Expert: Jayendra Upadhye - 4/3/2009

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 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.  

Answer
Hi,
Mansi,
I am surprised when you mention a binary, how come you neglected doppler spectroscopy?
The to and fro wobble is a dead give away if it is really a binary system.

B6 Class shows Neutral Helium and Hydrogen lines.
refer:- http://nrumiano.free.fr/Estars/classes.html

I will select the possible correct statements.
The other star isnt a white dwarf as the hottest dwarf is only a soft source of x rays.
It could be a newutron star with its poles at quadrature to our oline of sight so we dont see the "winking beam".
Neureon stars

My choices (others i deleted).
Some time in the next few decades, this system will undergo a nova explosion.  
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 black hole.

regards
Jayen