_version_ 1866929338735132672
author Jones, Sinclaire E.
Stefansson, Gudmundur
Masuda, Kento
Libby-Roberts, Jessica E.
Gardner, Cristilyn N.
Holcomb, Rae
Beard, Corey
Robertson, Paul
Cañas, Caleb I.
Mahadevan, Suvrath
Kanodia, Shubham
Lin, Andrea S. J.
Kobulnicky, Henry A.
Parker, Brock A.
Bender, Chad F.
Cochran, William D.
Diddams, Scott A.
Fernandes, Rachel B.
Gupta, Arvind F.
Halverson, Samuel
Hawley, Suzanne L.
Hearty, Fred R.
Hebb, Leslie
Kowalski, Adam
Lubin, Jack
Monson, Andrew
Ninan, Joe P.
Ramsey, Lawrence
Roy, Arpita
Schwab, Christian
Terrien, Ryan C.
Wisniewski, John
author_facet Jones, Sinclaire E.
Stefansson, Gudmundur
Masuda, Kento
Libby-Roberts, Jessica E.
Gardner, Cristilyn N.
Holcomb, Rae
Beard, Corey
Robertson, Paul
Cañas, Caleb I.
Mahadevan, Suvrath
Kanodia, Shubham
Lin, Andrea S. J.
Kobulnicky, Henry A.
Parker, Brock A.
Bender, Chad F.
Cochran, William D.
Diddams, Scott A.
Fernandes, Rachel B.
Gupta, Arvind F.
Halverson, Samuel
Hawley, Suzanne L.
Hearty, Fred R.
Hebb, Leslie
Kowalski, Adam
Lubin, Jack
Monson, Andrew
Ninan, Joe P.
Ramsey, Lawrence
Roy, Arpita
Schwab, Christian
Terrien, Ryan C.
Wisniewski, John
contents We report the discovery of a close-in ($P_{\mathrm{orb}} = 3.349\:\mathrm{days}$) warm Neptune with clear transit timing variations (TTVs) orbiting the nearby ($d=47.3\:\mathrm{pc}$) active M4 star, TOI-2015. We characterize the planet's properties using TESS photometry, precise near-infrared radial velocities (RV) with the Habitable-zone Planet Finder (HP) Spectrograph, ground-based photometry, and high-contrast imaging. A joint photometry and RV fit yields a radius $R_p~=~3.37_{-0.20}^{+0.15} \:\mathrm{R_\oplus}$, mass $m_p~=~16.4_{-4.1}^{+4.1}\:\mathrm{M_\oplus}$, and density $ρ_p~=~2.32_{-0.37}^{+0.38} \:\mathrm{g cm^{-3}}$ for TOI-2015b, suggesting a likely volatile-rich planet. The young, active host star has a rotation period of $P_{\mathrm{rot}}~=~8.7 \pm~0.9~\mathrm{days}$ and associated rotation-based age estimate of $1.1~\pm~0.1\:\mathrm{Gyr}$. Though no other transiting planets are seen in the TESS data, the system shows clear TTVs of super period $P_{\mathrm{sup}}~\approx~430\:\mathrm{days}$ and amplitude $\sim$$100\:\mathrm{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 resonance -- cannot be conclusively excluded without further observations. Assuming a 2:1 resonance in the joint TTV-RV modeling suggests a mass of $m_b~=~13.3_{-4.5}^{+4.7}\:\mathrm{M_\oplus}$ for TOI-2015b and $m_c~=~6.8_{-2.3}^{+3.5}\:\mathrm{M_\oplus}$ 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.
format Preprint
id arxiv_https___arxiv_org_abs_2310_11775
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle TOI-2015b: A Warm Neptune with Transit Timing Variations Orbiting an Active mid M Dwarf
Jones, Sinclaire E.
Stefansson, Gudmundur
Masuda, Kento
Libby-Roberts, Jessica E.
Gardner, Cristilyn N.
Holcomb, Rae
Beard, Corey
Robertson, Paul
Cañas, Caleb I.
Mahadevan, Suvrath
Kanodia, Shubham
Lin, Andrea S. J.
Kobulnicky, Henry A.
Parker, Brock A.
Bender, Chad F.
Cochran, William D.
Diddams, Scott A.
Fernandes, Rachel B.
Gupta, Arvind F.
Halverson, Samuel
Hawley, Suzanne L.
Hearty, Fred R.
Hebb, Leslie
Kowalski, Adam
Lubin, Jack
Monson, Andrew
Ninan, Joe P.
Ramsey, Lawrence
Roy, Arpita
Schwab, Christian
Terrien, Ryan C.
Wisniewski, John
Earth and Planetary Astrophysics
We report the discovery of a close-in ($P_{\mathrm{orb}} = 3.349\:\mathrm{days}$) warm Neptune with clear transit timing variations (TTVs) orbiting the nearby ($d=47.3\:\mathrm{pc}$) active M4 star, TOI-2015. We characterize the planet's properties using TESS photometry, precise near-infrared radial velocities (RV) with the Habitable-zone Planet Finder (HP) Spectrograph, ground-based photometry, and high-contrast imaging. A joint photometry and RV fit yields a radius $R_p~=~3.37_{-0.20}^{+0.15} \:\mathrm{R_\oplus}$, mass $m_p~=~16.4_{-4.1}^{+4.1}\:\mathrm{M_\oplus}$, and density $ρ_p~=~2.32_{-0.37}^{+0.38} \:\mathrm{g cm^{-3}}$ for TOI-2015b, suggesting a likely volatile-rich planet. The young, active host star has a rotation period of $P_{\mathrm{rot}}~=~8.7 \pm~0.9~\mathrm{days}$ and associated rotation-based age estimate of $1.1~\pm~0.1\:\mathrm{Gyr}$. Though no other transiting planets are seen in the TESS data, the system shows clear TTVs of super period $P_{\mathrm{sup}}~\approx~430\:\mathrm{days}$ and amplitude $\sim$$100\:\mathrm{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 resonance -- cannot be conclusively excluded without further observations. Assuming a 2:1 resonance in the joint TTV-RV modeling suggests a mass of $m_b~=~13.3_{-4.5}^{+4.7}\:\mathrm{M_\oplus}$ for TOI-2015b and $m_c~=~6.8_{-2.3}^{+3.5}\:\mathrm{M_\oplus}$ 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.
title TOI-2015b: A Warm Neptune with Transit Timing Variations Orbiting an Active mid M Dwarf
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2310.11775