Al Fawaris / Delta Cygni Star Facts (Type, Distance, Magnitude, Age, Colour, Location and more)
Al Fawaris, also known as Delta Cygni (Bayer) is a giant star located in the constellation of Cygnus, The Swan. Al Fawaris is a major star and forms part of the constellation.
Based on the spectral type (B9.5III), Al Fawaris colour is blue, which means that the star is one of the hottest stars in the Universe, hotter than our star.


Al Fawaris temperature is in the range of 10,000 to 30,000 Kelvin. Based on the spectral type (B9.5III) as we don't have the exact temperature', we can deduce that the surface temperature of Al Fawaris is in the order of 10,000 and 25,000K based on the notes from Harvard University. To put this in context, the temperature of our Sun is about 5,778 Kelvin as said by Google.
Based on a parallax of 19.77, Al Fawaris distance from Earth can be calculated at being 164.98 light years away or 52.44 parsecs.
Al Fawaris is a naked-eye star, so you don't need a telescope or binoculars when you look up on a clear night. The lower the magnitude, the easier it will be to see it.
Location
The location of the Al Fawaris in the night sky is determined by the right ascension (R.A.) and declination (Dec.). These are equivalent to the Longitude and Latitude on Earth. The Right Ascension (Longitude) is expressed in time (hh:mm:ss) and is how far the star is along Earth's celestial equator. If the R.A. is positive, then it's eastwards and vice versa.
The Declination (Latitude) is how far north or south the object is compared to the celestial equator and is expressed in degrees. If the value is positive, it is north of the celestial equator. For Al Fawaris, the location is 19h 44m 58.44 and +45° 07` 50.5 .
Based on the location of Cygnus, Al Fawaris can be located in the northern hemisphere of the celestial sky. The celestial hemisphere is equivalent to the hemispheres on Earth. Al Fawaris is north of the Ecliptic. The Ecliptic is the path that the Earth takes as it orbits the Sun. As the Earth is titled, we therefore have Celestial and Ecliptic hemispheres and they can be different for a star.
Physical Properties
Spectral Type
Al Fawaris spectral type of B9.5III which means its colour and type is blue giant star. There is no relationship between colour and size. For example, a red star can be large or small. Small stars are more energy efficient than larger stars and live longer.
Al Fawaris Luminosity
Luminosity is the amount of energy a star pumps out relative to the amount that our star, the Sun, gives out. Our star, the Sun's value is 1. Al Fawaris luminosity figure of 199.64 is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012. The star generates more energy than our star.
Magnitude (Apparent / Absolute / Visible)
A number represents a star’s magnitude, whether apparent/visual or absolute. The smaller the number, the brighter the star is. The Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.
Al Fawaris apparent magnitude is 2.86, which is a measure of the star's brightness as seen from Earth. Apparent Magnitude is also known as Visual Magnitude.
If you use the 1997 parallax value, Al Fawaris' absolute magnitude is -0.74. If you use the 2007 parallax value, Al Fawaris' absolute magnitude is -0.66. Absolute Magnitude is the star's apparent magnitude from 10 parsecs or 32.6 light years. The magnitude assumes nothing is between the object and the viewer, such as dust clouds. To compare different stars' actual brightness, you would best use Absolute rather than Apparent Magnitude.
Al Fawaris is visible from Earth without needing binoculars or a telescope. The lower the Apparent Magnitude of a star or other object is, the easier it is to see in the night sky. An object with a magnitude greater than 6.5 cannot be seen without a telescope or other device.
Radial Velocity and Proper Motion
In simplistic terms, all non-rogue stars, like planets, orbit around a central object, although that is actually not true. Where is the centre of the Solar System. For simplicity it's the central star, such as the Sun. In the case of a star, it's the galactic centre. The constellations we see today will be different than they were 50,000 years ago or 50,000 years from now.
Proper motion details the movements of these stars and is measured in milliarcseconds. Al Fawaris is moving 48.66 ± 0.41 milliarcseconds/year towards the north and 44.07 ± 0.48 milliarcseconds/year east if we saw them in the horizon.
The radial velocity, the speed at which the Al Fawaris is towards the Sun, is -23.60000 km/s with an error of about 3.00 km/s . When the value is negative, the star and the Sun are getting closer to one another; likewise, a positive number means that two stars are moving away. It's nothing to fear as the stars are so far apart they won't collide in our lifetime, if ever.
Al Fawaris Fact Table
The table is scrollable if you can't see everything, just swipe the table to see the hidden information.
| Primary Name | Al Fawaris |
|---|---|
| Spectral Type | B9.5III |
| Star Type | High proper-motion Star |
| Colour | blue |
| Galaxy | Milky Way |
| Constellation | Cygnus |
| Main Star | Yes |
| Absolute Magnitude | -0.74 / -0.66 |
| Visual / Apparent Magnitude | 2.86 |
| Visible From Earth | Yes |
| Right Ascension (R.A.) | 19h 44m 58.44 |
| Declination (Dec.) | +45° 07` 50.5 |
| Galactic Latitude | 10.24305979 ° |
| Galactic Longitude | 78.70939320 ° |
| 1997 Distance from Earth | 19.07000 Parallax (milliarcseconds) |
| 171.03 Light Years | |
| 52.44 Parsecs | |
| 2007 Distance from Earth | 19.77000 Parallax (milliarcseconds) |
| 164.98 Light Years | |
| 50.58 Parsecs | |
| 10,432,801.203 Astronomical Units | |
| Galacto-Centric Distance | 24,103.471 Light Years / 7,390 Parsecs |
| Proper Motion Dec. | 48.66000 ± 0.41000 milliarcseconds/year |
| Proper Motion RA. | 44.07000 ± 0.48000 milliarcseconds/year |
| B-V Index | 0 |
| Radial Velocity | -23.60000 ± 3 km/s |
| Eccentricity | 0.05530 |
| Semi-Major Axis | 7079.0000000 |
| Luminosity (Lsun) | 199.6400000 |
Sources and Links
| Modified Date | 24th July 2024 |
| Published Date | Jan 2015 |
| SIMBAD Source | Link |
Cygnus's Main Stars in Brightness Order
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