John Johnson (astronomer)

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John Johnson
John Asher Johnson.png
Johnson at the 2012 Cool Stars Meeting in Barcelona
Born
John Asher Johnson

(1977-01-04) January 4, 1977 (age 47)
NationalityAmerican
CitizenshipUnited States
Alma mater Missouri University of Science and Technology
University of California at Berkeley
Known for Exoplanet research
Awards Sloan Fellowship (2012)
Newton Lacy Pierce Prize (2012)
Scientific career
Fields Astronomy
Institutions California Institute of Technology
Harvard University
Doctoral advisor Geoffrey Marcy
Website Harvard Astronomy page

John Asher Johnson (4 January 1977) is an American astrophysicist and professor of astronomy at Harvard. He is the first tenured African-American physical science professor in the history of the university. Johnson is well known for discovering three of the first known planets smaller than the Earth outside of the solar system, including the first Mars-sized exoplanet.

Contents

Early life and education

Johnson grew up in St. Louis. He graduated from the University of Missouri at Rolla (since renamed the Missouri University of Science and Technology) in 1999 with a Bachelors of Science degree in physics. In-between his undergraduate degree and graduate school, he also worked as a research scientist with LIGO at Caltech. He entered graduate school at UC Berkeley having never taken a course in astronomy. Johnson completed his Ph.D. in astrophysics in 2007 under Geoff Marcy. His thesis was titled "Planet Hunting In New Stellar Domains" and included the detection of several unusual hot Jupiters. [1] [2] [3] [4] [5]

Scientific career

Johnson is currently a professor of astronomy at Harvard, where he is one of several professors who study exoplanets along with David Charbonneau, Dimitar Sasselov, and others. [6] When he was appointed to this position in 2013, he became the first tenured African-American professor in any of the physical sciences at the university. [7] He was formerly a professor at the California Institute of Technology and a researcher with NASA's Exoplanet Science Research Institute. Before attaining a faculty job, Johnson was a National Science Foundation (NSF) post-doctoral fellow at the Institute for Astronomy, a part of the University of Hawaiʻi.

Research

Johnson does research on the detection and characterization of exoplanets, that is, planets located outside the solar system. [8] His work involves planets detected with a variety of methods. He is a founding principal investigator of the Miniature Exoplanet Radial Velocity Array (MINERVA), a ground-based robotic telescope array that searches for exoplanets primarily through the radial velocity method while also looking for transits. [9] More related to transiting planets, Johnson has worked on precisely measuring the properties of planet-hosting stars found with the Kepler mission, a vital task for determining the properties of the planets themselves. [10] He is also involved with K2, the successor to the original Kepler mission. [11]

In 2012, Johnson's team discovered three small rocky exoplanets in a red dwarf star system observed with the Kepler space telescope. [12] The system was renamed Kepler-42 and the outermost planet was found to be nearly as small as Mars, making it the smallest known exoplanet at the time. [13] A subsequent study used the host star's similarity to Barnard's Star and observations from the Keck Observatory to more precisely measure the properties of the system, including the sizes of the three planets. [14]

Diversity initiatives

Johnson is the founder of the Banneker Institute, a summer program hosted at the Center for Astrophysics | Harvard & Smithsonian. [15] The program provides funding for undergraduate students from backgrounds underrepresented in astronomy, with a focus on students of color. It has merged with a similar program into the joint Banneker & Aztlán Institute, which also targets Latin and Native American students. In addition to research, the institute emphasizes discussions on social justice issues and their relevance in the field of astronomy. [16]

Related Research Articles

<span class="mw-page-title-main">Lists of planets</span>

These are lists of planets. A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a young protostar orbited by a protoplanetary disk. There are eight planets within the Solar System; planets outside of the solar system are also known as exoplanets.

<span class="mw-page-title-main">Michel Mayor</span> Swiss astrophysicist & Nobel laureate of Physics

Michel Gustave Édouard Mayor is a Swiss astrophysicist and professor emeritus at the University of Geneva's Department of Astronomy. He formally retired in 2007, but remains active as a researcher at the Observatory of Geneva. He is co-laureate of the 2019 Nobel Prize in Physics along with Jim Peebles and Didier Queloz, and the winner of the 2010 Viktor Ambartsumian International Prize and the 2015 Kyoto Prize.

<span class="mw-page-title-main">Geoffrey Marcy</span> American astronomer

Geoffrey William Marcy is an American astronomer. He was an early influence in the field of exoplanet detection, discovery, and characterization. Marcy was a professor of astronomy at the University of California, Berkeley, and an adjunct professor of physics and astronomy at San Francisco State University. Marcy and his research teams discovered many extrasolar planets, including 70 out of the first 100 known exoplanets and also the first planetary system around a Sun-like star, Upsilon Andromedae. Marcy was a co-investigator on the NASA Kepler space telescope mission. His collaborators have included R. Paul Butler, Debra Fischer and Steven S. Vogt, Jason Wright, Andrew Howard, Katie Peek, John Johnson, Erik Petigura, Lauren Weiss, Lea Hirsch and the Kepler Science Team. Following an investigation for sexual harassment in 2015, Marcy resigned his position at the University of California, Berkeley.

<span class="mw-page-title-main">HAT-P-11b</span> Super Neptune orbiting HAT-P-11

HAT-P-11b is an extrasolar planet orbiting the star HAT-P-11. It was discovered by the HATNet Project team in 2009 using the transit method, and submitted for publication on 2 January 2009.

<span class="mw-page-title-main">Kepler-16b</span> Gas giant orbiting Kepler-16 star system

Kepler-16b is a Saturn-mass exoplanet consisting of half gas and half rock and ice. It orbits a binary star, Kepler-16, with a period of 229 days. "[It] is the first confirmed, unambiguous example of a circumbinary planet – a planet orbiting not one, but two stars," said Josh Carter of the Center for Astrophysics | Harvard & Smithsonian, one of the discovery team.

<span class="mw-page-title-main">Kepler-42</span> Red dwarf star in the constellation Cygnus

Kepler-42, formerly known as KOI-961, is a red dwarf located in the constellation Cygnus and approximately 131 light years from the Sun. It has three known extrasolar planets, all of which are smaller than Earth in radius.

<span class="mw-page-title-main">Kepler-62f</span> Super-Earth orbiting Kepler-62

Kepler-62f is a super-Earth exoplanet orbiting within the habitable zone of the star Kepler-62, the outermost of five such planets discovered around the star by NASA's Kepler space telescope. It is located about 982 light-years from Earth in the constellation of Lyra.

<span class="mw-page-title-main">Kepler-90</span> Star in the constellation Draco, orbited by eight planets

Kepler-90, also designated 2MASS J18574403+4918185, is a F-type star located about 2,790 light-years (855 pc) from Earth in the constellation of Draco. It is notable for possessing a planetary system that has the same number of observed planets as the Solar System.

<span class="mw-page-title-main">Kepler-438b</span> Super-Earth orbiting Kepler-438

Kepler-438b is a confirmed near-Earth-sized exoplanet. It is likely rocky. It orbits on the inner edge of the habitable zone of a red dwarf, Kepler-438, about 460.2 light-years from Earth in the constellation Lyra. It receives 1.4 times our solar flux. The planet was discovered by NASA's Kepler spacecraft using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. NASA announced the confirmation of the exoplanet on 6 January 2015.

<span class="mw-page-title-main">Nexus for Exoplanet System Science</span> Dedicated to the search for life on exoplanets

The Nexus for Exoplanet System Science (NExSS) initiative is a National Aeronautics and Space Administration (NASA) virtual institute designed to foster interdisciplinary collaboration in the search for life on exoplanets. Led by the Ames Research Center, the NASA Exoplanet Science Institute, and the Goddard Institute for Space Studies, NExSS will help organize the search for life on exoplanets from participating research teams and acquire new knowledge about exoplanets and extrasolar planetary systems.

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<span class="mw-page-title-main">Stephen R. Kane</span>

Stephen Kane is a full professor of astronomy and planetary astrophysics at the University of California, Riverside who specializes in exoplanetary science. His work covers a broad range of exoplanet detection methods, including the microlensing, transit, radial velocity, and imaging techniques. He is a leading expert on the topic of planetary habitability and the habitable zone of planetary systems. He has published hundreds of peer reviewed scientific papers and has discovered/co-discovered several hundred planets orbiting other stars. He is a prolific advocate of interdisciplinarity science and studying Venus as an exoplanet analog.

Kepler-1229 is a red dwarf star located about 875 light-years (268 pc) away from the Earth in the constellation of Cygnus. It is known to host a super-Earth exoplanet within its habitable zone, Kepler-1229b, which was discovered in 2016.

<span class="mw-page-title-main">Jessie Christiansen</span> American astrophysicist

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Kepler-160 is a main-sequence star approximately the width of our Galactic arm away in the constellation Lyra, first studied in detail by the Kepler Mission, a NASA-led operation tasked with discovering terrestrial planets. The star, which is very similar to the Sun in mass and radius, has three confirmed planets and one unconfirmed planet orbiting it.

References

  1. "Black History Month - Profile of a Scientist". NASA. February 2017. Archived from the original on 16 June 2020. Retrieved 7 May 2018.
  2. "John Asher Johnson" (PDF). National Science Foundation. Retrieved 8 May 2018.
  3. "Intelligence in Astronomy: The Growth of My Intelligence". Mahalo.ne.trash. Retrieved 8 May 2018.
  4. Johnson, John Asher (2007). "Planet hunting in new stellar domains". The SAO/NASA Astrophysics Data System. Bibcode:2007PhDT.........7J.
  5. "About the Speakers of AbGradCon 2012". AbGradCon. Archived from the original on 8 May 2018. Retrieved 8 May 2018.
  6. "John Asher Johnson". Harvard Magazine. 2013-12-16. Retrieved 8 May 2018.
  7. "'Party of One': Diversity and Isolation in Harvard's Faculty". Harvard Crimson. Retrieved 8 May 2018.
  8. Dawson, Rebekah I.; Johnson, John Asher (14 September 2018). "Origins of Hot Jupiters". Annual Review of Astronomy and Astrophysics. 56 (1): 175–221. arXiv: 1801.06117 . Bibcode:2018ARA&A..56..175D. doi:10.1146/annurev-astro-081817-051853. S2CID   119332976 . Retrieved 5 April 2022.
  9. "A dedicated Exoplanet Observatory". Harvard. 3 February 2016. Retrieved 2 April 2016.
  10. "The California-Kepler Survey". California Kepler Survey. Retrieved 8 May 2018.
  11. "Kepler 'rising from the ashes'". The Harvard Gazette. 2014-12-18. Retrieved 8 May 2018.
  12. Philip S. Muirhead, John Asher Johnson, Kevin Apps, Joshua A. Carter, Timothy D. Morton, Daniel C. Fabrycky, J. Sebastian Pineda, Michael Bottom, Barbara Rojas-Ayala, Everett Schlawin, Katherine Hamren, Kevin R. Covey, Justin R. Crepp, Keivan G. Stassun, Joshua Pepper, Leslie Hebb, Evan N. Kirby, Andrew W. Howard, Howard T. Isaacson, Geoffrey W. Marcy, David Levitan, Tanio Diaz-Santos, Lee Armus, James P. Lloyd, «  Characterizing the Cool KOIs III. KOI-961: A Small Star with Large Proper Motion and Three Small Planets  » published in The Astrophysical JournalarXiv : 1201.2189v1.
  13. Cowen, Ron (2012). "Three tiny exoplanets suggest Solar System not so special". Nature. doi:10.1038/nature.2012.9786. S2CID   120884022 . Retrieved 7 May 2018.
  14. "Discovery of the Smallest Exoplanets: The Barnard's Star Connection". SpaceRef. 11 January 2012. Retrieved 7 May 2018.[ permanent dead link ]
  15. Sokol, Joshua (August 23, 2016). "Why the Universe Needs More Black and Latino Astronomers". Smithsonian . Retrieved May 3, 2019.
  16. "Harvard Astronomer, Institute Offer Support for Students of Color in Sciences". The Harvard Crimson. Retrieved 8 May 2018.