 1907 with Pickering's ambitious plan to ascertain photographically standardized values for stellar magnitudes. The vastly increased accuracy permitted by photographic techniques, which unlike the subjective eye were not misled by the different colours of the stars, depended upon the establishment of a basic sequence of standard magnitudes for comparison. The problem was given to Leavitt, who began with a sequence of 46 stars in the vicinity of the north celestial pole. Devising new methods of analysis, she determined their magnitudes and then those of a much larger sample in the same region, extending the scale of standard brightnesses down to the 21st magnitude. These standards were published in 1912 and 1917.

She then established secondary standard sequences of from 15 to 22 reference stars in each of 48 selected “Harvard Standard Regions” of the sky, using photographs supplied by observatories around the world. Her North Polar Sequence was adopted for the Astrographic Map of the Sky, an international project undertaken in 1913, and by the time of her death she had completely determined magnitudes for stars in 108 areas of the sky. Her system remained in general use until improved technology made possible photoelectrical measurements of far greater accuracy. One result of her work on stellar magnitudes was her discovery of 4 novas and some 2,400 variable stars, the latter figure comprising more than half of all those known even by 1930.

Leavitt's outstanding achievement was her discovery in 1912 that in a certain class of variable stars, the Cepheid variables, the period of the cycle of fluctuation in brightness is highly regular and proportional to the actual luminosity of the star. (The subsequent calibration of the period-luminosity curve allowed Edwin Hubble, Harlow Shapley, and others to determine the distances of many Cepheid stars and consequently of the star clusters and galaxies in which they were observed.) Leavitt continued her work at the Harvard Observatory until her death.

 

 

http://hoa.aavso.org/posterswan.htm

Henrietta Swan Leavitt

She Discovered How To Calculate The Distances To Galaxies

Henrietta Swan Leavitt (1868-1921) was born in Lancaster, Massachusetts, and graduated from Radcliffe College in 1892. In 1902 she became a permanent staff member of the Harvard College Observatory. She soon rose "by her scientific ability and intense application" to head the department of photographic stellar photometry.

Miss Leavitt inherited, in a somewhat chastened form, the stern virtues of her puritan ancestors. She took life seriously. Her sense of duty, justice and loyalty was strong. For light amusements she appeared to care little. She was a devoted member of her intimate family circle, unselfishly considerate in her friendships, steadfastly loyal to her principles, and deeply conscientious and sincere in her attachment to her religion and church. 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.

 

 

 

Project #2: Solar Puppets

 

 

 

AspectsandPhasesofthePlanets(IV[1][1].3).doc