The Dog Days of Summer are upon us, and down here on the Gulf Coast, Sunna is working overtime. Late July/early August is also the time when Sirius becomes the morning star, rising at dawn before the Sun and twinkling with extra vigor due to the unsettled summer weather.
Sirius A, also known as the "Dog Star," is the brightest star in Canis Major (the constellation forming one of Orion's two hunting dogs which help him fight his adversary, Taurus the Bull). Burning brightly at a temperature of about 10,000 Celsius, it's about twice as heavy as our Sun and a relative spring chicken as age goes (only 230 million years old compared with our Sól at 5,500 million). It's not really all that bright as stars go, but it has the advantage of being nearby the Earth (a mere 8.6 light years away), which makes it appear extra bright to us. Its companion, Sirius B (nicknamed "The Pup"), is a white dwarf, once a star more massive than Sirius but now cooling down into an eventual dead black orb in about 2 billion years or so.
The Greeks called it Seirios ("Scorcher") and were the ones who named these hot, humid days of late summer the "dog days," because dogs were thought to suffer and become listless in the heat brought by this star. The Zoroastrians in Persia called it Tishtrya and honored it as the divinity of rain and fertility. Chinese astronomers knew it as the star of the "celestial wolf," and it was also associated with dogs by a number of indigenous North American tribes. The Egyptians regarded its rising early as good news, because it was a sign that the Nile was about to flood and bring fertility and a good harvest to the surrounding lands.
In Norse folklore, however, Sirius was known as Lokabrenna ("Loki's torch" or "the burning by Loki"), a name reminiscent of the conflagration of the universe at Ragnarok. The name may also have referred to the summer heat rather than the star itself. In Iceland, it was associated with the ignis fatuus, or will 'o the wisp, a phosphorescent light sometimes seen floating over marshy ground at night. Certainly it's an appropriate time for Loki, when wildfires are rife and tempers are combustible.
It's also a good time of year to sit outdoors in the wee hours, enjoy the Perseid meteors and a few cold beverages, tell a few tales, sing some bawdy songs, and wait for the predawn hours and the rising of one of the brightest stars in the summer sky.
...resplendent as the star
Autumnal, of all stars in dead of night
Conspicuous most, and named Orion's dog;
brightest it shines, but ominous and dire
Disease portends to miserable man.
Homer's Iliad (transl. William Cowper)