The Magellan-TESS Survey. I. Survey Description and Midsurvey Results*
               
               †

Teske, Johanna; Wang, Sharon Xuesong; Wolfgang, Angie; Gan, Tianjun; Plotnykov, Mykhaylo; Armstrong, David J.; Butler, R. Paul; Cale, Bryson; Crane, Jeffrey D.; Howard, Ward S.; Jensen, Eric L. N.; Law, Nicholas M.; Shectman, Stephen; Plavchan, Peter; Valencia, Diana; Vanderburg, Andrew; Ricker, G.; Vanderspek, R.; Latham, David W.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Adibekyan, V.; Barrado, D.; Barros, S. C. C.; Benkhaldoun, Z.; Brown, D. J. A.; Bryant, Edward M.; Burt, Jennifer; Caldwell, Douglas A.; Charbonneau, David; Cloutier, Ryan; Collins, Karen A.; Collins, Kevin I.; Colón, Knicole D.; Conti, Dennis M.; Demangeon, O.; Eastman, Jason D.; Elmufti, Mohammed; Feng, Fabo; Flowers, Erin; Guerrero, Natalia; Hojjatpanah, S.; Irwin, Jonathan; Isopi, Giovanni; Lillo-Box, J.; Mallia, F.; Massey, Bob; Mori, Mayuko; Mullally, Susan E.; Narita, Norio; Nishiumi, Taku; Osborn, Ares; Paegert, Martin; Leon, Jerome P. de; Quinn, Samuel N.; Reefe, Michael; Schwarz, Richard P.; Shporer, Avi; Soubkiou, Abderahmane; Sousa, S. G.; Stockdale, Chris; Strøm, Paul A.; Tan, Thiam Guan; Tang, Jiaxin; Tenenbaum, P.; Wheatley, P. J.; Wittrock, Justin M.; Yahalomi, Daniel A.; Zohrabi, F.

doi:10.3847/1538-4365/ac0f0a

“…However, when Otegi et al (2020a) curated a high-fidelity sample of exoplanet mass and radius measurements from the We only include planets with better than 15% fractional measurement precision in radius and 33% fractional precision in mass. We note that the sample of planets shown here may lack completeness for low-density sub-Neptunes due to our fractional precision requirements, but they should not impact completeness at high density (Burt et al 2018;Montet 2018;Teske et al 2021). Planets and their 1σ measurement uncertainties are colored by equilibrium temperature assuming zero Bond albedo.…”

Section: Kepler-145 Bmentioning

confidence: 82%

“…While we found that our mass measurement for K2-182 b was consistent between RV models with and without a GP trained on the K2 photometry, we suggest that additional monitoring will better inform the influence of stellar activity on the spectroscopic observations. Furthermore, cases where starspots contribute to planet RV amplitude may be subject to publication bias because the inflated signal can more easily overcome standard fractional precision thresholds, like M p s  5 M p (Burt et al 2018;Montet 2018;Batalha et al 2019;Teske et al 2021).…”

Section: Superdense Sub-neptunesmentioning

confidence: 99%

Another Superdense Sub-Neptune in K2-182 b and Refined Mass Measurements for K2-199 b and c*

Murphy

¹

,

Kosiarek

²

,

Batalha

³

et al. 2021

AJ

8

0

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We combine multiple campaigns of K2 photometry with precision radial velocity measurements from Keck-HIRES to measure the masses of three sub-Neptune-sized planets. We confirm the planetary nature of the massive sub-Neptune K2-182 b (P b = 4.7 days, R b = 2.69 R ⊕) and derive refined parameters for K2-199 b and c (P b = 3.2 days, R b = 1.73 R ⊕ and P c = 7.4 days, R c = 2.85 R ⊕). These planets provide valuable data points in the mass–radius plane, especially as TESS continues to reveal an increasingly diverse sample of sub-Neptunes. The moderately bright (V = 12.0 mag) early K dwarf K2-182 (EPIC 211359660) was observed during K2 campaigns 5 and 18. We find that K2-182 b is potentially one of the densest sub-Neptunes known to date (20 ± 5 M ⊕ and 5.6 ± 1.4 g cm−3). The K5V dwarf K2-199 (EPIC 212779596; V = 12.3 mag), observed in K2 campaigns 6 and 17, hosts two recently confirmed planets. We refine the orbital and planetary parameters for K2-199 b and c by modeling both campaigns of K2 photometry and adding 12 Keck-HIRES measurements to the existing radial velocity data set (N = 33). We find that K2-199 b is likely rocky, at 6.9 ± 1.8 M ⊕ and 7.2 − 2.0 + 2.1 g cm−3, and that K2-199 c has an intermediate density at 12.4 ± 2.3 M ⊕ and 2.9 − 0.6 + 0.7 g cm−3. We contextualize these planets on the mass–radius plane, discuss a small but intriguing population of “superdense” sub-Neptunes (R p < 3 R ⊕, M p >20 M ⊕), and consider our prospects for the planets’ atmospheric characterization.

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“…There are several ongoing, ground-based TESS RV surveys, e.g., MTS (Teske et al 2021), NCORES (Armstrong & consortium 2021), KESPRINT (Kabath et al 2021), etc., many of which have science interests that overlap with those of TKS. Our target selection procedure was strategically implemented to achieve the most optimal sample that simultaneously addressed the different science goals within the survey (see Section 5 for more details).…”

Section: Coordination With Other Surveysmentioning

confidence: 99%

“…Therefore, a critical ingredient for the realization of these surveys is understanding the process by which targets were initially selected. Indeed, recent groundbased TESS follow-up programs such as the Magellan-TESS Survey (MTS; Teske et al 2021) have begun to describe target selection functions, providing a pathway to properly correct for survey biases or incompleteness.…”

Section: Introductionmentioning

confidence: 99%

The TESS-Keck Survey: ^* Science Goals and Target Selection

Chontos

¹

,

Murphy

²

,

MacDougall

³

et al. 2022

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The Kepler and TESS missions 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, six sub-day-period planets and three 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 and can be adapted for any survey that requires a balance of multiple science interests within a given telescope allocation.

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“…Due to the relatively large TESS pixels spanning 22″ on the sky, fainter visual eclipsing binaries can blend with the nearby bright target stars and produce false positives (barring instrumental artifacts). This is an important consideration, particularly when only a single transiting planet is found in the TESS 27 day time baseline of sector observations, at lower ecliptic latitudes, and away from the ecliptic poles (Lissauer et al 2012;Vanderburg et al 2019;Rodríguez Martínez et al 2020;Hobson et al 2021;Addison et al 2021;Osborn et al 2021;Dreizler et al 2020;Brahm et al 2020;Nowak et al 2020;Teske et al 2020;Sha et al 2021;Gan et al 2021;Bluhm et al 2020).…”

Section: Introductionmentioning

confidence: 99%

A Close-in Puffy Neptune with Hidden Friends: The Enigma of TOI 620

Reefe¹,

Luque²,

Gaidos³

et al. 2022

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We present the validation of a transiting low-density exoplanet orbiting the M2.5 dwarf TOI 620 discovered by the NASA Transiting Exoplanet Survey Satellite (TESS) mission. We utilize photometric data from both TESS and ground-based follow-up observations to validate the ephemerides of the 5.09 day transiting signal and vet false-positive scenarios. High-contrast imaging data are used to resolve the stellar host and exclude stellar companions at separations ≳0.″2. We obtain follow-up spectroscopy and corresponding precise radial velocities (RVs) with multiple precision radial velocity (PRV) spectrographs to confirm the planetary nature of the transiting exoplanet. We calculate a 5σ upper limit of M P < 7.1 M ⊕ and ρ P < 0.74 g cm−3, and we identify a nontransiting 17.7 day candidate. We also find evidence for a substellar (1–20 M J ) companion with a projected separation ≲20 au from a combined analysis of Gaia, adaptive optics imaging, and RVs. With the discovery of this outer companion, we carry out a detailed exploration of the possibilities that TOI 620 b might instead be a circum-secondary planet or a pair of eclipsing binary stars orbiting the host in a hierarchical triple system. We find, under scrutiny, that we can exclude both of these scenarios from the multiwavelength transit photometry, thus validating TOI 620 b as a low-density exoplanet transiting the central star in this system. The low density of TOI 620 b makes it one of the most amenable exoplanets for atmospheric characterization, such as with the James Webb Space Telescope and Ariel, validated or confirmed by the TESS mission to date.

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The Magellan-TESS Survey. I. Survey Description and Midsurvey Results* †

Cited by 28 publications

References 161 publications

Another Superdense Sub-Neptune in K2-182 b and Refined Mass Measurements for K2-199 b and c*

Another Superdense Sub-Neptune in K2-182 b and Refined Mass Measurements for K2-199 b and c*

The TESS-Keck Survey: ^* Science Goals and Target Selection

A Close-in Puffy Neptune with Hidden Friends: The Enigma of TOI 620

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The Magellan-TESS Survey. I. Survey Description and Midsurvey Results* †

Cited by 28 publications

References 161 publications

Another Superdense Sub-Neptune in K2-182 b and Refined Mass Measurements for K2-199 b and c*

Another Superdense Sub-Neptune in K2-182 b and Refined Mass Measurements for K2-199 b and c*

The TESS-Keck Survey: * Science Goals and Target Selection

A Close-in Puffy Neptune with Hidden Friends: The Enigma of TOI 620

Contact Info

Product

Resources

About

The TESS-Keck Survey: ^* Science Goals and Target Selection