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J/A+A/243/386       Hyades members distances (Schwan 1991)

The distance and main sequence of the Hyades cluster based on 145 stars with highly accurate proper motions obtained from work on the catalogues FK5 and PPM. Schwan H. <Astron. Astrophys. 243, 386 (1991)> =1991A&A...243..386S (SIMBAD/NED BibCode)
ADC_Keywords: Proper motions ; Space velocities ; Stars, distances ; Clusters, open Keywords: open clusters - Hyades distance - Hyades main sequence - CM diagram Description: Distances for 145 Hyades members in an extended region of the Hyades cluster were derived on the basis of new, highly accurate proper motions obtained from work on the catalogues FK5 and PPM. The cluster membership on the stars has been discussed and a few new candidates are proposed. From a selected subset of our sample we have obtained the convergence point α=6h30.7m±1.7m=97deg41'±25', δ=5deg59'±11'. Combining this point with the mean cluster radial velocity of 39.1km/s by Detweiler et al. (1984AJ.....89.1038D) one find the galactic space velocity (U, V, W)=(-42.02, -20.12, -1.04)km/s. The galactic coordinates of the centre of our sample are (X, Y, Z)=(-44.3, +0.5, -18.2)pc. The distance of this centre from the Sun is 47.9±0.8pc corresponding to a modulus m-M=3.40±0.04mag. Individual distance moduli, coordinates and velocity residuals per star are given. The Hyades main sequence has been constructed in the range B-V<1.2mag and it is presented analytically as well as by tabular values. The dispersion σ(Mv)=0.14mag of the absolute magnitudes about the main sequence indicates its high internal accuracy. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1 92 181 Basic data table2 101 181 Essential data used as membership criterion
See also: J/AJ/80/379 : Hyades cluster (Hanson+, 1975) J/MNRAS/257/257 : Proper motions in the Hyades (Reid 1992) Byte-by-byte Description of file: table1
Bytes Format Units Label Explanations
1 I1 --- Member [1/4] Membership flag (1) 3- 5 I3 --- Seq Sequential number 7- 12 I6 --- No Star number in the catalogue (2) 14- 16 A3 --- vB van Bueren (1952BAN....11..385V) number (3) 18- 25 A8 --- BD BD number 27- 32 I6 --- HD ? HD number (cat. III/135) 34 I1 h RAh Right ascension (B1950) 36- 37 I2 min RAm Right ascension (B1950) 39- 40 I2 s RAs Right ascension (B1950) 41 A1 --- DE- Declination sign 42- 43 I2 deg DEd Declination (B1950) 45- 46 I2 arcmin DEm Declination (B1950) 48- 51 I4 10-4arcsec/yr pmRA Proper motion in right ascension 53- 54 I2 10-4arcsec/yr e_pmRA rms uncertainty on pmRA 56- 60 I5 10-4arcsec/yr pmDE Proper motion in declination 62- 63 I2 10-4arcsec/yr e_pmDE rms uncertainty on pmDE 65- 69 F5.1 km/s RV ? Radial velocity 71 A1 --- r_RV [GW] References for radial velocity (4) 73- 77 F5.2 mag Vmag V magnitude 79- 82 F4.2 mag B-V B-V colour index 84 A1 --- r_B-V [M+] B-V references (5) 86- 89 F4.2 mag Mv Absolute V magnitude 91- 92 I2 --- w_Mv ? Weight for those stars which were used in the determination of the convergence point.
Note (1): The membership code is as follows: 1: Stars adopted as Hyades members 2: Possible Hyades members 3: Probable non-members 4: van Bueren stars which have been rejected as Hyades members Note (2): Numbers smaller than 4000 are from the Basic FK5 I/149 or from the FK4 Sup I/143 Numbers from 4000 to 10000 are N30 I/80 numbers increased by 4000 Numbers exceeding 10000 are the numbers used in the PPM I/146 catalog. Note (3): Numbers are given from table 2a and 2b in that paper, and letters "c" or "d" denote stars in table 2c and 2d, respectively. Note (4): the references are noted G: Griffin 1988AJ.....96..172G W: General catalogue of stellar Radial Velocities, III/21 Note (5): the origin is noted M: from Mermilliod, otherwise from the SIMBAD data base +: when a reference was found on possible membership
Byte-by-byte Description of file: table2
Bytes Format Units Label Explanations
1 I1 --- Member [1/4] Membership flag (1) 3- 8 I6 --- No Star number in the catalogue as in table1 10- 13 F4.1 pc r Distance 15- 18 F4.2 mag m-M Distance modulus 20- 24 F5.1 pc X-Xc Residual X coordinate (2) 25 A1 --- n_X-Xc [*] *: discordant value 26- 30 F5.1 pc Y-Yc Residual Y coordinate (2) 31 A1 --- n_Y-Yc [*] *: discordant value 32- 36 F5.1 pc Z-Zc Residual Z coordinate (2) 37 A1 --- n_Z-Zc [*] *: discordant value 39- 43 F5.2 km/s U-Uc Residual U velocity (2) 45- 49 F5.2 km/s V-Vc Residual V velocity (2) 51- 55 F5.2 km/s W-Wc Residual W velocity (2) 57- 62 F6.2 deg d-Teta Angle between the star's proper motion and the direction of the convergence point 63 A1 --- n_d-Teta [*] *: discordant value 65- 69 F5.2 0.01arcsec/yr My-Tau Velocity component perpendicular to the direction to the convergence point in angular measure 72- 75 F4.2 0.01arcsec/yr e_My-Tau rms uncertainty on My-Tau 77- 81 F5.2 km/s V-Tau Velocity component perpendicular to the direction to the convergence point in linear measure 84- 87 F4.2 km/s e_V-Tau rms uncertainty on V-Tau 89- 93 F5.1 km/s d-Vr ? Difference between the observed and expected radial velocity 94 A1 --- n_d-Vr [*] *: discordant value 96-100 F5.2 mag d-Mv Difference between the observed and expected magnitude 101 A1 --- n_d-Mv [*] *: discordant value
Note (1): The membership code is as follows: 1: Stars adopted as Hyades members 2: Possible Hyades members 3: Probable non-members 4: van Bueren stars which have been rejected as Hyades members Note (2): Data with respect to the cluster center (see Table 2b)
Table 2a: Mean values for our sample --------------------------------------------------------- Ro (m-M)o Xo Yo Zo Uo Vo Wo pc mag pc pc pc km/s km/s km/s --------------------------------------------------------- 49.5 3.47 -46.2 +0.3 -17.7 -42.06 -20.05 -0.98 --------------------------------------------------------- Table 2b: The centre of the Hyades cluster --------------------------------------------------------- Rc (m-M)c Xc Yc Zc Uc Vc Wc pc mag pc pc pc km/s km/s km/s --------------------------------------------------------- 47.9 3.40 -44.3 +0.5 -18.2 -42.02 -20.12 -1.04 --------------------------------------------------------- Acknowledgements: Heiner Schwan
(End) Patricia Bauer [CDS] 12-Nov-1996
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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