Sirius B and the Measurement of the Gravitational Redshift

Roseveare N. T. , Mercury's perihelion from Le Verrier to Einstein (Oxford, 1982).

The Adams result was published in the US and reprinted in the UK: Adams Walter S. , “The relativity displacement of the spectral lines in the companion of Sirius”, Proceedings of the National Academy of Sciences , xi (1925), 382–7, and Adams Walter S. , “The relativity displacement of the spectral lines in the companion of Sirius”, The observatory, xlviii (1925), 1925–42.

Crelinsten Jeffrey , Einstein's jury: The race to test relativity (Princeton 2006), 277–82. As Crelinsten shows, the announcement of the Sirius B results came at a critical period when both the validity and the interpretation of the deflection of starlight measurements were being debated.

Holberg J. B. Wesemael F. , “The discovery of the companion of Sirius and its aftermath”, Journal for the history of astronomy, xxxviii (2007), 161–74.

Holberg J. B. , “The discovery of the existence of white dwarf stars: 1862–1930”, Journal for the history of astronomy, xl (2009), 137–54.

Hetherington Norriss S. , “Sirius B and the gravitational redshift: An historical review”, Quarterly journal of the Royal Astronomical Society, xxi (1980), 246–52; Greenstein Jesse L. Oke J. B. , and Shipman H. L. , “On the redshift of Sirius B”, Quarterly journal of the Royal Astronomical Society, xxvi (1985), 1985–88; and Wesemael F. , “A comment on Adams' measurement of the gravitational redshift of Sirius B”, Quarterly journal of the Royal Astronomical Society, xxvi (1985), 1985–8.

Barstow Martin A. Bond H. E. Holberg J. B. Burleigh M. R. Hubeny I. Koester D. , “Hubble Space Telescope spectroscopy of the Balmer lines in Sirius B”, Monthly notices of the Royal Astronomical Society, ccclxii (2005), 1134–42.

Barstow , op. cit. (ref. 7), 1140–1.

Eisenstaedt Jean , The curious history of relativity: How Einstein's theory of gravity was lost and found again, transl. by Sangalli Arturo (Princeton, 2006), 150–9.

For a discussion of the historical solar redshift question, see Earman John Glymour Clark , “The gravitational redshift as a test of General Relativity: History and analysis”, Studies in history and philosophy of science, xi (1980), 175–214; Forbes Eric Gray , “A history of the solar red shift problem”, Annals of science, xvii (1961), 1961–64; and Hentschel Klaus , The Einstein tower: An intertexture of dynamic construction, relativity theory and astronomy, transl. by Hentschel Ann M. (Stanford, 1997).

Devorkin David H. , “Michelson and the problem of stellar diameters”, Journal for the history of astronomy, vi (1975), 1–18.

Holberg , op. cit. (ref. 5), 146–7.

Adams Walter S. , “The relativity displacement of the spectral lines in the companion of Sirius”, Proceedings of the National Academy of Sciences, xi (1925), 382–7.

Reproductions of the relevant Eddington—Adams correspondence are contained in Appendix D of Stefano Lecchini, How dwarfs became giants: The discovery of the mass—luminosity relation (Bern, 2007). Several of Eddington's letters are quoted from in A. Vibert Douglas. The life of Arthur Stanley Eddington (London, 1956), and several of Adams's and Eddington's letters are quoted from in Jeffrey Crelinsten, op. cit. (ref. 2), 277–82. Complete transcripts of the Eddington—Adams letters are provided in the Appendix.

Eddington A. S. , “On the relation between the masses and luminosities of the stars”, Monthly notices of the Royal Astronomical Society, lxxxiv (1924), 308–32, p. 322.

Eddington to Adams, 13 January 1924, Arthur Eddington Collection, Queen's University Archive. Handwritten letter, see Appendix.

Hetherington Norriss S. , “Sirius B and the gravitational redshift: An historical review”, Quarterly journal of the Royal Astronomical Society, xxi (1980), 246–52.

Eddington A. S. , Stars and atoms (Oxford, 1927), 53: “To me personally Einstein's theory gives much stronger assurance of the real existence of the effects [the solar Einstein shift]”.

Holberg , op. cit. (ref. 5), 142 and 146.

Campbell W. W. , “Notes on the binary star Sirius”, Publications of the Astronomical Society of the Pacific, xxxii (1920), 199–200.

Eddington A. S. , The internal constitution of the stars (Cambridge, 1926), 171.

Eddington to Adams, 6 February 1924, Folder 19.336 of the Walter Sydney Adams Papers, Huntington Library. Handwritten letter, see Appendix. The last sentence refers to Adams's 1915 spectrum of Sirius B, which was assigned an A' spectral type.

Adams to Eddington, 12 February 1924, Folder 19.336 of the Walter Sydney Adams Papers, Huntington Library. Typewritten letter, see Appendix. The last sentence refers to a film copy of a Sirius B spectrum, which has not come to light.

Eddington to Adams, 3 March 1924, Folder 19.336 of the Walter Sydney Adams Papers, Huntington Library. Handwritten letter, see Appendix.

It is not clear here if Adams refers to his pre-existing Sirius B plates or to recently obtained ones, or both. He undoubtedly had the opportunity to obtain further observations during February 1924.

Eddington to Adams, 22 March 1924, Folder 19.336 of the Walter Sydney Adams Papers, Huntington Library. Handwritten letter, see Appendix. Included with the letter was a copy of Eddington's now famous plot of mass v. luminosity contained in his op. cit. (ref. 15).

Adams to Eddington, 24 April 1924, Folder 19.336 of the Walter Sydney Adams Papers, Huntington Library. Typewritten letter, see Appendix.

Crelinsten , op. cit. (ref. 3), 178.

Adams , op. cit. (ref. 13).

“New Test Supports Einstein's Theory”, The New York Times, 21 July 1925, 21. The article was prompted by Eddington's IAU announcement and dealt primarily with his ideas on degenerate stars.

Strömberg Gustaf , “Note concerning the radial velocity of the companion of Sirius”, Publications of the Astronomical Society of the Pacific, xxxviii (1926), 44.

Adams Walter S. , “The radial velocity of the companion of Sirius”, The observatory, xlix (1926), 88.

Adams , op. cit. (ref. 13), 387.

Adams , op. cit. (ref. 13), 387.

Eddington , op. cit. (ref. 21), 173.

Adams , op. cit. (ref. 13), 383. “The distribution of light in the continuous spectrum is noticeably different from that of the scattered light from Sirius, and resembles that of an F-type star in being considerably more intense toward the longer wave-lengths. As a result, the spectrum of the companion may be obtained nearly free from the spectrum of Sirius at Hβ, while at Hγ the superposition is very pronounced. At wave-lengths shorter than Hδ the spectrum of the companion can hardly be seen upon that produced by the scattered light of Sirius. A consideration of these various features indicates that a classification of the spectrum as F0 is probably not seriously in error, although the line spectrum by itself would indicate a somewhat earlier type. It should be noted, moreover, that the increase in the amount of scattering towards shorter wave-lengths would tend to make the violet portion of the continuous spectrum from the scattered light somewhat more intense than the case for Sirius itself. This may well account for a part of the difference observed. It seems probable, therefore, that the spectrum of the companion should be classified somewhat earlier rather than later than F0”.

Adams , op. cit. (ref. 13), 387.

Moore J. H. , “Recent spectrographic observations of the companion of Sirius”, Publications of the Astronomical Society of the Pacific, xl (1928), 229–33.

Moore , op. cit. (ref. 38), 231.

Eddington , op. cit. (ref. 21), 164–5.

Lecchini , op. cit. (ref. 14), 57–90.

Eddington A. S. , “On the relation between the masses and luminosities of the stars”, The observatory, xlvii (1924), 107–12, p. 110.

Moore , op. cit. (ref. 38), 229–31.

Searches of the plate vault at the Mt Wilson Observatory failed to yield any of the 28 high dispersion plates of Sirius B obtained by Adams or others during the mid-1920s. As mentioned, the Sirius B plates and Adams's logbook were examined by Jesse Greenstein in 1985. Examination of inventories of Adams files at the Huntington Library and of Dr Greenstein's files at the California Institute of Technology and inquiries at Mt Palomar have not succeeded in locating Adams's observing logbook or the plates, nor have inquiries with Adams's niece and biographer, Sue Kelly Adams.

The plates were scanned at high resolution (∼ 2800 lines per inch) on a flatbed scanner (by Anthony Mirsh of Lick Observatory). The corresponding image files were then sampled as one-dimensional intensity plots on an arbitrary intensity scale.

DeVorkin David H. , “Internationalism, Kapteyn and the Dutch pipleline”, in The legacy of J. C. Kapteyn, ed. by Van Der Kruit P. C. Van Berkel K. (Dordrecht, 2000), 129–50.

Kuiper Gerard P. , “List of known white dwarfs”, Publications of the Astronomical Society of the Pacific, liii (1941), 248–353.

Russell Henry Norriss , “The constitution of the stars”, Science, lxxvi (1933), 65–79.

Wesemael François , “Unaffected by fortune, good or bad: Context and reception of Chandrasekhar's mass—radius relationship for white dwarfs, 1935–1965”, Annals of science, lxvi (2009), in press.

Kuiper G. P. , “White dwarfs: Discovery, observations, surface conditions”, in Novae and white dwarfs, iii: White dwarfs, ed. by Shaler A. J. (Paris, 1941), 201–37.

Schatzman E. , White dwarfs (Amsterdam, 1958), 68–73.

Marshak R. E. , “The internal temperature of white dwarf stars”, The astrophysical journal, xcii (1940), 321–53.

Marshak , op. cit. (ref. 52), 351.

Popper Daniel M. , “Red shift in the spectrum of 40 Eridani B”, The astrophysical journal, cxx (1954), 316–22.

Holberg , op. cit. (ref. 4), 143–5.

Greenstein Jesse L. Oke J. B. Shipman Harry , “Effective temperature, radius and gravitational redshift of Sirius B”, The astrophysical journal, clxix (1971), 563–6.

Greenstein , op. cit. (ref. 56), 563.

Barstow , op. cit. (ref. 7).

Kragh Helge Smith Robert W. , “Who discovered the expanding universe?”, History of science, xli (2003), 141–62.

Einstein Albert , Out of my later years (New York, 1950), 58.

Finlay-Freundlich E. , “On the empirical foundation of the General Theory of Relativity”, Vistas in astronomy, i (1955), 239–46, p. 242.

See for example Duncan John Charles , Astronomy: A text book (New York, 1946), 380, and Baker Robert H. , Astronomy: A text book for university college students (Princeton, 1955), 386.

Larousse encyclopedia of astronomy (New York, 1962), 464.

Pound R. V. Rebka G. A. Jr , “The apparent weight of photons”, Physical review letters, iv (1960), 337–41. This reference concerns a precise laboratory measurement of the gravitational redshift of gamma rays using the Mössbauer effect.

Bondi H. , “Fact and inference in theory and in observation”, Vistas in astronomy, i (1955), 155–62, p. 159.

Hetherington , op. cit. (ref. 17), 246–52.

Hetherington , op. cit. (ref. 17), 250.

Greenstein , op. cit. (ref. 56), 563. Harry Shipman confirms that although he was third author he basically wrote the published version of the paper and that he was responsible for the phrase “of historical interest only”, although he recalls hearing the phrase from J. B. Oke prior to writing the paper. Hetherington, it seems, attributed the phrase to Greenstein.

See, for example, Earman John Glymour Clark , “Relativity and eclipses: The British eclipse expeditions of 1919 and their predecessors”, Historical studies in the physical sciences, xi (1980), 49–85, and Collins Harry Pinch Trevor , The Golem: What everyone should know about science (Cambridge, 1993), 43–55. These references raise questions about Eddington's treatment of the eclipse data and imply that his enthusiasm for General Relativity and his eagerness to rehabilitate German science following the First World War coloured his results. More recent examinations of Eddington and the eclipse data, for example, Stanley Matthew , Practical mystic: Religion, science and A. S. Eddington (Chicago, 2007), and Kennefick Daniel , “Testing relativity from the 1919 eclipse: A question of bias”, Physics today, lxii (2009), 2009–42, show that these reservations are largely unfounded.

Greenstein Jesse L. Oke J. B. , and Shipman Harry , “On the redshift of Sirius B”, Quarterly journal of the Royal Astronomical Society, xxvi (1985), 279–88.

Greenstein , op. cit. (ref. 70), 285.

Wesemael F. , “A comment on Adams' measurement of the gravitational redshift of Sirius B”, Quarterly journal of the Royal Astronomical Society, xxvi (1985), 273–8.

Smith Robert W. , “Beyond the galaxy”, Journal for the history of astronomy, xl (2009), 71–107, p. 73.

See Gamow G. Critchfield C. L. , Theory of atomic nucleus and nuclear energy-sources (Oxford, 1949), 293. In their discussion of the Sirius B radius the authors note the incompatibility with the gravitational redshift and go on state in a footnote that: “Nevertheless this explanation [a faulty redshift] has been proved in 1948 to be correct. The point is that the spectrum of Sirius B is strongly blended with that of the main star, which affects the apparent positions of its absorption lines. If allowance is made for the blending, one arrives at the value of radius consistent with the degenerated model with zero hydrogen content.” This is of course the correct answer but the authors give no source for this information. Nothing appears to have been published on this in 1948 and subsequent discussions of the Sirius B redshift contain no mention of such a demonstration. Nevertheless the above statement indicates that some at least were aware of the scattered light explanation prior to 1950. The source of this information could not have been new observations of Sirius B since it was unobservable at the time. The origin is likely to have been an unpublished re-examination of the original Mt Wilson or Lick plates by an experienced astronomer.