When you look up in a dark sky location, you see a cosmic quilt of stars. But did you know that some of them come in bunches known as open star clusters? In fact, most stars begin their lives in open …
When you look up in a dark sky location, you see a cosmic quilt of stars. But did you know that some of them come in bunches known as open star clusters? In fact, most stars begin their lives in open star clusters because of the processes by which stars form. Vast clouds of gas and dust that resulted from the aftereffects of the Big Bang collapse gravitationally from denser areas in these clouds. When these areas accrete enough material to be dense and hot enough to cause nuclear fusion in their cores, stars are born. The newborn stars are scattered about like a cluster of billiard balls on a three-dimensional cosmic pool table.
There are two such clusters in the image you see here. The apparently larger cluster to the upper right is M 35, so named because it’s the 35th object listed in Charles Messier’s famous catalog of deep space objects. M 35 consists of at least 418 stars in a roughly triangular pattern that lies 3,870 light years away in the constellation Gemini the Twins. The smaller denser looking reddish cluster is NGC 2158 which is the 2,158th object in the New General Catalog (an expanded version of the list that William, Caroline and John Herschel published in 1788). Looks can be deceiving as is illustrated by the two clusters. Let’s assume for the purpose of this article that both clusters are actually the same size but that NGC 2158 is much farther away from M 35 by more than 9,000 light years. This comparison is a lesson in depth of field and knowing the distance between the two clusters relative to Earth gives you a kind of 3D look into the blackness of space.
The colors of the stars tell you about their surface temperatures. Think of a flame on a gas stove. The blue part is the hottest followed by white, yellow and red, which is the coolest. We would need more information to better understand the nature of each star such as its size, mass and age. You see more red stars in this image because most of them are red dwarfs which are the most abundant of all types of stars that we know of in the universe.
You can see M 35 using binoculars, but dimmer NGC 2158 requires a telescope equipped with a high-power eyepiece. You won’t see colors or as many stars as shown here because of the limitations of human night vision. This image is a compilation of 15 five-minute exposures through three different color filters for a total of one hour and 15 minutes. It was imaged from Mount Sangre Observatory near Angel Fire NM on Feb. 8, 2019.
Astronomical Events in March
March 1 (Friday) Saturn-Moon Conjunction. About an hour before sunrise (5:30 a.m. MST), look to the southeast to see a string of bright objects starting low with brilliant planet Venus and continuing up and to the right with Saturn, the thin crescent Moon and Jupiter. You may need binoculars to see much dimmer yellow-caramel colored Saturn to the left of the Moon.
March 20 (Wednesday) Spring Equinox. The long winter is finally over ... or is it? Sadly, the Spring Equinox is not a weather event. Because of the lag in how long it takes the Earth to heat up, springlike weather will be delayed at least a month for folks living at our latitude. The Spring Equinox is an astronomical event which marks the moment when the Sun crosses the celestial equator from south to north. The celestial equator is Earth’s equator projected out into the sky. An easier way to visualize this (although not completely accurate) is the transition from winter to spring when everyone on Earth experiences equal day and equal night.
Gary Zeintara tracks the night sky from his observatory in Angel Fire, New Mexico.
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