Photometric Confirmation and Characterization of the Ennomos Collisional Family in the Jupiter Trojans
Collisional families offer a unique window into the interior composition of asteroid populations. Previous dynamical studies of the Jupiter Trojans have uncovered a handful of potential collisional families, two of which have been subsequently confirmed through spectral characterization. In this pap...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2022-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/ac9eb3 |
| _version_ | 1828715960739037184 |
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| author | Ian Wong Michael E. Brown |
| author_facet | Ian Wong Michael E. Brown |
| author_sort | Ian Wong |
| collection | DOAJ |
| description | Collisional families offer a unique window into the interior composition of asteroid populations. Previous dynamical studies of the Jupiter Trojans have uncovered a handful of potential collisional families, two of which have been subsequently confirmed through spectral characterization. In this paper, we present new multiband photometric observations of the proposed Ennomos family and derive precise g − i colors of 75 candidate family members. While the majority of the targets have visible colors that are indistinguishable from background objects, we identify 13 objects with closely grouped dynamical properties that have significantly bluer colors. We determine that the true Ennomos collisional family is tightly confined to $a{{\prime} }_{p}\gt 5.29\,\mathrm{au}$ and $0.45\lt \sin {i}_{p}\lt 0.47$ , and the majority of its confirmed members have near-solar spectral slopes, including some of the bluest objects hitherto discovered in the Trojan population. The property of distinctly neutral colors that is shared by both the Ennomos family and the previously characterized Eurybates family indicates that the spectral properties of freshly exposed surfaces in the Jupiter region are markedly different than the surfaces of uncollided Trojans. This implies that the processes of ice sublimation and space weathering at 5.2 au yield a distinct regolith chemistry from the primordial environment within which the Trojans were initially accreted. It also suggests that the Trojans were emplaced in their present-day location from elsewhere sometime after the initial population formed, which is a key prediction of recent dynamical instability models of solar system evolution. |
| first_indexed | 2024-03-12T04:45:22Z |
| format | Article |
| id | doaj.art-cd711e7723974634b84446cc4f084fef |
| institution | Directory Open Access Journal |
| issn | 1538-3881 |
| language | English |
| last_indexed | 2024-03-12T04:45:22Z |
| publishDate | 2022-01-01 |
| publisher | IOP Publishing |
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| series | The Astronomical Journal |
| spelling | doaj.art-cd711e7723974634b84446cc4f084fef2023-09-03T09:29:29ZengIOP PublishingThe Astronomical Journal1538-38812022-01-0116511510.3847/1538-3881/ac9eb3Photometric Confirmation and Characterization of the Ennomos Collisional Family in the Jupiter TrojansIan Wong0https://orcid.org/0000-0001-9665-8429Michael E. Brown1https://orcid.org/0000-0002-8255-0545NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USA ; ian.wong@nasa.govDivision of Geological and Planetary Sciences, California Institute of Technology , Pasadena, CA 91125, USACollisional families offer a unique window into the interior composition of asteroid populations. Previous dynamical studies of the Jupiter Trojans have uncovered a handful of potential collisional families, two of which have been subsequently confirmed through spectral characterization. In this paper, we present new multiband photometric observations of the proposed Ennomos family and derive precise g − i colors of 75 candidate family members. While the majority of the targets have visible colors that are indistinguishable from background objects, we identify 13 objects with closely grouped dynamical properties that have significantly bluer colors. We determine that the true Ennomos collisional family is tightly confined to $a{{\prime} }_{p}\gt 5.29\,\mathrm{au}$ and $0.45\lt \sin {i}_{p}\lt 0.47$ , and the majority of its confirmed members have near-solar spectral slopes, including some of the bluest objects hitherto discovered in the Trojan population. The property of distinctly neutral colors that is shared by both the Ennomos family and the previously characterized Eurybates family indicates that the spectral properties of freshly exposed surfaces in the Jupiter region are markedly different than the surfaces of uncollided Trojans. This implies that the processes of ice sublimation and space weathering at 5.2 au yield a distinct regolith chemistry from the primordial environment within which the Trojans were initially accreted. It also suggests that the Trojans were emplaced in their present-day location from elsewhere sometime after the initial population formed, which is a key prediction of recent dynamical instability models of solar system evolution.https://doi.org/10.3847/1538-3881/ac9eb3Jupiter trojansMulti-color photometrySurface composition |
| spellingShingle | Ian Wong Michael E. Brown Photometric Confirmation and Characterization of the Ennomos Collisional Family in the Jupiter Trojans The Astronomical Journal Jupiter trojans Multi-color photometry Surface composition |
| title | Photometric Confirmation and Characterization of the Ennomos Collisional Family in the Jupiter Trojans |
| title_full | Photometric Confirmation and Characterization of the Ennomos Collisional Family in the Jupiter Trojans |
| title_fullStr | Photometric Confirmation and Characterization of the Ennomos Collisional Family in the Jupiter Trojans |
| title_full_unstemmed | Photometric Confirmation and Characterization of the Ennomos Collisional Family in the Jupiter Trojans |
| title_short | Photometric Confirmation and Characterization of the Ennomos Collisional Family in the Jupiter Trojans |
| title_sort | photometric confirmation and characterization of the ennomos collisional family in the jupiter trojans |
| topic | Jupiter trojans Multi-color photometry Surface composition |
| url | https://doi.org/10.3847/1538-3881/ac9eb3 |
| work_keys_str_mv | AT ianwong photometricconfirmationandcharacterizationoftheennomoscollisionalfamilyinthejupitertrojans AT michaelebrown photometricconfirmationandcharacterizationoftheennomoscollisionalfamilyinthejupitertrojans |