_version_ 1866911118529658880
author DiTomasso, Victoria
Charbonneau, David
Vanderburg, Andrew
López-Morales, Mercedes
Vissapragada, Shreyas
Mortier, Annelies
Wilson, Thomas G.
Incha, Elyse
Cameron, Andrew Collier
Malavolta, Luca
Buchhave, Lars A.
Latham, David W.
Pinamonti, Matteo
Striegel, Stephanie
Fausnaugh, Michael
Bouma, Luke
Falk, Ben
Aloisi, Robert
Dumusque, Xavier
John, A. Anna
Lakeland, Ben S.
Fiorenzano, A. F. Martínez
Naponiello, Luca
Nicholson, Belinda
Pass, Emily K.
Pepe, Francesco Alfonso
Rescigno, Federica
Sozzetti, Alessandro
Turner, Daisy A.
Rappaport, Saul A.
Omohundro, Mark
Powell, Brian P.
Gagliano, Robert
Jacobs, Thomas L.
Kostov, Veselin B.
Kristiansen, Martti H.
LaCourse, Daryll M.
Schmitt, Allan R.
Schwengeler, Hans Martin
Terentev, Ivan A.
author_facet DiTomasso, Victoria
Charbonneau, David
Vanderburg, Andrew
López-Morales, Mercedes
Vissapragada, Shreyas
Mortier, Annelies
Wilson, Thomas G.
Incha, Elyse
Cameron, Andrew Collier
Malavolta, Luca
Buchhave, Lars A.
Latham, David W.
Pinamonti, Matteo
Striegel, Stephanie
Fausnaugh, Michael
Bouma, Luke
Falk, Ben
Aloisi, Robert
Dumusque, Xavier
John, A. Anna
Lakeland, Ben S.
Fiorenzano, A. F. Martínez
Naponiello, Luca
Nicholson, Belinda
Pass, Emily K.
Pepe, Francesco Alfonso
Rescigno, Federica
Sozzetti, Alessandro
Turner, Daisy A.
Rappaport, Saul A.
Omohundro, Mark
Powell, Brian P.
Gagliano, Robert
Jacobs, Thomas L.
Kostov, Veselin B.
Kristiansen, Martti H.
LaCourse, Daryll M.
Schmitt, Allan R.
Schwengeler, Hans Martin
Terentev, Ivan A.
contents We present the discovery of the planetary system orbiting the bright (V = 7.2), nearby (35 pc), Sun-like star HD 60779, which has a mass of 1.050 +/- 0.044 solar masses and a radius of 1.129 +/- 0.013 solar radii. We report two TESS transits and a subsequent CHEOPS transit of HD 60779 b, a sub-Neptune with a radius of 3.250 (+0.100 / -0.098) Earth radii on a 29.986175 (+0.000030 / -0.000033) day orbit. Additionally, 286 HARPS-N radial velocity measurements reveal the mass of planet b (14.7 +1.1 / -1.0 Earth masses) and the presence of an outer planet, HD 60779 c, with an orbital period of 104.25 (+0.30 / -0.29) days and a minimum mass (m sin i) of 27.7 +/- 1.6 Earth masses. Both planets' orbits are consistent with being circular, suggesting that they have a dynamically quiet history. The data are not sufficient to determine whether planet c transits. HD 60779's uniquely high systemic radial velocity (129.75 +/- 0.12 km/s) allows its Lyman-alpha emission to avoid absorption by the interstellar medium, making it a prime candidate for probing atmospheric escape from HD 60779 b. HD 60779 is also the third-brightest host of a sub-Neptune with orbital period greater than 25 days and with both mass and radius measured, distinguishing it in terms of accessibility to spectroscopic characterization.
format Preprint
id arxiv_https___arxiv_org_abs_2508_16805
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The HD 60779 Planetary System: A Transiting Sub-Neptune on a 30-day Orbit and a More Massive Outer World
DiTomasso, Victoria
Charbonneau, David
Vanderburg, Andrew
López-Morales, Mercedes
Vissapragada, Shreyas
Mortier, Annelies
Wilson, Thomas G.
Incha, Elyse
Cameron, Andrew Collier
Malavolta, Luca
Buchhave, Lars A.
Latham, David W.
Pinamonti, Matteo
Striegel, Stephanie
Fausnaugh, Michael
Bouma, Luke
Falk, Ben
Aloisi, Robert
Dumusque, Xavier
John, A. Anna
Lakeland, Ben S.
Fiorenzano, A. F. Martínez
Naponiello, Luca
Nicholson, Belinda
Pass, Emily K.
Pepe, Francesco Alfonso
Rescigno, Federica
Sozzetti, Alessandro
Turner, Daisy A.
Rappaport, Saul A.
Omohundro, Mark
Powell, Brian P.
Gagliano, Robert
Jacobs, Thomas L.
Kostov, Veselin B.
Kristiansen, Martti H.
LaCourse, Daryll M.
Schmitt, Allan R.
Schwengeler, Hans Martin
Terentev, Ivan A.
Earth and Planetary Astrophysics
We present the discovery of the planetary system orbiting the bright (V = 7.2), nearby (35 pc), Sun-like star HD 60779, which has a mass of 1.050 +/- 0.044 solar masses and a radius of 1.129 +/- 0.013 solar radii. We report two TESS transits and a subsequent CHEOPS transit of HD 60779 b, a sub-Neptune with a radius of 3.250 (+0.100 / -0.098) Earth radii on a 29.986175 (+0.000030 / -0.000033) day orbit. Additionally, 286 HARPS-N radial velocity measurements reveal the mass of planet b (14.7 +1.1 / -1.0 Earth masses) and the presence of an outer planet, HD 60779 c, with an orbital period of 104.25 (+0.30 / -0.29) days and a minimum mass (m sin i) of 27.7 +/- 1.6 Earth masses. Both planets' orbits are consistent with being circular, suggesting that they have a dynamically quiet history. The data are not sufficient to determine whether planet c transits. HD 60779's uniquely high systemic radial velocity (129.75 +/- 0.12 km/s) allows its Lyman-alpha emission to avoid absorption by the interstellar medium, making it a prime candidate for probing atmospheric escape from HD 60779 b. HD 60779 is also the third-brightest host of a sub-Neptune with orbital period greater than 25 days and with both mass and radius measured, distinguishing it in terms of accessibility to spectroscopic characterization.
title The HD 60779 Planetary System: A Transiting Sub-Neptune on a 30-day Orbit and a More Massive Outer World
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2508.16805