Pulsating White Dwarfs Essay

A red dwarf star’s HZ, for example, would be much closer to the star itself compared with that of our sun. It is also important to determine the planet’s size and mass, which is imperative in deciding whether it can sustain an atmosphere. Maintaining an atmosphere is essential for life to exist and small a planet with a small gravitational force at its surface may not be capable of retaining one. The Kepler transit data can only measure planet masses, diameters, orbital periods, and parent star types and although this information is useful for determining habitable zones, further data is required to determine true habitability. The latter can be done by studying the composition of the exoplanet’s atmosphere.

For the low-mass stars, the expansion to the red giant phase will begin when about 90% of its hydrogen has been converted to helium. During the contraction of its core, a complicated sequence of events occurs. The shrinkage required to produce the energy radiated by the large giant causes the core to shrink to the dimensions of a white dwarf, while hydrogen continues to burn by nuclear fusion in a thin shell surrounding the core. This shell provides most of the energy that is radiated away by

One solar mass is equal to the mass of the Sun, about 2 nonillion kilograms. If a white dwarf were to exceed ~1.44 solar masses, its electron degeneracy pressure would not be able to support it.

In this paper I will explain how astronomers determine the composition, temperature, speed, and rotation rate of distant objects using various methods. I will explain the properties of stars. I will also summarize the complete lifecycle of the Sun and determine where the Sun is currently in its lifecycle.

It is no secret that the earth’s sun is “special” to say the least. Some would say it was designed to be unique to help sustain life on planet earth. However, other nearby stars were not designed to sustain life. One example would be the star Proxima Centauri. This star recently had a short increase in radiation, known as a flare. This flare caused the star to become a thousand times brighter for ten seconds. Earth’s sun also has flares, but they are much smaller. When Proxima Centauri is at its brightest point it is still ten times brighter than our suns largest flare. This is just one example of how special our sun really is.

The amount of fuel and the rate at which nuclear fusion occurs depends on the mass of the star. The mass of a star is the determining factor of how long it lives. A red-dwarf star is a star about half the size of our Sun. Due to its extremely low fusion rate, it is estimated that they could last for 10 trillion years. A medium-sized star like our Sun spends its main sequence stage up to 10 billion years.

However, the Hubble Space Telescope has taken imagines of both Sirius A and his companion Sirius B. Sirius A and Sirius B revolve around each other every 50 years, which makes us wonder when was the last time they revolved around each other? Though Sirius A is still a star, Sirius B is a white dwarf. White dwarf’s are what stars become once they cool and die. Sirius B is what our Sun will turn into one day, since it, Sirius B, was at one time or another, similar to our Sun. More research is being done to increase the knowledge we have on Sirius B, because there is very little information on it but it was discovered more than 150 years ago. NASA believes that with the technology and telescope equipment they have, they can create a whole telescope that could potentially be used to learn more about “The Pup”, Sirius

In 1610 on the 7th of January four moons, called the Galilean moons were discovered by Galileo Galilei. Using his homemade telescope he observed them for many nights, he drew notes and recorded the movement in a journal (Figure 3). Ganymede is one of the largest, most well-known moons of Jupiter and it is also the largest satellite in our solar system. It is larger than Mercury and Pluto, and three quarters the size of Mars. If Ganymede didn’t orbit Jupiter as moon it would easily be classified as a planet.

The Hubble Space Telescope is one of the most amazing machines in orbit right now. In 1946, an astrophysicist named Dr. Lyman Spitzer proposed that a telescope in space would reveal better and clearer images that are even far from earth than any ground telescope. This idea was very extravagant because no one had yet launched a rocket into outer space. As the US space program excelled quickly over the early years, Spitzer lobbied NASA and Congress to develop a space telescope. In 1975, the European Space Agency and NASA began to develop the telescope that would change astronomy for ever. In 1977, Congress approved funding for the development of the space telescope and NASA named Lockheed Martin Aerospace Company as the prime contractor

     Stars are a marvelous wonder to many people, that is why some people spend most of their lives wondering what is “above the world so high” (Gardner 98). These people study and map the little twinkling stars in order to get a better meaning of them; they are astronomers. Great astronomers like Edwin Hubble, Immanuel Kant, and William Huggins, never stopped valuing the beauty of the stars. While they developed great astronomical principals. One astronomer who fits this mold most is, Edwin Powell Hubble. Wondering about what was

Distributed over 90 sq. deg. of the sky, they lie from 4 to 23 kpc from the Sun. The most significant group of RRLS is the Virgo Stellar Stream which is composed of at least 10 RRLS and 3 BHB stars. It has a mean distance of 19.6 kpc and a mean radial velocity Vgsr = 128 km/s, as estimated from its RRLS members. With the revised velocities reported here, there is no longer an offset in velocity between the RRLS in the VSS and the prominent peak in the velocities of main-sequence turnoff stars reported by Newberg et al in the same direction and at a similar distance. The location in phase space of two other groups suggests a possible connection with the VSS, which cannot be discarded at this point, although the turnoff colors of the VSS and group H, as identified from Newberg. Two more groups are found at mean distances of 19 and 5.7 kpc, and mean radial velocities of -94 and 32 km/s. None of our groups seems to relate to streams. The excess of stars observed in Virgo appears to be composed of several halo substructures along the same line of

In the article, the author explains how astronomers have discovered a star system that have possibly left behind a white dwarf after a weak supernova explosion. For instance, Type Ia are mini supernovas and are important because they are used to measure the distance and the expansion of the universe. Therefore, the Type Ia demonstrates supernova, they noticed they were viewing the light of the star that lost its outer hydrogen cover, which caused it to reveal its helium core. In addition, astronomers predicted that the Type lax supernovea were developed by a white dwarf and a helium binary star system. Astronomers explained a possible reason for SN 2012Z became a weak supernova, since it is one of the most powerful Type lax supernovae. For

The radial velocity method was used to detect the first exoplanet, 51 Pegasi b (51 Peg b) around a main sequence star, 51 Pegasi (51 Peg). The radial velocity method uses the variations in velocity of a star due to the gravitational pull from an exoplanet (Lissauer 2002). Furthermore the velocity isn’t measured in terms of actual speed but in terms of light based on the Doppler effect. The Doppler effect occurs when a star moves. When it moves toward us, its wavelengths of light are shortened and when a star moves away from us, its wavelengths of light are lengthened. Through the continued observation of the Doppler effect on a stars spectrum of light, the velocity of a star is inferred. Any change in a stars velocity is caused by a sufficiently massive companion, an exoplanet (Lissaeur 2002).

Since ancient times, the universe had captivated people’s imagination and curiosity. With the limitation on technology, early sky watchers were only capable of classifying objects they observed as either a star or a planet. During the twentieth century, with advancement in telescopes to see further into space with more accurate details, scientists were able to find numerous stars and planet like objects within the solar system. Scientists had no trouble classifying objects such as Uranus and Neptune as planets. However, the real trouble came when they discovered a planetary object called Ceres. Objects like Ceres and Pluto behaved similarly to regular planets. Because of the limitations on the technology at the time, it was very difficult

Main sequence stars like our own sun enduring in a state of nuclear fusion during which they will produce energy for billions of years by replacing hydrogen to helium. Stars change over billions of years. When their main sequence phase ends they pass through other states of existence according to their size and other characteristics. The larger a star's mass, the shorter its lifespan is. As stars move toward the end of their lives, much of their hydrogen will be converted to helium. Helium sinks to the star's core and raises the star's temperature—causing its outer shell to expand. These large, puffy stars are known as Red Giants. The red giant phase is actually a prelude to a star shedding its outer layers and becoming a small, dense body called a White Dwarf. White dwarfs cool down for billions and billions of years, until they finally go dark and produce no energy at all. Once this happens, scientists have yet to observe, such stars become known as Black Dwarfs. A few stars avoid this evolutionary path and instead go out with a bang, exploding as Supernovae. These violent explosions leave behind a small core that will then turn into something called a Neutron Star or even, if the remainder is large enough, it is then turned into something called a Black Hole.