The Ellensburg, WA sky for the week of December 28, 2024

Saturday: Red is a popular Christmas color. It is also a popular star color. And R Leporis, also known as Hind’s Crimson Star, is one of the reddest stars in the sky. It is a star near the end of its life that has burned its helium nuclei into carbon. Convective currents, like those in a pot of boiling water, bring this carbon to the surface. There it forms a layer of soot that scatters away the light from the blue end of the visible spectrum leaving the light from the red end of the spectrum to reach our eyes. For more information about Hind’s Crimson Star and a list of other deep red stars, go to http://goo.gl/EnhRe4. Hind’s Crimson star is one fist to the lower right of Rigel, the brightest star in Orion. You’ll need binoculars or a small telescope to see Hind's Crimson star. But you can easily spot Rigel two and a half fists held upright and at arm’s length above due southeast at 8:00 p.m.

Sunday: Mercury is a half a fist above the southeastern horizon at 7:00 a.m.

Monday: Venus is two fists above the southwestern horizon and Saturn is three fists above the south-southwestern horizon at 6:00 p.m.

Tuesday: Jupiter is six fists above due southeast and Mars is three fists above due east at 9:00 p.m.

Wednesday: Today is the day we celebrate the anniversary of something new – a new classification of celestial objects. Giuseppe Piazzi discovered Ceres [pronounced sear’-ease], the first of what are now called “asteroids”, on January 1, 1801. Ceres is the largest asteroid in the belt between Mars and Jupiter. At first, Piazzi thought it was a star that didn’t show up on his charts. But he noted its position changed with respect to the background stars from night to night. This indicated to him that it had to be orbiting the Sun. The International Astronomical Union promoted Ceres to the status of “dwarf planet” in August of 2006.

Thursday: Late tonight and early morning’s weather forecast: showers. Meteor showers, that is. The Quadrantid meteor shower peaks late tonight and early tomorrow morning between midnight and dawn. Meteor showers are named after the constellation from which the meteors appear to originate. That makes this shower mysterious because there isn’t any constellation with this name now. The shower was named after Quadrans Muralis, an obsolete constellation found in some early 19^th century star atlases. These meteors appear to come from a point in the modern constellation Draco the dragon. This point is about three fists above the northeastern horizon at 1:00 a.m. This year, the Moon sets early in the evening so even the dimmer meteors will be visible.

Meteors are tiny rocks that hit the Earth and burn up in the atmosphere. Most meteors are associated with the path of a comet. This shower consists of the debris from an asteroid discovered in 2003. Keeping with the comet-origin paradigm, astronomers think the asteroid is actually an “extinct” comet, a comet that lost all its ice as it passed by the Sun during its many orbits. For more information about the Quadrantid meteor shower, go to http://earthsky.org/?p=155137.

Friday: Now that you know meteors are rocks that burn up in the atmosphere, you will soon start to wonder what would happen if those rocks hit the surface of the Earth. Well, wonder no more. The browser-based app called Asteroid Launcher will simulate the collisions. You select the asteroid type, size, speed, and angle of impact. The most common impactor material is stone, and the typical speed is 40,000 miles per hour, in case you want to introduce some realism into your simulation. Go to https://neal.fun/asteroid-launcher/, click on the map where you want the asteroid to land and then launch your virtual asteroid.

The positional information in this column about stars and planets is typically accurate for the entire week. For up-to-date information about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm. All times are Pacific Time unless noted.