The kinematics, metallicities, and orbits of six recently discovered Galactic star clusters with Magellan/M2FS spectroscopy-Reference-Cited by-同舟云学术

The kinematics, metallicities, and orbits of six recently discovered Galactic star clusters with Magellan/M2FS spectroscopy

Published:2023-09-12 Issue:1 Volume:526 Page:1075-1094
ISSN:0035-8711
Container-title:Monthly Notices of the Royal Astronomical Society
language:en
Short-container-title:

Author:

Pace Andrew B¹^ORCID,Koposov Sergey E¹²³⁴^ORCID,Walker Matthew G¹^ORCID,Caldwell Nelson⁵,Mateo Mario⁶,Olszewski Edward W⁷,Roederer Ian U⁶⁸,Bailey John I⁹,Belokurov Vasily³^ORCID,Kuehn Kyler¹⁰,Li Ting S¹¹^ORCID,Zucker Daniel B¹²¹³

Affiliation:

1. McWilliams Center for Cosmology, Carnegie Mellon University , 5000 Forbes Ave, Pittsburgh, PA 15213 , USA

2. Institute for Astronomy, University of Edinburgh , Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ , UK

3. Institute of Astronomy, University of Cambridge , Madingley Road, Cambridge CB3 0HA , UK

4. Kavli Institute for Cosmology, University of Cambridge , Madingley Road, Cambridge CB3 0HA , UK

5. Harvard-Smithsonian Center for Astrophysics , 60 Garden Street, MS-15, Cambridge, MA 02138 , USA

6. Department of Astronomy, University of Michigan , Ann Arbor, MI 48109 , USA

7. Steward Observatory, The University of Arizona , 933 N. Cherry Avenue, Tucson, AZ 85721 , USA

8. Joint Institute for Nuclear Astrophysics – Center for the Evolution of the Elements (JINA-CEE) , East Lansing, MI 48824 , USA

9. Department of Physics, University of California Santa Barbara (UCSB) , Santa Barbara, CA 93016 , USA

10. Lowell Observatory , 1400 W Mars Hill Road, Flagstaff, AZ 86001 , USA

11. Department of Astronomy and Astrophysics, University of Toronto , 50 St George Street, Toronto ON, M5S 3H4 , Canada

12. School of Mathematical and Physical Sciences, Macquarie University , Sydney, NSW 2109 , Australia

13. Macquarie University Research Centre for Astronomy, Astrophysics & Astrophotonics , Sydney, NSW 2109 , Australia

Abstract

ABSTRACT We present Magellan/M2FS spectroscopy of four recently discovered Milky Way star clusters (Gran 3/Patchick 125, Gran 4, Garro 01, and LP 866) and two newly discovered open clusters (Gaia 9 and Gaia 10) at low Galactic latitudes. We measure line-of-sight velocities and stellar parameters ([Fe/H], log g, Teff, and [Mg/Fe]) from high-resolution spectroscopy centred on the Mg triplet and identify 20–80 members per star cluster. We determine the kinematics and chemical properties of each cluster and measure the systemic proper motion and orbital properties by utilizing Gaia astrometry. We find Gran 3 to be an old, metal-poor (mean metallicity of [Fe/H] = −1.83) globular cluster located in the Galactic bulge on a retrograde orbit. Gran 4 is an old, metal-poor ([Fe/H] = −1.84) globular cluster with a halo-like orbit that happens to be passing through the Galactic plane. The orbital properties of Gran 4 are consistent with the proposed LMS-1/Wukong and/or Helmi streams merger events. Garro 01 is metal-rich ([Fe/H] = −0.30) and on a near-circular orbit in the outer disc but its classification as an open cluster or globular cluster is ambiguous. Gaia 9 and Gaia 10 are among the most distant known open clusters at $R_{\mathrm{GC}}\sim 18,~21.2~\mathrm{\, kpc}$ and most metal-poor with [Fe/H] ∼−0.50, −0.34 for Gaia 9 and Gaia 10, respectively. LP 866 is a nearby, metal-rich open cluster ([Fe/H] = +0.10). The discovery and confirmation of multiple star clusters in the Galactic plane shows the power of Gaia astrometry and the star cluster census remains incomplete.

Funder

NSF

Australian Research Council

Carnegie Institution for Science

Carnegie Mellon University

Instituto de Astrofísica de Canarias

University of Tokyo

Lawrence Berkeley National Laboratory

Max-Planck-Institut für Astronomie

Max-Planck-Institut für Astrophysik

New Mexico State University

New York University