The Universe Is Full of Wonderful Objects

Science of Stars

Josh Wilkinson

SCI/151

August 24, 2015

Prof. Ken Watanabe

Introduction  

        The universe is full of wonderful objects. On earth, most of these objects are referred to as stars. This paper is intended to inform readers to how and what instruments astronomers use to figure out the temperature, composition, speed, and rotation rates of distant objects, along with discussing the lifecycle of the sun and explaining the properties of stars.

How to Determine the Properties of Distant Objects

         The properties of distant objects such as stars, asteroids, and other planets are determined by the light that is emitted by them. Light is a form of energy that can be absorbed by objects and travel at a very fast rate of speed. Light is made up of particles known as photons. Photons are the particles that can be absorbed and deflect off objects. Over several millennia, these photons can grow into objects such as protostars. These are clumps of photons are how stars are formed and born.

        When trying to figure out the temperature, composition, speed, and rotation of distant objects in space, astronomers use a tool known as the spectroscopy. A star gives off light that can be measured by the spectroscopy. By using the spectroscopy, astronomers know that stars are made up mostly of hydrogen. Depending on how much light the star emits, astronomers can figure out the origin, age, and luminosity of a star.

        The spectroscopy also helps determine the temperature of a star. Astronomers determine the temperature of a star by measuring the color of the star and the spectrum of light the star emits. Every star has its own form of energy or light radiation. This is what astronomers use to gauge the temperature of a star. Astronomers also discover the temperature of a star by measuring the spectral lines a star has.

        Electromagnetic energy is very prevalent in space. One type of electromagnetic energy is spectra, which is separated into three types; emission line, continuous, and absorption. Each type of ion, atom, and molecule have a unique or rare type of energy level, this is discovered by the emission and absorption lines. Atoms have their own fingerprint in the spectrum. This is due to the atoms having a special set of energy levels. Knowing that most matter is made from hydrogen, it helps us to maintain that it is capable of absorbing light and becomes possible to detect the presence of matter in distant objects.

Properties of Stars in the HR Diagram

        In Chapter 12 of The Essential Cosmic Perspective, there is a diagram known as the Hertzsprung-Russell diagram (H-R Diagram). This diagram is a tool used to understand stellar evolution. The diagram has several dots that represent stars. The luminosity and temperature of the dots are judged by the position of the dots on the diagram. The luminosity of stars is the amount of light, or energy a star emits in a single second. This is represented by the vertical axis on the H-R Diagram. The horizontal axis is what represents the temperature of a star. Only the surface temperature is determined by using this diagram. On the diagram, hotter stars are placed on the left side of the axis, while cooler stars are on the right side. To be able to read the diagram, you must understand how graphing works. For example, if a star is in the top left corner of the diagram, it would be a very bright, hot star, while if a star was in the lower right corner, it is a cool star that does not shine brightly.