Addressing confusion in double star nomenclature: The Washington Multiplicity Catalog William I. Hartkopf & Brian D. Mason U.S. Naval Observatory U.S. Naval Observatory

A Welcome “Problem” New observing and reduction techniques  New classes of companions (e.g., brown dwarfs, exoplanets) Previously distinct classes (e.g., “visual” and “SB”) now observable by multiple techniques Future interferometers, astrometric satellites, etc means the problem will become worse! Result is greater understanding for the scientist, but greater challenges for the cataloger! U.S. Naval Observatory

So What IS the Problem? Different techniques mean different nomenclature! Visual binaries: “discoverer designations” (e.g., S or STF 1413, b or BU 96) Spectroscopic binaries: HD, etc. Eclipsing binaries: variable star designation Occultation binaries: SAO, ZC Multiple method may yield multiple designations Component confusion! One person’s AB pair may be another’s ab or BA or primary/secondary! U.S. Naval Observatory

Addressing the Problem Informal working group (1999) came up with four suggested schemes: KoMa (D. Kovaleva & O. Malkov): Alphabetic, numeric and Roman numerals to indicate hierarchy and companion type UC ( S. Urban & T. Corbin): numeric scheme similar to library call numbers Sequential (L. Dickel & P. Dubois): components assigned numbers in order of discovery WMC (Washington Multiplicity Catalog): based on upper/lower case letters of WDS, with extensions U.S. Naval Observatory

Addressing the Problem, II IAU Symposium 200: WMC favored. Sequential scheme deemed sufficiently different from others for further discussion. IAU-GA XXIV: methods for clearing up nomenclature ambiguities discussed. WMC endorsed and Class C resolution ratified by Commissions 5 (Documentation & Astronomical Data), 8+24 (Astrometry), 26 (Double & Multiple Stars), 42 (Close Binary Stars), and 45 (Stellar Classification): U.S. Naval Observatory

On Designating Components of Binary/Multiple Star Systems Recognizing the increasing synergy of techniques for the investigation of stellar companions blurring the traditional distinction between astrometric,spectroscopic, and photometric binary and multiple stars; the detection of substellar (including planets) as well as stellar components by these techniques and, the need for a simple, unambiguous, flexible, and computer friendly designation scheme for components of binary and multiple star systems, Noting that future ground and space-based telescope projects have the potential to detect both substellar as well as stellar components in increasingly large numbers, Recommends that a uniform designation scheme, based on expansion of the new WDS system, be developed during the next 3 years to include all types of components and that this be reviewed in time for its adoption to be considered at General Assembly XXV. U.S. Naval Observatory

Implementation Present sample of resulting scheme at Colloquium 191. MODIFY! Present modified scheme to SOC of IAU-GA XXV Special Session 3: A New Classification Scheme for Double Stars. MODIFY AGAIN! Present further modified scheme at SPS3, July 18, 2003. If approved, present all-sky WMC at 2006 GA. Continue updates to WMC. U.S. Naval Observatory

Roots of the WMC WDS: principal database of visual double and multiple star data for the astronomical community Maintained at USNO, updated nightly 597,579 measures for 99,284 pairs (as of Feb 2003) Delta-m catalog: differential magnitudes not in WDS Orbit Catalog: 1,692 systems Interferometric Catalog: 138,532 high-res observations for 53,063 stars U.S. Naval Observatory

Applying WDS rules to the WMC WDS lists all resolved systems. Many components are detected but not resolved, however: spectroscopic doubles (SB1 and SB2), photometric or eclipsing binaries, astrometric doubles, lunar occultation doubles, other doubles, planets, other substellar objects WDS nomenclature rules (with slight modification) can accommodate all types of double stars. U.S. Naval Observatory

WDS and Hierarchy WDS is system-based rather than object-based. For object-based scheme, N objects  N entries For system-based WDS, N objects  up to N(N-1)/2 entries WDS also contains measures between photocenters. Multiple systems may become quite complex as N increases. However, WDS lists only pairings actually measured. Observers’ common sense usually implies system hierarchy. WDS also includes measures of optical pairs. U.S. Naval Observatory

Determination of Hierarchies Hierarchy based on orbital period and/or separation. The 3:1 ratio of semi-major axes (R.S. Harrington) generally followed. Exceptions: Separations >1” usually given upper-case letters. 3:1 ratio assumes physicality. However, most visual doubles do not have enough measures to determine whether motion is Keplerian or rectilinear. Assume all double stars within some small separation are of interest. U.S. Naval Observatory

Rules of Component Designation WDS nomenclature handles second level hierarchies. WMC will cover more complex systems: Level 1  capital letters STF1523 AB Level 2  lower case letters FIN 347 Aa,Ab Level 3  numbers ORD 666 Ba1,Ba2 Higher levels  alternate lower case letters and numbers U.S. Naval Observatory

Component Designation, II Delimiter: comma, with full component identifier before and after (e.g., Aa,Ab). Exceptions: Assume “A,B” if no designation (e.g., A 1248 = A 1248 A,B). Delimiter assumed if only two characters (e.g., WAK 8 CD = WAK 8 C,D). WMC will strive to maintain hierarchies, but this is not always possible, given often very limited knowledge. We’ll do the best we can! If a subsystem cannot be assigned unequivocally, a tentative “best guess” assignment will be given and a note added to the catalog. U.S. Naval Observatory

Illustrating a Complex System U.S. Naval Observatory

The Sample WMC RA = 11h – 11h30m band. Historically compelling (“home” of x UMa), and has a variety of component types: astrometric binaries, X-ray binaries, cataclysmic variables, related objects, eclipsing binaries, occultation binaries, spectroscopic (SB1 + SB2) and spectrum binaries, interferometric binaries, visual binaries, and planetary companions (by extending to 10h59m.5 …) U.S. Naval Observatory

Sources of Multiplicity WDS and other USNO double star catalogs Downes et al. 2001, “A Catalog and Atlas of Cataclysmic Variables: On-line Version”, PASP 113, 764 (http://icarus.stsci.edu/~downes/cvcat/) Ritter & Kolb 1998, “Catalogue of cataclysmic binaries, low-mass X-ray binaries , and related objects (Sixth edition)”, A&AS 129, 83 Batten et al, 1989, “Eighth Catalog of the Orbital Elements of Spectroscopic Binary Systems”, Pub. DAO, v. 17 Pourbaix et al., 2003, “Ninth Catalogue of Spectroscopic Binary Orbits” (http://sb9.astro.ulb.ac.be/) Svechnikov & Bessonova 1984, “Catalog of Orbital elements, Masses and Luminosities of close double stars”, Bull. Inf. CDS 26, 99 van Paradijs 1995, “A Catalogue of X-Ray Binaries”, in ‘X-ray Binaries’, Lewin et al, eds., Cambridge Univ. Press, ch. 14, p 536-577 California & Carnegie Planet Search website (http://exoplanets.org) and links Other sources needed! U.S. Naval Observatory

Contributions by Technique Techniques contribute to the sample WMC as follows: 95.8% = visual binaries and optical pairs, 50.6% = interferometric binaries and optical pairs, 1.7% = spectroscopic binaries, 1.4% = cataclysmic variables or related objects, 1.0% = occultation binaries, 0.3% = astrometric binaries, 0.2% each eclipsing binaries and X-ray binaries, 0.1% each spectrum binaries and planets. Techniques are complementary, so sum is >100%. U.S. Naval Observatory

Coordinate Matching System matches are based on stars’ arcsecond precise coordinates. The most time-consuming aspect of the WMC construction (by far!) was the improvement of the WDS’ arcminute coordinates: 80% matched to Hipparcos or Tycho-2. additional 19% matched to GSC2, USNO A2, 2MASS, etc. via individual inspection using ALADIN. 1.3% (21 pairs) still have only arcminute accuracy coordinates. Nearly all are older, unconfirmed, visual doubles (very wide cpm pairs or suspect coordinates). U.S. Naval Observatory

Sample Statistics The 1,465 systems in this slice of the sky may be broken down as follows: 1,336 (91%) simple binaries 80 (5.5%) non-hierarchical triples 16 (1.1%) non-hierarchical systems, >3 components 25 (1.7%) hierarchical triples 8 (0.5%) hierarchical systems, >3 components U.S. Naval Observatory

Explanation of the Columns 1 = WMC designation (WDS or J2000 arcminute coordinates) 2 = component designation (AB; Aa,Ab; etc.) 3 = name (HD, DM, variable star desig., discoverer desig., etc.) 4 = name (Tycho-2, GSC2, USNO A2, 2MASS, etc.) 5 = angular separation (vector sep, predicted from SB, etc.) 6 = orbital period 7, 8 = magnitudes (filter codes if not V, flags for variability) 9,10 = spectral types 11 = parallax (from Hipparcos, orbital parallax, etc) 12,13 = masses (or mass function, mass ratio. etc.) 14 = binary type (visual, spectroscopic, etc.) 15 = references (with web links) 16 = J2000 arcsecond coordinates U.S. Naval Observatory

WMC Page 1 Text U.S. Naval Observatory

WMC Page 2 Text U.S. Naval Observatory

Int 4 Page Text U.S. Naval Observatory

Orb Page 1 Text U.S. Naval Observatory

Orb Page 2 Text U.S. Naval Observatory

SB9 Page Text U.S. Naval Observatory

CCV Page Text U.S. Naval Observatory

CCP Page Text U.S. Naval Observatory

Sample WMC Examples U.S. Naval Observatory WMC....... Comp..... ?? NAME........ Sep....* Period.y Mag1.f Mag2.f Spec1..... Spec2... ---------------------------------------------------------------------------------------------- 11131-4217 AB CD -41 6409 2.503 . 10.55 11.69 . . 11131-4217 AC CD -41 6409 5.46 . 10.55 13.6 . . 10595+4026 AB * 47 UMa 0.14 2.982y 5.05 G0V planet 10595+4026 AC * 47 UMa 0.26 7.1 y 5.05 G0V planet U.S. Naval Observatory

Sample WMC Examples U.S. Naval Observatory WMC....... Comp..... ?? NAME........ Sep....* Period.y Mag1.f Mag2.f Spec1..... Spec2... ---------------------------------------------------------------------------------------------- 11018+2952 Aa,Ab HD 95515 0.262 . 7.8 . K0 . 11018+2952 Aa,B HD 95515 1.13 . 7.00 9.36 K0 . U.S. Naval Observatory

Sample WMC Examples U.S. Naval Observatory WMC....... Comp..... ?? NAME........ Sep....* Period.y Mag1.f Mag2.f Spec1..... Spec2... ---------------------------------------------------------------------------------------------- 11080-7742 Aa,Ab ** GHE 35 0.72 . 7.03k 8.38k ?e . 11080-7742 AB ** GHE 35 2.7 . 7.03k 9.5 k ?e . 11080-7742 Ab1,Ab2 ** BNK 1 0.100 . 8.92k 9.32k . . 11080-7742 AC ** SZR 1 17. . 7.03k 10.1 k ?e . U.S. Naval Observatory

Sample WMC Examples U.S. Naval Observatory WMC....... Comp..... ?? NAME........ Sep....* Period.y Mag1.f Mag2.f Spec1..... Spec2... ---------------------------------------------------------------------------------------------- 11291+3920 AB HD 99787 5.45 . 5.35 10.67 A2V . 11291+3920 AC HD 99787 216.55 . 5.35 11.6 A2V . 11291+3920 AD HD 99787 344.36 . 5.35 7.73 A2V K0 11291+3920 AE HD 99787 100.33 . 5.35 10.6 A2V . 11291+3920 AF HD 99787 131.03 . 5.35 10.3 A2V . 11291+3920 AG HD 99787 330.27 . 5.35 10.3 A2V . U.S. Naval Observatory

Sample WMC Examples U.S. Naval Observatory WMC....... Comp..... ?? NAME........ Sep....* Period.y Mag1.f Mag2.f Spec1..... Spec2... ---------------------------------------------------------------------------------------------- 11182+3132 Aa,Ab * xi UMa 0.053 669.18 d 4.41 . G0V M3V? 11182+3132 AB HD 98231 2.536 59.878y 4.41 4.87 G0V F8.5V 11182+3132 AC HD 98231 54.31 . 4.41 15.0 G0V . 11182+3132 Ba,Bb * xi UMa 0.33 m 3.981d 4.87 . F8.5V planet? 11182+3132 Ba,Bc HD 98230 0.026 . 4.87 . F8.5V K2-3V? U.S. Naval Observatory

Sample WMC Examples U.S. Naval Observatory WMC....... Comp..... ?? NAME........ Sep....* Period.y Mag1.f Mag2.f Spec1..... Spec2... ---------------------------------------------------------------------------------------------- 11151-6116 Aa,Ab HD 97950 0.339 . 10.5 11.1 . . 11151-6116 Aa,Ac HD 97950 0.371 . 10.5 11.3 . . 11151-6116 Aa,Ad HD 97950 0.784 . 10.5 10.3 WN... WN... 11151-6116 AB HD 97950 1.81 . 9.03 10.8 WN... WN... 11151-6116 AC HD 97950 2.69 . 9.03 11.3 WN... . 11151-6116 AD HD 97950 3.54 . 9.03 12.3 WN... . 11151-6116 AE HD 97950 4.59 . 9.03 11.8 WN... . U.S. Naval Observatory

Help! Your suggestions needed (format, information to add or delete, etc.). See WMC website (link from WDS website: http://ad.usno.navy.mil/wds/wds.html) is arcminute-accuracy WMC designation sufficient? should planet designations be different? Your data are needed (for WDS, Orb6, SB9, etc as well!) send comments, etc. to wih@usno.navy.mil or bdm@draco.usno.navy.mil U.S. Naval Observatory