How did the first generation of stars differ from stars that form today?
How did the first generation of stars differ from stars that form today? They were all high-mass stars. When does a forming star become a protostar? When radiation can no longer escape the central region.
Why are the very first stars thought to have been much more massive than the sun?
We think that the first generation of stars must have been more massive than the Sun because there were no elements heavier than hydrogen and helium to form the molecules that cool molecular clouds. Since the clouds would have been warmer, the clouds would have had to form larger fragments to collapse.
Which kind of pressure prevents the formation of stars of extremely large mass?
The maximum mass is 150 solar masses. Radiation pressure limits the mass of a star. How do the numbers of low mass stars compare with those of high mass stars in new star clusters? Observations of newly formed populations of stars have shown us that very few high mass stars form, while many low mass stars form.
What is the approximate range of masses that newborn main sequence stars can have?
What is the approximate range of masses that newborn main sequence stars can have? 0.1 to 150 solar masses. The vast majority of stars in a newly formed star cluster are: Less massive than the sun.
What happened to the first stars?
Fractions-of-a-second later, most of the particle-antiparticle pairs had annihilated away. Atomic nuclei were fused together, neutral atoms formed, and gravitation pulled matter together into clumps. Eventually, some of the largest clumps collapsed, creating the first stars.
Can first generation stars appear?
Astronomers Find No Evidence of Elusive First-Generation Stars in Early Universe. Astronomers using the NASA/ESA Hubble Space Telescope have found no evidence of hypothetical first-generation stars — called Population III stars — as far back as when the Universe was just 500 million years old.
Which of the following Cannot be true of the very first stars formed in the universe?
Which of the following cannot be true of the very first stars formed in the Universe? They may have had rocky planets around them.
Why are the very first stars thought to have been?
Why are the very first stars thought to have been much more massive than the Sun? a) The clouds that made them were much more massive than today's star-forming clouds.
What are the factors that affect star formation at present?
In detail, though, the star formation rate depends on many other factors, including the temperature of the gas, turbulent motions, the gravitational potential of the surroundings, magnetic effects, ionizing photons from nearby stars, and more.
What is thought to prevent the formation of stars with masses larger than about 300 times that of our sun?
What is thought to prevent the formation of stars with masses larger than about 300 times that of our Sun? Such massive stars would generate so much light that radiation pressure would blow them apart.
Which two factors are most important in determining the current appearance of a star?
Which two factors are most important in determining the current appearance of a star? Mass and stage of life (Mass determines the star's life progression, so the star's current place along that progression depends on its current stage of life.)
What must occur for an object to be considered a main sequence star?
What must occur for an object to be considered a main sequence star? Hydrostatic equilibrium, and Nuclear fusion reaction in the core.
What is a first generation star?
A team of astronomers has found the best evidence yet for the very first generation of stars, ones made only from ingredients provided directly by the big bang. Made of essentially only hydrogen and helium, these so-called population III stars are predicted to be enormous in size and to live fast and die young.
Are there any 1st generation stars left?
Astronomers using the NASA/ESA Hubble Space Telescope have found no evidence of hypothetical first-generation stars — called Population III stars — as far back as when the Universe was just 500 million years old. An artist's impression of the early Universe.
Why can’t our current theories describe the conditions that existed in the universe during the Planck era?
Why can't our current theories describe the conditions that existed in the universe during the Planck era? At the time, the energy was fluctuating causing the gravitational field to randomly warp space and time. What are grand unified theories? According to these theories, how many forces operated during the GUT era?
How were the first stars formed?
The universe primarily consisted of neutral hydrogen gas floating in an omnipresent sea of background radiation leftover from the Big Bang. Over time, gravity slowly shepherded the densest regions of hydrogen gas into compact clouds, which ultimately collapsed to form the first stars.
Are there any first generation stars left?
Astronomers using the NASA/ESA Hubble Space Telescope have found no evidence of hypothetical first-generation stars — called Population III stars — as far back as when the Universe was just 500 million years old. An artist's impression of the early Universe.
What prevents star formation?
Pressure from fast moving electrons keeps these stars from collapsing. The more massive the core, the denser the white dwarf that is formed. Thus, the smaller a white dwarf is in diameter, the larger it is in mass!
What determines the mass distribution of forming stars the initial mass function?
In theory, the IMF should vary with different star-forming conditions. Higher ambient temperature increases the mass of collapsing gas clouds (Jeans mass); lower gas metallicity reduces the radiation pressure thus make the accretion of the gas easier, both lead to more massive stars being formed in a star cluster.
Why do we not expect to find a 5 solar-mass neutron star?
Why do we not expect to find a 5 solar mass neutron Star? If neutron star exceeds 3 solar masses, it would collapse into a black hole.
Why does the evolution of a protostar slow down as the star approaches the main sequence?
Why does the evolution of a protostar slow down as it approaches the main sequence? The cause of this slowdown is heat 14even gravity must struggle to compress a hot object. The contraction is governed largely by the rate at which the protostar 19s internal energy can be radiated away into space.
What factor is most important in determining the apparent brightness of a star?
Which units are appropriate for measurement of apparent brightness? Watts per square meter (Apparent brightness is defined as the power of starlight reaching us per unit area.
What is the main factor driving the evolution of a star and why?
The primary factor determining how a star evolves is its mass as it reaches the main sequence. The following is a brief outline tracing the evolution of a low-mass and a high-mass star. Stars are born out of the gravitational collapse of cool, dense molecular clouds.
What would you be most likely to find if you returned to the solar system in 10.0 billion years?
What would you be most likely to find if you returned to the solar system in 10.0 billion years? If the Sun had been born as a high-mass star 4 1/2 billion years ago rather than as a low-mass star, the planet Jupiter would probably have Earth-like conditions today, while Earth would be hot like Venus.
What main factor determines the stages a star will follow after the main sequence?
mass The amount of mass a star has determines which of the following life cycle paths it will take from there. The life cycle of a low mass star (left oval) and a high mass star (right oval).
Why would it have been hard for the first generation of stars to have planets?
If they did have planets, of what would those bodies have been composed? Heavy elements like oxygen, carbon, and silicon first needed to be created from explosions of huge stars called supernovas and the stellar cores of stars from the first generation before the first planets could be formed.
Why can’t we see past the cosmological horizon?
We cannot see past the cosmological horizon because we can only see things in the night sky that produce (or reflect) light, and light takes time to…
How do we determine the conditions that existed in the very early universe?
How do we determine the conditions that existed in the early universe? We work backward from current conditions to calculate what temperatures and densities must have been when the observable universe was much smaller in size.
Which of the following Cannot be true of the very first stars that formed in the universe?
Which of the following cannot be true of the very first stars formed in the Universe? They may have had rocky planets around them.
Why do galaxies eventually stop forming stars?
The gas reservoirs clearly drive star-formation in these galaxies, and star-formation ceases because these reservoirs are somehow drained away and do not get replenished.