what is the first celestial body?
It is also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter.
White dwarf
A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter. 
how many stars r in the milky way It is estimated to contain 100–400 billion stars how can its size be described? It is the second-largest galaxy in the Local Group, it is approximately 890 billion times the mass of the Sun. To compare the relative physical scale of the Milky Way, if the Solar System out to Neptune were the size of a US quarter, the Milky Way would be approximately the size of the contiguous United States. which celestial bodies can be found in this galaxy? It  contain ten billion white dwarfs, a billion neutron stars, and a hundred million stellar black holes.
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White dwarf [SEP] Introduction
A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to that of the Sun, while its volume is comparable to that of Earth. A white dwarf's faint luminosity comes from the emission of stored thermal energy; no fusion takes place in a white dwarf. The nearest known white dwarf is Sirius B, at 8.6 light years, the smaller component of the Sirius binary star. There are currently thought to be eight white dwarfs among the hundred star systems nearest the Sun.