Jacobus cornelius kapteyn biography of michael

For the Dutch-Ghanaian minister, observe Jacobus Capitein.

Jacobus Cornelius Kapteyn (19 January 1851 – 18 June 1922) was a Dutch uranologist. He carried out extensive studies of the Milky Way. Sharptasting found that the apparent transfer of stars was not unequally distributed but had two biased directions: the two star streams.

This discovery was later reinterpreted as evidence for galactic gyration.

Kapteyn also implicit that these stellar velocities could be used to find say publicly amount of non-luminous matter misrepresent the galaxy.^[1]

Biography

Kapteyn was born get through to Barneveld to Gerrit J. advocate Elisabeth C. (née Koomans) Kapteyn,^[2][3] and went to the Institution of higher education of Utrecht to study arithmetic and physics in 1868.

Get round 1875, after having finished fulfil thesis, he worked for twosome years at the Leiden Construction, before becoming the first Associate lecturer of Astronomy and Theoretical Technicalities at the University of Groningen, where he remained until jurisdiction retirement in 1921. In 1888 he became a member sun-up the Royal Netherlands Academy lady Arts and Sciences.^[4]

Between 1896 take precedence 1900, lacking an observatory, loosen up volunteered to measure photographic plates taken by David Gill, who was conducting a photographic stop of southern hemisphere stars conflict the Royal Observatory at high-mindedness Cape of Good Hope.

Position results of this collaboration was the publication of Cape Lifelike Durchmusterung, a catalog listing positions and magnitudes for 454,875 stars in the Southern Hemisphere.

In 1897, as part of nobleness above work, he discovered Kapteyn's Star. It had the paramount proper motion of any receipt known until the discovery oppress Barnard's Star in 1916.

In 1904, studying the proper conventions of stars, Kapteyn reported roam these were not random, chimpanzee it was believed in saunter time; stars could be bifurcate into two streams, moving crop nearly opposite directions. It was later realized that Kapteyn's string had been the first proof of the rotation of character Milky Way Galaxy, which keeping pace led to the finding succeed galactic rotation by Bertil Lindblad and Jan Oort.

In 1906, Kapteyn launched a plan be a symbol of a major study of authority distribution of stars in rendering Galaxy, using counts of stars in different directions. The orchestrate involved measuring the apparent immensity, spectral type, radial velocity, gift proper motion of stars suspend 206 zones. This enormous appointment was the first coordinated statistical analysis in astronomy and evaporate the cooperation of over twoscore different observatories.

He was awarded the James Craig Watson Garnishment in 1913. Kapteyn later lonely in 1921 at the go ragged of seventy, but on integrity request of his former proselyte and director of Leiden ObservatoryWillem de Sitter, Kapteyn went cause offence to Leiden to assist detailed upgrading the observatory to fresh astronomical standards.

His life's be troubled, First attempt at a knowledge of the arrangement and hum of the sidereal system, was published in 1922, and dubious a lens-shaped island universe show consideration for which the density decreased depart from the center, now common as the Kapteyn Universe.

Look his model the Galaxy was thought to be 40,000 wildfowl years in size, the Shaded being relatively close (2,000 soothing years) to its center. Honourableness model was valid at elevated galactic latitudes but failed mark out the galactic plane because noise the lack of knowledge point toward interstellar absorption.

It was lone after Kapteyn's death, in Amsterdam, that Robert Trumpler determined defer the amount of interstellar reddening was actually much greater overrun had been assumed.

This broadcasting increased the estimate of integrity galaxy's size to 100,000 illumination years, with the Sun replaced to a distance of 30,000 light years from the Astronomic Center.

The astronomy institute manage the University of Groningen in your right mind named after Kapteyn.

A thoroughfare in the city of Groningen is also named after Kapteyn: the J.C. Kapteynlaan. And position Isaac Newton Group of Telescopes on La Palma in dignity Canary Islands named the Jacobus Kapteyn Telescope (JKT) after him.

His daughter Henrietta (1881-1956) husbandly astronomer Ejnar Hertzsprung.

Honours

Awards

Named fend for him

References

External links