TY - JOUR
T1 - TOI-2015 b
T2 - A warm Neptune with transit timing variations orbiting an active mid-type M dwarf
AU - Jones, Sinclaire E.
AU - Stefánsson, Guđmundur
AU - Masuda, Kento
AU - Libby-Roberts, Jessica E.
AU - Gardner, Cristilyn N.
AU - Holcomb, Rae
AU - Beard, Corey
AU - Robertson, Paul
AU - Cañas, Caleb I.
AU - Mahadevan, Suvrath
AU - Kanodia, Shubham
AU - Lin, Andrea S. J.
AU - Kobulnicky, Henry A.
AU - Parker, Brock A.
AU - Bender, Chad F.
AU - Cochran, William D.
AU - Diddams, Scott A.
AU - Fernandes, Rachel B.
AU - Gupta, Arvind F.
AU - Halverson, Samuel
AU - Hawley, Suzanne L.
AU - Hearty, Fred R.
AU - Hebb, Leslie
AU - Kowalski, Adam
AU - Lubin, Jack
AU - Monson, Andrew
AU - Ninan, Joe P.
AU - Ramsey, Lawrence
AU - Roy, Arpita
AU - Schwab, Christian
AU - Terrien, Ryan C.
AU - Wisniewski, John
N1 - © 2024. The Author(s). Published by the American Astronomical Society. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.
PY - 2024/8/1
Y1 - 2024/8/1
N2 - We report the discovery of a close-in (Porb = 3.349 days) warm Neptune with clear transit timing variations (TTVs) orbiting the nearby (d = 47.3 pc) active M4 star, TOI-2015. We characterize the planet's properties using Transiting Exoplanet Survey Satellite (TESS) photometry, precise near-infrared radial velocities (RVs) with the Habitable-zone Planet Finder Spectrograph, ground-based photometry, and high-contrast imaging. A joint photometry and RV fit yields a radius Rp = 3.37−0.20+0.15 R⊕ , mass mp = 16.4−4.1+4.1 M⊕ , and density ρp = 2.32−0.37+0.38 g cm−3 for TOI-2015 b, suggesting a likely volatile-rich planet. The young, active host star has a rotation period of Prot = 8.7 ± 0.9 days and associated rotation-based age estimate of 1.1 ± 0.1 Gyr. Though no other transiting planets are seen in the TESS data, the system shows clear TTVs of super-period Psup ≈ 430 days and amplitude ∼100 minutes. After considering multiple likely period-ratio models, we show an outer planet candidate near a 2:1 resonance can explain the observed TTVs while offering a dynamically stable solution. However, other possible two-planet solutions—including 3:2 and 4:3 resonances—cannot be conclusively excluded without further observations. Assuming a 2:1 resonance in the joint TTV-RV modeling suggests a mass of mb = 13.3−4.5+4.7 M⊕ for TOI-2015 b and mc = 6.8−2.3+3.5 M⊕ for the outer candidate. Additional transit and RV observations will be beneficial to explicitly identify the resonance and further characterize the properties of the system.
AB - We report the discovery of a close-in (Porb = 3.349 days) warm Neptune with clear transit timing variations (TTVs) orbiting the nearby (d = 47.3 pc) active M4 star, TOI-2015. We characterize the planet's properties using Transiting Exoplanet Survey Satellite (TESS) photometry, precise near-infrared radial velocities (RVs) with the Habitable-zone Planet Finder Spectrograph, ground-based photometry, and high-contrast imaging. A joint photometry and RV fit yields a radius Rp = 3.37−0.20+0.15 R⊕ , mass mp = 16.4−4.1+4.1 M⊕ , and density ρp = 2.32−0.37+0.38 g cm−3 for TOI-2015 b, suggesting a likely volatile-rich planet. The young, active host star has a rotation period of Prot = 8.7 ± 0.9 days and associated rotation-based age estimate of 1.1 ± 0.1 Gyr. Though no other transiting planets are seen in the TESS data, the system shows clear TTVs of super-period Psup ≈ 430 days and amplitude ∼100 minutes. After considering multiple likely period-ratio models, we show an outer planet candidate near a 2:1 resonance can explain the observed TTVs while offering a dynamically stable solution. However, other possible two-planet solutions—including 3:2 and 4:3 resonances—cannot be conclusively excluded without further observations. Assuming a 2:1 resonance in the joint TTV-RV modeling suggests a mass of mb = 13.3−4.5+4.7 M⊕ for TOI-2015 b and mc = 6.8−2.3+3.5 M⊕ for the outer candidate. Additional transit and RV observations will be beneficial to explicitly identify the resonance and further characterize the properties of the system.
UR - http://www.scopus.com/inward/record.url?scp=85199712438&partnerID=8YFLogxK
U2 - 10.3847/1538-3881/ad55ea
DO - 10.3847/1538-3881/ad55ea
M3 - Article
AN - SCOPUS:85199712438
SN - 0004-6256
VL - 168
SP - 1
EP - 24
JO - Astronomical Journal
JF - Astronomical Journal
IS - 2
M1 - 93
ER -