The metal-poor atmosphere of a Neptune/Sub-Neptune planet progenitor

Fuente: arXiv
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Main Authors: Barat, Saugata, Désert, Jean-Michel, Vazan, Allona, Baeyens, Robin, Line, Michael R., Fortney, Jonathan J., David, Trevor J., Livingston, John H., Jacobs, Bob, Panwar, Vatsal, Shivkumar, Hinna, Todorov, Kamen O., Pino, Lorenzo, Mraz, Georgia, Petigura, Erik A.
Format: Preprint
Published: 2023
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author Barat, Saugata
Désert, Jean-Michel
Vazan, Allona
Baeyens, Robin
Line, Michael R.
Fortney, Jonathan J.
David, Trevor J.
Livingston, John H.
Jacobs, Bob
Panwar, Vatsal
Shivkumar, Hinna
Todorov, Kamen O.
Pino, Lorenzo
Mraz, Georgia
Petigura, Erik A.
author_facet Barat, Saugata
Désert, Jean-Michel
Vazan, Allona
Baeyens, Robin
Line, Michael R.
Fortney, Jonathan J.
David, Trevor J.
Livingston, John H.
Jacobs, Bob
Panwar, Vatsal
Shivkumar, Hinna
Todorov, Kamen O.
Pino, Lorenzo
Mraz, Georgia
Petigura, Erik A.
contents Young transiting exoplanets offer a unique opportunity to characterize the atmospheres of fresh and evolving products of planet formation. We present the transmission spectrum of V1298 Tau b; a 23 Myr old warm Jovian sized planet orbiting a pre-main sequence star. We detect a primordial atmosphere with an exceptionally large atmospheric scale height and a water vapour absorption at 5$σ$ level of significance. We estimate a mass and density upper limit (24$\pm$5$M_{\oplus}$, 0.12gm/$cm^{3}$ respectively). V1298 Tau b is one of the lowest density planets discovered till date. We retrieve a low atmospheric metallicity (logZ=$-0.1^{+0.66}_{-0.72}$ solar), consistent with solar/sub-solar values. Our findings challenge the expected mass-metallicity from core-accretion theory. Our observations can be explained by in-situ formation via pebble accretion together with ongoing evolutionary mechanisms. We do not detect methane, which hints towards a hotter than expected interior from just the formation entropy of this planet. Our observations suggest that V1298 Tau b is likely to evolve into a Neptune/sub-Neptune type of planet.
format Preprint
id arxiv_https___arxiv_org_abs_2312_16924
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle The metal-poor atmosphere of a Neptune/Sub-Neptune planet progenitor
Barat, Saugata
Désert, Jean-Michel
Vazan, Allona
Baeyens, Robin
Line, Michael R.
Fortney, Jonathan J.
David, Trevor J.
Livingston, John H.
Jacobs, Bob
Panwar, Vatsal
Shivkumar, Hinna
Todorov, Kamen O.
Pino, Lorenzo
Mraz, Georgia
Petigura, Erik A.
Earth and Planetary Astrophysics
Young transiting exoplanets offer a unique opportunity to characterize the atmospheres of fresh and evolving products of planet formation. We present the transmission spectrum of V1298 Tau b; a 23 Myr old warm Jovian sized planet orbiting a pre-main sequence star. We detect a primordial atmosphere with an exceptionally large atmospheric scale height and a water vapour absorption at 5$σ$ level of significance. We estimate a mass and density upper limit (24$\pm$5$M_{\oplus}$, 0.12gm/$cm^{3}$ respectively). V1298 Tau b is one of the lowest density planets discovered till date. We retrieve a low atmospheric metallicity (logZ=$-0.1^{+0.66}_{-0.72}$ solar), consistent with solar/sub-solar values. Our findings challenge the expected mass-metallicity from core-accretion theory. Our observations can be explained by in-situ formation via pebble accretion together with ongoing evolutionary mechanisms. We do not detect methane, which hints towards a hotter than expected interior from just the formation entropy of this planet. Our observations suggest that V1298 Tau b is likely to evolve into a Neptune/sub-Neptune type of planet.
title The metal-poor atmosphere of a Neptune/Sub-Neptune planet progenitor
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2312.16924