The Hottest Neptunes Orbit Metal-rich Stars
The Neptune desert is no longer empty. A handful of close-in planets with masses between those of Neptune and Saturn have now been discovered, and their puzzling properties have inspired a number of interesting theories on the formation and evolution of desert-dwellers. While some studies suggest th...
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IOP Publishing
2025-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/ada143 |
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| author | Shreyas Vissapragada Aida Behmard |
| author_facet | Shreyas Vissapragada Aida Behmard |
| author_sort | Shreyas Vissapragada |
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| description | The Neptune desert is no longer empty. A handful of close-in planets with masses between those of Neptune and Saturn have now been discovered, and their puzzling properties have inspired a number of interesting theories on the formation and evolution of desert-dwellers. While some studies suggest that Neptune desert planets form and evolve similarly to longer-period Neptunes, others argue that they are products of rare collisions between smaller planets, or that they are the exposed interiors of giant planets (i.e., “hot Jupiters gone wrong”). These origin stories make different predictions for the metallicities of Neptune desert host stars. In this paper, we use the homogeneous catalog of stellar metallicities from Gaia Data Release 3 to investigate the origins of Neptune desert dwellers. We find that planets in the Neptune desert orbit stars that are significantly more metal rich than the hosts of longer-period Neptunes ( p = 0.0016) and smaller planets ( p = 0.00014). In contrast, Neptune desert host star metallicities are statistically indistinguishable from those of hot Jupiter host stars ( p = 0.55). Therefore, we find it relatively unlikely that Neptune desert planets formed and evolved similarly to longer-period Neptunes, or that they resulted from collisions between smaller planets, at least without another metallicity-selective process involved. A more straightforward explanation for this result is that planets in the desert truly are the exposed interiors of larger planets. Atmospheric spectroscopy of Neptune desert worlds may therefore provide a rare glimpse into the interiors of giant exoplanets. |
| format | Article |
| id | doaj-art-35daac964622476392f6e630fdac82c2 |
| institution | Kabale University |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astronomical Journal |
| spelling | doaj-art-35daac964622476392f6e630fdac82c22025-02-04T07:12:23ZengIOP PublishingThe Astronomical Journal1538-38812025-01-01169211710.3847/1538-3881/ada143The Hottest Neptunes Orbit Metal-rich StarsShreyas Vissapragada0https://orcid.org/0000-0003-2527-1475Aida Behmard1https://orcid.org/0000-0003-0012-9093Carnegie Science Observatories , 813 Santa Barbara Street, Pasadena, CA 91101, USA ; svissapragada@carnegiescience.eduCenter for Computational Astrophysics , Flatiron Institute, 162 Fifth Avenue, New York, NY 10010, USA ; abehmard@flatironinstitute.org; American Museum of Natural History , 200 Central Park West, Manhattan, NY 10024, USAThe Neptune desert is no longer empty. A handful of close-in planets with masses between those of Neptune and Saturn have now been discovered, and their puzzling properties have inspired a number of interesting theories on the formation and evolution of desert-dwellers. While some studies suggest that Neptune desert planets form and evolve similarly to longer-period Neptunes, others argue that they are products of rare collisions between smaller planets, or that they are the exposed interiors of giant planets (i.e., “hot Jupiters gone wrong”). These origin stories make different predictions for the metallicities of Neptune desert host stars. In this paper, we use the homogeneous catalog of stellar metallicities from Gaia Data Release 3 to investigate the origins of Neptune desert dwellers. We find that planets in the Neptune desert orbit stars that are significantly more metal rich than the hosts of longer-period Neptunes ( p = 0.0016) and smaller planets ( p = 0.00014). In contrast, Neptune desert host star metallicities are statistically indistinguishable from those of hot Jupiter host stars ( p = 0.55). Therefore, we find it relatively unlikely that Neptune desert planets formed and evolved similarly to longer-period Neptunes, or that they resulted from collisions between smaller planets, at least without another metallicity-selective process involved. A more straightforward explanation for this result is that planets in the desert truly are the exposed interiors of larger planets. Atmospheric spectroscopy of Neptune desert worlds may therefore provide a rare glimpse into the interiors of giant exoplanets.https://doi.org/10.3847/1538-3881/ada143ExoplanetsHot NeptunesMetallicity |
| spellingShingle | Shreyas Vissapragada Aida Behmard The Hottest Neptunes Orbit Metal-rich Stars The Astronomical Journal Exoplanets Hot Neptunes Metallicity |
| title | The Hottest Neptunes Orbit Metal-rich Stars |
| title_full | The Hottest Neptunes Orbit Metal-rich Stars |
| title_fullStr | The Hottest Neptunes Orbit Metal-rich Stars |
| title_full_unstemmed | The Hottest Neptunes Orbit Metal-rich Stars |
| title_short | The Hottest Neptunes Orbit Metal-rich Stars |
| title_sort | hottest neptunes orbit metal rich stars |
| topic | Exoplanets Hot Neptunes Metallicity |
| url | https://doi.org/10.3847/1538-3881/ada143 |
| work_keys_str_mv | AT shreyasvissapragada thehottestneptunesorbitmetalrichstars AT aidabehmard thehottestneptunesorbitmetalrichstars AT shreyasvissapragada hottestneptunesorbitmetalrichstars AT aidabehmard hottestneptunesorbitmetalrichstars |