CaltechAUTHORS
Published November 2021 | Version Accepted Version + Published
Journal Article Open

A Search for Planetary Metastable Helium Absorption in the V1298 Tau System

Creators

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon Princeton University
  • 3. ROR icon University of Amsterdam
  • 4. ROR icon Pennsylvania State University
  • 5. ROR icon The University of Texas at Austin
  • 6. ROR icon Harvard-Smithsonian Center for Astrophysics
  • 7. ROR icon American Museum of Natural History
  • 8. ROR icon Jet Propulsion Lab
  • 9. ROR icon University of Washington
  • 10. ROR icon Hobart and William Smith Colleges
  • 11. ROR icon University of Colorado Boulder
  • 12. ROR icon Laboratory for Atmospheric and Space Physics
  • 13. ROR icon University of Tokyo
  • 14. ROR icon National Institute of Standards and Technology
  • 15. ROR icon University of California, Berkeley
  • 16. ROR icon Space Telescope Science Institute
  • 17. ROR icon Johns Hopkins University
  • 18. ROR icon Macquarie University
  • 19. ROR icon Carleton College
  • 20. ROR icon University of California, Santa Cruz
  • 21. ROR icon University of Oklahoma

Abstract

Early in their lives, planets endure extreme amounts of ionizing radiation from their host stars. For planets with primordial hydrogen and helium-rich envelopes, this can lead to substantial mass loss. Direct observations of atmospheric escape in young planetary systems can help elucidate this critical stage of planetary evolution. In this work, we search for metastable helium absorption—a tracer of tenuous gas in escaping atmospheres—during transits of three planets orbiting the young solar analog V1298 Tau. We characterize the stellar helium line using HET/HPF, and find that it evolves substantially on timescales of days to months. The line is stable on hour-long timescales except for one set of spectra taken during the decay phase of a stellar flare, where absoprtion increased with time. Utilizing a beam-shaping diffuser and a narrowband filter centered on the helium feature, we observe four transits with Palomar/WIRC: two partial transits of planet d (P = 12.4 days), one partial transit of planet b (P = 24.1 days), and one full transit of planet c (P = 8.2 days). We do not detect the transit of planet c, and we find no evidence of excess absorption for planet b, with ΔR_b/R⋆ < 0.019 in our bandpass. We find a tentative absorption signal for planet d with ΔR_d/R⋆ = 0.0205 ± 0.054, but the best-fit model requires a substantial (−100 ± 14 minutes) transit-timing offset on a two-month timescale. Nevertheless, our data suggest that V1298 Tau d may have a high present-day mass-loss rate, making it a priority target for follow-up observations.

Additional Information

© 2021. The American Astronomical Society. Received 2021 June 25; accepted 2021 August 5; published 2021 November 1. We thank the Palomar Observatory staff and directorate for the herculean effort to establish safe, remote operations during the COVID-19 pandemic. In particular we thank Kajse Peffer, Carolyn Heffner, Joel Pearman, Paul Nied, Kevin Rykoski, and Tom Barlow for telescope operations and remote support, and we thank Andy Boden for facilitating scheduling of these observations. S.V. is supported by an NSF Graduate Research Fellowship and the Paul & Daisy Soros Fellowship for New Americans. H.A.K. acknowledges support from NSF CAREER grant 1555095. This work was partially supported by funding from the Center for Exoplanets and Habitable Worlds. The Center for Exoplanets and Habitable Worlds is supported by the Pennsylvania State University, the Eberly College of Science, and the Pennsylvania Space Grant Consortium. This work was supported by NASA Headquarters under the NASA Earth and Space Science Fellowship Program through grants 80NSSC18K1114. We acknowledge support from NSF grants AST-1006676, AST-1126413, AST-1310885, AST-1517592, AST-1310875, AST-1910954, AST-1907622, AST-1909506, the NASA Astrobiology Institute (NAI; NNA09DA76A), and PSARC in our pursuit of precision radial velocities in the NIR. We acknowledge support from the Heising-Simons Foundation via grant 2017-0494 and 2019-1177. Computations for this research were performed on the Pennsylvania State University's Institute for Computational and Data Sciences (ICDS). These results are based on observations obtained with the Habitable-zone Planet Finder Spectrograph on the Hobby–Eberly Telescope. We thank the Resident astronomers and Telescope Operators at the HET for the skillful execution of our observations of our observations with HPF. The Hobby–Eberly Telescope is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximilians-Universität München, and Georg-August Universität Gottingen. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly. The HET collaboration acknowledges the support and resources from the Texas Advanced Computing Center. Facility: Hale (WIRC), HET (HPF), ARC 3.5 m (ARCTIC), ADS, Exoplanet Archive. Software: allesfitter (Günther & Daylan 2019, 2021), astropy (Astropy Collaboration et al. 2013, 2018), celerite (Foreman-Mackey et al. 2017), celerite2 (Foreman-Mackey 2018), exoplanet (Foreman-Mackey et al. 2020), lightkurve (Lightkurve Collaboration et al. 2018), matplotlib (Hunter 2007), molecfit (Smette et al. 2015; Kausch et al. 2015), numpy (Harris et al. 2020), photutils (Bradley et al. 2019), pymc3 (Salvatier et al. 2016), scipy (Virtanen et al. 2020), starry Luger et al. 2019, theano (The Theano Development Team et al. 2016).

Attached Files

Published - Vissapragada_2021_AJ_162_222.pdf

Accepted Version - 2108.05358.pdf

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2108.05358.pdf

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Additional details

Identifiers

Eprint ID
111841
Resolver ID
CaltechAUTHORS:20211111-164555348

Related works

Describes
https://arxiv.org/abs/2108.05358 (URL)

Funding

NSF Graduate Research Fellowship
Paul and Daisy Soros Fellowships for New Americans
NSF
AST-1555095
Pennsylvania State University
Eberly College of Science
Pennsylvania Space Grant Consortium
NASA
80NSSC18K1114
NSF
AST-1006676
NSF
AST-1126413
NSF
AST-1310885
NSF
AST-1517592
NSF
AST-1310875
NSF
AST-1910954
NSF
AST-1907622
NSF
AST-1909506
NASA
NNA09DA76A
Penn State Astrobiology Research Center (PSARC)
Heising-Simons Foundation
2017-0494
Heising-Simons Foundation
2019-1177
Henry Norris Russell Fellowship
NASA Earth and Space Science Fellowship

Dates

Created
2021-11-11
Created from EPrint's datestamp field
Updated
2021-11-11
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Division of Geological and Planetary Sciences (GPS)