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Nancy Houk | |
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| Alma mater | |
| Known for | Atlas of Objective Prism Spectra |
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| Institutions | University of Michigan |
Nancy Houk is an American astronomer who led the effort to establish a comprehensive database of stellar temperatures and luminosities. [1] [ third-party source needed ]
After earning her Doctorate in Astronomy from Case Western Reserve University in 1967, Nancy Houk was a postdoctoral student at Case Western and the Kapteyn Laboratory in the Netherlands.
During her undergraduate years at the University of Michigan, Houk researched at the Maria Mitchell Observatory, a memorial to Maria Mitchell, America's first woman professional astronomer.
Houk joined the Astronomy Department at the University of Michigan in 1970 as a Research Associate, [2] followed by promotions to Research Associate in 1973, the Associate Research Scientist in 1977, then Research Scientist in 1985.
Houk led the effort to establish a comprehensive database of stellar temperatures and luminosities. Houk's photographic observations of stars were made using the University of Michigan 0.61-m Curtis Schmidt telescope located at Cerro Tololo Interamerican Observatory (CTIO). CTIO, established in 1960, is a campus of astronomical telescopes located east of La Serena, Chile at an altitude of 2200 meters. CTIO is part of the National Optical Astronomy Observatory (NOAO). The telescope that Houk used was moved from Portage Lake Observatory in Michigan to CTIO in 1966. Houk began her observations in 1971. By 2014, the project had assembled five volumes covering the sky from the south celestial pole to +5° declination, consisting of 162,900 stars in total. [3]
The plates images are spectral images, taken with an objective prism at the front of the telescope. The images provide information about the physical properties of stars such as their composition of atomic elements and molecules, mass, temperature, rotational properties, age, distance, spectra classification and more. Houk used this data to construct the fundamental diagram used in astrophysics called the Hertzsprung-Russell Diagram that forms the basis of modern astrophysics. [4]
Houk retired in 2001 and donated half her plate collection which surveyed the entire southern hemisphere night sky to the Astronomical Photographic Data Archive (APDA) in 2004. [5] The other half of her collection resides in Japan. APDA, located at the Pisgah Astronomical Research Institute, plans to digitize her photographic plates. [6]
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Her research is published in 5 volumes of the Michigan Spectral Catalog where the first set of HR diagrams are presented from her data. The publications resulting from her research, and conferences where she presented her results are listed below:
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Iota Carinae, officially named Aspidiske, is a star in the southern constellation of Carina. With an apparent visual magnitude of 2.2, it is one of the brighter stars in the night sky.
Epsilon Carinae, officially named Avior, is a binary star in the southern constellation of Carina. At apparent magnitude +1.86 it is one of the brightest stars in the night sky, but is not visible from most of the northern hemisphere. The False Cross is an asterism formed of Delta Velorum, Kappa Velorum, Iota Carinae and ε Carinae. It is so called because it is sometimes mistaken for the Southern Cross, causing errors in astronavigation.
Kappa2 Sculptoris, Latinized from κ2 Sculptoris, is a solitary, orange-hued star in the southern constellation of Sculptor. It is faintly visible to the naked eye, with a combined apparent visual magnitude of +5.42. Based upon an annual parallax shift of 4.11 mas as measured from Earth, it is located approximately 800 light years from the Sun.
Iota Volantis, Latinized as ι Volantis, is the Bayer designation for a star in the southern constellation of Volans. It has an apparent visual magnitude of 5.39, which indicates it is faintly visible to the naked eye. With a parallax of 0.00579″, it lies at an estimated distance of roughly 560 light years from the Sun.
Pi Puppis, Latinized from π Puppis, also named Ahadi, is the second-brightest star in the southern constellation of Puppis. It has an apparent visual magnitude of 2.733, so it can be viewed with the naked eye at night. Parallax measurements yield an estimated distance of roughly 810 light-years from the Earth. This is a double star with a magnitude 6.86 companion at an angular separation of 0.72 arcsecond and a position angle of 148° from the brighter primary.
p Carinae is the Bayer designation of a star in the southern constellation of Carina. It has the variable star designation PP Carinae and, at an apparent visual magnitude of +3.3, is readily visible to the naked eye from the southern hemisphere. From the observed parallax shift of this star as the Earth orbits the Sun, its distance can be estimated as roughly 480 light-years with a 6% margin of error. It is considered to be a member of the open cluster IC 2602 although it lies well outside the core visible group of stars.
1 Centauri, or i Centauri, is a yellow-white-hued binary star system in the southern constellation Centaurus. It can be seen with the naked eye, having an apparent visual magnitude of +4.23. Based upon an annual parallax shift of 51.54 mas as seen from Earth's orbit, it is located 51.5 light-years from the Sun. The system is moving closer to the Sun with a radial velocity of −21.5 km/s.
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HD 153221 is a double star in the southern constellation of Ara. As of 2012, the pair have an angular separation of 1.10″ along a position angle of 172°.
HD 158220 is a giant Be star in the southern constellation of Ara. This is a pulsating variable star that changes brightness by an amplitude of 0.030 magnitude over a period of 1.15 days.
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x2 Centauri is a star located in the constellation Centaurus. It is also known by its designations HD 108114 and HR 4724. The apparent magnitude of the star is about 5.7, meaning it is only visible to the naked eye under excellent viewing conditions. Its distance is about 440 light-years, based on its parallax measured by the Hipparcos astrometry satellite.
V518 Carinae is a naked-eye variable star in the constellation Carina. It is a member of the bright open cluster IC 2602 near the Carina Nebula.
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HD 181342 is a star in the constellation of Sagittarius. With an apparent magnitude of 7.55, it cannot be seen with the naked eye. Parallax measurements made by Gaia spacecraft put the star at a distance of 394 light-years away.
W Crucis is a single-lined eclipsing variable star system in the constellation Crux. It has a spectral class of F8/G1Ia/abe indicating a yellow supergiant with emission lines in its spectrum.
Xi Octantis, Latinized from ξ Octantis, is a solitary variable star in the southern circumpolar constellation Octans. It has an apparent magnitude of about 5.3, allowing it to be faintly seen with the naked eye; however, this varies slightly. Located 514 light years away, the object is receding with a heliocentric radial velocity of 22 km/s.
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