Kepler de Souza Oliveira

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Kepler de Souza Oliveira Filho (born 16 February 1956), also known as S. O. Kepler, is a Brazilian astronomer primarily known for his work on white dwarfs, variable stars, and magnetars. A member of the Brazilian Academy of Sciences, he is currently a professor at Universidade Federal do Rio Grande do Sul (UFRGS). [1]

Contents

Biography

Born in Salvador, Bahia, Brazil, Kepler obtained his Ph.D. from the University of Texas at Austin in 1984. In January 2006, Oliveira and researchers at the University of Texas identified a pulsating white dwarf star, G117-B15A, as the most stable known optical clock, more stable than an atomic clock. The team's findings were published in The Astrophysical Journal . [2]

He was president of the Sociedade Brasileira de Astronomia from 2002 to 2004, and is its current vice-president (2014-2016). [3] He served on the SOAR and Gemini Board for the Association of Universities for Research in Astronomy, which is responsible for managing the Gemini Observatory. [4] Together with Antonio Nemmer Kanaan Neto and other researchers, he is the co-discoverer of BPM37093, the "Diamond Star", a crystallized carbon-oxygen core pulsating white dwarf. With Detlev Koester and Gustavo Ourique, he discovered SDSSJ1240+6710, an oxygen white dwarf, "Dox". [5]

Together with Maria de Fátima Oliveira Saraiva, he is the author of the book and site Astronomia e Astrofísica. [6]

Related Research Articles

BPM 37093 White-dwarf star in the constellation Centaurus

BPM 37093 is a variable white dwarf star of the DAV, or ZZ Ceti, type, with a hydrogen atmosphere and an unusually high mass of approximately 1.1 times the Sun's. It is about 50 light-years from Earth, in the constellation Centaurus, and vibrates; these pulsations cause its luminosity to vary. Like other white dwarfs, BPM 37093 is thought to be composed primarily of carbon and oxygen, which are created by thermonuclear fusion of helium nuclei in the triple-alpha process.

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A pulsating white dwarf is a white dwarf star whose luminosity varies due to non-radial gravity wave pulsations within itself. Known types of pulsating white dwarfs include DAV, or ZZ Ceti, stars, with hydrogen-dominated atmospheres and the spectral type DA; DBV, or V777 Her, stars, with helium-dominated atmospheres and the spectral type DB; and GW Vir stars, with atmospheres dominated by helium, carbon, and oxygen, and the spectral type PG 1159. GW Vir stars may be subdivided into DOV and PNNV stars; they are not, strictly speaking, white dwarfs but pre-white dwarfs which have not yet reached the white dwarf region on the Hertzsprung-Russell diagram. A subtype of DQV stars, with carbon-dominated atmospheres, has also been proposed, and in May 2012, the first extremely low mass variable (ELMV) white dwarf was reported.

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GD 61 is a white dwarf with a planetary system located 150 light-years from Earth in the constellation Perseus. It is thought to have been a main-sequence star of spectral type A0V with around three times the mass of the Sun that has aged and passed through a red-giant phase, leaving a dense, hot remnant that has around 70% of the Sun's mass and a surface temperature of 17,280 K. It is thought to be around 600 million years old, including both its life as a main-sequence star and as a white dwarf. It has an apparent magnitude of 14.8. GD 61 was first noted as a potential degenerate star in 1965, in a survey of white-dwarf suspects by astronomers from the Lowell Observatory in Arizona.

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References

  1. Kepler de Souza Oliveira Filho Archived 2015-12-08 at the Wayback Machine . Brazilian Academy of Sciences. Retrieved 2 December 2015.
  2. "Press release: Astronomers find most stable optical clock in the heavens | McDonald Observatory". Mcdonald Observatory. 1 December 2005.
  3. Diretoria: Biênio 2014/2016 Archived 2015-12-08 at the Wayback Machine (in Portuguese). Sociedade Brasileira de Astronomia. Retrieved 2 December 2015.
  4. "AURA Directory". Association of Universities for Research in Astronomy . Retrieved 2 December 2015.
  5. Kepler, S. O.; Koester, D.; Ourique, G. (31 March 2016). "A white dwarf with an oxygen atmosphere". Science. 352 (6281): 67–69. Bibcode:2016Sci...352...67K. doi: 10.1126/science.aad6705 . PMID   27034367.
  6. "Astronomia e Astrofísica" . Retrieved 7 June 2016.