Discovering the Nature of Unseen Companions with 1.3 Solar Masses

What is the likely nature of an unseen companion with a mass of 1.3 solar masses orbiting a star?

Is it a white dwarf, neutron star, or black hole?

Answer:

The unseen companion with a mass of 1.3 solar masses orbiting a star is likely a black hole.

When astronomers detect an unseen companion orbiting a star, with the calculated mass being 1.3 solar masses, the most likely nature of this companion is a black hole. This conclusion is drawn based on various factors, including the mass threshold for different types of stellar remnants.

White dwarfs, which are stars that have exhausted their nuclear fuel, have mass limits ranging from 0.15 to 1.2 solar masses. Neutron stars, on the other hand, have higher mass limits but are still below the threshold for black holes. Astronomers use Kepler's law and astronomical observations to determine the mass of unseen companions, and a mass exceeding about 3 solar masses indicates a black hole.

The detection of black holes in binary systems, like Cygnus X-1, highlights how massive unseen companions can hint at the presence of a black hole. Additionally, studies of stars orbiting the center of the Milky Way have pointed towards the existence of a supermassive black hole with millions of solar masses.

In summary, the mass of 1.3 solar masses for the unseen companion is beyond the limits of white dwarfs and neutron stars, making a black hole the most probable nature for this celestial object.