The Radial Distribution and Excitation of H2 around Young Stars in the HST-ULLYSES Survey
The spatial distribution and evolution of gas in the inner 10 au of protoplanetary disks form the basis for estimating the initial conditions of planet formation. Among the most important constraints derived from spectroscopic observations of the inner disk are the radial distributions of the major...
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IOP Publishing
2023-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/ace34c |
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| author | Kevin France Nicole Arulanantham Erin Maloney P. Wilson Cauley P. Ábrahám Juan M. Alcalá Justyn Campbell-White Eleonora Fiorellino Gregory J. Herczeg Brunella Nisini Miguel Vioque |
| author_facet | Kevin France Nicole Arulanantham Erin Maloney P. Wilson Cauley P. Ábrahám Juan M. Alcalá Justyn Campbell-White Eleonora Fiorellino Gregory J. Herczeg Brunella Nisini Miguel Vioque |
| author_sort | Kevin France |
| collection | DOAJ |
| description | The spatial distribution and evolution of gas in the inner 10 au of protoplanetary disks form the basis for estimating the initial conditions of planet formation. Among the most important constraints derived from spectroscopic observations of the inner disk are the radial distributions of the major gas phase constituents, how the properties of the gas change with inner disk dust evolution, and how the chemical abundances and excitation conditions are influenced by the high-energy radiation from the central star. We present a survey of the radial distribution, excitation, and evolution of inner disk molecular hydrogen (H _2 ) obtained as part of the Hubble Space Telescope-ULLYSES program. We analyze far-UV spectroscopy of 71 (63 accreting) pre-main-sequence systems in ULLYSES DR5 to characterize the H _2 emission lines, H _2 dissociation continuum emission, and major photochemical/disk evolution driving the UV emissions (Ly α , UV continuum, and C iv ). We use the widths of the H _2 emission lines to show that most fluorescent H _2 arises between 0.1 and 1.4 au from the parent star, and show positive correlations of the average emitting radius with the accretion luminosity and with the dust disk mass. We find a strong correlation between H _2 dissociation emission and both the accretion-dominated Ly α luminosity and the inner disk dust clearing, painting a picture where water molecules in the inner 3 au are exposed to and dissociated by strong Ly α emission as the opacity of the inner disk declines with time. |
| first_indexed | 2024-03-12T03:52:47Z |
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| issn | 1538-3881 |
| language | English |
| last_indexed | 2024-03-12T03:52:47Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj.art-b88795ae9fdf40e49a32e6c0d98de62a2023-09-03T12:16:09ZengIOP PublishingThe Astronomical Journal1538-38812023-01-0116626710.3847/1538-3881/ace34cThe Radial Distribution and Excitation of H2 around Young Stars in the HST-ULLYSES SurveyKevin France0https://orcid.org/0000-0002-1002-3674Nicole Arulanantham1https://orcid.org/0000-0003-2631-5265Erin Maloney2P. Wilson Cauley3https://orcid.org/0000-0001-9207-0564P. Ábrahám4https://orcid.org/0000-0001-6015-646XJuan M. Alcalá5https://orcid.org/0000-0001-8657-095XJustyn Campbell-White6https://orcid.org/0000-0002-3913-3746Eleonora Fiorellino7https://orcid.org/0000-0002-5261-6216Gregory J. Herczeg8https://orcid.org/0000-0002-7154-6065Brunella Nisini9https://orcid.org/0000-0002-9190-0113Miguel Vioque10https://orcid.org/0000-0002-4147-3846Laboratory for Atmospheric and Space Physics, University of Colorado Boulder , Boulder, CO 80303, USA ; kevin.france@colorado.eduSpace Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USALaboratory for Atmospheric and Space Physics, University of Colorado Boulder , Boulder, CO 80303, USA ; kevin.france@colorado.eduLaboratory for Atmospheric and Space Physics, University of Colorado Boulder , Boulder, CO 80303, USA ; kevin.france@colorado.eduKonkoly Observatory, Research Centre for Astronomy and Earth Sciences , Eötvös Loránd Research Network (ELKH), Konkoly-Thege Miklós út 15-17, 1121 Budapest, Hungary; CSFK, MTA Centre of Excellence , Konkoly Thege Miklós út 15-17., H-1121 Budapest, Hungary; ELTE Eötvös Loránd University , Institute of Physics, Pázmány Péter sétány 1/A, H-1117 Budapest, HungaryINAF-Osservatorio Astronomico di Capodimonte , via Moiariello 16, I-80131 Napoli, ItalyEuropean Southern Observatory , Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München, GermanyINAF-Osservatorio Astronomico di Capodimonte , via Moiariello 16, I-80131 Napoli, ItalyKavli Institute for Astronomy and Astrophysics, Peking University , Beijing 100871, People's Republic of China; Department of Astronomy, Peking University , Beijing 100871, People's Republic of ChinaINAF—Osservtorio Astronomico di Roma. Via di Frascati 33 , I-00078 Monte Porzio Catone, ItalyJoint ALMA Observatory , Alonso de Córdova 3107, Vitacura, Santiago 763-0355, Chile; National Radio Astronomy Observatory , 520 Edgemont Road, Charlottesville, VA 22903, USAThe spatial distribution and evolution of gas in the inner 10 au of protoplanetary disks form the basis for estimating the initial conditions of planet formation. Among the most important constraints derived from spectroscopic observations of the inner disk are the radial distributions of the major gas phase constituents, how the properties of the gas change with inner disk dust evolution, and how the chemical abundances and excitation conditions are influenced by the high-energy radiation from the central star. We present a survey of the radial distribution, excitation, and evolution of inner disk molecular hydrogen (H _2 ) obtained as part of the Hubble Space Telescope-ULLYSES program. We analyze far-UV spectroscopy of 71 (63 accreting) pre-main-sequence systems in ULLYSES DR5 to characterize the H _2 emission lines, H _2 dissociation continuum emission, and major photochemical/disk evolution driving the UV emissions (Ly α , UV continuum, and C iv ). We use the widths of the H _2 emission lines to show that most fluorescent H _2 arises between 0.1 and 1.4 au from the parent star, and show positive correlations of the average emitting radius with the accretion luminosity and with the dust disk mass. We find a strong correlation between H _2 dissociation emission and both the accretion-dominated Ly α luminosity and the inner disk dust clearing, painting a picture where water molecules in the inner 3 au are exposed to and dissociated by strong Ly α emission as the opacity of the inner disk declines with time.https://doi.org/10.3847/1538-3881/ace34cProtoplanetary disksCircumstellar gasPlanet formation |
| spellingShingle | Kevin France Nicole Arulanantham Erin Maloney P. Wilson Cauley P. Ábrahám Juan M. Alcalá Justyn Campbell-White Eleonora Fiorellino Gregory J. Herczeg Brunella Nisini Miguel Vioque The Radial Distribution and Excitation of H2 around Young Stars in the HST-ULLYSES Survey The Astronomical Journal Protoplanetary disks Circumstellar gas Planet formation |
| title | The Radial Distribution and Excitation of H2 around Young Stars in the HST-ULLYSES Survey |
| title_full | The Radial Distribution and Excitation of H2 around Young Stars in the HST-ULLYSES Survey |
| title_fullStr | The Radial Distribution and Excitation of H2 around Young Stars in the HST-ULLYSES Survey |
| title_full_unstemmed | The Radial Distribution and Excitation of H2 around Young Stars in the HST-ULLYSES Survey |
| title_short | The Radial Distribution and Excitation of H2 around Young Stars in the HST-ULLYSES Survey |
| title_sort | radial distribution and excitation of h2 around young stars in the hst ullyses survey |
| topic | Protoplanetary disks Circumstellar gas Planet formation |
| url | https://doi.org/10.3847/1538-3881/ace34c |
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