Dwarf stars are the most plentiful in our sky. But as their name suggests, they are smaller in mass and thus less intrinsically bright. Our August fundamentals will focus on some white and red dwarf stars. Although each of these stars are dwarf stars, they are more different to each other than just their color. Red dwarfs are part of the main sequence stars, and are among the most plentiful in the universe. In addition, a good percentage of the stars nearest our solar system are also red dwarfs. Proxima Centauri, our nearest star is a red dwarf. Also not as easy to see is Barnard’s Star, a red dwarf star about six light years away. Main sequence stars are burning their main fuel of hydrogen, and red dwarfs have a long lifespan as the star undergoes fusion in its core.
White dwarfs on the other hand are bright, because they are the hot dense cores of sun-like stars that have burned through the main sequence and ended up as just the carbon core of a star. White dwarfs are also commonly found with planetary nebulae, since those outer layers puff off as the star cycles from hydrogen to helium and onto heavier elements as the life of the star progresses. These white dwarfs are about the mass of our sun but compacted to a diameter of Earth. Although they are very hot, they are also intrinsically faint. Fortunately, there are about 5 white dwarfs within about 16 light years of Earth. 40 Eridani B is about 4.4 magnitude and easily visible in a small scope. Interested in taking a tour of these mighty, yet smaller mass stars? Make sure to catch our August Fundamentals meeting with our presenter, NAA member Jim Hopkins.
Astronomy Fundamentals: A Look at the History of Alvan Clark Telescopes
In the 19th century, Alvan Graham Clark was one of the premier lens makers for telescopes. His craftsmanship was sought after and many observatories in the late 19th and early 20th centuries were built to house his refractor telescopes. In fact, smaller Alvan Clark...
The Cosmologist’s Puzzle: The Age and Expansion Rate of the Universe.
We are confused about how old the Universe is. Until recently, astronomers estimated that the Big Bang occurred between 12 and 14 billion years ago. Astronomers can place a lower limit to the age of the universe by studying globular clusters. Globular clusters are a...
April ’25 – Rick’s Picks
Transient Events That Can Give Us a Good Enough Reason to Get Outside and Do a Little ObservingAll month: the solar system balances morning and evening targets this month as Mercury, Venus, Saturn, and Neptune move into the predawn sky, while Mars, Jupiter, and Uranus...
Astronomy Fundamentals: What We Can Learn from Impact Craters
Impact craters can be found throughout the solar system. NASA scientists use impact craters and volcanic activity to learn about the process throughout the solar system. By studying craters on Earth, scientists gain knowledge of volcanic landform formation and...