THE ASTRONOMICAL JOURNAL      VOLUME 106, NUMBER 4, PAGE 1508      OCTOBER 1993

                   DYNAMICS OF THE GLOBULAR CLUSTER NGC 362

                               PHILLIPPE FISCHER

  Department of Physics and Astronomy, McMaster University, Hamilton, Ontario
L8S 4M1, Canada, and AT&T Bell Laboratories, 600 Mountain Ave., 1D-316, Murray
                            Hill, New Jersey 07974
                    Electronic mail: philf@physics.att.com

                               DOUGLAS L. WELCH

  Department of Physics and Astronomy, McMaster University, Hamilton, Ontario
                                L8S 4M1, Canada
               Electronic mail: welch@physun.physics.mcmaster.ca

                                  MARIO MATEO

 The Observatories of the Carnegie Institute of Washington, 813 Santa Barbara
                      Street, Pasadena, California 91101
                         Electronic mail: 6036::mateo


                                 PATRICK COTE

  Department of Physics and Astronomy, McMaster University, Hamilton, Ontario
                                L8S 4M1, Canada
               Electronic mail: cote@physun.physics.mcmaster.ca



                                   ABSTRACT

    In this paper we have examined the internal dynamics of the globular
    cluster NGC 362 using a combination of V-band CCD images and echelle
    spectra of the member red giants.  A V-band surface brightness profile
    (SBP) was constructed from the CCD images, and, after it was determined
    that the cluster is not post core-collapse, fit with single- and
    multi-pass King-Michie (KM) models.  We found that for small values of
    the mass function slope, x, anisotropic models were favored while for
    steeper mass functions isotropic orbits provided superior fits. The
    total cluster luminosity is 1.70 +/- 0.1 x 10^5 L(Vsun) [assumes
    (m-M)0 = 14.77].  A total of 285 stellar spectra were obtained of 215
    stars for radial velocity determinations.  Three stars were obvious
    nonmembers and four showed strong evidence for radial velocity
    variations; these latter stars are probably members of binary systems
    with periods less than a few years.  The true cluster binary fraction
    was determined from simulations to be 0.15 for circular orbits or 0.27
    for orbits with a distribution function f(e) = e (e is eccentricity).
    This relatively high binary detection frequency may indicate that NGC
    362 is overabundant in binaries compared to other clusters.  The 208
    remaining stellar velocities showed no sign of rotation and had
    kinematics which were incompatible with KM models having isotropic
    orbits and luminosity profiles consistent with the SBP.  Therefore,
    the best agreement with both the kinematic data and the SBP were for
    shallow mass functions x = 0.0-0.5 and intermediate amounts of
    anisotropy in the velocity dispersion tensor.  In this best-fit range,
    the derived cluster mass is M = 2.5-3.5x10^5 Msun for a global
    mass-to-light ratio of M/L(V) = 1.5-2.0 Msun/L(Vsun).  This low value
    for x is in disagreement with the correlation between x and the height
    above the Galactic disk seen for a sample of other clusters.  The
    results are also different from the sharp turnup in the low mass end of
    mass functions derived from the deep luminosity functions of three
    other globular clusters.