A Hungry Black Hole has no Remorse

In recent space news, astronomers found a black hole within a globular cluster tearing apart a white dwarf. This gruesome action was completed without remorse for this already dead star. As discussed in a later lecture, white dwarfs are the results of low mass stars, much like our own, that burn up all their energy from nuclear fusion and later eject their outer layers and leave behind this small, compact star in its place. This article had me thinking about the process in which a star must maintain equilibrium before its death, whether it be by virtue of running out of fuel or gravity pulling it into a black hole.

artwork depicting 47 Tuc X9

In class we discussed the topic about how stars live and maintain energy. This process is referred to as nuclear fusion. When a star is created from a solar nebula, gravity pulls the cloud of gas in, shrinking its size, causing temperatures to rise, and upon building up to a dense core, gravity created a protostar. Once a protostar is created, gravitational contraction continues until a star can maintain nuclear fusion. The process of nuclear fusion is the action in which hydrogen atoms bind to each other in order to maintain energy. In order for a star to survive, it must maintain equilibrium between creating energy in its core and releasing it into space, also referred to as energy balance. Without this, the balance between pressure and gravity will not remain steady and will cause the star to collapse on itself. Thus, stars continuously bind hydrogen atoms, making new elements and releasing energy, while gravitational equilibrium monitors the change in temperature and causes the increase or decrease of nuclear fusion.

When reflecting upon star life and deaths, I see them as a balancing act that eventually tips a scale and causes an end. For example, the force of the black hole pulling in this white dwarf is much stronger than the force keeping the star in balance, but unlike actual death on this planet, the stars particles have a potential of being recycled and becoming something new. The way things “die” in space is not as much gruesome as the void makes it out to be.  This idea gives me hope for another life I guess, not to become all spiritual but life is just an overall interesting topic to talk about with people. we all want to know. Is recycled life a possibility? In our lifetime, I guess we’ll never know.

Source: Bad Astronomy

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H-R= Hella Rad!

In the history of this course, this conceptual objective had to be my favorite one. In class, we learned that the HertzsprungRussell diagram classifies stars based on their luminosity, temperature, spectral type, and absolute magnitude. When it comes to classifying and understanding stars, scientists use the H-R diagram in order to compare them to other stars they are related to. Just so we’re clear, the H-R diagram separates stars into 3 major categories: main sequence, red giants, and white dwarf stars. In each section, stars share certain commonalities. With these stars clustered, scientists can make observations on star types and star lifetimes to further understanding on composition and what will happen to these stars in the future. The H-R diagram is also like a timeline, because it shows information about stars throughout their life cycle. This diagram can also show relationships between the radii of the main sequence, which ranges from small sizes in the lower left with high-temperature, low-luminosity stars to the large sizes in the low-temperature, high luminosity stars in the upper right.Image result for HR diagram

What I like most about this objective is that it basically brings together all the ideas we have covered in lecture about stars throughout the semester into one easy to understand diagram. When going back on past objectives where I talked about the Castor and Pollux, two stars that make up the constellation Gemini. These stars as I have explained twice before, display very different qualities, one of which is the type of star they are, Pollux being a Red giant, and Castor being a “star” made up of 3 binary star systems working together. Within these 2  stars (or 7 to be exact), an understanding development can be made based off of just one or two known properties. What I also enjoy is the amount of doors of understanding opened by this diagram. It takes knowing one or two qualities to understand the whole star. For example, Pollux, which is actually located on the diagram above as well, is a red giant. Within knowing this classification, one can assume that it is larger, more luminous, and cooler than our sun just by looking at this diagram. When given specific information, such as Pollux being 100 times more luminous than our sun, we can use this information in conjunction with its apparent luminosity to figure out the distance to our Earth. Overall, I believe this to be a revolutionary find for astronomers and glad this diagram was created because it makes understanding outer space easier. Thanks science!

Source: Twins again, I’m sorry

Going Back to the Twins

In a past conceptual objective, I have discussed the the existence of two stars that make up the constellation Gemini, Castor and Pollux. Just as a recap: these two stars, well actually one dying red giant and the other the product of three binary systems (you hear that, 6 stars for the price of one!), display different qualities that are explained thoroughly in the article. However, information shared in class about luminosity and temperature lead me down the path of deeper understanding. Today I will be revisiting this article within a different focus, distance, size, and mass.

During lecture, we discussed how scientists study the properties of stars including the distance, size, and mass. When accounting for the distance of stars, we learned, in the Lecture-Tutorial on the Parsec, that scientists use telescopes to determine the parallax angle, which is the smallest angle created in the right triangle between the Earth, Sun, and the star whose distance you are measuring. First, scientists observe a star in the night sky which goes through parallax in our night sky. Parallax is defined as the apparent motion of nearby objects relative to distant objects. On Earth, objects also experience parallax. For example, in class we mentioned how if we place a finger in front of our nose, close one eye, and then switch which eye is closed, we can observe parallax. The finger’s position has not actually changed; However, when observing it one eye at a time and relating it to our background, we can determine how close it is to our face because of how dramatically different each side sees it “change” distance. The further away from our face we place our finger, the smaller the parallax, until it is so far away that it just blends in with the background (maybe if we had detachable fingers, but I digress). Similarly, scientists determine the distance a star is from Earth. A “close” star is observed in relation to the “fixed” stars in the background and the two are compared when the Earth on opposite sides of its orbit. This way scientists see the two extremes of the star’s parallax motion in the night sky. They then use geometry to come up with the parallax angle.

Image result for parallax angle

Knowing this parallax angle, scientists use some more geometry to figure out the distance to the star. This distance is is described in the unit of length called the parsec. One parsec is the distance to a star that has a parallax angle of 1 arcsecond. Also, parsecs and parallax angles are reciprocally related; The smaller the parallax angle, the larger the distance to the star. For example, if a star has a parallax angle of 1/6 of an arcsecond, the distance to that star is 6 parsecs. However, no star is actually that close, so the act of figuring out the distance is a little harder on an even smaller-angle and larger-distance scale. In relation to distance, these two stars in Gemini are actually relatively close, one being at 50 light years and the other at 34.  Since these stars are so “close”, it can be assumed that the parallax they display every 6 months is greater than other constellations that are farther away.

When it came to measuring the size and mass of other stars, scientists use distance in conjunction with its luminosity to determine those traits. When comparing two equidistant to us but near each other stars and comparing their luminosities, the larger star will appear to be more luminous, therefore knowing the distance and luminosity to a star can determine its size. A more massive star will appear to be more luminous at a distance as well. Relating to the article, while both Pollux and Castor seem to be about the same apparent luminosity, Pollux is about 16 light years closer than Castor, meaning that its actual luminosity is much dimmer than that of Castor.

Upon constant reflection on how stars are are studied and characterized, I feel as though I am more comfortable with sharing my knowledge with others. Besides being a thoroughly useful topic in understanding the world beyond us, astronomy is a field in which many take interest into but do not know where to start in gaining understanding. Attending these lectures and taking this class encourages me to inspire others to pursue an education in the sky, even if it is just for fun.

Distance and Size of the Stars

I found an article at, https://www.universetoday.com/25331/size-of-stars/ , which talks about the sizes of stars. Stars can be smaller and they can be even bigger than our Sun. Red dwarfs are the smallest stars out there and there are no more than 50 percent of the mass of the Sun. They could also have little as 7.5 percent the mass of the Sun.

That is the minimum mass that a star needs to hold in order to support its nuclear fusion in the core. Below that mass it is a brown dwarfs. One example of a red dwarf is Proxima Centauri which is the closest star to Earth. This star has 12 percent of mass of the Sun and about 14 percent the size of the Sun. It’s about approximately 200,000 km across which is a little larger than jupiter.

Our Sun has a diameter of 1.4 million kilometers. When the Sun hits the end of its life it will become a red giant and will grow 300 times its original size and will consume the inner planets, including Earth. A larger star than our Sun is the blue supergiant Rigel which is in the constellation Orion. The star is 17 times the mass of our Sun. It has 66,000 times as much energy. It 62 times as big as our Sun.

Let’s talk even bigger. For example Betelgeuse which is 20 times the mass of the Sun. Astronomers think that Betelgeuse might explode within the 1,000 years. It has increased out to more 1,000 times the size of our Sun. The monster VY Canis Majoris is the biggest star in the Universe so far. It’s thought to be as 1,800 times the size of the Sun. If this star was in our solar system, it would touch the orbit of Saturn. My overall personal opinion of the article was very good because I learned so much about the stars. I would recommend that people should read it because it is pretty fascinating. This article relates to what I have done in class because it talks about the size and distance of stars which is what we talked about in class. I learned from class that atoms are widely spaced about 1 molecule per cm3 a nearly perfect vacuum. Convection cycle is the same with the sun. The sun is energy balanced. The clicker questions helped too when study the material.

Spin Fast, Release Mass

In recent space news, I learned about Jupiter not being an exactly spherical planet (WHAAAT?). According to bad astronomy blog, Jupiter naturally has an oblate shape that is due to the speed at which this planet is spinning, causing the centrifugal force to fling material out from its equator, making it a 3-D oval (or an egg, I guess). This information led me to think about the properties of the planets in our solar system that were discussed in lecture.

We have learned about the characteristics of our solar system and how it was formed. To begin with, we are all familiar with the Sun being the center of our solar system, orbited by 8 planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Each of these planets is pulled in by the sun’s gravity, illuminated by its light, warmed by its rays, and shaped by the charged particles it gives off. The 4 inner planets (Mercury, Venus, Earth, and Mars) are small, composed of metal and rock, and more tightly spaced as opposed to the outer 4 planets. Due to their composition, these planets are referred to as the terrestrial planets, however they are very different on the surface. Mercury is heavily cratered, dry, and desolate; Venus is hot, molten, and vicious; Earth is the only livable planet, with its liquid water; and finally, Mars is a mysterious possible Earth number two, with evidence of past existing river beds and other potential life-like attributes. Next, separating the inner and outer planets is the asteroid belt, composed of many small, rock-and-metal chunks floating around the Sun. Beyond the belt are the 4 outer planets (Jupiter, Saturn, Uranus, and Neptune). These planets are regarded as Jovian planets because they are all similar to Jupiter, the largest in the bunch. All four are composed of gases without a solid core, unlike the terrestrial planets which are all primarily rock. If you were to attempt “landing” on any of these planets, you would only plunge deeper into its atmosphere until you would be crushed by the pressure at its core. It is with this notion that I understood why Jupiter can be oblate; Since it is mainly composed of gas, Jupiter does not have the atmospheric pressure near its edge to keep all the material in. Items in the core are held more tightly, but even like our atmosphere on Earth, the pressure feathers out. Unlike terrestrial planets, Jovian planets can have many moons and all four of our solar system’s Jovial planets are orbited around by small particles that make up their rings. Our solar system overall displays similar characteristics between the planets. All planetary orbits are similarly circular and lay within the same plane. They also all orbit in the same direction, and most rotate in the same direction of their orbit around the sun as well.

All of these characteristics lead to the scientific understanding of how our solar system formed. In a Lecture tutorial on the Temperature and Formation of Our Solar System, we learned that distance from the Sun and average temperature were deciding factors on how and why the different planets were created. In the temperature range of about 500-1000 Kelvin and about 0.3-1.25 AU from the Sun created terrestrial planets, while temperatures of about 45-150 Kelvin at a distance of about 5-45 AU created large Jovian planets.

Learning about our solar system not only helped me understand the qualities of our planets (such as Jupiter) and how they came to being, but also, with this information, I can apply understanding of planet types when reading about future space news. I no longer have to act like I know what is going on when I hear about qualities of other planets that are being found beyond our system, and I can hope to take part in space discussions related to this topic. The universe is always expanding and that means more room for new stars, planets, moons, and LIFE. I’m ready for the next big space discovery.

Source: badastronomyblog.com

Star-Studded Space Pants

In recent space news, the stars are at it again. In an article from badastronomyblog.com, two major stars that mark the constellation Gemini are baffling people and scientists alike. Ironically enough, these two stars, Castor and Pollux, that make up a constellation for the zodiac sign Gemini (which are supposed to be twins), are anything far from similar. These two stars, we actually one dying red giant and the other the product of three binary systems (you hear that, 6 stars for the price of one!), display different qualities that are explained thoroughly in the article. However knowing the material that was covered in class made me understand what the author was referring to much clearer. Without further ado, I will explain what helped me put this article together to make it sound better than a pile of space jargon.

In class we studied how astronomers determine the luminosity, temperature, and size of stars. Luminosity, or absolute brightness, refers to the total amount of power given off by a star into space. What we see on Earth refers to the apparent brightness, which is the amount of starlight that reaches the Earth and can appear brighter or dimmer than the luminosity depending on distance to that star. The closer the star is to Earth, the brighter it appears and vice versa. In the case of this article, the two stars appear to be of equal brightness, but in reality, Pollux is a lot closer to the Earth than Castor, meaning that it is in fact less luminous if they were at the same distance. When it comes to measuring this luminosity, scientists first use an instrument to calculate the stars apparent brightness and obtain its distance to Earth using stellar parallax. Then, scientists use the inverse square law for light to determine the absolute brightness, or luminosity.

When it comes to determining the surface temperature, scientists once again study the spectral lines given off by that star. The hotter the star, the more blue light waves it gives off, giving it a more blue color. Stars that are cooler appear to be more red in color because they give off more red light. Stars in the middle, like our sun, emit light waves from the middle of the spectrum and appear to be white or yellow in color. To be more exact, by studying the spectral lines in comparison to a stars chemical make up, it can be inferred that stars that have more ionized particles are hotter because they need more energy to ionize atoms. Furthermore, stars on the red side generally are less hot and the spectral lines show a composition of molecules in its atmosphere. This promotes the notion that these stars are cooler; Molecules need less heat otherwise they will break apart into atoms, so stars made of molecules must be cool.

Scientists use surface temperature data along with spectral lines to classify stars from hottest to coolest with the letters OBAFGKM. In class we were asked to come up with our own mnemonic other than “Oh Be A Fine Girl, Kiss Me”, in which I memorized the sequence of letters with “Or Buy A Few Great Khakis Maybe?” (I was trying to make up a scenario where I was telling my friend that pants were on sale. Space pants, with stars). The star Pollux is mentioned in the article to be classified as a K star, meaning its temperature is on the lower side of the spectrum. As for Castor, it is a lot more complicated being a combination of 6 stars. The largest 2 stars are type A stars, which are on the hotter end, followed by 2 red dwarfs, and the whole system being followed by 2 cool M type stars.

Finally, when it comes to measuring the size of a star, scientists use other stars to calculate its massiveness. The easiest way to calculate mass is to use stars that is part of a binary system. These stars occasionally pass over each other, causing eclipses that can be measured by a doppler shift. This shift can be used to calculate the orbital period and velocity, giving the orbital distance. With the orbital distance and period, scientists use Newton’s  version of Kepler’s third law in order to come up with the mass of the star.

Learning about the luminosity of stars helped me further expand my knowledge about the universe. I never realized how much information one little scientific discovery can lead up to. In further objectives, the importance of luminosity will shine through as we discuss the classifications of stars and other qualities. For now, just keep shining.

Source: badatronomyblog.com

Stellar Evolution and Deaths

I found an article at, https://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve    , It talks about how the stars are the building blocks of our galaxy. They are born within dusty clouds and are scattered through galaxies. The gas and dust begin to collapse under its own gravitational attraction. The cloud then collapses and the material begins to heat up.

This is known as a protostar, which the material of the center of this collapsing cloud becomes a star. A prediction is made through three-dimensional computer models about how the spinning clouds of collapsing gas, including dust, breaks up into two or three blobs which explains why most of the stars in our Milky Way are in groups of multiple stars.

When the cloud collapses, a core that is hot begins to gather gas and dust. Note not all the material ends up as part of the star. It could end up as, comets, planets, asteroids, or stay as dust. Sometimes the clown wouldn’t collapse at a steady pace.

There was a star which was approximately the size of our Sun required about 50 million years year for it to mature. Beginning of the collapse all the way into adulthood. For our Sun, it will stay at its mature phase for about 10 billion years. Stars, we know, are indeed filled with nuclear fusion of hydrogen in which it forms helium deep in the stars interiors. Hypergiants, which is the most massive star, is 100 or more times greater than the Sun. It could have a surface temperature of 30,000 k or more. They do emit more energy by hundreds of thousands more than our Sun but may have only have a lifetime of only 3 million years.

The larger the star is, the shorter its life is. After a star has fused all its hydrogen in its core, it becomes even hotter because hydrogen is still available outside the core. It then pushes outer layers of the star outward which causes them to expand and cool. This star becomes a red giant. The collapsing core may become hot enough to support more exotic nuclear reactions if the star is sufficiently massive. As time goes on, the star’s internal nuclear fires becoming unstable. Sometimes it burns furiously or just dies down. Everything depends on its core.

Personally I enjoyed reading about this article because I found it pretty fascinating. There is in my opinion a lot of good information on the article. I have learned that stars are born when gravity causes the collapse of molecular clouds, they shine for millions and billions of years with energy produced by nuclear fusion, and in their deaths they ultimately return much of their material back to the interstellar medium. This article relates to the main objective because the article talks about the life cycle of the stars.