Confirmation of WASP-107b’s Extended Helium Atmosphere with Keck II/NIRSPEC

Kirk, James; Alam, Munazza K.; López‐Morales, Mercedes; Zeng, Li

doi:10.3847/1538-3881/ab6e66

Cited by 88 publications

(138 citation statements)

References 82 publications

(124 reference statements)

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“…At T 0 =7000 K (12,000 K) we obtain a corresponding mass-loss rate of  = ). The mass-loss rate for WASP-69b is therefore very similar to those reported for HAT-P-11b and WASP-107b (Allart et al 2018(Allart et al , 2019Mansfield et al 2018;Spake et al 2018;Kirk et al 2020), which should be typical for planets at similar distances and gravitational potentials (Salz et al 2016). For WASP-52b, we can set a 95th percentile upper limit of ( )  < --M 10 g s 10 g s 10.1 1 11.1 1 at T 0 =7000 K (12,000 K).…”

Section: Mass-loss Modelingsupporting

confidence: 77%

“…Assuming the same line structure shape as is observed for WASP-69b (Nortmann et al 2018), this converts to an amplitude of 1.31%±0.94% in the deepest line of the triplet. This is meant only to give a sense of what one might expect at high resolution; in reality, line shapes can vary from planet to planet, and there is no guarantee that assuming the line shape of WASP-69b is correct (Allart et al 2018(Allart et al , 2019Nortmann et al 2018;Salz et al 2018;Alonso-Floriano et al 2019;Kirk et al 2020). We obtained a per-point rms of 35.6 ppm/pt across 177 points.…”

Section: Wasp-52bmentioning

confidence: 99%

“…Despite our lack of a significant detection for WASP-52b, we model potential outflows from this planet to set an upper limit on the mass-loss rate corresponding to our upper limit on the excess absorption. As WASP-52b is a high-priority target for future observations (Kirk et al 2020), this is a particularly important constraint that we can obtain from our light curve.…”

Section: Mass-loss Modelingmentioning

confidence: 99%

“…Soon after, ground-based observations with the CARMENES high-resolution (R∼80,000) spectrograph on the 3.5 m telescope at Calar Alto Observatory have confirmed the absorption signal and measured the He I line shape for HAT-P-11b (Allart et al 2018) and WASP-107b (Allart et al 2019), and have additionally revealed excess helium absorption signals for HD 189733b (Salz et al 2018), HD 209458b (Alonso-Floriano et al 2019), and WASP-69b (Nortmann et al 2018). HST WFC3 observations were also used to identify He I absorption for HAT-P-11b (Mansfield et al 2018), and recently Keck II/ NIRSPEC and the Habitable-zone Planet Finder have observed helium in the atmospheres of WASP-107b (Kirk et al 2020) and GJ 3470b (Ninan et al 2020), respectively. We note also the reported nondetections of helium in the atmospheres of KELT-9b, GJ 436b (both Nortmann et al 2018), WASP-12b (Kreidberg & Oklopčić 2018), GJ 1214b (Crossfield et al 2019), and K2-100b (Gaidos et al 2020).…”

Section: Introductionmentioning

confidence: 99%

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Constraints on Metastable Helium in the Atmospheres of WASP-69b and WASP-52b with Ultranarrowband Photometry

Vissapragada

Knutson

Jovanović

et al. 2020

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Infrared observations of metastable 2 3 S helium absorption with ground-and space-based spectroscopy are rapidly maturing, as this species is a unique probe of exoplanet atmospheres. Specifically, the transit depth in the triplet feature (with vacuum wavelengths near 1083.3 nm) can be used to constrain the temperature and mass-loss rate of an exoplanet's upper atmosphere. Here, we present a new photometric technique to measure metastable 2 3 S helium absorption using an ultranarrowband filter (FWHM 0.635 nm) coupled to a beam-shaping diffuser installed in the Wide-field Infrared Camera on the 200 inch Hale Telescope at Palomar Observatory. We use telluric OH lines and a helium arc lamp to characterize refractive effects through the filter and to confirm our understanding of the filter transmission profile. We benchmark our new technique by observing a transit of WASP-69b and detect an excess absorption of 0.498%±0.045% (11.1σ), consistent with previous measurements after considering our bandpass. We then use this method to study the inflated gas giant WASP-52b and place a 95th percentile upper limit on excess absorption in our helium bandpass of 0.47%. Using an atmospheric escape model, we constrain the massloss rate for WASP-69b to be-+-M 5.25 10 Gyr 0.46

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Section: Mass-loss Modelingsupporting

confidence: 77%

Section: Wasp-52bmentioning

confidence: 99%

Section: Mass-loss Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Constraints on Metastable Helium in the Atmospheres of WASP-69b and WASP-52b with Ultranarrowband Photometry

Vissapragada

Knutson

Jovanović

et al. 2020

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“…Our observations target the 10833 Å He triplet feature, which has recently emerged as a way to probe the escaping atmospheres of larger planets (Allart et al 2018(Allart et al , 2019Kreidberg & Oklopčić 2018;Mansfield et al 2018;Nortmann et al 2018;Salz et al 2018;Spake et al 2018;Alonso-Floriano et al 2019;dos Santos et al 2020;Gaidos et al 2020;Kirk et al 2020;Ninan et al 2020;Palle et al 2020;Vissapragada et al 2020). The He triplet feature arises from a metastable transition.…”

Section: Introductionmentioning

confidence: 99%

Nondetection of Helium in the Upper Atmospheres of Three Sub-Neptune Exoplanets

Kasper

Bean

Oklopčić

et al. 2020

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We present a search for helium in the upper atmospheres of three sub-Neptune-sized planets to investigate the origins of these ubiquitous objects. The detection of helium for a low-density planet would be strong evidence for the presence of a primary atmosphere accreted from the protoplanetary nebula because large amounts of helium are not expected in the secondary atmospheres of rocky planets. We used Keck+NIRSPEC to obtain high-resolution transit spectroscopy of the planets GJ 1214b, GJ 9827d, and HD 97658b around the 10833 Å He triplet feature. We did not detect helium absorption for any of the planets despite achieving a high level of sensitivity. We used the nondetections to set limits on the planets' thermosphere temperatures and atmospheric loss rates by comparing grids of 1D models to the data. We also performed coupled interior structure and atmospheric loss calculations, which suggest that the bulk atmospheres (winds) of the planets would be at most modestly enhanced (depleted) in helium relative to their primordial composition. Our lack of detections of the helium triplet for GJ 1214b and GJ 9827d is highly inconsistent with the predictions of models for the present-day mass loss on these planets. Higher signal-to-noise data would be needed to detect the helium feature predicted for HD 97658b. We identify uncertainties in the extreme-ultraviolet fluxes of the host stars and the lack of detailed mass-loss models specifically for cool and metal-enhanced atmospheres as the main limitations to the interpretation of our results. Ultimately, our results suggest that the upper atmospheres of sub-Neptune planets are fundamentally different from those of gas giant planets.

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Observations of planetary winds and outflows

Santos

2021

Proc. IAU

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We have recently hit the milestone of 5,000 exoplanets discovered. In stark contrast with the Solar System, most of the exoplanets we know to date orbit extremely close to their host stars, causing them to lose copious amounts of gas through atmospheric escape at some stage in their lives. In some planets, this process can be so dramatic that they shrink in timescales of a few million to billions of years, imprinting features in the demographics of transiting exoplanets. Depending on the transit geometry, ionizing conditions, and atmospheric properties, a planetary outflow can be observed using transmission spectroscopy in the ultraviolet, optical or near-infrared. In this review, we will discuss the main techniques to observe evaporating exoplanets and their results. To date, we have evidence that at least 28 exoplanets are currently losing their atmospheres, and the literature has reported at least 42 non-detections.

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Confirmation of WASP-107b’s Extended Helium Atmosphere with Keck II/NIRSPEC

Cited by 88 publications

References 82 publications

Constraints on Metastable Helium in the Atmospheres of WASP-69b and WASP-52b with Ultranarrowband Photometry

Constraints on Metastable Helium in the Atmospheres of WASP-69b and WASP-52b with Ultranarrowband Photometry

Nondetection of Helium in the Upper Atmospheres of Three Sub-Neptune Exoplanets

Observations of planetary winds and outflows

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