Henrietta Swan Leavitt

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Henrietta Swan Leavitt

Henrietta Swan Leavitt (born July 4, 1868 in Lancaster , Massachusetts , † December 12, 1921 in Cambridge , Massachusetts) was an American astronomer . In 1912 she discovered the period-luminosity relationship in the Cepheid star type , that is, the relationship between the absolute brightness of these pulsating stars and the period of their fluctuations in brightness.

Leavitt thus laid the foundation for using the Cepheids as standard candles in order to first be able to determine distances to nearby galaxies . The method extends to a distance of 20 million light years. Before Leavitt noticed this relationship, astronomers used parallax and triangulation, which can be used for up to a few hundred light years. Our galaxy, the Milky Way , is already 100,000 light years in size. For measuring greater distances, one also uses the maximum mass of white dwarfs , calculated by Subrahmanyan Chandrasekhar .

life and work

For astronomy to Leavitt already interested in the college . She became almost completely deaf from an illness . Even so, she got a volunteer position at Harvard College Observatory in 1895 , and seven years later she was offered a permanent position (for 30 cents an hour). There Leavitt observed and cataloged variable stars , in 1904 alone she was able to discover 172 variable stars in the large and 59 in the small Magellanic Cloud . She had to limit her observations to the evaluation of photographs because women were forbidden to use the telescope . A year later, she reported 843 new variable stars in the small Magellanic Cloud. In 1912 Leavitt discovered the period-luminosity relationship in Cepheids .

In 1913, Ejnar Hertzsprung succeeded in determining the distance to some of the Cepheids in the Milky Way , with which the distance to all Cepheids could be calibrated. When Edwin Hubble identified Cepheids millions of light-years away in 1920 , he used Leavitt's model to show that they were stars in other galaxies such as the Andromeda Galaxy . For the first time, distances between different galaxies could also be determined. Before these discoveries, distances of up to 100 light years could only be expected, after which distances of up to 10 million light years were no longer a problem.

In all of her years of stargazing, Leavitt has observed four novae and discovered over 2,400 new variable stars. In addition, she developed a new photographic measuring technique , which found international recognition in 1913 and is known as the Harvard standard .

Henrietta Swan Leavitt is considered a pioneer of science, and not just because she was one of the few and first women in higher sciences. She was a member of various associations such as 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 .

In 1921, Henrietta Swan Leavitt died of cancer. The asteroid (5383) Leavitt, discovered in 1973, and a lunar crater ( Lunar Crater Leavitt ) bear their names in her honor. Unaware of her death, the Swedish mathematician Gösta Mittag-Leffler considered proposing Leavitt for a Nobel Prize in 1925. However, since this is not awarded posthumously , it ultimately came away empty-handed.

Fonts

The communications are initially mostly signed by Edward C. Pickering , the director of the observatory, and Leavitt and her contribution are named therein.

  • New variable stars in Harvard map, Nos. 3 and 6 , Harvard College Observatory Circular 127, April 12, 1907 bibcode : 1907HarCi.127 .... 1L (English)
  • 25 new variable stars in Harvard map, Nos. 24, 36, and 42 , Harvard College Observatory Circular 135, December 17, 1907 bibcode : 1907HarCi.135 .... 1L (English)
  • 29 new variable stars near Nova Sagittarii , Harvard College Observatory Circular 141, July 22, 1908 bibcode : 1908HarCi.141 .... 1L (English)
  • 1777 variables in the Magellanic Clouds , Annals of Harvard College Observatory 60, 1908, pp. 87–108 bibcode : 1908AnHar..60 ... 87L (English)
  • Adopted photographic magnitudes of 96 polar stars , Harvard College Observatory Circular 170, February 21, 1912, pp. 1–5 bibcode : 1912HarCi.170 .... 1P (English)
  • Periods of 25 variable stars in the Small Magellanic Cloud , Harvard College Observatory Circular 173, March 3, 1912, pp. 1–3 bibcode : 1912HarCi.173 .... 1L (English)
  • The north polar sequence , Annals of Harvard College Observatory 71, 1917, pp. 47–232 bibcode : 1917AnHar..71 ... 47L (English)
  • Standards of magnitude for the astrographic catalog , Annals of Harvard College Observatory 85, January 29, 1919, pp. 1–33 bibcode : 1930AnHar..85 .... 1L (English)

literature

  • Solon I. Bailey : Henrietta Swan Leavitt , Popular Astronomy 30, April 1922, pp. 197–199 bibcode : 1922PA ..... 30..197B (English; obituary; with picture)
  • Helena Korneck: Women in Astronomy , Stars and Space 21, 1982, ISSN  0039-1263 , pp. 412-414
  • George Johnson: Miss Leavitt's Stars: the untold story of the woman who discovered how to measure the universe , WW Norton, New York 2005, ISBN 0-393-05128-5 (English)
  • Marilyn Bailey Ogilvie : Women in science: antiquity through the nineteenth century: a biographical dictionary with annotated bibliography . 3rd Edition. MIT Press, Cambridge, MA 1991, ISBN 0-262-65038-X , p. 121

Play

Web links

Commons : Henrietta Swan Leavitt  - Collection of Images, Videos and Audio Files

Individual evidence

  1. ^ Expanding space-time and dark energy , Josef M. Gaßner , on Henrietta Leavitt, 2016-03-15.
  2. ^ Expanding space-time and dark energy , Josef M. Gaßner , on Subrahmanyan Chandrasekhar , 2016-03-15.
  3. ↑ Elmar Schenkel: Kepler's demon - encounter between literature, dream and science. S. Fischer Verlag, Berlin 2016, ISBN 978-3-10-073567-6 .
  4. ↑ Johnson: Miss Leavitt's Stars , pp. 118f
  5. ↑ Silent sky / by Lauren Gunderson in the Joint Union Catalog (GVK) of the GBV (GBV)
  6. ↑ Kerry Reid, 'Silent Sky': Story of women astronomers told with warmth at First Folio , Chicago Tribune , April 4, 2017
  7. ↑ Don Aucoin: In 'Silent Sky,' a pioneer claims her place among astronomy's stars , Boston Globe , March 15, 2017
personal data
SURNAME Leavitt, Henrietta Swan
BRIEF DESCRIPTION American astronomer
BIRTH DATE 4th July 1868
PLACE OF BIRTH Lancaster , Massachusetts
DATE OF DEATH December 12, 1921
PLACE OF DEATH Cambridge , Massachusetts