Object Classification in SIMBAD

(Last revision of the classification: 27-Aug-2006)

The Object Type in Simbad is defined as a hierarchical classification: a numeric type is made of up to four levels corresponding to classes detailed below.

A presentation of the system can be found in the paper by F. Ochsenbein and P. Dubois in 'Astronomy from Large Databases II:' ed. A. Heck & F. Murtagh, 1992, pp 405-410

Note that Simbad emphasizes the physical nature of the object rather than a peculiar emission in some region of the electromagnetic spectrum or the location in peculiar clusters or external galaxies. Therefore objects are classified as peculiar emitters (classes 01. to 07.) only if nothing more about the nature of the object is known, i.e. it cannot be decided whether the object is a star, a multiple system, a nebula or a galaxy.

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Each class has normally a standard designation, a condensed one (used in tables) and an extended explanation.

Numeric Standard name Cond. Extended Explanation Unknown ? Object of unknown nature Radio Rad Radio-source Radio(m) mR metric Radio-source Radio(cm) cm centimetric Radio-source Radio(mm) mm millimetric Radio-source Radio(sub-mm) smm sub-millimetric source Maser Mas Maser IR IR Infra-Red source IR>30µ FIR Far-IR source (λ >= 30 µm) IR<10µ NIR Near-IR source (λ < 10 µm) Red red Very red source RedExtreme ERO Extremely Red Object Blue blu Blue object UV UV UV-emission source X X X-ray source gamma gam gamma-ray source gammaBurst gB gamma-ray Burst Gravitation grv Gravitational Source LensingEv Lev (Micro)Lensing Event PossibleGravLens Le? Possible gravitationally lensed image GravLens gLe Gravitational Lens Candidates ..? Candidate objects Possible_ClG Cl? Possible Cluster of Galaxies Possible_GrG Gr? Possible Group of Galaxies Candidate_** **? Interacting Binary Candidate Candidate_EB* EB? Eclipsing Binary Candidate Candidate_CV* CV? Cataclysmic Binary Candidate Candidate_XB* XB? X-ray binary Candidate Candidate_LMXB LX? Low-Mass X-ray binary Candidate Candidate_HMXB HX? High-Mass X-ray binary Candidate Candidate_Pec* Pec? Possible Peculiar Star Candidate_YSO Y*? Young Stellar Object Candidate Candidate_pMS* pr? Pre-main sequence Star Candidate Candidate_TTau* TT? T Tau star Candidate Candidate_C* C*? Possible Carbon Star Candidate_S* S*? Possible S Star Candidate_OH OH? Possible Star with envelope of OH/IR type Candidate_CH CH? Possible Star with envelope of CH type Candidate_WR* WR? Possible Wolf-Rayet Star Candidate_HB* HB? Possible Horizontal Branch Star Candidate_AGB* AB? Possible Asymptotic Giant Branch Star Candidate_post-AGB* pA? Post-AGB Star Candidate Candidate_WD* WD? White Dwarf Candidate Candidate_NS N*? Neutron Star Candidate Candidate_BH BH? Black Hole Candidate Candidate_brownD* BD? Brown Dwarf Candidate multiple_object mul Composite object Region reg Region defined in the sky Void vid Underdense region of the Universe SuperClG SCG Supercluster of Galaxies ClG Cluster of Galaxies GroupG GrG Group of Galaxies Compact_Gr_G CGG Compact Group of Galaxies PairG PaG Pair of Galaxies IG Interacting Galaxies GlCl? Gl? Possible Globular Cluster Cl* Cl* Cluster of Stars GlCl GlC Globular Cluster OpCl OpC Open (galactic) Cluster Assoc* As* Association of Stars ** Double or multiple star EB* EB* Eclipsing binary EB*Algol Al* Eclipsing binary of Algol type EB*betLyr bL* Eclipsing binary of beta Lyr type EB*WUMa WU* Eclipsing binary of W UMa type EB*Planet EP* Star showing eclipses by its planet SB SB* Spectroscopic binary CataclyV* CV* Cataclysmic Variable Star DQHer DQ* Cataclysmic Var. DQ Her type AMHer AM* Cataclysmic Var. AM Her type Nova-like NL* Nova-like Star Nova No* Nova DwarfNova DN* Dwarf Nova XB XB* X-ray Binary LMXB LXB Low Mass X-ray Binary HMXB HXB High Mass X-ray Binary Neb Neb Nebula of unknown nature PartofCloud PoC Part of Cloud PN? PN? Possible Planetary Nebula ComGlob CGb Cometary Globule EmObj EmO Emission Object HH HH Herbig-Haro Object Cloud Cld Cloud of unknown nature GalNeb GNe Galactic Nebula BrNeb BNe Bright Nebula DkNeb DNe Dark Nebula RfNeb RNe Reflection Nebula HI HI HI (neutral) region MolCld MoC Molecular Cloud HVCld HVC High-velocity Cloud HII HII HII (ionized) region PN PN Planetary Nebula HIshell sh HI shell SNR? SR? SuperNova Remnant Candidate SNR SNR SuperNova Remnant Star * Star *inCl *iC Star in Cluster *inNeb *iN Star in Nebula *inAssoc *iA Star in Association *in** *i* Star in double system V*? V*? Star suspected of Variability Pec* Pe* Peculiar Star HB* HB* Horizontal Branch Star YSO Y*O Young Stellar Object Em* Em* Emission-line Star Be* Be* Be Star AGB* AB* Asymptotic Giant Branch Star post-AGB* pA* Post-AGB Star WD* WD* White Dwarf pulsWD* ZZ* Pulsating White Dwarf brownD* BD* Brown Dwarf C* C* Carbon Star S* S* S Star OH/IR OH* Star with envelope of OH/IR type CH CH* Star with envelope of CH type pMS* pr* Pre-main sequence Star (optically detected) TTau* TT* T Tau-type Star WR* WR* Wolf-Rayet Star PM* PM* High proper-motion Star HV* HV* High-velocity Star V* V* Variable Star Irregular_V* Ir* Variable Star of irregular type Orion_V* Or* Variable Star of Orion Type Rapid_Irreg_V* RI* Variable Star with rapid variations Eruptive* Er* Eruptive variable Star Flare* Fl* Flare Star FUOr FU* Variable Star of FU Ori type Erupt*RCrB RC* Variable Star of R CrB type RotV* Ro* Rotationally variable Star RotV*alf2CVn a2* Variable Star of alpha2 CVn type RotV*Ell El* Ellipsoidal variable Star Pulsar Psr Pulsar BYDra BY* Variable of BY Dra type RSCVn RS* Variable of RS CVn type PulsV* Pu* Pulsating variable Star Mira Mi* Variable Star of Mira Cet type RRLyr RR* Variable Star of RR Lyr type Cepheid Ce* Cepheid variable Star PulsV*semi-reg sr* Semi-regular pulsating Star PulsV*delSct dS* Variable Star of delta Sct type PulsV*RVTau RV* Variable Star of RV Tau type PulsV*WVir WV* Variable Star of W Vir type PulsV*bCep bC* Variable Star of beta Cep type deltaCep cC* Classical Cepheid (delta Cep type) gammaDor gD* Variable Star of gamma Dor type SN SN* SuperNova Symbiotic* Sy* Symbiotic Star Sub-stellar su* Sub-stellar object Planet? Pl? Extra-solar Planet Candidate Galaxy G Galaxy PartofG PoG Part of a Galaxy GinCl GiC Galaxy in Cluster of Galaxies GinGroup GiG Galaxy in Group of Galaxies GinPair GiP Galaxy in Pair of Galaxies High_z_G HzG Galaxy with high redshift AbsLineSystem ALS Absorption Line system Ly-alpha_ALS LyA Ly alpha Absorption Line system DLy-alpha_ALS DLA Damped Ly-alpha Absorption Line system metal_ALS mAL metallic Absorption Line system Ly-limit_ALS LLS Lyman limit system Broad_ALS BAL Broad Absorption Line system RadioG rG Radio Galaxy HII_G H2G HII Galaxy LSB_G LSB Low Surface Brightness Galaxy AGN_Candidate AG? Possible Active Galaxy Nucleus QSO_Candidate Q? Possible Quasar EmG EmG Emission-line galaxy StarburstG SBG Starburst Galaxy BlueCompG BCG Blue compact Galaxy LensedImage LeI Gravitationally Lensed Image LensedG LeG Gravitationally Lensed Image of a Galaxy LensedQ LeQ Gravitationally Lensed Image of a Quasar AGN AGN Active Galaxy Nucleus LINER LIN LINER-type Active Galaxy Nucleus Seyfert SyG Seyfert Galaxy Seyfert_1 Sy1 Seyfert 1 Galaxy Seyfert_2 Sy2 Seyfert 2 Galaxy Blazar Bla Blazar BLLac BLL BL Lac - type object OVV OVV Optically Violently Variable object QSO QSO Quasar