J/AJ/105/226 J/AJ/105/226 Stellar kinematic groups. I. Ursa Major Group D R Soderblom M Mayor Astron. J. 105 226 1993 1993AJ....105..226S Associations, stellar Astrometric data Radial velocities Spectroscopy The Ursa Major Group (UMaG) is studied as a test case for the authenticity of Stellar Kinematic Groups, using Coravel radial velocities, recent compilations of astrometric data and new spectroscopic observations. Spectroscopic age indicators, particularly indices of the strength of chromospheric emission, are applied to solar-type candidate members of UMaG, and it is shown that stars that meet the spectroscopic criteria also have kinematics that agree better with the space motions of the nucleus of UMaG than does the starting sample as a whole. The primary limitation on the precision of kinematics is now parallaxes instead of radial velocities. These more restrictive kinematic criteria are then applied to other UMaG candidates and a list summarizing membership is presented.

Name Group name --- U U space velocity km/s V V space velocity km/s W W space velocity km/s Ref References --- HD Henry Draper number --- m_HD Multiplicity index on HD number --- l_vsini limit flag on vsini --- vsini Rotational velocity km/s l_WHalpha Limit flag on Walpha --- WHalpha Equivalent width of Halpha line 0.1pm l_W8498 Limit flag on W8498 --- W8498 Equivalent width of 8498A feature 0.1pm l_W8542 Limit flag on W8542 --- W8542 Equivalent width of 8542A feature 0.1pm l_W8662 Limit flag on W8662 --- W8662 Equivalent width of 8662A feature 0.1pm l_RHalpha Limit flag on RHalpha --- log(RHalpha) Chromospheric flux ratio (stellar surface flux divided by bolometric flux) for Halpha --- u_RHalpha Uncertainty flag (only for star HD 141003B) --- l_R8498 Limit flag on R8498 --- log(R8498) Chromospheric flux ratio for 8498A feature --- l_R8542 Limit flag on R8542 --- log(R8542) Chromospheric flux ratio for 8542A feature --- l_R8662 Limit flag on R8662 --- log(R8662) Chromospheric flux ratio for 8662A feature --- Member a: Probable spectroscopic member b: Possible spectroscopic member c: Probable spectroscopic non-member --- Wooley Number in catalog of Woolley, et al. (1970) --- HD/HDE Henry Draper number --- m_HD/HDE Multiplicity index on HD or HDE number --- HR Harvard Revised (Bright Star) number --- m_HR Multiplicity index on HR number --- Name Other name --- Sp Spectral type number=1 Spectral type from the Bright Star Catalog (Hoffleit & Jaschek 1982), Levato & Abt (1978), Hoffleit et al. (1983), and Woolley, et al. (1970) except for HD 26913/23 (see notes in printed paper). --- B-V (B-V) color from Nicolet (1978) or Woolley et al. (1970) mag u_B-V uncertainty flag on B-V --- Teff Effective temperature K u_Teff uncertainty flag on Teff --- l_R' limit flag on R'(HK). An 'H' indicating that Log(R') is instead an eye estimate of H and K emission strength from Wilson & Woolley (1970) --- logR' Chromospheric flux ratio of the Ca II H and K emission features --- u_logR' uncertainty flag on R' --- n_R(hk) An 'I', indicating logR(hk) is an I(Mg II) value --- logR(hk) Rescaled index, the Mg II h and k emission flux divided by the stellar bolometric flux and reduced to the scale of the Ca II H and K emission in logR' --- l_R(TR) limit flag on R(TR) --- logR(TR) Rescaled index, the emission flux of three strong features in IUE spectra (N I 1240 A, Si IV 1400 A, and C IV 1550 A) combined to produce an index of emission from the star's transition region (TR), reduced to the scale of the Ca II H and K lines as above. --- l_R(Halpha) uncertainty flag on R(Halpha) --- logR(Halpha) Rescaled index, logR(Halpha). --- u_R(Halpha) rms uncertainty on R(Halpha) --- l_R(IRT) uncertainty flag on R(IRT) --- logR(IRT) Rescaled index, for the Ca II infrared triplet. --- l_vsini limit flag on vsini --- vsini Rotational velocity km/s e_vsini rms uncertainty in v sin i km/s HD Henry Draper number --- m_HD Multiplicity index on HD number --- plx Parallax from the latest Yale Parallax Catalog (van Altena et al. 1992) mas e_plx rms uncertainty on plx mas pmRA Proper motion in right ascension from the Catalog of Positions and Proper Motions (PPM, Roeser & Bastian 1989) mas/yr e_pmRA rms uncertainty on pmRA mas/yr pmDE Proper motion in declination from the PPM mas/yr e_PMDE rms uncertainty on pmDE mas/yr RV Radial velocity from Evans (1980) km/s e_RV rms uncertainty on RV km/s U Resultant U component of space motion km/s e_U rms uncertainty on U km/s V Resultant V component of space motion km/s e_V rms uncertainty on V km/s W Resultant W component of space motion km/s e_W rms uncertainty on W km/s plx2 Parallax the star must have if V is forced to a value of +2.0 km/s, given its observed radial velocity RV (table7 only) mas MV2 Absolute visual magnitude that follows from the parallax plx2 (table7 only) mag RV2 Radial velocity that results if the parallax is held fixed and the space motion V is forced to +2.0 km/s (table7 only) km/s U2 U space velocity derived from using the observed radial velocity RV2 and the parallax plx2 (table7 only) km/s W2 W space velocity derived from using the observed radial velocity RV2 and the parallax plx2 (table7 only) km/s Member = Probable Members, ? = Possible Members number=1 +: Probable Members: These are stars for which every indicator supports UMaG membership, which includes: (1) The stars of the nucleus. (2) The probable spectroscopic member stars of Table 5, with Xi Boo excluded. (3) Other stars, such as Sirius, that have well-defined space motions that agree (to within one standard deviation) with the mean motion of the nucleus. ?: Possible Members: In these cases the 3-sigma error ellipsoid overlaps the mean motion of the nucleus. The possible spectroscopic member stars of Table5 that have kinematics in accord with the nucleus are included here. Probable Nonmembers: Any star not listed in Table 11 has been rejected as a UMaG member. --- HD Henry Draper number --- m_HD Multiplicity index on HD number --- HR Harvard Revised number --- m_HR Multiplicity index on HR number --- Name Other name --- Sp Spectral type --- B-V (B-V) color mag Teff Effective temperature K Mv Absolute visual magnitude mag Rem Remarks --- Patricia Bauer CDS 1994Jul06AAS CD-ROM series, Volume 1, 1993 J_AJ_105_226.xml