Stars over Sisters

The February night sky contains a large and rather prominent geometric figure. Face south and you will see an equilateral triangle.

The winter triangle is formed by three bright stars located in three different constellations. The two northern-most points of the triangle are marked by Betelgeuse, in Orion, and Procyon, in Canis Minor (the smaller dog). The third, and most luminous, member of the triangle is Sirius, located in Canis Major (the larger dog). In fact, Sirius is the brightest star in the entire sky.

To find Sirius, locate the three stars in Orion's belt, then look to the southeast for the brilliant star.

Excluding the sun, Sirius is the fifth-nearest star to the earth, lying a mere 8.6 light-years away. It turns out that Sirius does not lead a solitary existence, but shares nearby space with a white dwarf companion star. Known as Sirius B, or the Pup, this companion star has some remarkable properties. Orbiting very close to Sirius, the star has about the same mass as our sun but is only 7,500 miles in diameter - that's smaller than the size of the earth.

This makes Sirius B extremely dense; one cubic inch of its material weighs more than two tons!

According to ancient mythology, Canis Major represents Orion's larger hunting dog that is pursuing Lepus the hare. Another version of the story claims the dog is helping Orion fight Taurus the bull.

A very fine star cluster, known as M41, is located about four degrees south of Sirius. It contains at least 100 stars and is visible without optical aid on a dark, moonless night. When viewed through a telescope, a bright reddish star can be seen near the center of the cluster. Astronomers estimate M41 to be at least 190 million years old.

Currently located in the constellation of Pisces, Venus continues to rise higher in the west throughout February and doesn't set until almost 10 p.m. by month's end. Still in Aries, Jupiter has now slipped into the western sky by nightfall and will set at about 10:45 p.m. as February draws to a close. A brightening Mars is on the ascent in the east, appearing as a prominent orange star in the constellation of Leo.

Moon phases for the month show that we will have a full moon on February 7, last quarter on February 14, and new moon on February 21. Since January had two first-quarter moons, no first-quarter phase will occur in February.