Question

Although it has a greater ____ than Sirius, Rigel does NOT look as bright in the night sky.

Answer 1

Option (d) is correct. The absolute magnitude of the Rigel is more than that of Sirius but it does not appear more bright in night sky.

Explanation:

The absolute magnitude of a star is defined as the magnitude of the brightness of the star. It depends on the total amount of the light emitted by the particular star.

The brightness of the star is measured in terms of two quantities. The absolute magnitude and the apparent magnitude of the star. The apparent magnitude of the star is the brightness observer by the observer which is present at a particular distance from the observer.

The distance of the star Sirius from the surface of the Earth is about $8\text{ light years}$ whereas the distance of the star Rigel from the surface of the Earth is about $850\text{ light years}$.

The huge distance of the Rigel from the Earth makes it less brighter than the Sirius in the night sky in spite of having greater absolute magnitude. It is because the apparent magnitude of the star as observed on the Earth is greater for the star Sirius due to its smaller distance as compared to the Rigel.

Thus, Option (d) is correct. The absolute magnitude of the Rigel is more than that of Sirius but it does not appear more bright in night sky.

Learn More:

1. How does reflection differ from refraction and diffraction brainly.com/question/3183125

2. When does an equinox occur brainly.com/question/1000562

3. Derive the formula for mass of the planet brainly.com/question/2289465

Answer Details:

Grade: High School

Subject: Physics

Chapter: Astronomy

Keywords:

apparent, absolute, magnitude, star, observer, brightness, Sirius, Rigel, parallax, bright, light year, distance.

Answer 2

Rigel has a much greater absolute magnitude than Sirius, but appears to be much dimmer. This is due to the fact that Rigel is about one hundred times further away than Sirius. Sirius is a much lower energy star, but appears to be the brightest star in the sky because of its relatively close proximity of 8 light years.