[17] It also lies at one vertex of the prominent and widely spaced asterism called the Summer Triangle, shared with the first-magnitude stars Vega in the constellation Lyra and Altair in Aquila.

[23] The north pole of Mars points to the midpoint of the line connecting Deneb and the star Alderamin.

Another distance estimate using its bolometric magnitude implied by its effective temperature and surface gravity gives 762 parsecs (2,490 ly).

[b] The original derivation of a parallax using measurements from the astrometric satellite Hipparcos gave an uncertain result of 1.01 ± 0.57 mas[25][26] that was consistent with this distance.

[2] The controversy over whether the direct Hipparcos measurements can be ignored in favour of a wide range of indirect stellar models and interstellar distance scales is similar to the better known situation with the Pleiades.

[29] Based on its temperature and luminosity, and also on direct measurements of its tiny angular diameter (a mere 0.002 seconds of arc), Deneb appears to have a diameter about 100 – 200 times that of the Sun;[30] if placed at the center of the Solar System, Deneb would extend to the orbit of Mercury or Earth.

[32] Deneb spent much of its early life as an O-type main-sequence star of about 23 M☉, but it has now exhausted the hydrogen in its core and expanded to become a supergiant.

[7][33] Stars in the mass range of Deneb eventually expand to become the most luminous red supergiants, and within a few million years their cores will collapse producing a supernova explosion.

It is now known that red supergiants up to a certain mass explode as the commonly seen type II-P supernovae, but more massive ones lose their outer layers to become hotter again.

[33] Stars evolving red-wards for the first time are most likely fusing hydrogen in a shell around a helium core that has not yet grown hot enough to start fusion to carbon and oxygen.

Deneb is thought to be increasing its temperature after a period as a red supergiant, although current models do not exactly reproduce the surface elements showing in its spectrum.

[33] On the contrary, it is possible that Deneb has just left the main sequence and is evolving to a red supergiant phase, which is in agreement with estimates of its current mass, while its spectral composition can be explained by Deneb having been a rapidly rotating star during its main sequence phase.

[39] Consequently, the Chinese name for Deneb itself is 天津四 (Tiān Jīn sì, English: the Fourth Star of the Celestial Ford).

[40] In the Chinese love story of Qi Xi, Deneb marks the magpie bridge across the Milky Way, which allows the separated lovers Niu Lang (Altair) and Zhi Nü (Vega) to be reunited on one special night of the year in late summer.