On November 6, 1572, German astronomer Wolfgang Schulër spotted an exploding star in the constellation Cassiopeia with his bare eyes, observing an object as bright as Venus that remained visible even during daylight.
At the end of the Dark Ages in Europe, these observations provided a piece of evidence that the heavens were not immutable, according to astronomer Alex Filippenko, who led a 2004 study on the origins of the Tycho supernova. The object is known today as SN 1572, a Type Ia supernova originating from a binary star system where a white dwarf drew material away from its partner before exploding. Astronomers at the time were thoroughly confused because the cosmic explosion looked like a star appearing out of nowhere. While Schulër observed the phenomenon first, Tycho Brahe studied it extensively.
Tycho Brahe Records Supernova Brightness
Brahe found that it showed no shift against the background stars, unlike the Moon, proving it had to lie far beyond the Moon. Brahe’s meticulous record of the brightening and dimming of the supernova now allows modern astronomers to identify its light signature as that of a Type Ia supernova.
Several people saw the new star in early November 1572, and Tycho Brahe noticed it on November 11. Brahe studied it in detail and wrote a whole book about this so-called “new star,” after which it became known as Tycho’s Star. At the time, supernovas had not yet been discovered, and Tycho’s Star was finally classified as a supernova in the 1940s. Researchers currently believe that an ancient explosion of a compact white dwarf star took place ages ago. Because Tycho’s Star is thousands of light-years from Earth, it took a while before anyone could see it.
On Nov. 6, 1572, the German astronomer Wolfgang Schulër observed a supernova later caleld the Tycho supernova with his bare eyes. Here's why it mattered. https://t.co/qvsenzWxCa
Telescopes Measure Supernova Remnant Distance
While NASA’s Chandra team estimates the distance to the expanding shell to be approximately 13,000 light-years, other research papers suggest figures as low as roughly 8,000. Tycho’s Supernova Remnant is a nearly round shell of hot gas, featuring a sharp blast-wave edge and clumpy debris inside. The expanding wreckage of SN 1572 appeared in Cassiopeia in November 1572 and was studied by Tycho Brahe. You can still find the field, sitting about 1.5 degrees northwest of Kappa Cassiopeiae.
Astronomers managed to capture a spectrum of the 436-year-old blast in 2008 when illumination from Tycho’s supernova reflected off far-off dust clouds and arrived at Earth, with Subaru Telescope observations of this light echo revealing a standard Type Ia supernova. Centuries after the blasts, Tycho’s Star and Cassiopeia A achieved recognition in 2008 by becoming the inaugural Milky Way supernovae categorized using the spectra of their individual light echoes. A group directed by Kristoffer Eriksen published findings in 2011 detailing an arrangement of X-ray stripes close to the outer edge, aligning with theoretical models for protons boosted to massive velocities as a potential indicator that supernova explosions generate cosmic rays, although the investigators emphasized that alternative interpretations are viable. Whether a surviving companion star sits inside is debated, as a candidate proposed in 2004 has been challenged by later studies.
T Corona Borealis belongs to a rare group of only 11 documented stars recognized for exhibiting repeated nova outbursts separated by roughly a century. Known alternatively as T Corona Borealis or the Blaze Star, this stellar system is anticipated to experience a nova eruption shortly—an outburst of lesser magnitude than a supernova that might leave the star intact. Today, astronomers are closely watching another star that might explode.