The density of Sirius B is 2×106 g/cm3 and its mass is 1.95×1030 kg. What is the radius of the white dwarf in km? (Hint: Density = mass/volume, and the volume of a sphere is 4/3πr3)

You've just discovered a new X-ray binary, which we will call Hyp-X1 ("Hyp" for hypothetical). The system Hyp-X1 contains a bright, 82 main- sequence star orbiting an unseen companion. The separation of the stars is estimated to be 23 million kilometers, and the orbital period of the visible star is 4 days Part C Determine the mass of the unseen companion.(Hint A main-sequence star with spectral type B2 has a mass of about 10M) Express your answer as a multiple of Sun's mass to two significant figures. Musso Submit Part D Request Answer | ΑΣΦ Is it a neutron star or a black hole? black hole neutron star ? Mun

Which of the following is least reasonable regarding stars on a Hertzsprung-Russell diagram?   1)Stars with the largest radii are found in the upper right of the diagram.   2) Red giants are found in the upper right of the diagram.   3)White dwarfs are found in the lower left of the diagram.   4) On the main sequence, the mass of stars generally increases to the right.

A 1.4 M. neutron star and a 0.5 M. white dwarf have been found orbiting each other with a period of 16 minutes. What is their average separation? Convert your answer to units of the Sun's radius, which is 0.0047 AU. (Hints: Use the version of Kepler's third law for binary stars, MA + MB make sure you express quantities in units of AU, solar masses, and years. Note: a year is 3.2 x 1o' s.) %3D solar radii

Please use the info to answer the question. Please circle your answer.

What is the size of a typical white dwarf? Group of answer choices   1.0 solar radii   0.5 solar radii   0.1 solar radii (roughly the size of Jupiter)   0.01 solar radii (roughly the size of Earth)   5 solar radii

Indicate whether the following statements are true or false.   (Select T-True, F-False. If the first is T and the rest F, enter TFFFFF). A) White dwarfs are small dense objects about the size of the Earth.   B) White dwarfs are composed mostly of hydrogen.   C) A planetary nebula forms when a star violently explodes.   D) A planetary nebula is the remnant of the outer envelope of a star.   E) A white dwarf is the remnant of the star's core visible after the outer layers have been ejected.

15: A star has a parallax angle of 0.0270 arcseconds and an apparent magnitude of 4.641. What is the distance to this star?  Answer: 37 16: What is the absolute magnitude of this star? Answer:1.8 17: Is this star more or less luminous than the Sun? Answer "M" for More luminous or "L" for Less luminous. (HINT: the absolute magnitude of the Sun is 4.8) Answer: M  18: What is the luminosity of this star? (HINT: The luminosity of the Sun is 3.85×1026 W.) Please answer question #18, #15-17 are correct, the photos provide the work for them.

Which of the following is a true statement? A smaller diameter star can never have a smaller number for its apparent magnitude than a larger star. Two stars with the same diameter and effective surface temperature will necessarily have the same absolute magnitude as well. Aristotle was the first person to detect stellar parallax. All G2 stars necessarily have the same absolute magnitude.

Choose the correct statements from the following list referring to white dwarfs. (Give ALL correct answers, i.e. B, AB, BCD...) A) Stars with a mass like the Sun will end up as a white dwarf star. B) White dwarfs with mass greater than 1.4 times the Sun's mass cannot exist. C) White dwarfs are less dense than red giants. D) The pressure that balances gravity in a white dwarf is called degenerate electron pressure. E) White dwarfs cool slowly because they are small and eventually fade-out to become black dwarfs. F) The power source of white dwarfs is left-over heat. G) White dwarfs are the coolest main sequence stars.