Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys
© 2021. The American Astronomical Society. All rights reserved. We analyze the dynamical properties of ∼1500 very metal-poor (VMP; [Fe/H] ≲ −2.0) halo stars, based primarily on medium-resolution spectroscopic data from the HK and Hamburg/ESO surveys. These data, collected over the past 30 yr, are su...
| Main Authors: | , , , , , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
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American Astronomical Society
2022
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| Online Access: | https://hdl.handle.net/1721.1/141826 |
| _version_ | 1811069174966910976 |
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| author | Limberg, Guilherme Rossi, Silvia Beers, Timothy C Perottoni, Hélio D Pérez-Villegas, Angeles Santucci, Rafael M Abuchaim, Yuri Placco, Vinicius M Lee, Young Sun Christlieb, Norbert Norris, John E Bessell, Michael S Ryan, Sean G Wilhelm, Ronald Rhee, Jaehyon Frebel, Anna |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Limberg, Guilherme Rossi, Silvia Beers, Timothy C Perottoni, Hélio D Pérez-Villegas, Angeles Santucci, Rafael M Abuchaim, Yuri Placco, Vinicius M Lee, Young Sun Christlieb, Norbert Norris, John E Bessell, Michael S Ryan, Sean G Wilhelm, Ronald Rhee, Jaehyon Frebel, Anna |
| author_sort | Limberg, Guilherme |
| collection | MIT |
| description | © 2021. The American Astronomical Society. All rights reserved. We analyze the dynamical properties of ∼1500 very metal-poor (VMP; [Fe/H] ≲ −2.0) halo stars, based primarily on medium-resolution spectroscopic data from the HK and Hamburg/ESO surveys. These data, collected over the past 30 yr, are supplemented by a number of calibration stars and other small samples, along with astrometric information from Gaia DR2. We apply a clustering algorithm to the 4D energy-action space of the sample, and identify a set of 38 dynamically tagged groups (DTGs), containing between 5 and 30 member stars. Many of these DTGs can be associated with previously known prominent substructures such as Gaia-Sausage/Enceladus (GSE), Sequoia, Helmi Stream (HStr), and Thamnos. Others are associated with previously identified smaller dynamical groups of stars and streams. We identify 10 new DTGs as well, many of which have strongly retrograde orbits. We also investigate possible connections between our DTGs and ∼300 individual r-process-enhanced (RPE) stars from a recent literature compilation. We find that several of these objects have similar dynamical properties to GSE (5), the HStr (4), Sequoia (1), and Rg5 (1), indicating that their progenitors might have been important sources of RPE stars in the Galaxy. Additionally, a number of our newly identified DTGs are shown to be associated with at least two RPE stars each (DTG-2: 3, DTG-7: 2; DTG-27: 2). Taken as a whole, these results are consistent with ultra-faint and/or dwarf spheroidal galaxies as birth environments in which r-process nucleosynthesis took place, and then were disrupted by the Milky Way. |
| first_indexed | 2024-09-23T08:06:53Z |
| format | Article |
| id | mit-1721.1/141826 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T08:06:53Z |
| publishDate | 2022 |
| publisher | American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/1418262023-07-10T19:34:08Z Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys Limberg, Guilherme Rossi, Silvia Beers, Timothy C Perottoni, Hélio D Pérez-Villegas, Angeles Santucci, Rafael M Abuchaim, Yuri Placco, Vinicius M Lee, Young Sun Christlieb, Norbert Norris, John E Bessell, Michael S Ryan, Sean G Wilhelm, Ronald Rhee, Jaehyon Frebel, Anna Massachusetts Institute of Technology. Department of Physics MIT Kavli Institute for Astrophysics and Space Research © 2021. The American Astronomical Society. All rights reserved. We analyze the dynamical properties of ∼1500 very metal-poor (VMP; [Fe/H] ≲ −2.0) halo stars, based primarily on medium-resolution spectroscopic data from the HK and Hamburg/ESO surveys. These data, collected over the past 30 yr, are supplemented by a number of calibration stars and other small samples, along with astrometric information from Gaia DR2. We apply a clustering algorithm to the 4D energy-action space of the sample, and identify a set of 38 dynamically tagged groups (DTGs), containing between 5 and 30 member stars. Many of these DTGs can be associated with previously known prominent substructures such as Gaia-Sausage/Enceladus (GSE), Sequoia, Helmi Stream (HStr), and Thamnos. Others are associated with previously identified smaller dynamical groups of stars and streams. We identify 10 new DTGs as well, many of which have strongly retrograde orbits. We also investigate possible connections between our DTGs and ∼300 individual r-process-enhanced (RPE) stars from a recent literature compilation. We find that several of these objects have similar dynamical properties to GSE (5), the HStr (4), Sequoia (1), and Rg5 (1), indicating that their progenitors might have been important sources of RPE stars in the Galaxy. Additionally, a number of our newly identified DTGs are shown to be associated with at least two RPE stars each (DTG-2: 3, DTG-7: 2; DTG-27: 2). Taken as a whole, these results are consistent with ultra-faint and/or dwarf spheroidal galaxies as birth environments in which r-process nucleosynthesis took place, and then were disrupted by the Milky Way. 2022-04-11T17:24:05Z 2022-04-11T17:24:05Z 2021 2022-04-11T17:16:28Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/141826 Limberg, Guilherme, Rossi, Silvia, Beers, Timothy C, Perottoni, Hélio D, Pérez-Villegas, Angeles et al. 2021. "Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys." Astrophysical Journal, 907 (1). en 10.3847/1538-4357/ABCB87 Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Astronomical Society The American Astronomical Society |
| spellingShingle | Limberg, Guilherme Rossi, Silvia Beers, Timothy C Perottoni, Hélio D Pérez-Villegas, Angeles Santucci, Rafael M Abuchaim, Yuri Placco, Vinicius M Lee, Young Sun Christlieb, Norbert Norris, John E Bessell, Michael S Ryan, Sean G Wilhelm, Ronald Rhee, Jaehyon Frebel, Anna Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys |
| title | Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys |
| title_full | Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys |
| title_fullStr | Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys |
| title_full_unstemmed | Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys |
| title_short | Dynamically Tagged Groups of Very Metal-poor Halo Stars from the HK and Hamburg/ESO Surveys |
| title_sort | dynamically tagged groups of very metal poor halo stars from the hk and hamburg eso surveys |
| url | https://hdl.handle.net/1721.1/141826 |
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