Questions About main sequence star orbits

What is the order in which two low-mass main-sequence stars orbit each other?

a. A white dwarf orbits a more massive main sequence star. b. Star 1(the more massive star) begins to evolve off the main sequence. c. Star 1 fills its Roche lobe and begins transferring mass to the white dwarf d. The white dwarf either becomes a nova or a supernova e. Star 2 gains mass, becoming hotter and more luminous f. Star 2 fills its Roche lobe and begins transferring mass to the white dwarf I think there is a problem with the test, because I'm almost positive I know the answer. I just want to see what everyone else says it is so I can back up my own prediction.
http://answers.yahoo.com/question/?qid=20121127005050AAFrH1y

A G main-sequence star and an unseen companion star are orbiting each other in a binary system?

A G main-sequence star and an unseen companion star are orbiting each other in a binary system ("unseen" means that the companion is much fainter than the G star, so it cannot be seen next to the brighter G star). By measuring the velocity of the G main-sequence star and the period of its orbit, you estimate that the combined mass of the two stars is 5 solar masses. The unseen companion is probably a A) neutron star B) red giant C) white dwarf D) O main sequence star E) black hole
http://answers.yahoo.com/question/?qid=20130312132215AAApwVH

Does anyone know how to answer this Astronomy question?

The Chandra X-Ray Observatory has detected X rays from a star system that contains a main-sequence star of spectral type B6. The X-ray emission is strong and fairly steady, and no sudden bursts have been observed. Which of the following statements are reasonable conclusions about this system? Check all that apply. The main-sequence star is emitting X rays. The main-sequence star orbits either a neutron star or a black hole. The main-sequence star must orbit a black hole. Gas from the main-sequence star makes an accretion disk around another object. The main-sequence star orbits either a white dwarf or a neutron star. The main-sequence star must orbit a neutron star. Some time in the next few decades, this system will undergo a nova explosion. The main-sequence star must orbit a white dwarf.
http://answers.yahoo.com/question/?qid=20121114185547AAOrrnz

Which of the following statements are reasonable conclusions about this system?ld you like to ask?

The Chandra X-Ray Observatory has detected X rays from a star system that contains a main-sequence star of spectral type B6. The X-ray emission is strong and fairly steady, and no sudden bursts have been observed. Which of the following statements are reasonable conclusions about this system?ld you like to ask? Check all that apply: - The main-sequence star orbits either a white dwarf or a neutron star. - Some time in the next few decades, this system will undergo a nova explosion. - The main-sequence star must orbit a white dwarf. - The main-sequence star orbits either a neutron star or a black hole. - Gas from the main-sequence star makes an accretion disk around another object. - The main-sequence star must orbit a neutron star. - The main-sequence star is emitting X rays. - The main-sequence star must orbit a black hole.
http://answers.yahoo.com/question/?qid=20090403215307AAOtWHu

Which of the following statements are reasonable conclusions about this system?

The Chandra X-Ray Observatory has detected X rays from a star system that contains a main-sequence star of spectral type B6. The X-ray emission is strong and fairly steady, and no sudden bursts have been observed. Which of the following statements are reasonable conclusions about this system? Check all that apply. 1. The main-sequence star must orbit a white dwarf. 2. The main-sequence star must orbit a neutron star. 3. Some time in the next few decades, this system will undergo a nova explosion. 4. Gas from the main-sequence star makes an accretion disk around another object. 5. The main-sequence star orbits either a neutron star or a black hole. 6. The main-sequence star is emitting X rays. 7. The main-sequence star orbits either a white dwarf or a neutron star. 8.The main-sequence star must orbit a black hole.
http://answers.yahoo.com/question/?qid=20121105103045AALuLL5

Do astronomers know what causes type Ia supernova?

Do they know exactly what causes them. I know it's supposed to involve a binary system with at least one white dwarf. Do they know exactly what causes the thermonuclear reaction just before the Chandrasekhar is reached? Is it collision of two white dwarfs or mass accretion from another main sequence star that it's orbiting? People think it's an implosion when Chandrasekhar limit is reached or exceeded but it's not. At least I know that much.
http://answers.yahoo.com/question/?qid=20121224125239AAxxHbn

What would a sunset look like on a planet orbiting a blue star?

Assume a planet much like earth, with a similar atmosphere, and supporting a diverse biosphere replete with plants, animals, bacteria, etc... similar to our own, with optimum conditions for life. And yes, I know blue stars have shorter main sequence lives and would be far less likely to develop life. But to answer the question, please assume that this one does have a planet supporting life. Since the star is blue, would the sunset be a bit more bluish and less reddish? Would the sky in general be a more intense blue because there was more blue light to scatter?
http://answers.yahoo.com/question/?qid=20130330133034AAgvFgz