[BITList] Fwd: Bright star

[John Feltham]

G'day 

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> From: oxforddnb-lotd at oup.com
> Date: 17 September 2012 8:00:00 GMT+02:00
> To: ODNBLIFEOFTHEDAY-L at WEBBER.UK.HUB.OUP.COM
> Subject: Bright star
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> To read this Life of the Day complete with a picture of the subject,
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> 
> Goodricke,  John  (1764-1786), astronomer, was born on 17 September 1764 in Groningen, Netherlands, the eldest child of Henry Goodricke (d. 1784), of the British consular service, and his wife, Levina Benjamina, the daughter of Peter Sessler of Namur. He became deaf and mute in infancy, and at the age of eight was sent to Edinburgh, where there was a school for deaf mutes. By 1778 he had progressed well enough to transfer to Warrington Academy, Lancashire, where he distinguished himself in mathematics.
> 
> In 1776 the Goodricke family had returned to York from the Netherlands, and from 1781 their neighbours included Nathaniel Pigott and his son Edward, accomplished astronomers with a small private observatory. Goodricke and Edward Pigott found a shared interest in stellar astronomy, and Edward was soon combing the literature for data on variable stars. In November he chanced upon a comet, and informed Goodricke, who noted the discovery as the first entry in his 'Journal of astronomical observations'. The following April Goodricke acquired a 2 foot achromatic refractor by Dollond, and the two friends joined forces to monitor variable stars.
> 
> On 7 November 1782 Goodricke routinely noted that the star Algol was as usual of second magnitude, but on 12 November he found it had declined to fourth magnitude. The following night, however, it was again of second magnitude. Such rapid changes in the brightness of a star were unprecedented, and so both men kept watch on Algol. On 28 December each saw the star change brightness in front of his very eyes, and next day Pigott sent a note to Goodricke suggesting that the star was being eclipsed by a dark companion.
> 
> In the following weeks the two friends monitored Algol's brightness and found that the variation occurred in a little under two days, twenty-one hours. Pigott allowed Goodricke to be the sole author of a paper read to the Royal Society on 15 May 1783 announcing the discovery. Variations in the brightness of a star were usually ascribed to the star's having dark patches, analogous to (but much larger than) sunspots: cyclic variations were due to the rotation of the star, while non-cyclic ones were due to changes in the dark patches. Still aged only seventeen, and hesitant to propose a dramatically new explanation of variable stars, Goodricke in his paper declared his purpose was 'to communicate facts', and the eclipse hypothesis he merely mentioned in passing, as a possible alternative to the accepted dark patches. The paper earned Goodricke a Copley medal of the Royal Society.
> 
> The eclipse hypothesis, which is the correct explanation of Algol's variations, was soon abandoned by Pigott and Goodricke. The hypothesis implied that the light curve of the star would have a symmetry about its minimum, and the two friends may have been deceived by changes in seeing conditions into thinking this was not the case. Also, the hypothesis did not fit the three other short-period variables discovered by the York astronomers. In September 1784 Goodricke found that b Lyrae varied in brightness, and in a paper read to the Royal Society on 27 January 1785 he assigned it a light curve with two minima and a period of twelve days, nineteen hours. Also in September 1784, Pigott discovered the variability of e Aquilae; and the following month Goodricke discovered that of d Cephei. Both stars are of the type known as Cepheid variables, with d Cephei as the type star; they are in fact pulsating stars, with light curves that rise rapidly to a maximum every few days and then slowly decline, changes that cannot be explained by eclipses. But the discoveries of the two York astronomers had enriched astronomy with a new class of variable stars, those whose periods occupy only a few days.
> 
> During 1785 and the first months of 1786 the bulk of Goodricke's observing time was dedicated to the re-examination of these known variables. On 30 March 1786 he examined b Lyrae for the twelfth time that month; but soon thereafter he was taken ill, apparently because of exposure to the night air, and he died in his home at Lendal, York, on 20 April. He had been elected to the Royal Society just two weeks earlier. He was buried in the family vault at Hunsingore, Yorkshire.
> 
> Michael Hoskin 
> 
> Sources  C. A. Goodricke, 'Gift to the society of a portrait of John Goodricke', Monthly Notices of the Royal Astronomical Society, 73 (1912-13), 3-4 + M. Hoskin, 'Goodricke, Pigott and the quest for variable stars', Journal for the History of Astronomy, 10 (1979), 23-41 + C. Gilman, 'John Goodricke and his variable stars', Sky and Telescope, 56 (1978), 400-03 + DNB
> Archives York City Archives, Goodricke and Piggott MSS + York City Archives, notebooks and corresp.
> Likenesses  pastel drawing, 1785, RAS [see illus.] · portrait; at Gilling Castle, Yorkshire in 1890
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