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William H. Jefferys | |
---|---|
Nationality | American |
Alma mater | Yale University |
Scientific career | |
Fields | Astronomy |
Institutions | University of Texas at Austin |
Thesis | Some Dynamical Systems of Two Degrees of Freedom in Celestial Mechanics (1965) |
Doctoral advisor | Gen'ichirō Hori |
William Hamilton Jefferys III (born 1940) is an American astronomer. He is a Harlan J. Smith Centennial Professor of Astronomy (Emeritus) of astronomy at The University of Texas at Austin, and an adjunct professor of statistics at the University of Vermont.
Jefferys specialized in astrometry, celestial mechanics, and astrophysics, including the kinematics and dynamics of astronomical bodies. He has also worked in the field of Bayesian statistics, particularly with astronomical applications. He was the Hubble Space Telescope Astrometry Science Team leader, and participated in the project that repaired the Hubble Space Telescope after the discovery of its initial optical defect.
Jefferys served as chairman of The University of Texas Department of Astronomy from 1994 to 1998. He retired from the University of Texas in 2004 and moved to Vermont in 2005, where he accepted an appointment as adjunct professor of statistics at the University of Vermont.
Polaris is a star in the northern circumpolar constellation of Ursa Minor. It is designated α Ursae Minoris and is commonly called the North Star or Pole Star. With an apparent magnitude that fluctuates around 1.98, it is the brightest star in the constellation and is readily visible to the naked eye at night. The position of the star lies less than 1° away from the north celestial pole, making it the current northern pole star. The stable position of the star in the Northern Sky makes it useful for navigation.
Sandra Moore Faber is an American astrophysicist known for her research on the evolution of galaxies. She is the University Professor of Astronomy and Astrophysics at the University of California, Santa Cruz, and works at the Lick Observatory. She has made discoveries linking the brightness of galaxies to the speed of stars within them and was the co-discoverer of the Faber–Jackson relation. Faber was also instrumental in designing the Keck telescopes in Hawaii.
NASA's series of Great Observatories satellites are four large, powerful space-based astronomical telescopes launched between 1990 and 2003. They were built with different technology to examine specific wavelength/energy regions of the electromagnetic spectrum: gamma rays, X-rays, visible and ultraviolet light, and infrared light.
The Guide Star Catalog (GSC), also known as the Hubble Space Telescope, Guide Catalog (HSTGC), is a star catalog compiled to support the Hubble Space Telescope with targeting off-axis stars. GSC-I contained approximately 20,000,000 stars with apparent magnitudes of 6 to 15. GSC-II contains 945,592,683 stars out to magnitude 21. As far as possible, binary stars and non-stellar objects have been excluded or flagged as not meeting the requirements of Fine Guidance Sensors. This is the first full sky star catalog created specifically for navigation in outer space.
Robert Charles Kennicutt, Jr. FRS is an American astronomer. He is currently a professor at Texas A&M University. He is a former Plumian Professor of Astronomy at the Institute of Astronomy in the University of Cambridge. He was formerly Editor-in-Chief of the Astrophysical Journal (1999–2006) and became a co-editor of the Annual Review of Astronomy and Astrophysics as of 2021. His research interests include the structure and evolution of galaxies and star formation in galaxies.
Nancy Grace Roman was an American astronomer who made important contributions to stellar classification and motions. The first female executive at NASA, Roman served as NASA's first Chief of Astronomy throughout the 1960s and 1970s, establishing her as one of the "visionary founders of the US civilian space program".
HD 33636 is a binary system located approximately 94 light-years away in Orion constellation. The visible member HD 33636 A is a 7th magnitude yellow main-sequence star. It is located at a distance of 91.6 light years from Earth. It has a metallicity of −0.05 ± 0.07.
Nicholas B. Suntzeff is an American astronomer and cosmologist. He is a University Distinguished Professor and holds the Mitchell/Heep/Munnerlyn Chair of Observational Astronomy in the Department of Physics & Astronomy at Texas A&M University where he is Director of the Astronomy Program. He is an observational astronomer specializing in cosmology, supernovae, stellar populations, and astronomical instrumentation. With Brian Schmidt he founded the High-z Supernova Search Team, which was honored with the Nobel Prize in Physics in 2011 to Schmidt and Adam Riess.
Beta Doradus, Latinized from β Doradus, is the second brightest star in the southern constellation of Dorado. It has a variable apparent visual magnitude, and is visible to the naked eye from the southern hemisphere. Based upon parallax measurements with the Hubble Space Telescope, it is located at a distance of 1,040 light-years from Earth.
Víctor Manuel Blanco was a Puerto Rican astronomer who in 1959 discovered Blanco 1, a galactic cluster. Blanco was the second Director of the Cerro Tololo Inter-American Observatory in Chile, which had the largest telescope in the Southern Hemisphere at the time. In 1995, the 4-meter telescope was dedicated in his honor and named the Víctor M. Blanco Telescope; it is also known as the "Blanco 4m."
Y Sagittarii is a variable star in the constellation of Sagittarius. It is a Cepheid variable with an apparent magnitude that ranges around +5.77. The measure of its parallax by Hubble Space Telescope puts Y Sagittarii to 1,293 light-years away from the Solar System.
Laura Ferrarese is a researcher in space science at the National Research Council of Canada. Her primary work has been performed using data from the Hubble Space Telescope and the Canada-France-Hawaii Telescope.
James Scott Dunlop is a Scottish astronomer and academic. He is Professor of Extragalactic Astronomy at the Institute for Astronomy, an institute within the School of Physics and Astronomy at the University of Edinburgh.
Fine Guidance Sensor (FGS) for the Hubble Space Telescope is a system of three instruments used for pointing the telescope in space, and also for astrometry and its related sciences. To enable aiming the telescope at a specific spot in the sky, each FGS combines optics and electronics. There are three Hubble FGS, and they have been upgraded over the lifetime of the telescope by crewed Space Shuttle missions. The instruments can support pointing of 2 milli-arc seconds. The three FGS are part of the Hubble Space Telescope's Pointing Control System, aka PCS. The FGS function in combination with the Hubble main computer and gyroscopes, with the FGS providing data to the computer as sensors which enables the HST to track astronomical targets.
Michael Perryman is a British astronomer, known for his work leading the Hipparcos and Gaia space astrometric projects.
Joseph E. Pesce is an Italian-American astrophysicist and Program Officer at the National Science Foundation in the US. He is a part-time professor at George Mason University and a visiting professor at the University of Colorado, Boulder.
In astronomy, a period-luminosity relation is a relationship linking the luminosity of pulsating variable stars with their pulsation period. The best-known relation is the direct proportionality law holding for Classical Cepheid variables, sometimes called the Leavitt law. Discovered in 1908 by Henrietta Swan Leavitt, the relation established Cepheids as foundational indicators of cosmic benchmarks for scaling galactic and extragalactic distances. The physical model explaining the Leavitt's law for classical cepheids is called kappa mechanism.
Kevin France is an astrophysicist and assistant professor in the Department of Astrophysical and Planetary Sciences at the University of Colorado. His research focuses on exoplanets and their host stars, protoplanetary disks, and the development of instrumentation for space-borne astronomy missions.
Hsiao-Wen Chen is a Taiwanese-American astronomer who uses absorption spectroscopy to study baryonic "normal matter" in the intergalactic medium and galactic halos, and the connections between this matter and the matter in star-forming regions of galaxies. She is a professor of astronomy and astrophysics at the University of Chicago.