Observational history Epsilon Aurigae

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the ε aurigae system during eclipse (artist impression)


although star visible naked eye, johann fritsch s 1821 observations suggest first notice system variable. eventually, 1842 1848, german mathematician eduard heis , prussian astronomer friedrich wilhelm argelander began observing once every few years. both heis , argelander s data revealed star had become dimmer 1847, attracting full attention of both men @ point. epsilon aurigae had brightened significantly, , had returned normal following september. attracted more attention, more , more data compiled. observational data revealed epsilon aurigae did not vary on long period, experienced short-term variations in brightness well. later eclipses took place between 1874 , 1875 and, thirty years later, between 1901 , 1902.


hans ludendorff, had been observing epsilon aurigae, first conduct detailed study of star. in 1904, published in astronomische nachrichten article titled untersuchungen über den lichtwechsel von ε aurigae (investigations of light changes of epsilon aurigae), suggested star algol variable , eclipsing binary.


the first hypothesis, set forth in 1937 astronomers gerard kuiper, otto struve, , bengt strömgren, suggested epsilon aurigae binary star system containing f2 supergiant , extremely cool semitransparent star eclipse companion. however, eclipsing star scatter light emitted eclipsed companion resulting in observed decrease in magnitude. scattered light detected on earth star visible naked eye, although light dimmed.


in 1961, italian astrophysicist margherita hack proposed secondary hot star surrounded shell of material, responsible eclipse, after observing though 1955-57 eclipse.


astronomer su-shu huang published paper in 1965 outlined defects of kuiper-struve-strömgren model, , proposed companion large disk system, edge-on perspective of earth. robert wilson, in 1971, proposed central opening lay in disk, possible reason system s sudden brightening midway through eclipse. in 2005, system observed in ultraviolet far ultraviolet spectroscopic explorer (fuse); star system not emitting energy @ rates characteristic of objects such neutron star binary system circinus x-1 or black hole binary system cygnus x-1, object occupying center of disk not expected of sort; in contrast, new hypothesis has suggested central object b5-type star.


epsilon aurigae targeted observation international year of astronomy observers 2009 2011, 3 years overlapped recent eclipse.








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