STARS
The magnitude scale was invented by an ancient Greek astronomer named Hipparchus in about 150 BC He ranked the stars he could see in terms of their brightness, with 1 representing the brightest down to 6 representing the faintest. Modern astronomy has extended this system to stars brighter than Hipparchus' 1st magnitude stars and ones much, much fainter than 6.
As it turns out, the eye senses brightness logarithmically, so each increase in 5 magnitudes corresponds to a decrease in brightness by a factor 100. The absolute magnitude is the magnitude the stars would have if viewed from a distance of 10 parsecs or some 32.6 light years. Obviously, Deneb is intrinsically very bright to make this list from its greater distance. Rigel, of nearly the same absolute magnitude, but closer, stands even higher in the list. Note that most of these distances are really nearby, on a cosmic scale, and that they are generally uncertain by at least 20%. All stars are variable to some extent; those which are visibly variable are marked with a "v".
What are apparent and absolute magnitudes? Apparent is how bright the appear to us in the sky. The scale is somewhat arbitrary, as explained above, but a magnitude difference of 5 has been set to exactly a factor of 100 in intensity. Absolute magnitudes are how bright a star would appear from some standard distance, arbitrarily set as 10 parsecs or about 32.6 light years. Stars can be as bright as absolute magnitude -8 and as faint as absolute magnitude +16 or fainter. There are thus (a very few) stars more than 100 times brighter than Sirius, while hardly any are known fainter than Wolf 356.
Star, large celestial body composed of gravitationally contained hot gases emitting electromagnetic radiation, especially light, as a result of nuclear reactions inside the star. The sun is a star. With the sole exception of the sun, the stars appear to be fixed, maintaining the same pattern in the skies year after year. In fact the stars are in rapid motion, but their distances are so great that their relative changes in position become apparent only over the centuries.
The number of stars visible to the naked eye from earth has been estimated to total 8000, of which 4000 are visible from the northern hemisphere and 4000 from the southern hemisphere. At any one time in either hemisphere, only about 2000 stars are visible.
Distances so vast that the light from those areas in space is billion years old. Illingworth was able to see these ancient giants with the Hubble Space Telescope. A telescope that is high above the atmosphere, because it can distort the image. 100 sextillion miles or 17,010,779,502.32 light years is the most distant galaxy Illingworth
On the H-R Diagram, the temperature of degrees Kelvin ranges from 3,000 to 30,000. The absolute magnitude of stars on the H-R Diagram ranges from +15 to -10. Absolute magnitude is how bright stars would appear if they were positioned at 32.6 light years away from earth. On this scale, the lower the number, the brighter the star. Thus, a start with an absolute magnitude of -10 would be much brighter than a star with an absolute magnitude of +15.
Perseus, or “the hero,” has twenty-eight stars. The brightest, most recognizable ones are Mirfak and Algol. Mirfak is the brightest star of Perseus. It is a little bit brighter than Polaris, the North Star. Algol is the most famous star. In the constellation, Algol is the eye of Medusa, translating to “demon star.” People used to think that Algol was cursed due to its constant change in brightness, but we know today that sometimes another star overlaps Algol, causing its magnitude to appear to change. Perseus has six stars with confirmed planets. (Coder pp. 85 & 87, Fanshawe, Perseus Constellation, Perseus Hero)
At a distance of 525 light years, blue class B (B1) Hadar is 130 times farther away than Rigel Kentaurus, and is bright because it is truly and very generously luminous, shining (accounting for the ultraviolet radiated from the 25,500-Kelvin surface) 112,000 times more brightly than the Sun. Hadar, however, is not one star, but two. Sophisticated observations that rely on the interference properties of light show that the single point of light actually consists of a pair of nearly identical stars each some 55,000 times more luminous than the Sun separated (from our perspective) by only 2.5 astronomical units. The temperature and luminosity show each to contain 15 solar masses. Spectra suggest an orbital period of not quite a year, this and the masses rendering them an actual 3 astronomical units apart. Twin Hadar also has a fourth magnitude sibling 1.3 seconds of arc away that, because of the brightness difference, is difficult to see and study. A class B dwarf, Hadar- B is a grand star in its own right, a star of 5 solar masses 1500 times more luminous than the Sun; it only pales by comparison with Hadar (or the Hadars) proper.
Did you know the distance from Earth to Sirius B is 8.611 light years?. Sirius B is a white dwarf star that can be located in the constellation of Canis Major. Alpha Canis Majoris B is the Bayer Classification for the star. ... Sirius B has an apparent magnitude of 8.44 which is how bright we see the star from Earth.
Stars are born and reborn from an explosion of a previous star. The particles and helium are brought together the same way the last star was born. Throughout the life of a star, it manages to avoid collapsing. The gravitational pull from the core of the star has to equal the gravitational pull of the gasses, which form a type of orbit. When this equality is broken, the star can go into several different stages. Some stars that are at least thirty times larger than our sun can form black holes and other kinds of stars.
Walking on a clear night a person can’t help but look up and see the stars. Each beautiful, illuminating the night sky along with the moon, far away yet close enough to admire and wonder. I sit sometimes outside and just look up and gaze in wonder at the stars, but the scientists in me thinks further. The stars are like our sun in the solar system, hydrogen balls, exploding, radiating energy and light in all directions yet we are so far that we see them as specks in the night sky. Then there are those night where Venus and Mercury can be seen among the stars, almost a spiritual experience. Science has taught us that gravity and other laws of nature control the movement of such celestial objects and control everyday happenings where most would not give it a second thought.
But despite the mid-infrared, each Alpha Centauri star will remain millions of times brighter than the planets that scientists are trying to locate and observe. This is where VISIR will utilize the coronagraphy method to reduce the stellar light of the Alpha Centauri stars. The coronagraphy method is used to see objects that reside very close to their parent star, for example, if an alien scientist was observing Mercury next to Sol.
The Sun is a huge, bright sphere that is mostly made up of gas that is about 5 billion years old. The Sun is the closest to the Earth, it is 145 million km distant (this distance is called an Astronomical Unit). The next closest star is 300,000 times further away. There are probably millions of similar stars in the Milky Way galaxy (and even more galaxies in the Universe), but the Sun is the most important to us because it supports life on Earth.
Sunspots are the most apparent features on the Sun’s surface or photosphere. Anyone could use a filter such as a welder’s helmet to observe groups of sunspots. A sunspot consists of two regions, the umbra and the penumbra. The temperature of the umbra can be as low as 4,000 K and the penumbra that surrounds the umbra has a temperature of about 5,500 K which contrasts to the photospheric temperature of 6,000 K. The difference in temperatures makes the sunspots appear dark against the brightness of the
Shklovskii, Iosif S. Stars: Their Birth, Life, and Death. Moscow: Central Press for Literature in Physics and Mathematics, 1975.
The Andromeda Galaxy being 220,000 light years across is the biggest of its local galaxy group which includes the Milky Way Galaxy, Triangulum Galaxy, and about 44 smaller galaxies. The Andromeda Galaxy contains about (1 trillion*10to the 12th power) stars, which is more then double the estimated 200- 400 billion stars located in our own Milky Way Galaxy. Along with this the Andromeda Galaxy has a brightness magnitude of 3.4 making it one of the brightest of all the Messier Object group.
Our sun is the central pivot point to which or entire planet and solar system is built around. With out it all life on our planet would cease to exist. Within this paper we will explore how our Sun and solar system formed and came to resemble what we see today.
Where did astronomy originate? According to the Department of Astronomy, the earliest people to keep astronomical records where the Akkadians (they lived in what is later known as the northern part of Babylon). The earliest date is from around 2,500 B.C. The ancient Akkadian priests were the first to record these astronomical records. They recorded these records because it helped them predict some of the Sun’s motions, and the Earth’s moons, and the stars. These records included observations of the daily, monthly, and yearly positions of the stars and planets. These records explained the geographical locations of the planets. The records also helped with them being able to judge when to plant and harvest crops and with religious ceremonies.
One thing us as humans have never been able to fully understand is astronomy. Always having an unexplained mystery, astronomy also has served as a way to keep time and predict the future. The word “astronomy” is defined as the study of heavenly bodies, meaning anything in the sky such as stars, galaxies, comets, planets, nebulae, and so on. Many people, if not everyone, is amazed by the night sky on a clear, moonless night.