Binary star formation
... Mechanisms for binary star formation Although very common, not obvious how to form binary stars: • Never observed the process happening • Wide range of scales involved in different binaries Possible mechanisms that have been suggested: • Fission - one star splits into two • Capture - one star captu ...
... Mechanisms for binary star formation Although very common, not obvious how to form binary stars: • Never observed the process happening • Wide range of scales involved in different binaries Possible mechanisms that have been suggested: • Fission - one star splits into two • Capture - one star captu ...
Unit 1
... • Recall that the velocity necessary to • Also recall that nothing can travel avoid being gravitationally drawn faster than the speed of light, c, or back from an object (the escape 3108 m/s velocity) is: ...
... • Recall that the velocity necessary to • Also recall that nothing can travel avoid being gravitationally drawn faster than the speed of light, c, or back from an object (the escape 3108 m/s velocity) is: ...
PowerPoint
... below 80 Jupiter masses. • The central density and temperature do not get large enough for nuclear fusion to occur. • These failed stars, gradually cool down and contract. • Recently, there have been a number of discovered brown ...
... below 80 Jupiter masses. • The central density and temperature do not get large enough for nuclear fusion to occur. • These failed stars, gradually cool down and contract. • Recently, there have been a number of discovered brown ...
14 The Interstellar Medium and Star Formation
... Star formation happens when part of a dust cloud begins to contract under its own gravitational force As it collapses, the center becomes hotter and hotter until nuclear fusion begins in the core. Interstellar clouds are usually stable and some form of shock is thought to be necessary to begin ...
... Star formation happens when part of a dust cloud begins to contract under its own gravitational force As it collapses, the center becomes hotter and hotter until nuclear fusion begins in the core. Interstellar clouds are usually stable and some form of shock is thought to be necessary to begin ...
Big Bang and Beyond
... – Nuclear reactions will be very efficient (fast) – Most or all hydrogen will be converted to Helium and then on into Iron – No hydrogen, no water, and thus, no life possible… ...
... – Nuclear reactions will be very efficient (fast) – Most or all hydrogen will be converted to Helium and then on into Iron – No hydrogen, no water, and thus, no life possible… ...
Replenishing the ISM - Stockton University
... clusters vs. distance to cluster. – Distance found from inverse square law of brightness. – He found a systematic increase of the linear size of the clusters with distance. – Unreasonable! It would mean that nature had put the Sun at a special place where the size of the clusters was the smallest. – ...
... clusters vs. distance to cluster. – Distance found from inverse square law of brightness. – He found a systematic increase of the linear size of the clusters with distance. – Unreasonable! It would mean that nature had put the Sun at a special place where the size of the clusters was the smallest. – ...
binary stars - El Camino College
... defined to be the average distance between the Earth and the Sun. (How many miles is that?) The nearest star to our Sun, Alpha Centauri, is a triple star system and is the third brightest star in the sky; however it can only be viewed from the southern hemisphere. The brightest (and largest) star in ...
... defined to be the average distance between the Earth and the Sun. (How many miles is that?) The nearest star to our Sun, Alpha Centauri, is a triple star system and is the third brightest star in the sky; however it can only be viewed from the southern hemisphere. The brightest (and largest) star in ...
H-R Diagram
... In the early 1900s, astronomers were able to identify many star characteristics such as color, size, temperature, and luminosity—or how bright a star is. Using the H-R Diagram Gizmo™, you will discover how some of these characteristics are related. Start by moving your cursor over the stars in the S ...
... In the early 1900s, astronomers were able to identify many star characteristics such as color, size, temperature, and luminosity—or how bright a star is. Using the H-R Diagram Gizmo™, you will discover how some of these characteristics are related. Start by moving your cursor over the stars in the S ...
Making Heavier Metals
... One place where this process occurs is inside very massive stars when they explode as supernovae . In such a dramatic event, the build-up proceeds very rapidly, via the so-called "r-process" ("r" for rapid). The AGB stars But not all heavy elements are created in such an explosive way. A second poss ...
... One place where this process occurs is inside very massive stars when they explode as supernovae . In such a dramatic event, the build-up proceeds very rapidly, via the so-called "r-process" ("r" for rapid). The AGB stars But not all heavy elements are created in such an explosive way. A second poss ...
Assessment Star Characteristics and Life Cycle
... B) Red Supergiants D) Red Giants 2. According to the H-R Diagram from question number 1, what color are the coolest stars on the main sequence? A) blue C) yellow B) white D) red 3. One physical property of a star is magnitude. Which of the following is used in determining the magnitude of a star? A) ...
... B) Red Supergiants D) Red Giants 2. According to the H-R Diagram from question number 1, what color are the coolest stars on the main sequence? A) blue C) yellow B) white D) red 3. One physical property of a star is magnitude. Which of the following is used in determining the magnitude of a star? A) ...
Stellar Stability and the Chandrasekhar Limit
... They are known as the white dwarves. A white dwarf is an astronomical object which is produced when a low to medium mass star dies. These stars are not heavy enough to generate the core temperatures required to fuse carbon in nucleosynthesis reactions. After one has become a red giant during its he ...
... They are known as the white dwarves. A white dwarf is an astronomical object which is produced when a low to medium mass star dies. These stars are not heavy enough to generate the core temperatures required to fuse carbon in nucleosynthesis reactions. After one has become a red giant during its he ...
February 16
... Discussion But, what if there is a lot of dust between us and the object we are observing. That would make the object appear fainter and we would be misled into thinking the object was much farther away than it really is. How can astronomers determine if dust is making things fainter? ...
... Discussion But, what if there is a lot of dust between us and the object we are observing. That would make the object appear fainter and we would be misled into thinking the object was much farther away than it really is. How can astronomers determine if dust is making things fainter? ...
The woman who dissected the Sun
... that was responsible for the most of the differences between stars. Just because a star's spectrum showed no light from, for instance, neutral iron, did not mean it had no iron, only that the star was so hot that there was no iron left with a full complement of electrons to emit the spectral lines c ...
... that was responsible for the most of the differences between stars. Just because a star's spectrum showed no light from, for instance, neutral iron, did not mean it had no iron, only that the star was so hot that there was no iron left with a full complement of electrons to emit the spectral lines c ...
The masses of stars
... broadly constant throughout its life, and that is its mass. The mass of a star cannot be observed directly, and neither can it be simply inferred from its size, as stars can have different densities. It is most easily calculated where we see two stars orbiting each other in a binary system. Each is ...
... broadly constant throughout its life, and that is its mass. The mass of a star cannot be observed directly, and neither can it be simply inferred from its size, as stars can have different densities. It is most easily calculated where we see two stars orbiting each other in a binary system. Each is ...
I CAN SEE THE STARS IN YOUR EYES
... at this speed, the trip from Earth to the sun, a distance of 93 million miles, would take about 8 minutes, not very long for such a long trip! Yet, to get to the next closest star, Proxima Centauri, would take 4.2 years. “Hmmm…,” you think to yourself, “that might be an interesting fact to include i ...
... at this speed, the trip from Earth to the sun, a distance of 93 million miles, would take about 8 minutes, not very long for such a long trip! Yet, to get to the next closest star, Proxima Centauri, would take 4.2 years. “Hmmm…,” you think to yourself, “that might be an interesting fact to include i ...
The Young Astronomers Newsletter Volume 24 Number 8 August
... toward the tightest gravitationally bound state that they can achieve. Gravity wins. More dense matter concentrates toward the center of the object and increases in kinetic energy and heat. The core becomes even more dense and hot, and if more matter is available in the surrounding space, gravity pu ...
... toward the tightest gravitationally bound state that they can achieve. Gravity wins. More dense matter concentrates toward the center of the object and increases in kinetic energy and heat. The core becomes even more dense and hot, and if more matter is available in the surrounding space, gravity pu ...
Stars and The Universe
... for non-majors in mathematics or a physical science. A companion science lab, Astronomy 30, is also available. 3 hours. [Typical contact hours: 52.5] Prerequisite Skills: None Expected Outcomes for Students: Upon completion of the course, the student should be able to: ...
... for non-majors in mathematics or a physical science. A companion science lab, Astronomy 30, is also available. 3 hours. [Typical contact hours: 52.5] Prerequisite Skills: None Expected Outcomes for Students: Upon completion of the course, the student should be able to: ...
Axions and White Dwarfs
... where t satisfies the condition t = T − tcool (l, M ) − tPS (M ) and l = − log(L/L⊙ ), M is the mass of the parent star (for convenience all white dwarfs are labeled with the mass of the main sequence progenitor), tcool is the cooling time down to luminosity l, τcool = dt/dMbol is the characteristic ...
... where t satisfies the condition t = T − tcool (l, M ) − tPS (M ) and l = − log(L/L⊙ ), M is the mass of the parent star (for convenience all white dwarfs are labeled with the mass of the main sequence progenitor), tcool is the cooling time down to luminosity l, τcool = dt/dMbol is the characteristic ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.