A Caltech Library Service

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

Vissapragada, Shreyas and Stefánsson, Gudmundur and Greklek-McKeon, Michael and Oklopčić, Antonija and Knutson, Heather A. and Ninan, Joe P. and Mahadevan, Suvrath and Cañas, Caleb I. and Chachan, Yayaati and Cochran, William D. and Collins, Karen A. and Dai, Fei and David, Trevor J. and Halverson, Samuel and Hawley, Suzanne L. and Hebb, Leslie and Kanodia, Shubham and Kowalski, Adam F. and Livingston, John H. and Maney, Marissa and Metcalf, Andrew J. and Morley, Caroline and Ramsey, Lawrence W. and Robertson, Paul and Roy, Arpita and Spake, Jessica J. and Schwab, Christian and Terrien, Ryan C. and Tinyanont, Samaporn and Vasisht, Gautam and Wisniewski, John (2021) A Search for Planetary Metastable Helium Absorption in the V1298 Tau System. Astronomical Journal, 162 (5). Art. No. 222. ISSN 0004-6256. doi:10.3847/1538-3881/ac1bb0.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Accepted Version
See Usage Policy.


Use this Persistent URL to link to this item:


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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Vissapragada, Shreyas0000-0003-2527-1475
Stefánsson, Gudmundur0000-0001-7409-5688
Greklek-McKeon, Michael0000-0002-0371-1647
Oklopčić, Antonija0000-0002-9584-6476
Knutson, Heather A.0000-0002-5375-4725
Ninan, Joe P.0000-0001-8720-5612
Mahadevan, Suvrath0000-0001-9596-7983
Cañas, Caleb I.0000-0003-4835-0619
Chachan, Yayaati0000-0003-1728-8269
Cochran, William D.0000-0001-9662-3496
Collins, Karen A.0000-0001-6588-9574
Dai, Fei0000-0002-8958-0683
David, Trevor J.0000-0001-6534-6246
Halverson, Samuel0000-0003-1312-9391
Hawley, Suzanne L.0000-0002-6629-4182
Hebb, Leslie0000-0003-1263-8637
Kanodia, Shubham0000-0001-8401-4300
Kowalski, Adam F.0000-0001-7458-1176
Livingston, John H.0000-0002-4881-3620
Maney, Marissa0000-0001-8222-9586
Metcalf, Andrew J.0000-0001-5000-1018
Morley, Caroline0000-0002-4404-0456
Ramsey, Lawrence W.0000-0002-4289-7958
Robertson, Paul0000-0003-0149-9678
Roy, Arpita0000-0001-8127-5775
Spake, Jessica J.0000-0002-5547-3775
Schwab, Christian0000-0002-0091-7105
Terrien, Ryan C.0000-0002-4788-8858
Tinyanont, Samaporn0000-0002-1481-4676
Vasisht, Gautam0000-0002-1871-6264
Wisniewski, John0000-0001-9209-1808
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).
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
Paul and Daisy Soros Fellowships for New AmericansUNSPECIFIED
Pennsylvania State UniversityUNSPECIFIED
Eberly College of ScienceUNSPECIFIED
Pennsylvania Space Grant ConsortiumUNSPECIFIED
Penn State Astrobiology Research Center (PSARC)UNSPECIFIED
Heising-Simons Foundation2017-0494
Heising-Simons Foundation2019-1177
Henry Norris Russell FellowshipUNSPECIFIED
NASA Earth and Space Science FellowshipUNSPECIFIED
Subject Keywords:Exoplanet astronomy; Exoplanet atmospheres; Planetary atmospheres
Issue or Number:5
Classification Code:Unified Astronomy Thesaurus concepts: Exoplanet astronomy (486); Exoplanet atmospheres (487); Planetary atmospheres (1244)
Record Number:CaltechAUTHORS:20211111-164555348
Persistent URL:
Official Citation:Shreyas Vissapragada et al 2021 AJ 162 222
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:111841
Deposited By: Tony Diaz
Deposited On:11 Nov 2021 16:58
Last Modified:11 Nov 2021 16:58

Repository Staff Only: item control page