Stars over Sisters 2/01/2023
Last updated 1/31/2023 at Noon
Despite February’s propensity for clouds and cold temperatures, there are many fine spectacles to behold in Central Oregon’s starry realm when skies are clear. This month’s constellation of focus is Canis Major. It is a medium-sized constellation, 43rd largest, and is situated southeast of Orion.
Canis Major is unique among the constellations in that it contains the brightest star in the sky, namely Sirius, which shines with a blazing apparent magnitude of -1.42. This brilliant luminary stands about 25 degrees above the southern horizon at 9 p.m. local time.
Sirius has yet another claim to fame, in that it is a binary star whose companion, Sirius B, is the brightest and nearest white dwarf star. White dwarfs are tiny, dim,very dense dying stars that have spent all their nuclear fuel, the ultimate fate of all medium- to low-mass stars, including our sun. A spoonful of material from Sirius B would weigh (on Earth) two metric tons!
The constellation’s most notable deep-sky object is Messier 41, an open cluster containing around 100 stars, found about 4 degrees south of Sirius. Other deep-sky items worthy of mention include the Canis Major Dwarf Galaxy, emission nebula NGC 2359 (Thor’s Helmet), and two galaxies in the process of colliding.
NGC 2207 and IC 2163 are a pair of spiral galaxies that are so close together in space that they are gravitationally interacting with each other. The larger galaxy NGC 2207 (at left in photo) is pulling vast amounts of gas and dust from its smaller neighbor, which will eventually increase the rate of star formation in both galaxies. They are expected to merge into a single elliptical galaxy in approximately one billion years.
According to Greek mythology, Canis Major, or the “greater dog,” follows Orion the hunter across the sky. The canine appears to be standing on its hind legs chasing a hare, representing the constellation Lepus. First-century Roman poet Marcus Manilius described Canis Major as “the dog with the blazing face” because brilliant Sirius is located within its jaws. He is associated with the Laelaps, the fastest hound in the world. Zeus put the speedy dog in the sky after he was stuck in an unending race with a fox.
On February 1, the sun will rise at 7:24 a.m. and set at 5:16 p.m. from our location here in Sisters. But as our life-sustaining star continues its slow ascent into the sky, sunrise will occur 39 minutes earlier and sunset 37 minutes later by the end of the month.
Discovered in March 2022, the green-colored comet C/2022 E3 (ZTF) is currently cruising through the inner solar system. It reached perihelion (closest point to the sun) on January 12 and will pass within 27 million miles of Earth on February 2. So far, the comet has only been seen/imaged through telescopes, but by late January into February it might become visible through a pair of ordinary binoculars or possibly the naked eye. Unless the comet brightens dramatically, the best chance of finding it might be on February 10 when it will pass very close to the planet Mars in Taurus. Take your best shot at this comet because it may turn out to be the brightest one in 2023.
The full moon on February 5 and an advanced waxing trend toward the end of the month will result in bright evening skies. Plan your stargazing activities for the darker conditions that will prevail near mid-month, such as searching for comet C/2022 E3 (ZTF).
February’s dark-sky tip is to turn off lights when not in use. Whenever possible, use electrical timers to turn your outdoor lights on and off at the same time every night. Otherwise, shut off porch and property lights when you go inside or go to bed for the night. This will conserve electricity, save you money, and help reduce our community’s growing light dome.