TOI-1728b: The Habitable-zone Planet Finder Confirms a Warm Super-Neptune Orbiting an M-dwarf Host

Kanodia, Shubham; Cañas, Caleb I.; Stefánsson, Guðmundur; Ninan, Joe P.; Hebb, Leslie; Lin, Andrea S. J.; Baran, Helen; Maney, Marissa; Terrien, Ryan C.; Mahadevan, Suvrath; Cochran, William D.; Endl, Michael; Dong, Jiayin; Bender, Chad F.; Diddams, Scott A.; Fredrick, Connor; Halverson, Samuel; Hearty, Fred; Metcalf, Andrew J.; Monson, Andrew; Ramsey, Lawrence W.; Robertson, Paul; Roy, Arpita; Schwab, Christian; Wright, Jason T.

doi:10.3847/1538-4357/aba0a2

Cited by 22 publications

(15 citation statements)

References 162 publications

(202 reference statements)

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“…All host stars are main-sequence M dwarfs, but TOI-674 is smaller and less luminous than TOI-1728 and TOI-442, and therefore even though its planet has a closer-in orbit, it has a slightly lower equilibrium temperature (for the same albedo). The similarity between these three recent TESS discoveries means that most of the qualitative information in the Discussion and Summary sections of Kanodia et al (2020) and Dreizler et al (2020) also applies to TOI-674b.…”

Section: Mass Radius and Compositionmentioning

confidence: 67%

“…According to Lucy & Sweeney (1971), an eccentricity should not be considered significant if it is less than 2.45σ from zero, which our eccentric fit does not achieve. Nonetheless, many Neptune-mass planets with short orbital periods are in non-circular orbits, HAT-P-11b (Bakos et al 2010;Yee et al 2018), GJ 436b (Gillon et al 2007;Lanotte et al 2014), and TOI-1728b (Kanodia et al 2020) to name some examples. Correia et al (2020) proposed that these non-circular orbits could be produced by any of several processes alone or in combination like a tidal torque created by photo-driven evaporation of the planet's atmosphere and/or gravitational interaction between the short-period planet and another planetary object in a longer period orbit in the system.…”

Section: Orbital Eccentricity Of Toi-674bmentioning

confidence: 99%

“…Comparing the mass and radius of TOI-674b with other planets discovered orbiting around M-type stars, we find that TOI-674b is one of the largest and most massive super-Neptune class planets discovered around an M dwarf to date. The planets orbiting M dwarfs closest to TOI-674b in the M-R diagram are TOI-1728b (Kanodia et al 2020) and TOI-442b (Dreizler et al 2020). TOI-1728b orbits an M0V star (T eff = 3980 K), and is a super-Neptune with R p = 5.05 ± 0.17 R ⊕ , M p = 26.78 ± 5.43 M ⊕ , and an orbital period of ∼3.5 days (T eq = 767 K).…”

Section: Mass Radius and Compositionmentioning

confidence: 99%

“…In recent years, more planets in the Neptunian desert have been identified. Some examples of planets with masses close to Neptune and in short orbital periods found recently are NGTS-4b (West et al 2019), TOI-132b (Díaz et al 2020), LTT 9779b (Jenkins et al 2020b), TOI-1728b (Kanodia et al 2020), TOI-442b (Dreizler et al 2020), and TOI-849b (Armstrong et al 2020). The addition of new objects in this mass, radius, and orbital period range can help shed some light on the physical mechanisms behind the Neptunian desert.…”

Section: Introductionmentioning

confidence: 96%

“…M dwarfs (e.g., GJ 876d Rivera et al 2005, TRAPPIST-1 system Gillon et al 2017, LHS 1140bDittmann et al 2017, LHS 1140cMent et al 2019, GJ 357b Luque et al 2019), but planets with masses and radii between those of Neptune and Jupiter have also been found (e.g., GJ 876c Marcy et al 2001, GJ 436b Gillon et al 2007HATS-71b Bakos et al 2020;GJ 3512b Morales et al 2019;TOI-1728bKanodia et al 2020. Relatively few gas planets orbiting around M dwarfs have been found in this mass and size range, in agreement with the prediction of a paucity of gas giants orbiting around M dwarfs for core accretion models (Laughlin et al 2004).…”

Section: Introductionmentioning

confidence: 99%

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TOI-674b: An oasis in the desert of exo-Neptunes transiting a nearby M dwarf

Murgas

Astudillo-Defru

Bonfils

et al. 2021

A&A

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Context. The NASA mission TESS is currently doing an all-sky survey from space to detect transiting planets around bright stars. As part of the validation process, the most promising planet candidates need to be confirmed and characterized using follow-up observations. Aims. In this article, our aim is to confirm the planetary nature of the transiting planet candidate TOI-674b using spectroscopic and photometric observations. Methods. We use TESS, Spitzer, ground-based light curves, and HARPS spectrograph radial velocity measurements to establish the physical properties of the transiting exoplanet candidate TOI-674b. We perform a joint fit of the light curves and radial velocity time series to measure the mass, radius, and orbital parameters of the candidate. Results. We confirm and characterize TOI-674b, a low-density super-Neptune transiting a nearby M dwarf. The host star (TIC 158588995, V = 14.2 mag, J = 10.3 mag) is characterized by its M2V spectral type with M⋆ = 0.420 ± 0.010 M⊙, R⋆ = 0.420 ± 0.013 R⊙, and Teff = 3514 ± 57 K; it is located at a distance d = 46.16 ± 0.03 pc. Combining the available transit light curves plus radial velocity measurements and jointly fitting a circular orbit model, we find an orbital period of 1.977143 ± 3 × 10−6 days, a planetary radius of 5.25 ± 0.17 R⊕, and a mass of 23.6 ± 3.3 M⊕ implying a mean density of ρp =0.91 ± 0.15 g cm−3. A non-circular orbit model fit delivers similar planetary mass and radius values within the uncertainties. Given the measured planetary radius and mass, TOI-674b is one of the largest and most massive super-Neptune class planets discovered around an M-type star to date. It is found in the Neptunian desert, and is a promising candidate for atmospheric characterization using the James Webb Space Telescope.

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Section: Mass Radius and Compositionmentioning

confidence: 67%

Section: Orbital Eccentricity Of Toi-674bmentioning

confidence: 99%

Section: Mass Radius and Compositionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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TOI-674b: An oasis in the desert of exo-Neptunes transiting a nearby M dwarf

Murgas

Astudillo-Defru

Bonfils

et al. 2021

A&A

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Mass and density of the transiting hot and rocky super-Earth LHS 1478 b (TOI-1640 b)

Soto

Anglada‐Escudé

Molaverdikhani

et al. 2021

A&A

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One of the main objectives of the Transiting Exoplanet Survey Satellite (TESS) mission is the discovery of small rocky planets around relatively bright nearby stars. Here, we report the discovery and characterization of the transiting super-Earth planet orbiting LHS 1478 (TOI-1640). The star is an inactive red dwarf (J ~ 9.6 mag and spectral type m3 V) with mass and radius estimates of 0.20 ± 0.01M⊙ and 0.25 ± 0.01R⊙, respectively, and an effective temperature of 3381 ± 54 K. It was observed by TESS in four sectors. These data revealed a transit-like feature with a period of 1.949 days. We combined the TESS data with three ground-based transit measurements, 57 radial velocity (RV) measurements from CARMENES, and 13 RV measurements from IRD, determining that the signal is produced by a planet with a mass of 2.33−0.20+0.20 M⊕ and a radius of 1.24−0.05+0.05 R⊕. The resulting bulk density of this planet is 6.67 g cm−3, which is consistent with a rocky planet with an Fe- and MgSiO3-dominated composition. Although the planet would be too hot to sustain liquid water on its surface (its equilibrium temperature is about ~595 K, suggesting aVenus-like atmosphere), spectroscopic metrics based on the capabilities of the forthcoming James Webb Space Telescope and the fact that the host star is rather inactive indicate that this is one of the most favorable known rocky exoplanets for atmospheric characterization.

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The GAPS programme at TNG

Maldonado¹,

Petralia²,

Mantovan³

et al. 2023

A&A

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Context. Massive substellar companions orbiting active low-mass stars are rare. They, however, offer an excellent opportunity to study the main mechanisms involved in the formation and evolution of substellar objects. Aims. We aim to unravel the physical nature of the transit signal observed by the TESS space mission on the active M dwarf TOI-5375. Methods. We analysed the available TESS photometric data as well as high-resolution (R ~ 115 000) HARPS-N spectra. We combined these data to characterise the star TOI-5375 and to disentangle signals related to stellar activity from the companion transit signal in the light-curve data. We ran a Markov chain Monte Carlo analysis to derive the orbital solution and applied state-of-the-art Gaussian process regression to deal with the stellar activity signal. Results. We reveal the presence of a companion in the boundary between the brown dwarfs and the very-low-mass stars orbiting around the star TOI-5375. The best-fit model corresponds to a companion with an orbital period of 1.721564 ± 10−6 d, a mass of 77 ± 8 MJ, and a radius of 0.99 ± 0.16 RJ. Conclusions. We derive a rotation period for the host star of 1.9692 ± 0.0004 d, and we conclude that the star is very close to synchronising its rotation with the orbital period of the companion.

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TOI-1728b: The Habitable-zone Planet Finder Confirms a Warm Super-Neptune Orbiting an M-dwarf Host

Cited by 22 publications

References 162 publications

TOI-674b: An oasis in the desert of exo-Neptunes transiting a nearby M dwarf

TOI-674b: An oasis in the desert of exo-Neptunes transiting a nearby M dwarf

Mass and density of the transiting hot and rocky super-Earth LHS 1478 b (TOI-1640 b)

The GAPS programme at TNG

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