Jormungandr: A Large Substructure Circling the Milky Way Identified from Gaia DR3 Data
We report the discovery of a large substructure in the Milky Way passing through the solar neighborhood, detected in actions $\left({J}_{\phi },{J}_{{\rm{R}}}\right)$ calculated from Gaia DR3 data. We perform extensive tests to evaluate the selection effects present in the sample and conclude that t...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adbc5f |
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| author | Xianhao Ye Gang Zhao Carlos Allende Prieto Jingkun Zhao Yong Yang Wenbo Wu |
| author_facet | Xianhao Ye Gang Zhao Carlos Allende Prieto Jingkun Zhao Yong Yang Wenbo Wu |
| author_sort | Xianhao Ye |
| collection | DOAJ |
| description | We report the discovery of a large substructure in the Milky Way passing through the solar neighborhood, detected in actions $\left({J}_{\phi },{J}_{{\rm{R}}}\right)$ calculated from Gaia DR3 data. We perform extensive tests to evaluate the selection effects present in the sample and conclude that they cannot produce an artifact with the same characteristics. This substructure, which we call Jormungandr, is orbiting the Milky Way with high L _Z , higher eccentricity (median ∼0.50) and larger rotation velocity V _ϕ compared to disk stars. It leaves obvious patterns in the integrals of motion and kinematics. The chemical abundances from the Apache Point Observatory Galactic Evolution Experiment DR17 for members of Jormungandr resemble those of the Galactic disk high- α sequence. It shows a significant spread in metallicity, as well as age, according to its color–magnitude diagram. Understanding its formation and nature requires further analysis and simulations. |
| format | Article |
| id | doaj-art-be7cc5c0355d41ecae2f31c5564936ea |
| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-be7cc5c0355d41ecae2f31c5564936ea2025-08-20T03:09:24ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198316510.3847/1538-4357/adbc5fJormungandr: A Large Substructure Circling the Milky Way Identified from Gaia DR3 DataXianhao Ye0https://orcid.org/0000-0002-5805-8112Gang Zhao1https://orcid.org/0000-0002-8980-945XCarlos Allende Prieto2https://orcid.org/0000-0002-0084-572XJingkun Zhao3https://orcid.org/0000-0003-2868-8276Yong Yang4https://orcid.org/0000-0001-7609-1947Wenbo Wu5https://orcid.org/0000-0002-3354-9492National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; gzhao@nao.cas.cn, zjk@nao.cas.cn; Instituto de Astrofísica de Canarias , Vía Láctea, 38205 La Laguna, Tenerife, Spain ; carlos.allende.prieto@iac.es; Universidad de La Laguna , Departamento de Astrofísica, 38206 La Laguna, Tenerife, SpainNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; gzhao@nao.cas.cn, zjk@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaInstituto de Astrofísica de Canarias , Vía Láctea, 38205 La Laguna, Tenerife, Spain ; carlos.allende.prieto@iac.es; Universidad de La Laguna , Departamento de Astrofísica, 38206 La Laguna, Tenerife, SpainNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; gzhao@nao.cas.cn, zjk@nao.cas.cnNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; gzhao@nao.cas.cn, zjk@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; gzhao@nao.cas.cn, zjk@nao.cas.cn; Instituto de Astrofísica de Canarias , Vía Láctea, 38205 La Laguna, Tenerife, Spain ; carlos.allende.prieto@iac.es; Universidad de La Laguna , Departamento de Astrofísica, 38206 La Laguna, Tenerife, SpainWe report the discovery of a large substructure in the Milky Way passing through the solar neighborhood, detected in actions $\left({J}_{\phi },{J}_{{\rm{R}}}\right)$ calculated from Gaia DR3 data. We perform extensive tests to evaluate the selection effects present in the sample and conclude that they cannot produce an artifact with the same characteristics. This substructure, which we call Jormungandr, is orbiting the Milky Way with high L _Z , higher eccentricity (median ∼0.50) and larger rotation velocity V _ϕ compared to disk stars. It leaves obvious patterns in the integrals of motion and kinematics. The chemical abundances from the Apache Point Observatory Galactic Evolution Experiment DR17 for members of Jormungandr resemble those of the Galactic disk high- α sequence. It shows a significant spread in metallicity, as well as age, according to its color–magnitude diagram. Understanding its formation and nature requires further analysis and simulations.https://doi.org/10.3847/1538-4357/adbc5fGalaxy kinematicsStellar kinematics |
| spellingShingle | Xianhao Ye Gang Zhao Carlos Allende Prieto Jingkun Zhao Yong Yang Wenbo Wu Jormungandr: A Large Substructure Circling the Milky Way Identified from Gaia DR3 Data The Astrophysical Journal Galaxy kinematics Stellar kinematics |
| title | Jormungandr: A Large Substructure Circling the Milky Way Identified from Gaia DR3 Data |
| title_full | Jormungandr: A Large Substructure Circling the Milky Way Identified from Gaia DR3 Data |
| title_fullStr | Jormungandr: A Large Substructure Circling the Milky Way Identified from Gaia DR3 Data |
| title_full_unstemmed | Jormungandr: A Large Substructure Circling the Milky Way Identified from Gaia DR3 Data |
| title_short | Jormungandr: A Large Substructure Circling the Milky Way Identified from Gaia DR3 Data |
| title_sort | jormungandr a large substructure circling the milky way identified from gaia dr3 data |
| topic | Galaxy kinematics Stellar kinematics |
| url | https://doi.org/10.3847/1538-4357/adbc5f |
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