Iris Nebula (NGC 7023) Facts, Formation, Location
The Iris Nebula (NGC 7023) is a reflection nebula located 1,300 light-years from Earth. A massive star illuminates the interstellar cloud, creating a glow resembling an eye’s iris. NGC 7023 spans 6 light-years across and contains a density of gas and dust contributing to star formation processes. William Herschel discovered the Iris Nebula on October 18, 1794. The nebula is illuminated by HD 200775, a 22,000 K B-type star, shining at magnitude 6.8. Dark clouds surround the Iris Nebula, creating contrast against its illuminated core. An open cluster associates with the nebula, adding to its complexity.
The Iris Nebula resides in the Cepheus constellation, a northern sky formation. Its coordinates are Right Ascension: 21h 01m 36.9s and Declination: +68° 09′ 48″. Cepheus is positioned near other notable constellations including Cassiopeia and Cygnus, making it possible for observers to locate the Iris Nebula.
The Iris Nebula consists of interstellar gas and dust clouds. NGC 7023 contains hydrogen, helium, and elements like iron, silicon, and magnesium. Dust particles comprise silicates and carbonaceous materials. Dust within the nebula obscures light from surrounding stars, creating patterns of dark lanes and bright regions. An illuminated central star lies at the heart of the Iris Nebula, serving as the source of light reflected by surrounding dust and gas.
What is an Iris Nebula (NGC 7023)?
The Iris Nebula (NGC 7023) is a reflection nebula located 1,300 light years from Earth. A hot, massive star illuminates the interstellar cloud, creating a bluish glow. Dust grains scatter radiation, giving the nebula its blue color. The nebula resembles an eye’s iris, with a central star surrounded by glowing gas and dust.
Reflection nebulae like NGC 7023 do not emit light. Instead, they reflect light from nearby stars. The Iris Nebula contains a density of gas and dust, which contributes to its structure and ongoing star formation processes. HD 200775, a star system, sits at the center of the nebula and drives outward flows of gas and dust. NGC 7023 contains hydrogen, helium, and elements that emit light at wavelengths, contributing to its complex visual appearance.
Astronomers classify the Iris Nebula as part of the interstellar medium (ISM) and estimate its age at 100,000 years. NGC 7023 represents a lived phase in stellar evolution, providing materials for star formation. The nebula’s features and visual appeal make it a target for astrophotographers and researchers studying nebular dynamics and stellar evolution.
What type of nebula is Iris Nebula?
Iris Nebula, known as NGC 7023 or Caldwell 4, is a reflection nebula. Reflection nebulae reflect light from stars rather than emitting their own. NGC 7023 is illuminated by a central star, giving it a bluish color. Located 1,300 light-years away in Cepheus, it contains gas and dust clouds.
What is the temperature of the Iris Nebula?
The temperature of the Iris Nebula varies across different regions. The central star illuminating the nebula has a surface temperature of 17,000 Kelvin. Massive stars like the one at the heart of the Iris Nebula exhibit high temperatures in their early stages of evolution. Areas within the nebula have been reported to reach temperatures of 5,000 degrees Celsius. The 5,000-degree measurement applies only to regions or features and does not represent the nebula’s temperature. Temperature during observations of the Iris Nebula is 1 degree Celsius or 274 Kelvin at the telescope site. The temperature relates to observation conditions and does not reflect the nebula’s internal temperature.
What is the radius of the Iris Nebula?
Iris Nebula has a radius of 3 light-years. NGC 7023, another name for Iris Nebula, spans 6 light-years across with a 1 light-year thickness. Iris Nebula is a reflection nebula located in the constellation Cepheus, 1,300 light-years from Earth. LBN 487 is an alternative designation for this nebula.
What is the magnitude of the Iris Nebula?
Iris Nebula has a magnitude of +6.8. Magnitude measures celestial object brightness logarithmically. Lower values indicate increased brightness. +6.8 magnitude makes Iris Nebula faint. The Nebula is visible with binoculars or telescopes under dark skies. Nebula is illuminated by star SAO 19158, a B-type main-sequence star.
What are interesting facts about the Iris Nebula?
Iris Nebula, NGC 7023, is a reflection nebula in the Cepheus constellation. Located 1,300 light-years away, it spans 6 light-years across. William Herschel discovered it in 1794. Illuminated by HD 200775, a 22,000 K B-type star, it shines at magnitude 6.8. Star formation occurs within its gas and dust composition.
The interesting facts about the Iris Nebula are outlined below.
- The Iris Nebula was discovered by William Herschel on October 18, 1794, signifying its historical discovery by a notable astronomer.
- NGC 7023 is the official designation of the Iris Nebulaofficial designation used in astronomical catalogs.
- The Iris Nebula is located in the Cepheus constellation, 1,300 light-years away from Earth.
- The Iris Nebula stretches 6 light-years across space.
- The Iris Nebula resembles an iris flower.
- The Iris Nebula’s appearance results from starlight reflected by dust particles.
- Dark clouds surround the Iris Nebula.
- There are red areas within the Iris Nebula, created by hydrogen gas emitting light.
- A central star, SAO 19158, illuminates the Iris Nebula. This star scatters blue light, contributing to its glow.
- The Iris Nebula was formed from a collapsing molecular cloud. Star formation continues within the nebula.
- John Louis Emil Dreyer cataloged the Iris Nebula, contributing to its documentation and recognition.
- Astrobin hosts images of the Iris Nebula, showcasing its beauty to a wide audience of astronomy enthusiasts.
What is the age of Iris Nebula?
Iris Nebula’s age is estimated around 400,000 years. Studies suggest a range of 300,000 to 500,000 years. Some researchers propose 1.5 million years. Star HD 200775 triggered nebula formation. Scientists determined age through expansion observations and star properties.
How was the Iris Nebula formed?
The Iris Nebula formed through a process of star formation and interaction with surrounding material. Star forming processes initiated the creation of the Iris Nebula 1,300 light-years away in the constellation Cepheus. Dust clouds and gas clouds collapsed under their gravity, providing the ingredients for the nebula’s formation. Interstellar material concentrated into a dense core at the center of the collapsing cloud.
A star formed at the heart of this dense core, emitting radiation and stellar winds. The star’s output carved a cavity in the surrounding interstellar material. This cavity allowed starlight to escape and illuminate dust particles. The illuminated portion became the Iris Nebula, spanning 6 light-years in diameter.
The Iris Nebula is classified as a reflection nebula due to its light-scattering properties. Dust particles in the nebula scatter and reflect light from the star, which has a surface temperature of 20,000 Kelvin. The expanding nebula continues to push due to ongoing stellar radiation and winds. Ultraviolet radiation from the star ionizes surrounding gas and dust, contributing to the nebula’s shape and colors.
What shape is the Iris Nebula?
Iris Nebula possesses a flower shape with concentric, elliptical shells of gas and dust. Nebula features a bright central cavity and dark tendrils. Nebula measures 6 light-years. Nebula has a distinctive bluish appearance due to reflection properties. Nebula’s shape is spherical with a 6 light-year diameter.
At its center, the Iris Nebula features an hourglass shape. The hourglass shape consists of a narrow waist separating two lobes. This structure is formed by the interaction between star radiation and surrounding gas and dust, creating a bipolar outflow of material funneled through the hourglass-shaped cavity. The hourglass shape results from radiation and strong stellar winds emanating from the central star, which have sculpted the surrounding interstellar medium.
Some observers have noted that the Iris Nebula’s shape resembles an arrow. The star and associated nebular material form the “head” of the arrow, while the surrounding gas and dust trail, creating the “shaft” of the arrow. However, this arrow-shaped description is not accurate, as the nebula’s shape combines curved and linear features.
The Iris Nebula’s shape is a result of interplay between star radiation, surrounding gas and dust, and gravitational forces. The nebula has a rim of gas and dust pointing away from the central star. The ring surrounding the central cavity is an ellipse with a major axis of 3.5 arcminutes and a minor axis of around 2.5 arcminutes.
How did Iris Nebula get its name?
Iris Nebula derives its name from the Greek goddess of the rainbow, reflecting its appearance. Sir William Herschel discovered and named the nebula in 1794. Located in Cepheus constellation, Iris Nebula is a cloud of gas and dust. NGC 7023 designation identifies this reflection nebula within the Cepheus Molecular Cloud Complex.
William Herschel discovered the Iris Nebula in 1794. Herschel, a British astronomer, described the nebula as having a flower-like shape. NGC 7023 became the designation for the Iris Nebula. The nebula’s central star, SAO 19158, is surrounded by a disk of gas and dust resembling iris flower petals in shape and size.
In which constellation is the Iris Nebula located?
The Iris Nebula resides in the Cepheus constellation, a deep northern sky formation named after the mythological Aethiopian king. Cepheus remains one of 88 constellations and was among Ptolemy’s 48 listed constellations. NGC 7023, the Iris Nebula’s alternative designation, is a reflection nebula illuminated by SAO 19158, a 7th-magnitude B-type star.
The Iris Nebula’s coordinates are Right Ascension: 21h 01m 36.9s and Declination: +68° 09′ 48″. The nebula is situated in a of Cepheus near the border with the constellation Cygnus. Cepheus is positioned near other notable constellations including Cassiopeia and Cygnus, making it easier for observers to locate the Iris Nebula. Amateur astronomers and astrophotographers target the Iris Nebula due to its appearance and bright magnitude of 6.8.
In which galaxy is the Iris Nebula located?
Iris Nebula resides within the Milky Way galaxy. Iris Nebula lies 1,300 light years from Earth. Cepheus constellation hosts this reflection nebula. NGC 7023 serves as a name for Iris Nebula. Cepheus OB2 association encompasses Iris Nebula, containing stars and star-forming activity.
How far is Iris Nebula from Earth?
Iris Nebula is located 1,300 light-years from Earth. William Herschel discovered the nebula in 1794. Astronomers determined its distance using the parallax method. Gaia spacecraft provided measurements in 2020. Iris Nebula spans 6 light-years across. NGC 7023 resides in the constellation Cepheus. Iris Nebula has a magnitude of 6.8.
How to find Iris Nebula through a telescope?
Iris Nebula is found North of Alderamin, the brightest star in Cepheus constellation. Astronomers locate the nebula in the southeast part of Cepheus. Telescopes with at least 80 mm diameter are recommended for observation. Cepheus is visible in the northern sky. Iris Nebula lies 1,300 light-years from Earth.
To find Iris Nebula through a telescope follow the steps listed below:
- Use a telescope with at least an 8-inch aperture.
- Locate the constellation Cepheus in the northern hemisphere.
- Identify the “house” shape of Cepheus to assist in locating key stars.
- Use the star-hopping technique starting from Errai through Alfirak.
- Extend a line from Errai through Alfirak to find T Cephei.
- Locate the Iris Nebula 1.5° north of T Cephei.
- Detect the nebula as a bluish haze around a bright central star.
- Use averted vision to reveal more details of the nebula’s structure.
- Allow time for eyes to adjust and detect nebulosity during viewing sessions.
- For astrophotography, use cameras with 400-500mm focal lengths attached to telescopes.
- Use long exposures to capture more detail of the Iris Nebula.
- Enhance visibility and contrast with nebula filters.
- Plan viewing sessions for summer months for optimal conditions.
Astronomers use a star-hopping technique to find the Iris Nebula. Stargazers spot the nebula by extending a line from Errai through Alfirak. The Iris Nebula is located 1.5° north of T Cephei. Telescopes detect the nebula as a bluish haze around a bright central star. Observers use averted vision to reveal more details of the nebula’s structure. Viewing sessions extend over time to allow eyes to adjust and detect nebulosity.
Astrophotographers capture the Iris Nebula’s extent with long exposures. Cameras attached to telescopes with 400-500mm focal lengths work for imaging the nebula. Nebula filters enhance the visibility and contrast of the Iris Nebula for both visual observers and astrophotographers. Observers target the Iris Nebula during summer months for viewing conditions.
What is Iris Nebula made of?
Iris Nebula consists of interstellar gas and dust clouds. NGC 7023 contains hydrogen, helium, and elements like iron, silicon, and magnesium. Dust particles comprise silicates and carbonaceous materials. Nebula’s composition forms materials for star formation. Diffuse regions of gas and dust create the nebula’s complex, irregular shape.
The composition of Iris Nebula is detailed in the table below.
| Component | Characteristics |
| Interstellar Dust | Particles measuring 0.01 to 1 micrometers in diameter, with a mean size of 0.1 micrometers; solid matter with a density of 10^-6 kg/m^3 |
| Interstellar Gas | Composed primarily of hydrogen (70%) and helium (28%) by mass, with a temperature of 10-100 K and a density of 10^2-10^4 particles/cm^3 |
| Carbon | Element present in nebula at an abundance of 10^-4 by mass, contributing to complex molecules formation such as CO, CH, and C2 |
| Nitrogen | Element present in nebula at an abundance of 10^-5 by mass, contributing to complex molecules formation such as N2, NH, and CN |
| Polycyclic Aromatic Hydrocarbons | Organic compounds found in the nebula, consisting of 10-100 carbon atoms, with a concentration of 10^-7 by mass |
| Light Reflection | Illuminated by a central star (SAO 19158) with a luminosity of 47 L, classified as a reflection nebula with a reflection efficiency of 0.1-0.5 |
| Nebula Span | Spans 6 light-years (1.8 parsecs) across, with a radius of 3 light-years (0.9 parsecs) |
| Composition Variation | Non-uniform composition with a density gradient of 10^-5 kg/m^3/pc, and a temperature gradient of 10 K/pc |
| Reddish Dust | Obscures light from surrounding stars, creating dark lanes and bright regions with a visual extinction of 2-5 magnitudes |
Composition of the Iris Nebula is not uniform throughout its structure. Reddish dust within the nebula obscures light from surrounding stars, creating patterns of dark lanes and bright regions. An illuminated central star lies at the heart of the Iris Nebula, serving as the source of light reflected by surrounding dust and gas. The Iris Nebula is classified as a reflection nebula, glowing due to the light reflected by its particles.
What is the surface area of Iris Nebula?
Iris Nebula’s surface area measures 113.1 square light-years. Astronomers calculated this using the formula A = 4 * π * r^2, with a radius of 3 light-years. Nebula’s diameter spans 6 light-years. Visible dimensions occupy 18 by 18 arcminutes in the sky. Spherical shape assumption aids surface area estimation.
What is at the center of the Iris Nebula?
HD 200775 lies at the center of the Iris Nebula. HD 200775 is a massive B-type main-sequence star with a spectral type B3Ve. HD 200775 has a surface temperature of 18,000 Kelvin and luminosity 4,000 times that of the Sun. SAO 200775 is a designation for this central star in NGC 7023.
