High resolution HDS/SUBARU chemical abundances of the young stellar cluster Palomar 1^⋆

¹ European Southern Observatory, Casilla 19001, Santiago, Chile
e-mail: lmonaco@eso.org
² Istituto Nazionale di Astrofisica – Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
³ GEPI, Observatoire de Paris, CNRS, Université Paris Diderot, Place Jules Janssen, 92190 Meudon, France
⁴ Istituto Nazionale di Astrofisica – Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, 34143 Trieste, Italy
⁵ Universidad de Concepción, Casilla 160-C, Concepción, Chile

Received: 1 August 2010
Accepted: 21 October 2010

Abstract

Context. Palomar 1 is a peculiar globular cluster (GC). It is the youngest Galactic GC and it has been tentatively associated to several of the substructures recently discovered in the Milky Way (MW), including the Canis Major (CMa) overdensity and the Galactic Anticenter Stellar Structure (GASS).

Aims. In order to provide further insights into its origin, we present the first high resolution chemical abundance analysis for one red giant in Pal 1.

Methods. We obtained high resolution (R = 30   000) spectra for one red giant star in Pal 1 using the high dispersion spectrograph (HDS) mounted at the SUBARU telescope. We used ATLAS-9 model atmospheres coupled with the SYNTHE and WIDTH calculation codes to derive chemical abundances from the measured line equivalent widths of 18 among α, Iron-peak, light and heavy elements.

Results. The Palomar 1 chemical pattern is broadly compatible to that of the MW open clusters population and similar to disk stars. It is, instead, remarkably different from that of the Sagittarius (Sgr) dwarf spheroidal galaxy.

Conclusions. If Pal 1 association with either CMa or GASS will be confirmed, this will imply that these systems had a chemical evolution similar to that of the Galactic disk.