What’s Up in the Sky
At any moment of the day, countless awe-inspiring celestial events are unfolding in the sky. With a universe of options, it can be hard to pin down what to observe, what to look into or what to remember. Each week, this column will take a peek at what’s happening in the sky and in the world of astronomy in general to provide a quick list of highlights that can jumpstart your own explorations.
What to observe:
November 5-6 - South Taurids Meteor Shower Peaks
Set to peak around November 5th, the South Taurids Meteor Shower usually does not produce a prolific amount of meteors per hour. But of the less than 10 that do occur, there is a greater chance that some of these might be of the quite spectacular and particularly bright “fireball” variety. The Taurids, which appear to radiate from the Taurus the Bull constellation, will appear best in the Northern Hemisphere and most active between midnight and dawn. The nearly full Moon will provide significant interference so patience will be required. To view the show, all you need is your naked eye and a good place to lie down under an open sky. The related North Taurids Meteor Shower will reach its peak next week around November 12th.
In mythology, Cassiopeia was a vain creature undone by her arrogance. But the circumpolar constellation that bears her name certainly has some celestial beauties worth boasting about. Visible from 90° North to 20° South, Cassiopeia is known for the striking “W”-shaped asterism that is formed by its five brightest stars. The yellow-white giant Beta Cassiopeiae anchors one end of the “W.” Also known as Caph, this star is one of the brightest Delta Scuti type variables to grace the sky and has an average apparent magnitude of 2.27. The next point in the “W” is the orange giant Schedar (Alpha Cassiopeiae), which marks the heart of the doomed queen. The brilliant blue Gamma Cassiopeiae lies at the center of the famous asterism. Categorized as an eruptive variable, this star can outshine both Schedar and Caph when its intensity peaks. Nicknamed Navi by U.S. Astronaut Gus Grissom because of its usefulness as a navigational point in space, Gamma Cassiopeiae has a bulging equator due to rapid rotation and is also a spectroscopic binary. The next point in the “W” is Delta Cassiopeiae, which is an eclipsing binary that is also identified as Ruchbah. Its apparent magnitude varies between 2.68 and 2.74. The last star that defines the asterism is Epsilon Cassiopeiae, which is also known as Segin. Located about 440 light years away, this blue-white giant shines from its post with an apparent magnitude of 3.38. The queen’s notable stellar offerings continue beyond the five that define her most recognizable feature. Best viewed with a telescope, Eta Cassiopeiae is a beautiful binary star system with a yellow dwarf primary component that is much like our own star and an orange dwarf companion. Cassiopeia is also home to two stars in the very rare yellow hypergiant class - Rho Cassiopeiae and V509 Cassiopeiae. Although they are each located thousands of light years from Earth, their extreme luminosity keeps them visible to the naked eye.
A quick tour of Cassiopeia’s deep sky offerings has to begin with the open cluster Messier 52. Although it can be enjoyed with binoculars, a moderate-sized telescope will reveal it as a fan of faint stars that includes a couple of bright yellow giants – one of which pops out from the cluster’s southwestern edge. A far more remote open cluster is Messier 103, which is best viewed through binoculars due to its loose structure. Located near Ruchbah, the cluster, which includes a red giant that truly shines in photographs, will manifest as a hazy V-shaped patch. Another treat is the “The White Rose Cluster,” which is also known as “Caroline’s Rose Cluster” because it was discovered by Caroline Herschel. The cluster’s pattern of bright stars and dark paths is similar to the curves and valleys of a blooming rose. The constellation also offers the Bubble Nebula, which is a diffuse nebula southwest of M52; the open star cluster NGC 457, which has around 100 stars and is sometimes called the Owl Cluster or ET Cluster due to an eye-like pairing of two bright stars; the irregular galaxy IC 10, which is the only starburst galaxy in our local group; and the Pacman Nebula, an emission nebula with an open cluster of brilliant blue supergiants at its core and several Bok globules.