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

Vissapragada, Shreyas; Stefánsson, Guðmundur; Greklek-McKeon, Michael; Oklopčić, Antonija; Knutson, Heather A.; Ninan, Joe P.; Mahadevan, Suvrath; Cañas, Caleb I.; Chachan, Yayaati; Cochran, William D.; Collins, Karen A.; Dai, Fei; Halverson, Samuel; Hawley, Suzanne L.; Hebb, Leslie; Kanodia, Shubham; Kowalski, Adam F.; Livingston, John H.; Maney, Marissa; Metcalf, Andrew J.; Morley, Caroline; Ramsey, Lawrence W.; Robertson, Paul; Roy, Arpita; Spake, Jessica; Schwab, Christian; Terrien, Ryan C.; Tinyanont, Samaporn; Vasisht, Gautam; Wisniewski, John P.

doi:10.3847/1538-3881/ac1bb0

Cited by 28 publications

(20 citation statements)

References 91 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As part of this same study we also observed a transit of WASP-52b but did not detect a strong signal. We have since used this same observing mode to detect an atmopsheric outflow from HAT-P-18b (Paragas et al 2021) and found a tentative evidence for an outflow from the young planet V1298 Tau d (Vissapragada et al 2021).…”

Section: Ngts-5bmentioning

confidence: 99%

“…All transits were observed in a custom metastable helium filter centered at 1083.3 nm with a full-width at half-maximum (FWHM) of 0.635 nm, previously introduced in Vissapragada et al (2020b). Each observation followed a similar sequence to that described in our previous papers (Vissapragada et al 2020b;Paragas et al 2021;Vissapragada et al 2021). We began each night by observing a helium arc lamp through the helium filter, allowing us to position the target star where the effective transmission function of the filter was centered on the helium feature.…”

Section: Palomar/wirc Observationsmentioning

confidence: 99%

“…After calculating the optimized photometry for each transit observation along with the corresponding decorrelation vectors (airmass, centroid offset, and absorption proxy), we proceeded to fit the transit light curves using exoplanet (Foreman-Mackey et al 2021a,b). Our procedure is similar to that described in Paragas et al (2021) and Vissapragada et al (2021). Briefly, each tar-get light curve is modeled with a limb-darkened starry transit light curve (Luger et al 2019), which is multiplied by a systematics model.…”

Section: Light-curve Modelingmentioning

confidence: 99%

See 2 more Smart Citations

The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

Vissapragada¹,

Knutson²,

Greklek-McKeon³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Transit surveys indicate that there is a deficit of Neptune-sized planets on close-in orbits. If this "Neptune desert" is entirely cleared out by atmospheric mass loss, then planets at its upper edge should only be marginally stable against photoevaporation, exhibiting strong outflow signatures in tracers like the metastable helium triplet. We test this hypothesis by carrying out a 12-night photometric survey of the metastable helium feature with Palomar/WIRC, targeting seven gas-giant planets orbiting K-type host stars. Eight nights of data are analyzed here for the first time along with reanalyses of four previously-published datasets. We strongly detect helium absorption signals for WASP-69b, HAT-P-18b, and HAT-P-26b; tentatively detect signals for WASP-52b and NGTS-5b; and do not detect signals for WASP-177b and WASP-80b. We interpret these measured excess absorption signals using grids of isothermal Parker wind models to derive mass-loss rates, which are typically around 10 10 − 10 11 g s −1 . Our empirically constrained mass-loss rates are in good agreement with predictions from the 1D hydrodynamical outflow code ATES for all planets except WASP-52b and WASP-80b, where our data suggest that the outflows are much smaller than predicted. Excluding these two planets, the outflows for the rest of the sample are consistent with a mean energy-limited outflow efficiency of ε = 0.41 +0.16 −0.13 . Even when we make the relatively conservative assumption that gas-giant planets experience energy-limited outflows at this efficiency for their entire lives, photoevaporation would still be too inefficient to carve the upper boundary of the Neptune desert. We conclude that this feature of the exoplanet population is a pristine tracer of giant planet formation and migration mechanisms.

show abstract

Section: Ngts-5bmentioning

confidence: 99%

Section: Palomar/wirc Observationsmentioning

confidence: 99%

Section: Light-curve Modelingmentioning

confidence: 99%

See 1 more Smart Citation

The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

Vissapragada¹,

Knutson²,

Greklek-McKeon³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…As part of this same study, we also observed a transit of WASP-52b but did not detect a strong signal. We have since used this same observing mode to detect an atmospheric outflow from HAT-P-18b (Paragas et al 2021) and found tentative evidence for an outflow from the young planet V1298 Tau d (Vissapragada et al 2021).…”

Section: Introductionmentioning

confidence: 99%

The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

Vissapragada¹,

Knutson²,

Greklek-McKeon³

et al. 2022

Self Cite

View full text Add to dashboard Cite

Transit surveys indicate that there is a deficit of Neptune-sized planets on close-in orbits. If this “Neptune desert” is entirely cleared out by atmospheric mass loss, then planets at its upper edge should only be marginally stable against photoevaporation, exhibiting strong outflow signatures in tracers like the metastable helium triplet. We test this hypothesis by carrying out a 12-night photometric survey of the metastable helium feature with Palomar/WIRC, targeting seven gas-giant planets orbiting K-type host stars. Eight nights of data are analyzed here for the first time along with reanalyses of four previously published data sets. We strongly detect helium absorption signals for WASP-69b, HAT-P-18b, and HAT-P-26b; tentatively detect signals for WASP-52b and NGTS-5b; and do not detect signals for WASP-177b and WASP-80b. We interpret these measured excess absorption signals using grids of Parker wind models to derive mass-loss rates, which are in good agreement with predictions from the hydrodynamical outflow code ATES for all planets except WASP-52b and WASP-80b, where our data suggest that the outflows are much smaller than predicted. Excluding these two planets, the outflows for the rest of the sample are consistent with a mean energy-limited outflow efficiency of ε = 0.41 − 0.13 + 0.16 . Even when we make the relatively conservative assumption that gas-giant planets experience energy-limited outflows at this efficiency for their entire lives, photoevaporation would still be too inefficient to carve the upper boundary of the Neptune desert. We conclude that this feature of the exoplanet population is a pristine tracer of giant planet formation and migration mechanisms.

show abstract

“…Due to its size, such a cloud would have to be optical thin in the He I line. Vissapragada et al (2021), also report no detection of He I absorption in a narrow He I-band filter associated with transits of 'b' but do find tentative evidence for absorption associated with partials transits of 'd' on UT 2020 October 8 and November 27. The corresponding EW of their measurement is 0.027 ± 0.014 nm, which is consistent with our measurement of an ≈0.19 nm change during the September 26 transit.…”

Section: S U M M a Ry A N D Discussionmentioning

confidence: 88%

Zodiacal exoplanets in time – XIII. Planet orbits and atmospheres in the V1298 Tau system, a keystone in studies of early planetary evolution

Gaidos

Hirano

Beichman

et al. 2021

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

Studies of planetary systems of stars in star-forming regions and young clusters open a window on the formative stages of planetary evolution. We obtained high-cadence high-resolution infrared spectroscopy of the solar-mass Taurus association-member V1298 Tau during a transit of its 10R⊕-size ‘b’ planet. We measured the systemic radial velocity (RV) and find that the kinematics of V1298 Tau suggest an affiliation with a ≳6 Myr-old subgroup. A comparison of V1298 Tau and the nearby, co-moving star 2M0405 with stellar evolution models suggests an age of ∼10–25 Myr. We measured the projected spin-orbit angle of ‘b’ as $\lambda =15_{-16}^{+15}$ and $\lambda = 2_{-4}^{+12}$ degrees using the apparent RV shift and change in line profile, respectively, induced by the transient occultation of the rotating star by the planet. These values indicate a prograde orbit like that of the interior ‘c’ planet of V1298 Tau and point to a co-planar multiplanet system that formed within a disc. We also measured variation in the strength of the 1083 nm triplet of neutral orthohelium as a probe of any extended/escaping atmosphere around ‘b’. We detect a steady decrease in absorption over the transit that appears to arise from the star or its planetary system. While this variation could be ascribed to ‘b’ or possibly to the immediately preceding transit of ‘d’, we cannot rule out that this is due to rapid variation in the stellar disc-integrated flux in the triplet. The amplitude of variation (∼0.04 nm) is consistent with moderate estimates of atmospheric escape driven by XUV radiation from the central star.

show abstract

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

Cited by 28 publications

References 91 publications

The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

Zodiacal exoplanets in time – XIII. Planet orbits and atmospheres in the V1298 Tau system, a keystone in studies of early planetary evolution

Contact Info

Product

Resources

About