What is the magnitude of the star Deneb?

Deneb, one of the brightest stars in the night sky, has an apparent magnitude of approximately 1.3. This value indicates that Deneb is very luminous and can be easily seen from Earth. The apparent magnitude scale is logarithmic, where lower numbers correspond to brighter objects. Specifically, this means that Deneb is significantly brighter than many stars that have higher magnitude values.

The apparent magnitude of Deneb reflects its intrinsic brightness and its distance from our planet. As a supergiant star in the constellation Cygnus, Deneb is situated about 1,425 light-years away and radiates much more energy than our Sun, which also contributes to its visibility despite being far away.

In contrast, the other choices reflect stars with lower brightness levels than Deneb. For instance, a magnitude of 0.4 is indicative of a very bright star but is still not as bright as Deneb. Similarly, magnitudes of 3.0 and 2.5 represent even fainter stars, making them less significant in comparison to Deneb's luminosity.