William Pendry Bidelman ( ; September 25, 1918 – May 3, 2011)Death record for William Bidelman on Mooseroots. Retrieved May 2, 2016. was an American astronomer. Born in Los Angeles, and raised in North Dakota, he was noted for classifying the spectra of stars, and considered a pioneer in recognizing and classifying sub-groups of the peculiar stars.Wing, Robert F. "Preface". The Carbon Star Phenomenon. (2000). 177th IAU Symposium, Turkey, 1996. Edited by Robert F. Wing. Kluwer Academic Publishers, Netherlands. pp. xvii- xxv. Retrieved July 27, 2016. .
Bidelman's undergraduate degree was from Harvard College, and his Ph.D. in astronomy was from the University of Chicago under advisor William Wilson Morgan."William P. Bidelman". Ph.D. Tree. Retrieved June 3, 2016. He was a physicist in the Army during World War II. A professional astronomer for over 50 years,"William P. Bidelman". Legacy.com. Retrieved February 1, 2017. Bidelman taught for ~41 yearsBidelman, W.P. "The bimillenary of Christ's birth". Planetarian. September 1991, 20(3). Retrieved June 6, 2016. at The University of Chicago, The University of California,
He co-discovered the class of barium stars with Philip Keenan,"William P. Bidelman". The Cleveland Plain Dealer. May 15, 2011. Retrieved May 2, 2016. the phosphorus and the mercury stars,Bidelman, William P. "The bimillenary of Christ's birth: the astronomical evidence". The International Planetarium Society. Reprinted from the Planetarian, September 1991. Retrieved June 7, 2016. and was the first to describe the hydrogen-deficient carbon stars.Jaschek, Carlos & Jaschek, Mercedes. (1990). "K-type stars". The Classification of Stars. Cambridge University Press. New York, USA. Retrieved October 17, 2016. .
Born in Los Angeles, California, Bidelman was raised in North Dakota, where he met his future wife of 69 years. He was a father of four and a grandfather. As an Emeritus Professor William P. Bidelman continued working in astronomy after he retired from teaching, and was 92 when he died in Murfreesboro, Tennessee.
Education
As an undergraduate at Harvard College, Bidelman received an Honorary Harvard College Scholarship for academic excellence in 1939."Honorary scholarships are awarded to 101 high ranking undergraduates". The Harvard Crimson. November 27, 1939. Retrieved May 18, 2016. He graduated in 1940. Bidelman entered the graduate program at the University of Chicago affiliated with Yerkes Observatory. His doctoral advisor was William W.Morgan,"World War II, 1939–1945". Yerkes Observatory, 1892–1950: The Birth, Near Death, and Resurrection of a Scientific Research Institution. (2008). Osterbrock, Donald E. University of Chicago Press. p. 261. Retrieved May 18, 2016. who discovered the first definite evidence that the Milky Way Galaxy is a spiral galaxy,Wilford, John Noble. "William Morgan dies at 88; a leading U.S. astronomer". The New York Times. June 24, 1994. Retrieved May 18, 2016. and, with Philip Keenan, the Morgan-Keenan (MK) system of stellar classification.Copage, Eric. "Philip C. Keenan, 92, Pioneer in the classification of stars". The New York Times. April 25, 2000. Retrieved June 10, 2016."Stellar classification." Encyclopedia Britannica. Retrieved June 10, 2016. As a graduate student, Bidelman assisted Morgan and Keenan by taking some of the spectrograms for their book, An Atlas of Stellar Spectra.Morgan W. W., Keenan Philip C. & Kellman, Edith. (1943) "Conclusion" . An Atlas of Stellar Spectra: with an Outline of Spectral Classification. Astrophysical Monographs, University of Chicago Press, Illinois. Page 30 in book or 40 online. Retrieved June 28, 2016. .
For his 1943 dissertation,"Thesis (Ph.D.) of William P. Bidelman, University of Chicago". SearchWorks. Retrieved January 30, 2017. Bidelman reported the Double Cluster in the I Persei association is physically associated with neighborhood supergiant stars, and is part of an association of O- and B-type stars,Elmegreen, Bruce & Efremov, Yuri. "The formation of star clusters". American Scientist, 86(3):264. May–June 1998. Retrieved September 14, 2016. and designated 47 stars as its members. Bidelman received his Ph.D. in 1943."Chicago Astronomy Degree Recipients: 1940 – 1949". The University of Chicago, Department of Astronomy and Astrophysics. Retrieved June 6, 2016. The Yerkes astronomy graduate program directed by Otto Struve began issuing degrees in 1940, and he was among their first ten graduates."World War II, 1939–1945". Yerkes Observatory, 1892–1950: The Birth, Near Death, and Resurrection of a Scientific Research Institution. (2008). Osterbrock, Donald E. University of Chicago Press. p. 261. Retrieved June 16, 2017.
Career
Bidelman served in the U.S. Army's Ballistic Research Laboratory at Aberdeen Proving Ground for over 2 years during World War II,. He attended the 1942 American Astronomical Society's annual meeting despite a small assembly due to gasoline rationing during World War II. Plate 1: Bidelman (#18) stands near the center in December 1942.
University of Chicago, Yerkes Observatory
In 1945, when Bidelman left Aberdeen he was hired at Yerkes as an Instructor. Under Otto Struve Yerkes became the leading astrophysics center, when he directed it.Hearnshaw, John B. (1990). The Analysis of Starlight: One Hundred and Fifty Years of Astronomical Spectroscopy. Cambridge University Press, USA. First printed 1986. Retrieved May 19, 2017. . In addition to Bidelman, by 1946 the Yerkes astronomy staff included Paul Ledoux, Arne Slettebak, Armin Deutsch, Marshall Wrubel, Arthur D. Code, Carlos Cesco, Víctor M. Blanco, W. W. Morgan, Otto Struve, Jesse L. Greenstein, Gerard P. Kuiper, George Van Biesbroeck, Louis G. Henyey Anne B. Underhill, Guido Münch, Nancy G. Roman,"Yerkes Observatory staff photo". The University of Chicago Photographic Archive. Retrieved May 9, 2017. and the two future Nobel Prize winners, Subrahmanyan Chandrasekhar and Gerhard Herzberg.DeVorkin, David. "Kaj Strand". American Institute of Physics. Oral history interviews. Thursday, December 8, 1983. Retrieved May 9, 2017. Other astronomers at Yerkes when Bidelman was there were Kaj Strand, W. Albert Hiltner, Aden B. Meinel, and visiting professors Bengt Strömgren from Denmark, and Jan Oort, Hendrik C. van de Hulst and Adriaan Blaauw from the Netherlands. George Herbig, also there, remembered it as an "exciting, stimulating place to work" and a "powerhouse in astronomy" while under Struve's direction.Reipurth, Bo. (2016). "The budding astronomer". George Herbig and Early Stellar Evolution. Institute for Astronomy Special Publications, No. 1. Retrieved July 9, 2016.
Bidelman spent long hours observing in remote west Texas at McDonald Observatory because he, like other Yerkes faculty, was also an astronomer at the University of Texas (UT). At the suggestion of Struve, the two universities had cooperated to create McDonald Observatory when the UT system had no astronomy department but W. J. McDonald gave them money in 1926 for an observatory, while in Wisconsin, the Yerkes astronomers needed a larger telescope but lacked the funds to obtain one.
Otto Struve, who directed both Yerkes and McDonald, has been described as dedicated yet demanding.Krisciunas, Kevin. "Otto Struve". Biographical Memoirs. 61:351-387. 1992. Washington, DC: The National Academies Press. Retrieved June 16, 2017. His managerial style included daily inspections of the faculty to see if they were working.Osterbrock, Donald E. (2008). "The boy president, 1929–1932". Yerkes Observatory, 1892–1950: The Birth, Near Death, and Resurrection of a Scientific Research Institution. University of Chicago Press. Page 131. . Retrieved May 18, 2016. Despite reports of tensions there was also "close knit camaraderie" and "boisterous parties" evidenced by Yerkes "spontaneous party songs" including "The Billy Bidelman Song". Sung to the tune of "The Battle Hymn of the Republic", it consisted of repeating three times the line: "Struve, Kuiper, Hiltner, Morgan, Chandrasekhar too," followed by: "And Billy Bidelman".Evans, David S. & Mulholland, J. Derral. (1986). "Texas independence". Big and Bright: A History of the McDonald Observatory. University of Texas Press, Austin, Texas. p. 132. Retrieved July 2, 2016. .The authors who have noted "The Billy Bidelman Song" stated: "No one seems to recall why William P. Bidelman deserved such august company, but it must have seemed a good idea at the time". They also noted that the "W. W. W. W. Morgan" song has apparently, and "perhaps fortunately" been lost.
In 1946, W. W. Morgan and William P. Bidelman published a paper on interstellar reddening using the MK system of spectral classifications and photoelectric photometry. Hearnshaw, J. B. (1996). The Measurement of Starlight: Two Centuries of Astronomical Photometry. Cambridge University Press, New York. p. 304. Retrieved June 6, 2016. . Morgan later said this paper with Bidelman on interstellar reddening was "the principal paper along the way" to the UBV system, which he devised with Harold Johnson.
In 1947, Bidelman became first to note the concentration of type M supergiant stars around χ Per, suggesting they were young Population I objects.
This group, along with the Double Cluster, was later named the Perseus OB1 Association. Based on its radial velocity, Bidelman also became first to see that S Persei is part of the Per OB1 association, which was later confirmed. Among the first stars that were studied at far-infrared wavelengths, M-type supergiants may be used to find the spiral arms of the Milky Way galaxy. Bidelman found four red supergiant stars in 1947, bringing the total then known to 13. How red supergiant stars evolved was considered an "astronomical puzzle", so the Double Cluster was used to test ideas about the evolution of red supergiant stars during the 1960s. The M-type supergiants of h and χ Per became the prototypes of this class of stars, and the major source of data for their properties.
Unlike most the usual relatively young star clusters including few supergiant stars, 18 were found in the Double Cluster of Perseus by 2007, which Robert F. Wing noted as the 60th anniversary of Bidelman's "important paper", saying Bidelman's 1947 two-dimensional classifications of the then-known supergiants in h and χ Per had "served as the benchmark" for later studies of the red supergiant stars.
Hydrogen is the most abundant element in the Universe, so stars displaying very little hydrogen in their atmospheres are chemically peculiar stars. There are many kinds of hydrogen-deficient stars. Upsilon Sagittarii is a hydrogen-deficient star. It is a very luminous, variable, and unusual eclipsing binary with a spectrum quite difficult to classify.Burnham, Robert. "Sagittarius: Upsilon". Burnham's Celestial Handbook: An Observer's Guide to the Universe Beyond the Solar System, 3:1566–1569. Courier Corporation, New York. 1978, reprinted 2013. . Retrieved May 16, 2017 In 1949, Bidelman was possibly the first to suggest that Upsilon (υ) Sagittarii's violet-shifted absorption lines, which apparently takes place during some conjunctions of this binary pair when star 2 advances in front of star 1, could be caused by gas streaming from the primary star. Bidelman suggested when the displaced H-alpha(Hα) absorption line was present, it happened at regular intervals when the primary star was furthest away from Earth.
Upsilon Sag was the only example of a star of its type until Bidelman discovered another star similar to it, HD 30353. This star became known as "Bidelman's star".Schmadel, Lutz D. (2012). "Catalogue of minor planet names and discovery circumstances". Dictionary of Minor Planet Names, 6th Edition, 2:686. Springer Science & Business Media. Retrieved June 3, 2016. .The Minor Planet Center. "(9398) Bidelman = 1994 SH3 = 1997 AC20". The International Astronomical Union. Retrieved July 1, 2016.