Aster Exam 3 T/f

the most common constituent of molecular clouds, H2, is rarely detected within them

molecular clouds appear more transparent at longer wavelengths

Clouds that appear dark in visible light often glow when observed at long infrared wavelengths.

most stars are born in clusters containing thousands of stars

stars only form in molecular clouds that contain more than 100 times the mass of our sun

No stars have been found composed solely of Hydrogen and Helium (and no heavier elements).

photographs of many young stars show long jets of material apparently being ejected from their poles

although some photographs show what looks like jets of material near many young stars, we now know that these "jets" actually represent gas from the surrounding nebula that is falling onto the stars

Protostars start off more luminous than the main sequence stars they become.

in any star cluster, stars with Lower masses greatly outnumber those with higher masses

There is no limit to the mass with which a star can be born.

Jupiter is a failed star

In any star cluster, stars with lower masses greatly outnumber those with higher masses.

Stars with high masses live longer than stars with lower masses.

stars with lower mass have deeper convection zones outside their core than stars of higher mass

convection never occurs in the core of any type of star

the helium fusion process works by fusing two helium nuclei into one beryllium nucleus

Our Sun will end its life in a planetary nebula and become a white dwarf.

the most massive stars generate energy at the end of their lives by fusing iron in their cores

the heaviest element produced by stars or in supernovae is silicon

All stars that become supernovae will leave behind a neutron star.

it is impossible to know whether our sun will end its life as a white dwarf or a neutron star

Brown dwarfs, white dwarfs, and neutrons stars are all kept from collapsing by degeneracy pressure.

The upper limit to the mass of a white dwarf is 1.4 solar masses.

more massive white dwarfs are smaller than less massive white dwarfs

there is no upper limit to the mass of a neutron star

the remnant left behind from a white-dwarf supernova is a neutron star

Our Sun will likely undergo a nova event in about 5 billion years.

All pulsars are neutron stars, but not all neutron stars are pulsars.

neutron stars are the densest objects that we can observe in the universe

No visible light can escape a black hole, but things such as gamma rays, X rays, and neutrinos can.

Light from white dwarfs shows a gravitational redshift.

All massive-star supernovae leave behind black holes as remnants.

Planets have been detected around a pulsar.

it is impossible to tell the difference between the two types of supernovae

gravitational waves that carry energy and angular momentum away from the system cause white dwarfs to gradually spiral in toward each other and merge

most of the gold, platinum, and rare-earth elements present in the universe are created by neutron star mergers

the total energy released during a neutron star merger can be even greater than that of a massive star supernova