TKS X: Confirmation of TOI-1444b and a Comparative Analysis of the Ultra-short-period Planets with Hot Neptunes

Dai, Fei; Howard, Andrew W.; Batalha, Natalie M.; Beard, Corey; Behmard, Aida; Blunt, Sarah; Brinkman, Casey; Chontos, Ashley; Crossfield, Ian J. M.; Dalba, Paul A.; Dressing, Courtney D.; Fulton, Benjamin J.; Giacalone, Steven; Hill, Michelle L.; Huber, Daniel; Isaacson, Howard; Kane, Stephen R.; Lubin, Jack; Mayo, Andrew W.; Močnik, Teo; Murphy, Joseph M. Akana; Petigura, Erik A.; Rice, Malena; Robertson, Paul; Rosenthal, Lee J.; Roy, Arpita; Rubenzahl, Ryan A.; Weiss, Lauren M.; Zandt, Judah Van; Beichman, Charles; Ciardi, David R.; Collins, Karen A.; Gonzales, Erica J.; Howell, Steve B.; Matson, Rachel A.; Matthews, Elisabeth C.; Schlieder, Joshua E.; Schwarz, Richard P.; Ricker, G.; Vanderspek, R.; Latham, David W.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Caldwell, Douglas A.; Colón, Knicole D.; Dragomir, Diana; Lund, Michael B.; McLean, B.; Rudat, Alexander; Shporer, Avi

doi:10.48550/arxiv.2105.08844

Cited by 2 publications

(2 citation statements)

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“…For these two planets, we obtained transit parameters by fitting the TESS light curves using the same methodology as Dai et al (2021). To summarize, we downloaded the TESS photometry from the Mikulski Archive for Space Telescopes (MAST).…”

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confidence: 99%

Detection of Atmospheric Escape from Four Young Mini-Neptunes

Knutson

Dai

Wang

et al. 2023

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We use Keck/NIRSPEC to survey a sample of of young (<1 Gyr), short-period mini-Neptunes orbiting nearby K dwarfs to measure their mass loss via the metastable helium line. We detect helium absorption from all four of the targets in our initial sample. The first detection, around TOI 560b, was announced in a previous paper. We now announce three additional detections around TOI 1430.01, 2076b, and 1683.01. All four planets show an average in-transit excess absorption of 0.7%–1.0%. However, the outflows differ in their kinematic properties. Object TOI 1430b exhibits preingress absorption, while TOI 2076b’s outflow is exceptionally optically thick and shows significant postegress absorption. For all four planets, the width of the measured helium absorption signal is consistent with expectations for a photoevaporative outflow (10–30 km s−1, 5000–10,000 K). Unless broadening mechanisms other than thermal velocity and the bulk outflow velocity are significant, our observations disfavor core-powered mass-loss models, which predict much slower (1–3 km s−1) outflows. We utilize both an isothermal Parker wind model and an order-of-magnitude method to estimate the mass-loss timescale and obtain ∼a few hundred megayears for each planet. We conclude that many, if not all, of these planets will lose their hydrogen-rich envelopes and become super-Earths. Our results demonstrate that most mini-Neptunes orbiting Sun-like stars have primordial atmospheres, and that photoevaporation is an efficient mechanism for stripping these atmospheres and transforming these planets into super-Earths.

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confidence: 99%

Detection of Atmospheric Escape from Four Young Mini-Neptunes

Knutson

Dai

Wang

et al. 2023

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“…Additionally, by targeting a range of small planets (1 R ⊕ < R p < 4 R ⊕ ) at various incident fluxes, TKS can specifically test the photoevaporation hypothesis. The compositions for ultrashort period planets (P<1 day) will be used as a window into the refractory core of small planets (Dai et al 2021). TKS will also measure masses for cooler planets in order to identify any that could have possible Earth-like compositions, especially for planets that are amenable to subsequent atmospheric characterization.…”

Section: Bulk Compositionsmentioning

confidence: 99%

The TESS-Keck Survey: Science Goals and Target Selection

Chontos,

Murphy,

MacDougall

et al. 2021

Preprint

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Space-based transit missions such as Kepler and TESS have demonstrated that planets are ubiquitous. However, the success of these missions heavily depends on ground-based radial velocity (RV) surveys, which combined with transit photometry can yield bulk densities and orbital properties. While most Kepler host stars are too faint for detailed follow-up observations, TESS is detecting planets orbiting nearby bright stars that are more amenable to RV characterization. Here we introduce the TESS-Keck Survey (TKS), an RV program using ∼100 nights on Keck/HIRES to study exoplanets identified by TESS. The primary survey aims are investigating the link between stellar properties and the compositions of small planets; studying how the diversity of system architectures depends on dynamical configurations or planet multiplicity; identifying prime candidates for atmospheric studies with JWST; and understanding the role of stellar evolution in shaping planetary systems. We present a fully-automated target selection algorithm, which yielded 103 planets in 86 systems for the final TKS sample. Most TKS hosts are inactive, solar-like, main-sequence stars (4500 K ≤ T eff < 6000 K) at a wide range of metallicities. The selected TKS sample contains 71 small planets (R p ≤ 4 R ⊕ ), 11 systems with multiple transiting candidates, 6 sub-day period planets and 3 planets that are in or near the habitable zone (S inc ≤ 10 S ⊕ ) of their host star. The target selection described here will facilitate the comparison of measured planet masses, densities, and eccentricities to predictions from planet population models. Our target selection software is publicly available a) and can be adapted for any survey which requires a balance of multiple science interests within a given telescope allocation.

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TKS X: Confirmation of TOI-1444b and a Comparative Analysis of the Ultra-short-period Planets with Hot Neptunes

Abstract: We report the discovery of TOI-1444b, a 1.4-R ⊕ super-Earth on a 0.47-day orbit around a Sun-like star discovered by TESS. Precise radial velocities from Keck/HIRES confirmed the planet and constrained

Cited by 2 publications

References 75 publications

Detection of Atmospheric Escape from Four Young Mini-Neptunes

Detection of Atmospheric Escape from Four Young Mini-Neptunes

The TESS-Keck Survey: Science Goals and Target Selection

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