JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B
We present 1–5 μ m spectroscopy of the young planetary mass companion TWA 27B (2M1207B) performed with NIRSpec on board the James Webb Space Telescope. In these data, the fundamental band of CH _4 is absent, and the fundamental band of CO is weak. The nondetection of CH _4 reinforces a previously ob...
| Main Authors: | , , , , , , , , , , |
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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/acd635 |
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| author | K. L. Luhman P. Tremblin S. M. Birkmann E. Manjavacas J. Valenti C. Alves de Oliveira T. L. Beck G. Giardino N. Lützgendorf B. J. Rauscher M. Sirianni |
| author_facet | K. L. Luhman P. Tremblin S. M. Birkmann E. Manjavacas J. Valenti C. Alves de Oliveira T. L. Beck G. Giardino N. Lützgendorf B. J. Rauscher M. Sirianni |
| author_sort | K. L. Luhman |
| collection | DOAJ |
| description | We present 1–5 μ m spectroscopy of the young planetary mass companion TWA 27B (2M1207B) performed with NIRSpec on board the James Webb Space Telescope. In these data, the fundamental band of CH _4 is absent, and the fundamental band of CO is weak. The nondetection of CH _4 reinforces a previously observed trend of weaker CH _4 with younger ages among L dwarfs, which has been attributed to enhanced nonequilibrium chemistry among young objects. The weakness of CO may reflect an additional atmospheric property that varies with age, such as the temperature gradient or cloud thickness. We are able to reproduce the broad shape of the spectrum with an ATMO cloudless model that has T _eff = 1300 K, nonequilibrium chemistry, and a temperature gradient reduction caused by fingering convection. However, the fundamental bands of CH _4 and CO are somewhat stronger in the model. In addition, the model temperature of 1300 K is higher than expected from evolutionary models given the luminosity and age of TWA 27B ( T _eff = 1200 K). Previous models of young L-type objects suggest that the inclusion of clouds could potentially resolve these issues; it remains to be seen whether cloudy models can provide a good fit to the 1–5 μ m data from NIRSpec. TWA 27B exhibits emission in Paschen transitions and the He I triplet at 1.083 μ m, which are signatures of accretion that provide the first evidence of a circumstellar disk. We have used the NIRSpec data to estimate the bolometric luminosity of TWA 27B (log L / L _⊙ = −4.466 ± 0.014), which implies a mass of 5–6 M _Jup according to evolutionary models. |
| first_indexed | 2024-03-12T03:14:37Z |
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| id | doaj.art-e7ba74772eaa4b0ba3c1bbc8e9d1453e |
| institution | Directory Open Access Journal |
| issn | 2041-8205 |
| language | English |
| last_indexed | 2024-03-12T03:14:37Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj.art-e7ba74772eaa4b0ba3c1bbc8e9d1453e2023-09-03T14:13:31ZengIOP PublishingThe Astrophysical Journal Letters2041-82052023-01-019492L3610.3847/2041-8213/acd635JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27BK. L. Luhman0https://orcid.org/0000-0003-2822-2951P. Tremblin1https://orcid.org/0000-0001-6172-3403S. M. Birkmann2E. Manjavacas3https://orcid.org/0000-0003-0192-6887J. Valenti4C. Alves de Oliveira5https://orcid.org/0000-0003-2896-4138T. L. Beck6https://orcid.org/0000-0002-6881-0574G. Giardino7https://orcid.org/0000-0002-9262-7155N. Lützgendorf8https://orcid.org/0000-0002-4034-0080B. J. Rauscher9https://orcid.org/0000-0003-2662-6821M. Sirianni10Department of Astronomy and Astrophysics, The Pennsylvania State University , University Park, PA 16802, USA ; kll207@psu.edu; Center for Exoplanets and Habitable Worlds, The Pennsylvania State University , University Park, PA 16802, USAUniversité Paris-Saclay , UVSQ, CNRS, CEA, Maison de la Simulation, F-91191, Gif-sur-Yvette, FranceEuropean Space Agency (ESA), ESA Office, Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USAAURA for the European Space Agency, Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Department of Physics & Astronomy, Johns Hopkins University , Baltimore, MD 21218, USASpace Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USAEuropean Space Agency, European Space Astronomy Centre , Camino Bajo del Castillo s/n, E-28692 Villanueva de la Cañada, Madrid, SpainSpace Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USAATG Europe for the European Space Agency , ESTEC, Noordwijk, The NetherlandsEuropean Space Agency (ESA), ESA Office, Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USANASA Goddard Space Flight Center , Observational Cosmology Laboratory, Greenbelt, USAEuropean Space Agency (ESA), ESA Office, Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USAWe present 1–5 μ m spectroscopy of the young planetary mass companion TWA 27B (2M1207B) performed with NIRSpec on board the James Webb Space Telescope. In these data, the fundamental band of CH _4 is absent, and the fundamental band of CO is weak. The nondetection of CH _4 reinforces a previously observed trend of weaker CH _4 with younger ages among L dwarfs, which has been attributed to enhanced nonequilibrium chemistry among young objects. The weakness of CO may reflect an additional atmospheric property that varies with age, such as the temperature gradient or cloud thickness. We are able to reproduce the broad shape of the spectrum with an ATMO cloudless model that has T _eff = 1300 K, nonequilibrium chemistry, and a temperature gradient reduction caused by fingering convection. However, the fundamental bands of CH _4 and CO are somewhat stronger in the model. In addition, the model temperature of 1300 K is higher than expected from evolutionary models given the luminosity and age of TWA 27B ( T _eff = 1200 K). Previous models of young L-type objects suggest that the inclusion of clouds could potentially resolve these issues; it remains to be seen whether cloudy models can provide a good fit to the 1–5 μ m data from NIRSpec. TWA 27B exhibits emission in Paschen transitions and the He I triplet at 1.083 μ m, which are signatures of accretion that provide the first evidence of a circumstellar disk. We have used the NIRSpec data to estimate the bolometric luminosity of TWA 27B (log L / L _⊙ = −4.466 ± 0.014), which implies a mass of 5–6 M _Jup according to evolutionary models.https://doi.org/10.3847/2041-8213/acd635Brown dwarfsL dwarfsExoplanet atmospheresCircumstellar disksProtoplanetary disksSubstellar companion stars |
| spellingShingle | K. L. Luhman P. Tremblin S. M. Birkmann E. Manjavacas J. Valenti C. Alves de Oliveira T. L. Beck G. Giardino N. Lützgendorf B. J. Rauscher M. Sirianni JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B The Astrophysical Journal Letters Brown dwarfs L dwarfs Exoplanet atmospheres Circumstellar disks Protoplanetary disks Substellar companion stars |
| title | JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B |
| title_full | JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B |
| title_fullStr | JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B |
| title_full_unstemmed | JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B |
| title_short | JWST/NIRSpec Observations of the Planetary Mass Companion TWA 27B |
| title_sort | jwst nirspec observations of the planetary mass companion twa 27b |
| topic | Brown dwarfs L dwarfs Exoplanet atmospheres Circumstellar disks Protoplanetary disks Substellar companion stars |
| url | https://doi.org/10.3847/2041-8213/acd635 |
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