Charles Thomas Bolton (April 15, 1943 – ) was an American-Canadian astronomer who was one of the first in his field to present strong evidence of the existence of a

stellar-mass black hole A stellar black hole (or stellar-mass black hole) is a black hole formed by the gravitational collapse of a star. They have masses ranging from about 5 to several tens of solar masses. The process is observed as a hypernova explosion or as a gam ...

Biography

Bolton was born in

Camp Forrest Camp Forrest, located in a wooded area east of the city of Tullahoma, Tennessee, was one of the U.S. Army's largest training bases during World War II. It was an active army post between 1941 and 1946. History The camp, named after Civil War cav ...

, a military base in

Tullahoma, Tennessee Tullahoma is a city in Coffee and Franklin counties in southern Middle Tennessee, United States. The population was 20,339 at the 2020 census. In 2019, the population was estimated to be 19,555. It is the principal city of the Tullahoma micropol ...

. He received his bachelor's degree in 1966 from the

University of Illinois The University of Illinois Urbana-Champaign (U of I, Illinois, University of Illinois, or UIUC) is a public land-grant research university in Illinois in the twin cities of Champaign and Urbana. It is the flagship institution of the University ...

, followed by a 1968 master's degree and a 1970 doctoral degrees from the

University of Michigan , mottoeng = "Arts, Knowledge, Truth" , former_names = Catholepistemiad, or University of Michigania (1817–1821) , budget = $10.3 billion (2021) , endowment = $17 billion (2021)As o ...

. Bolton then worked as a postdoctoral researcher at the

David Dunlap Observatory The David Dunlap Observatory (DDO) is an astronomical observatory site in Richmond Hill, Ontario, Canada. Established in 1935, it was owned and operated by the University of Toronto until 2008. It was then acquired by the city of Richmond Hill, ...

Richmond Hill, Ontario Richmond Hill (Canada 2021 Census, 2021 population: 202,022) is a city in south-central Regional Municipality of York, York Region, Ontario, Canada. Part of the Greater Toronto Area, it is the York Region's third most populous municipality and th ...

, teaching there until 1972. He taught at

Scarborough College Scarborough College is an independent coeducational day and boarding school aged 3–18 years in Scarborough, North Yorkshire, England. It was founded in 1898 and opened in 1901. The school has been an International Baccalaureate (IB) World ...

from 1971 to 1972, and at Erindale College from 1972 to 1973. Thereafter, he was affiliated with the

University of Toronto The University of Toronto (UToronto or U of T) is a public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution ...

astronomy department, eventually becoming an emeritus professor. In 1970, Bolton developed the first computer models for

stellar spectra Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, ultraviolet, X-ray, infrared and radio waves that radiate from stars and othe ...

that were precise enough to compare with data from real stars. In 1971, as a post-doctoral fellow and part-time faculty member studying binary systems at the Dunlap Observatory, Bolton observed star HDE 226868 wobble as if it were orbiting around an invisible but massive companion emitting powerful X-rays, independently of the work by

Louise Webster Betty Louise Turtle (née Webster lso Webster in published works (20 May 1941 - 29 September 1990) was an Australian astronomer and physicist. In 1971, with her colleague Paul Murdin, she identified the powerful X-ray source Cygnus X-1 as the fi ...

and

Paul Murdin Paul Geoffrey Murdin (born 5 January 1942) is a British astronomer. He identified the first clear candidate for a black hole, Cygnus X-1, with his colleague Louise Webster. He studied Mathematics and Physics at the universities of Oxford and ...

, at the

Royal Greenwich Observatory The Royal Observatory, Greenwich (ROG; known as the Old Royal Observatory from 1957 to 1998, when the working Royal Greenwich Observatory, RGO, temporarily moved south from Greenwich to Herstmonceux) is an observatory situated on a hill in G ...

. Further analysis gave an estimate about the amount of mass needed for the gravitational pull, which proved to be too much for a

neutron star A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects (e.g. white ...

. After more observations confirmed the results, by 1973, the astronomical community generally recognized

black hole A black hole is a region of spacetime where gravitation, gravity is so strong that nothing, including light or other Electromagnetic radiation, electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts t ...

Cygnus X-1 Cygnus X-1 (abbreviated Cyg X-1) is a galactic X-ray source in the constellation Cygnus and was the first such source widely accepted to be a black hole. It was discovered in 1964 during a rocket flight and is one of the ...

, lying in the plane of the

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye ...

galaxy at a galactic latitude of about 3 degrees. In 1985, Bolton and Douglas Gies showed that hot, massive "runaway OB stars" (stars that travel at an abnormally high

velocity Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity is a ...

relative to the surrounding

interstellar medium In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstella ...

), could be accelerated through stellar interactions within star clusters, in addition to being ejected from binary systems after

supernova A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when ...

explosions. Bolton was instrumental in passing the first light-pollution regulation Canada, a 1995 bylaw to limit

light pollution Light pollution is the presence of unwanted, inappropriate, or excessive use of artificial Visible spectrum, lighting. In a descriptive sense, the term ''light pollution'' refers to the effects of any poorly implemented lighting, during the day ...

in the town Richmond Hill, home of the David Dunlap Observatory. He was a fellow of the

Royal Society of Canada The Royal Society of Canada (RSC; french: Société royale du Canada, SRC), also known as the Academies of Arts, Humanities and Sciences of Canada (French: ''Académies des arts, des lettres et des sciences du Canada''), is the senior national, bil ...

. Bolton died in February 2021, at his home in Richmond Hill.

References

{{DEFAULTSORT:Bolton, Tom 1943 births 2021 deaths 20th-century American astronomers 21st-century Canadian astronomers Academic staff of the University of Toronto Mississauga Academic staff of the University of Toronto Scarborough Fellows of the Royal Society of Canada University of Illinois alumni University of Michigan alumni People from Tullahoma, Tennessee People from Richmond Hill, Ontario