The high-altitude, inner-disc, and chemically peculiar open cluster UBC 1052
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| Autori principali: | , , , , , , , , , , |
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| Natura: | Preprint |
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2026
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| author | Donada, Judit Casamiquela, Laia Anders, Friedrich Balaguer-Núñez, Lola Blanco-Cuaresma, Sergi Luri, Xavier Slumstrup, Ditte Jordi, Carme Castro-Ginard, Alfred Carrera, Ricardo Carrasco, Josep Manel |
| author_facet | Donada, Judit Casamiquela, Laia Anders, Friedrich Balaguer-Núñez, Lola Blanco-Cuaresma, Sergi Luri, Xavier Slumstrup, Ditte Jordi, Carme Castro-Ginard, Alfred Carrera, Ricardo Carrasco, Josep Manel |
| contents | Out of all the discovered open clusters (OCs) that are located in the inner part of the Galaxy, only a small fraction has been observed with high-resolution spectroscopy. An intriguing population of inner-disc OCs at relatively high altitudes ($Z$) from the Galactic plane remains poorly studied. There are few reliable detections of such OCs, and their occurrence rate, dynamical origin and survival mechanism remain uncertain. We perform a detailed spectroscopic analysis of UBC 1052, located at a cylindrical galactocentric radius $R_{GC} = 6.1$ kpc and $Z = 340$ pc, which stands out as the oldest and highest-|$Z$| inner-disc OC studied at high resolution to date. We used FLAMES/VLT to acquire high signal-to-noise ratio UVES spectra of four red clump (RC) members ($G\sim14$ mag). From them we derived high-precision radial velocities ($v_{r}$) and local thermodynamic equilibrium chemical abundances for 23 elements through a strict line-by-line differential analysis, achieving a median precision in [X/H] of $\simeq0.06$ dex for each star. The four RC stars have fully compatible chemical abundances, with [X/H] dispersions among them <$0.03$ dex for 20 elements. We also acquired GIRAFFE spectra of other candidate members and derived their $v_{r}$. We find that UBC 1052 has an age of $2.25\pm0.25$ Gyr, a distance of $3.11\pm0.07$ kpc, an extinction $A_{V} =1.23$ mag, a mean radial velocity of $34.0\pm0.6$ $km$ ${s}^{-1}$, and a slightly super-solar [Fe/H] = $0.05\pm0.01$ dex. Such relatively low [Fe/H] at its $R_{GC}$ suggests that UBC 1052 is a rare candidate for an inward-migrated OC in the inner disc. Its detailed abundance pattern (e.g. [Ba/Zr] and [Nd/Y]) shows some interesting features that appear to be unique in the current census of OCs studied at high resolution, making it an interesting object for potential strong chemical-tagging searches for already dispersed member stars. [Abridged] |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_11291 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | The high-altitude, inner-disc, and chemically peculiar open cluster UBC 1052 Donada, Judit Casamiquela, Laia Anders, Friedrich Balaguer-Núñez, Lola Blanco-Cuaresma, Sergi Luri, Xavier Slumstrup, Ditte Jordi, Carme Castro-Ginard, Alfred Carrera, Ricardo Carrasco, Josep Manel Astrophysics of Galaxies Solar and Stellar Astrophysics Out of all the discovered open clusters (OCs) that are located in the inner part of the Galaxy, only a small fraction has been observed with high-resolution spectroscopy. An intriguing population of inner-disc OCs at relatively high altitudes ($Z$) from the Galactic plane remains poorly studied. There are few reliable detections of such OCs, and their occurrence rate, dynamical origin and survival mechanism remain uncertain. We perform a detailed spectroscopic analysis of UBC 1052, located at a cylindrical galactocentric radius $R_{GC} = 6.1$ kpc and $Z = 340$ pc, which stands out as the oldest and highest-|$Z$| inner-disc OC studied at high resolution to date. We used FLAMES/VLT to acquire high signal-to-noise ratio UVES spectra of four red clump (RC) members ($G\sim14$ mag). From them we derived high-precision radial velocities ($v_{r}$) and local thermodynamic equilibrium chemical abundances for 23 elements through a strict line-by-line differential analysis, achieving a median precision in [X/H] of $\simeq0.06$ dex for each star. The four RC stars have fully compatible chemical abundances, with [X/H] dispersions among them <$0.03$ dex for 20 elements. We also acquired GIRAFFE spectra of other candidate members and derived their $v_{r}$. We find that UBC 1052 has an age of $2.25\pm0.25$ Gyr, a distance of $3.11\pm0.07$ kpc, an extinction $A_{V} =1.23$ mag, a mean radial velocity of $34.0\pm0.6$ $km$ ${s}^{-1}$, and a slightly super-solar [Fe/H] = $0.05\pm0.01$ dex. Such relatively low [Fe/H] at its $R_{GC}$ suggests that UBC 1052 is a rare candidate for an inward-migrated OC in the inner disc. Its detailed abundance pattern (e.g. [Ba/Zr] and [Nd/Y]) shows some interesting features that appear to be unique in the current census of OCs studied at high resolution, making it an interesting object for potential strong chemical-tagging searches for already dispersed member stars. [Abridged] |
| title | The high-altitude, inner-disc, and chemically peculiar open cluster UBC 1052 |
| topic | Astrophysics of Galaxies Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2604.11291 |