Hot Jupiters Have Giant Companions: Evidence for Coplanar High-eccentricity Migration
This study considers the characteristics of planetary systems with giant planets based on a population-level analysis of the California Legacy Survey planet catalog. We identified three characteristics common to hot Jupiters (HJs). First, while not all HJs have a detected outer giant planet companio...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/acfdab |
| _version_ | 1797660557961068544 |
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| author | Jon K. Zink Andrew W. Howard |
| author_facet | Jon K. Zink Andrew W. Howard |
| author_sort | Jon K. Zink |
| collection | DOAJ |
| description | This study considers the characteristics of planetary systems with giant planets based on a population-level analysis of the California Legacy Survey planet catalog. We identified three characteristics common to hot Jupiters (HJs). First, while not all HJs have a detected outer giant planet companion ( $M\sin i=0.3\mbox{--}30\,{M}_{\mathrm{Jup}}$ ), such companions are ubiquitous when survey completeness corrections are applied for orbital periods out to 40,000 days. Giant-harboring systems without an HJ also host at least one outer giant planet companion per system. Second, the mass distributions of HJs and other giant planets are indistinguishable. However, within a planetary system that includes an HJ, the outer giant planet companions are at least 3× more massive than the inner HJs. Third, the eccentricity distribution of the outer companions in HJ systems (with an average model eccentricity of 〈 e 〉 = 0.34 ± 0.05) is different from the corresponding outer planets in planetary systems without HJs (〈 e 〉 = 0.19 ± 0.02). We conclude that the existence of two gas giants, where the outermost planet has an eccentricity ≥0.2 and is 3× more massive, are key factors in the production of an HJ. Our simple model based on these factors predicts that ∼10% of warm and cold Jupiter systems will by chance meet these assembly criteria, which is consistent with our measurement of a 16% ± 6% relative occurrence of HJ systems to all giant-harboring systems. We find that these three features favor coplanar high-eccentricity migration as the dominant mechanism for HJ formation. |
| first_indexed | 2024-03-11T18:32:38Z |
| format | Article |
| id | doaj.art-225edcdfcdda413885cb3f8bc98ae701 |
| institution | Directory Open Access Journal |
| issn | 2041-8205 |
| language | English |
| last_indexed | 2024-03-11T18:32:38Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj.art-225edcdfcdda413885cb3f8bc98ae7012023-10-13T09:42:43ZengIOP PublishingThe Astrophysical Journal Letters2041-82052023-01-019561L2910.3847/2041-8213/acfdabHot Jupiters Have Giant Companions: Evidence for Coplanar High-eccentricity MigrationJon K. Zink0https://orcid.org/0000-0003-1848-2063Andrew W. Howard1https://orcid.org/0000-0001-8638-0320Department of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA ; jzink@caltech.eduDepartment of Astronomy, California Institute of Technology , Pasadena, CA 91125, USA ; jzink@caltech.eduThis study considers the characteristics of planetary systems with giant planets based on a population-level analysis of the California Legacy Survey planet catalog. We identified three characteristics common to hot Jupiters (HJs). First, while not all HJs have a detected outer giant planet companion ( $M\sin i=0.3\mbox{--}30\,{M}_{\mathrm{Jup}}$ ), such companions are ubiquitous when survey completeness corrections are applied for orbital periods out to 40,000 days. Giant-harboring systems without an HJ also host at least one outer giant planet companion per system. Second, the mass distributions of HJs and other giant planets are indistinguishable. However, within a planetary system that includes an HJ, the outer giant planet companions are at least 3× more massive than the inner HJs. Third, the eccentricity distribution of the outer companions in HJ systems (with an average model eccentricity of 〈 e 〉 = 0.34 ± 0.05) is different from the corresponding outer planets in planetary systems without HJs (〈 e 〉 = 0.19 ± 0.02). We conclude that the existence of two gas giants, where the outermost planet has an eccentricity ≥0.2 and is 3× more massive, are key factors in the production of an HJ. Our simple model based on these factors predicts that ∼10% of warm and cold Jupiter systems will by chance meet these assembly criteria, which is consistent with our measurement of a 16% ± 6% relative occurrence of HJ systems to all giant-harboring systems. We find that these three features favor coplanar high-eccentricity migration as the dominant mechanism for HJ formation.https://doi.org/10.3847/2041-8213/acfdabExoplanet formationExoplanet migrationExoplanetsHJs |
| spellingShingle | Jon K. Zink Andrew W. Howard Hot Jupiters Have Giant Companions: Evidence for Coplanar High-eccentricity Migration The Astrophysical Journal Letters Exoplanet formation Exoplanet migration Exoplanets HJs |
| title | Hot Jupiters Have Giant Companions: Evidence for Coplanar High-eccentricity Migration |
| title_full | Hot Jupiters Have Giant Companions: Evidence for Coplanar High-eccentricity Migration |
| title_fullStr | Hot Jupiters Have Giant Companions: Evidence for Coplanar High-eccentricity Migration |
| title_full_unstemmed | Hot Jupiters Have Giant Companions: Evidence for Coplanar High-eccentricity Migration |
| title_short | Hot Jupiters Have Giant Companions: Evidence for Coplanar High-eccentricity Migration |
| title_sort | hot jupiters have giant companions evidence for coplanar high eccentricity migration |
| topic | Exoplanet formation Exoplanet migration Exoplanets HJs |
| url | https://doi.org/10.3847/2041-8213/acfdab |
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