Q: Is a star a luminous sphere of plasma held together by its own gravity? ¶
Q: Were stars permanently affixed to a heavenly sphere and that they were immutable? ¶
Q: Is a star determined by its radius and surface temperature? ¶
Q: Are stars those that undergo a dramatic change in their properties? ¶
Q: Are stars thought to be rare? ¶
Q: Are stars observed to be members of binary star systems? ¶
A: Yes, and the properties of those binaries are the result of the conditions in which they formed.
Q: Is a star determined by the rate of energy production of its core and by its radius? ¶
A: Yes, and is often estimated from the star's color index.
Q: Are stars greater than the current age of the universe? ¶
A: Yes, and no stars under about 0.85 M☉ are expected to have moved off the main sequence.
Q: Are stars so dim that their light is as bright as a birthday candle on the Moon when viewed from the Earth? ¶
Q: Is a star cooler than the core? ¶
Q: Is a star the main factor that determines its evolution and eventual fate? ¶
Q: Were stars also given names? ¶
A: Yes, and particularly with Arabic or Latin designations.
Q: Were stars equally distributed in every direction? ¶
A: Yes, and an idea prompted by the theologian Richard Bentley.
Q: Is a star at least 5,000,000 times more luminous than the Su? ¶
A: Yes, and t least 5,000,000 times more luminous than the Sun.
Q: Are stars generally referred to as being spheres of plasma? ¶
Q: Are stars likely to have existed in the very early universe? ¶
A: Yes, and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life.
Q: Were stars like the Sun? ¶
A: Yes, and may have other planets, possibly even Earth-like, in orbit around them, an idea that had been suggested earlier by the ancient Greek philosophers, Democritus and Epicurus, and by medieval Islamic cosmologists such as Fakhr al-Din al-Razi.
Q: Are stars often surrounded by a protoplanetary disk and powered mainly by the conversion of gravitational energy? ¶
Q: Are stars longer than the age of the universe? ¶
A: Yes, and no such star has yet reached the white dwarf stage.
Q: Are stars much too small in angular size to be observed with current ground-based optical telescopes? ¶
A: Yes, and so interferometer telescopes are required to produce images of these objects.
Q: Are stars red dwarfs? ¶
A: Yes, and most stars in the Milky Way are likely single from birth.
Q: Are stars visible to the naked eye from Earth during the night? ¶
A: Yes, and appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth.
Q: Are stars given a single-letter classification according to their spectra? ¶
A: Yes, and ranging from type O, which are very hot, to M, which are so cool that molecules may form in their atmospheres.
Q: Are stars believed to be part of multiple-star systems? ¶
Q: Is a star the amount of light and other forms of radiant energy it radiates per unit of time? ¶
Q: Is a star expressed in terms of its apparent magnitude? ¶
Q: Is a star in a state of hydrostatic equilibrium: the forces on any small volume almost exactly counterbalance each other? ¶
Q: Are stars not spread uniformly across the universe? ¶
A: Yes, but are normally grouped into galaxies along with interstellar gas and dust.
Q: Are stars between 1 billion and 10 billion years old? ¶
Q: Are stars also found? ¶
Q: Were stars made primarily of hydrogen and helium in her 1925 PhD thesis? ¶
Q: Were stars further understood through advances in quantum physics? ¶
Q: Is a star generated within regions of the interior where convective circulation occurs? ¶
Q: Is a star determined by its initial mass? ¶
A: Yes, and including such characteristics as luminosity, size, evolution, lifespan, and its eventual fate.
Q: Is a star at least on the order of 107 K? ¶
A: Yes, The resulting temperature and pressure at the hydrogen-burning core of a main sequence star are sufficient for nuclear fusion to occur and for sufficient energy to be produced to prevent further collapse of the star.
Q: Is a star several million kelvins? ¶
Q: Were stars classified from A to Q based on the strength of the hydrogen line? ¶
Q: Were stars grouped into constellations and asterisms? ¶
A: Yes, and the brightest of which gained proper names.
Q: Are stars said to be on the main sequence? ¶
A: Yes, and are called dwarf stars.
Q: Is a star found? ¶
A: Yes, such as by measuring the parallax, then the luminosity of the star can be derived.
Q: Are stars through occultation? ¶
Q: Was a star formed? ¶
Q: Is a star manifested as the stellar wind? ¶
A: Yes, and which streams from the outer layers as electrically charged protons and alpha and beta particles.