|Specifications concerning designations for astronomical radiation sources outside the solar system| |
Short title: IAU Recommendations for Nomenclature
Key words: Designations IAU
(version 2008 November 26)
All source listings should always contain positional information and/or a
second designation next to a principal designation in order to avoid
ambiguities that can arise with a single designation.
The designation of an astronomical source should consist of the
following parts :
Note that the ^ is used here to denote a blank. It is used for
emphasis in showing where spaces occur in a designation. (Users are expected
to use an actual blank and not this character.) Parentheses are required if
a specifier is included. Acronym and sequence are essential, specifier is
optional; the number of blanks may be larger in machine-readable files to
right justify numerical or tabular data.
The following examples illustrate the recommended form of astronomical
designations :
The acronym (earlier called origin) is a code
(i.e., alphanumerical string of characters)
that specifies the catalog or collection of sources.
It may be constructed from catalog names (e.g., NGC, BD),
the names of authors (RCW),
instruments or observatories used for large surveys (VLA, IRAS, 3C, 51W), etc – see helpful hints on
creating acronyms.
The following rules apply to the construction of new acronyms:
The sequence (or numbering) is an alphanumeric string of characters,
normally only numerical, that uniquely determines the source
within a catalog or collection. It may be a sequence number
within a catalog (e. g., HD^224801), a combination of fields,
or it may be based on coordinates.
The way the sequence is constructed is called the format
of the sequence; the symbols used are summarized in the
Inventory of the Formats, a document which also
includes examples of use and misuse.
Coordinate-based designations are just ``names'' and should have enough
significant figures to unambiguously identify the sources.
It is expected that precise coordinates will be provided
in the paper (e.g., in a table),
accompanied by any needed explanations and other relevant information.
If coordinates in any form are used to encode a source of radiation,
a set of rules applies, which we will illustrate with a source,
namely the QSO with coordinates:
Ex: QSO^004848–4242.8
= QSO^B004848–4242.8
= QSO^J005109–4226.5
A galactic-based designation is inappropriate for extragalactic
sources such as a QSO. Examples of galactic-based designations for
sources within the Milky Way Galaxy may be found in section S3
(Ex. H2O) and section S3.5.1 (Ex. PN).
Ex: QSO^004848–4242.8 could have been designated by
QSO^0048–427 or QSO^0048–42
Ex: QSO^004848–4242.8 could be named QSO^00488–4242
but not QSO^00484–4242 (wrong truncation of RA)
nor QSO^00488–4243 (rounded Dec).
Ex: BD^+25^9 stays, even though its declination has
now changed to +26 degrees due to precession from its
original position (at the 1855 equinox).
The specifier is optional and allows one to indicate other source
parameters. However, they are not required syntax and are enclosed in
parentheses.
If the designation requires the use of punctuation or special
characters, the recommendations are the following :
Ex: DR^21/23 refers to DR^21 and DR^23, not
(DR^21, DR^22, DR^23)
If, at some stage, subcomponents or multiplicity of sources is
recognized, the current practice is to name the
subcomponents with letters or numerals such as W 51 A. Alternatively
the subcomponent receives a standard designation
which may be added to the sequence of the parent source with a colon;
e.g., ABELL^1644:[D80]^053
where D80 refers to Dressler's
catalog of morphological types in 55 rich clusters of galaxies
(1980ApJS...42..565D).
For further elaboration on designating subcomponents and
also on finding the reference to a subcomponent refer to
current practices regarding subcomponents.
The examples in the table above are from pre-existing designations. A look at
the Second Dictionary of Nomenclature reveals that unique 2-letter
combinations for acronyms are nearly exhausted.
That is the reason for the change in the rule for new acronyms where
at least three characters are now required. Note that ``R^136'' is a
pre-existing designation, and thus it is not altered when creating
the designation for a subcomponent even though ``R^136'' does not conform to the
rules for creating a new acronym.
Advice on specific problems may be obtained from representatives of the
``Clearing house'', a subset of the Working Group on Designations of IAU
Commission 5:
For general information, in particular about existing designations,
consult the following references :
© UDS/CNRS
A look at the current literature reveals that unclear, ambiguous or
confusing designations of astronomical sources of radiation are too often
encountered. Therefore, all contributors to databases, and authors of
papers, catalogs and surveys, are urged to adhere to the following set
of specifications (developed and endorsed by the International
Astronomical Union); otherwise, significant data may be irretrievably
lost.
1. General recommendations
2. Case of existing designations
3. Creation of new designations
|
Acronym
^
Sequence
^
(Specifier)
PKS^1817–43
CO^J0326.0+3041.0
H2O^G123.4+57.6^(VLSR=–185)
3C^196
3.1 Acronym
3.2 Sequence
3.2.1 Use of coordinates
(J2000.0) 00h51m09.38s –42° 26' 33.8''
(B1950.0) 00h48m48.97s –42° 42' 52.1''
3.3 Specifier
3.4 Punctuation and special characters
3.5 Examples
3.5.1 Examples of complete designations
Designation Position
Acronym^Sequence^(Specifier)
RA(J2000.0) Dec(J2000.0)
h m s
° ' ''
RX^J1426.8+6950 14 26 49.3 +69 50 21
PSR^J1302–6350 13 02 47.72 –63 50 08.5
PN^G001.2–00.3 17 49 36.9 –28 03 59
TYC^1234–545–1 03 32 53.6417 +15 32 59.314
AC^211^(=1E^2127+119; M^15)
21 30 15.54 +11 43 39.0
R^136:a3^(30^Dor) 05 38 42.4 –69 06 03
BD^–03^5750 00 02 02.4 –02 45 59
3.5.2 Examples of improper designations
BD^4°14 use of ``deg symbol'', declination sign missing
N221 no space, unclear source : NGC or N in LMC ?
GRO^J317-85 leading zero missing
P^43578 one letter acronym is ambiguous
RC^0401+0456 missing flag letter J for Julian 2000 equatorial
coordinates, corrected to
RC^J0401+0456 in an erratum
3.6 Helpful Hints
There are further documents which provide help on:
4. Advice on designations
MS 100-22
PASADENA, CA 91125, USA
Phone: +1 626 395 1873 ⋅ Fax: .
Email:
Univ. of New Mexico
800 Yale Blvd., NE
Albuquerque, NM 87131, USA
Phone: +1 505 277-0433 ⋅ Fax: +1 505 277-1520
Email:
11, rue de l'Université
F-67000 Strasbourg, France
Phone: +33 390 242 412 ⋅ Fax: +33 390 242 420
Email:
Towson University
Towson, MD 21252-0001
Phone: +1 410 704 3020 ⋅ Fax: .
Email:
61, avenue de l'Observatoire
F-75014 Paris, France
Phone: +33 1 4051 2238 ⋅ Fax: +33 1 4354 1804
Email:
Dept. of Astron.
116 Church Street SE
Minneapolis, MN 55455 USA
Phone: +1 612 624 2895 ⋅ Fax: +1 612 624 2029
Email:
Apdo. Postal 144
Guanajuato, C.P. 36000, Mexico
Phone: +52 473 732 9548
Email:
11, rue de l'Université
67000 Strasbourg, France
Phone: +33 390-242 429 ⋅ Fax: +33 390-242 420
Email:
Computational and Data Sciences Department, MS 6A2
Fairfax, VA 22030, USA
Phone: +1 703.993.8402 ⋅ Fax: +1 703.993.9300
Email:
Institute of Astronomy of the Russian Academy of Sciences
48 Pyatnitskaya St.
109017 Moscow, Russia
Phone: -— ⋅ Fax: -—
Email:
5. Further information