AAC Taxonomy Categories [^]
Categories exist with different types of galactic, stellar, and planetary objects -- from galaxies to globular clusters, stars to black holes, and planets to moons and asteroids. Adapted, mostly from ISKO's, Astronomy's Three Kingdom System (82 classes) and a few journal articles about astronomy taxonomy -- aside from shifting Kingdom to Domain and rearranging parts of stellar organization, Ascendents™ Astronomy Taxonomy for the AAC/AADB has expanded phylums and classes while preserving most of their remaining hierarchical structure and elements. The following tree is the Astronomical Taxonomy Ascendents.net has organized:
| | Domain > Kingdom > Phylum > Class
★
│
│
Galactic domain
│
└─Galaxy
│ └─Normal Galaxy
│ │ └─Elliptical
│ │ └─Lenticular
│ │ └─Spiral
│ │ └─Irregular
│ │ └─Unknown
│ └─Active Galaxy
│ │ └─Seyfert
│ │ └─Radio Galaxy
│ │ └─Quasar
│ │ └─Blazar
│ │ └─Unknown
│ │ └─Other
│ └─Protogalaxy
│ └─Unknown Galaxy
│
└─Universe
│ └─Galaxy Systems
│ │ └─Binary Galaxies
│ │ └─Interacting Galaxies
│ │ └─Galaxy Group
│ │ └─Galaxy Cluster
│ │ └─Galaxy Supercluster
│ │ └─Filaments and Voids
│ │ └─Unknown
│ │ └─Other
│ └─Other
│
└─Galaxy Component
│ └─Galactic Halo
│ └─Galactic Edge
│ │ └─Galactic Anticenter
│ │ └─Unknown
│ │ └─Other
│ └─Globular Region
│ └─Open Region
│ └─Galactic Core/Bulge
│ └─Galactic Barycenter
│ └─Spiral Arm
│ └─Galactic Bar
│ └─Galactic Jet
│ └─Other
│
└─Intergalactic Medium
│ └─Gas
│ │ └─Warm Hot IGM
│ │ └─Lyman Alpha Blob
│ │ └─Unknown
│ │ └─Other
│ └─Dust
│ └─Energetic Particles
│ │ └─Galactic Wind
│ │ └─Extragalactic Cosmic Rays
│ │ └─Unknown
│ │ └─Other
│ └─Other
│
└─Star Cluster
│ └─Open Cluster
│ └─Globular Cluster
│ └─Other
│
└─Unknown
│ └─Other
│
└─Other
│ └─Other
│
│
Stellar domain
│
└─Star
│ └─Pre-main Sequence Star
│ │ └─T Tauri star
│ │ └─Herbig Ae/Be star
│ └─Main Sequence Star
│ │ └─Cool Red Subdwarf
│ │ └─Red Dwarf
│ │ └─Orange Dwarf
│ │ └─Yellow Dwarf
│ │ └─Large White Star
│ │ └─Large Blue Star
│ │ └─Unknown
│ │ └─Other
│ └─Post-main Sequence Star
│ │ └─RGB
│ │ └─HB
│ │ └─AGB
│ │ └─Blue
│ │ └─Wolf-Rayet
│ │ └─Subgiant
│ │ └─Unknown
│ │ └─Other
│ └─Unknown
│ └─Other
│
└─Stellar Evolutionary Endpoint
│ └─Nova
│ └─Supernova
│ └─White Dwarf
│ │ └─Small < .5 mSun (He limit)
│ │ └─Medium < 8 mSun (C limit)
│ │ └─Large > 8 mSun (Ne limit)
│ │ └─Iax Supernova (Fe limit)
│ │ └─Black Dwarf
│ │ └─Unknown
│ │ └─Other
│ └─Neutron Star/Pulsar
│ └─Stellar Black Hole
│ └─Supermassive Black Hole
│ └─Intermediate Black Hole
│ └─Miniature Black Hole
│ └─Other Black Hole
│
└─Circumstellar
│ └─Debris Disc
│ └─Debris Shell
│ └─Shell (Dying Stars)
│ └─Planetary Nebula
│ └─Nova Remnant
│ └─Core Collapse Supernova Remnant
│ └─Stellar Jet
│ └─Herbig-Haro Object
│ └─Unknown
│ └─Other
│
└─Star System
│ └─Single Star System Barycenter
│ └─Binary Star System Barycenter
│ │ └─Normal Binary Star System
│ └─Circumbinary Planetary System
│ └─Binary Star System Barycenter
│ │ └─Eclipsing Binary Star System
│ │ └─X-Ray Binary Star System
│ │ └─Other Binary Star System
│ └─Multiple Star System Barycenter
│
└─Interstellar Medium
│ └─Gas
│ │ └─Cool Atomic Cloud
│ │ └─Hot Ionized Cloud
│ │ └─Molecular Cloud
│ │ └─White Dwarf Supernova Remnant
│ │ └─Unknown
│ │ └─Other
│ └─Dust
│ │ └─Dark Nebula
│ │ └─Reflection Nebula
│ │ └─Unknown
│ │ └─Other
│ └─Energetic Particles
│ │ └─Stellar Wind
│ │ └─Galactic Cosmic Rays
│ │ └─Unknown
│ │ └─Other
│ └─Other
│
└─Protostellar
│ └─Protostar
│ └─Other
│
└─Substellar
│ └─Brown Dwarf
│ │ └─L
│ │ └─Y
│ │ └─T
│ │ └─Unknown
│ │ └─Other
│
└─Unknown
│ └─Other
│
└─Other
│ └─Other
│
│
Planetary domain
│
└─Planet
│ └─Planet
│ │ └─Terrestrial (Rocky)
│ │ └─Gas Giant
│ │ └─Ice Giant
│ │ └─Pulsar Planet
│ └─Dwarf Planet
│ └─Exoplanet
│ └─Rogue planet
│ └─Other
│
└─Planetary Component
│ └─Ring
│ └─Radiation Belt
│ └─Other
│
└─Planetary Satellite
│ └─Moon
│ └─Other
│
└─Planetary System
│ └─Planet with satellites
│ └─Asteroid Groups
│ └─Meteoroid Stream
│ └─Other
│
└─Subplanetary
│ └─Asteroid
│ └─Meteoroid
│ └─Comet
│
└─Interplanetary Medium
│ └─Gas
│ └─Dust
│ └─Solar Wind
│ └─Other Energetic Particles
│ │ └─Anomalous Cosmic Ray
│ │ └─Unknown
│ │ └─Other
│ └─Other
│
└─Protoplanetary
│ └─Protoplanetary Disc
│ └─Other
│
└─Other
│ └─Unknown
│ └─Other
│
│
Anthropic domain
│
└─Spacecraft
│ └─Flyby Spacecraft
│ └─Orbiter Spacecraft
│ └─Atmospheric Spacecraft
│ └─Lander Spacecraft
│ └─Penetrator Spacecraft
│ └─Rover Spacecraft
│ └─Observatory Spacecraft
│ └─Communications Spacecraft
│ └─Navigation Spacecraft
│ └─Unknown
│ └─Other
│
└─Unknown
│ └─Other
│
└─Other
│ └─Other
│
│
Other domain
│
└─Unknown
│ └─Other
│
└─Other
│ └─Other
│
★
Total: 171 |
AAC Epochs [^]
Astronomic object positions are measured in time periods called, "epochs." Other than the current position, popular epochs used for astonomic positioning and finding paths/orbits are the Julian J2000 positioning which is to be followed by J2050. Note: The IAU constellation boundaries are defined relative to the equinox of B1875.0. The Henry Draper Catalog uses the equinox B1900.0. The classical star atlas Tabulae Caelestes used B1925.0 for its equinox. Ascendents.net Astronomy tracks all major epochs. If you know more precise timestamps of the lesser known epochs or to add another epoch for the list, please email astronomy@ascendents.net or send us feedback, thanks.
Julian
Day | Epoch
Name | Timestamp | Comments | | 2396758.203 | B1850.0 | 1850-01-01
00:00:00 | | | 2398584.5 | B1855.0 | 1855-01-01
00:00:00 | The Bonner Durchmusterung started by Friedrich Wilhelm August Argelander uses B1855.0 | | 2405889.5 | B1875.0 | 1875-01-01
00:00:00 | Constellation boundaries were defined in 1930 along lines of right ascension and declination for the B1875.0 epoch. | | 2415020.31352 | B1900.0 | 1900-01-01
12:00:00 | The Henry Draper Catalog uses B1900.0 | | 2424151.5 | B1925.0 | 1925-01-01
00:00:00 | The classical star atlas Tabulae Caelestes used B1925.0 as its equinox. | | 2433282.4235 | B1950.0 | 1949-12-31
23:59:50 | RW Epoch based on the Besselian year of 365.242198781 days, which is a tropical year measured at the point where the Sun's longitude is exactly 280°. Since 1984, Besselian equinoxes and epochs have been superseded by Julian equinoxes and epochs. The current standard equinox and epoch is J2000.0, which is a Julian epoch. | | 2440587.5 | B1970.0 | 1970-01-01
00:00:00 | Unix timestamp epoch | | 2448316.5 | J1991.25 | 1991-03-01
00:00:00 | The Hipparcos Catalog uses the International Celestial Reference System (ICRS) coordinate system (which is essentially[clarification needed] equinox J2000.0) but uses an epoch of J1991.25. For objects with a significant proper motion, assuming that the epoch is J2000.0 leads to a large position error. Assuming that the equinox is J1991.25 leads to a large error for nearly all objects. | | 2451545 | J2000.0 | 2000-01-01
12:00:00 | RW The J2000.0 epoch is precisely Julian date 2451545.0 TT (Terrestrial Time), or January 1, 2000, noon TT. This is equivalent to January 1, 2000, 11:59:27.816 TAI or January 1, 2000, 11:58:55.816 UTC.
Since the right ascension and declination of stars are constantly changing due to precession, (and, for relatively nearby stars due to proper motion), astronomers always specify these with reference to a particular epoch. The earlier epoch that was in standard use was the B1950.0 epoch. | | 2455200.5 | J2010.0 | 2010-01-01
00:00:00 | 00:00:00 | | 2469807.5 | J2050.0 | 2050-01-01
00:00:00 | 00:00:00 |
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