HD 35843: A Sun-like Star Hosting a Long-period Sub-Neptune and Inner Super-Earth

Katharine Hesse; Ismael Mireles; François Bouchy; Diana Dragomir; Solène Ulmer-Moll; Nora L. Eisner; Keivan G. Stassun; Samuel N. Quinn; Hugh P. Osborn; Sergio G. Sousa; Cristilyn N. Watkins; Karen A. Collins; Edward M. Bryant; Jonathan M. Irwin; Coel Hellier; Marshall C. Johnson; Carl Ziegler; Steve B. Howell; David R. Anderson; Daniel Bayliss; Allyson Bieryla; César Briceño; R. Paul Butler; David Charbonneau; Ryan Cloutier; Jeffrey Crane; Jason Dittmann; Jason D. Eastman; Sebastián A. Freigeiro; Benjamin J. Fulton; Samuel Gill; Maximilian Günther; Haedam Im; Jon M. Jenkins; Michelle Kunimoto; Baptiste Lavie; Monika Lendl; Michael B. Lund; Andrew W. Mann; Belinda Nicholson; David Osip; Martin Paegert; Nuno C. Santos; Richard P. Schwarz; Sara Seager; Stephen Shectman; Johanna Teske; Joseph D. Twicken; Stéphane Udry; Vincent Van Eylen; José Vinés; Sharon X. Wang; Peter J. Wheatley; Joshua N. Winn; Edward E. Zuidema

doi:10.3847/1538-3881/add7d7

HD 35843: A Sun-like Star Hosting a Long-period Sub-Neptune and Inner Super-Earth

Katharine Hesse
, Ismael Mireles
, François Bouchy
, Diana Dragomir
, Solène Ulmer-Moll
, Nora L. Eisner
, Keivan G. Stassun
, Samuel N. Quinn
, Hugh P. Osborn
, Sergio G. Sousa
, Cristilyn N. Watkins
, Karen A. Collins
, Edward M. Bryant
, Jonathan M. Irwin
, Coel Hellier
, Marshall C. Johnson
, Carl Ziegler
, Steve B. Howell
, David R. Anderson
, Daniel Bayliss

Allyson Bieryla, César Briceño, R. Paul Butler, David Charbonneau, Ryan Cloutier, Jeffrey Crane, Jason Dittmann, Jason D. Eastman, Sebastián A. Freigeiro, Benjamin J. Fulton, Samuel Gill, Maximilian Günther, Haedam Im, Jon M. Jenkins, Michelle Kunimoto, Baptiste Lavie, Monika Lendl, Michael B. Lund, Andrew W. Mann, Belinda Nicholson, David Osip, Martin Paegert, Nuno C. Santos, Richard P. Schwarz, Sara Seager, Stephen Shectman, Johanna Teske, Joseph D. Twicken, Stéphane Udry, Vincent Van Eylen, José Vinés, Sharon X. Wang, Peter J. Wheatley, Joshua N. Winn, Edward E. Zuidema

Astrophysical Sciences

Research output: Contribution to journal › Article › peer-review

Abstract

We report the discovery and confirmation of two planets orbiting the metal-poor Sun-like star HD 35843 (TOI 4189). HD 35843 c is a temperate sub-Neptune transiting planet with an orbital period of 46.96 days that was first identified by Planet Hunters TESS. We combine data from TESS and follow-up observations to rule out false-positive scenarios and validate the planet. We then use ESPRESSO radial velocities (RVs) to confirm the planetary nature and characterize the planet’s mass and orbit. Further analysis of these RVs reveals the presence of an additional planet, HD 35843 b, with a period of 9.90 days and a minimum mass of 5.84 ± 0.84 M_⊕. For HD 35843 c, a joint photometric and spectroscopic analysis yields a radius of 2.54 ± 0.08 R_⊕, a mass of 11.32 ± 1.60 M_⊕, and an orbital eccentricity of e = 0.15 ± 0.07. With a bulk density of 3.80 ± 0.70 g cm⁻³, the planet might be rocky with a substantial H₂ atmosphere or it might be a “water world.” With an equilibrium temperature of ∼480 K, HD 35843 c is among the coolest ∼5% of planets discovered by TESS. Combined with the host star’s relative brightness (V = 9.4), HD 35843 c is a promising target for atmospheric characterization that will probe this sparse population of temperate sub-Neptunes.

Original language	English (US)
Article number	108
Journal	Astronomical Journal
Volume	170
Issue number	2
DOIs	https://doi.org/10.3847/1538-3881/add7d7
State	Published - Aug 4 2025

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

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10.3847/1538-3881/add7d7

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Hesse, K., Mireles, I., Bouchy, F., Dragomir, D., Ulmer-Moll, S., Eisner, N. L., Stassun, K. G., Quinn, S. N., Osborn, H. P., Sousa, S. G., Watkins, C. N., Collins, K. A., Bryant, E. M., Irwin, J. M., Hellier, C., Johnson, M. C., Ziegler, C., Howell, S. B., Anderson, D. R., ... Zuidema, E. E. (2025). HD 35843: A Sun-like Star Hosting a Long-period Sub-Neptune and Inner Super-Earth. Astronomical Journal, 170(2), Article 108. https://doi.org/10.3847/1538-3881/add7d7

@article{a3f6fa5b897841e7a0ec5b5ac9c2086a,

title = "HD 35843: A Sun-like Star Hosting a Long-period Sub-Neptune and Inner Super-Earth",

abstract = "We report the discovery and confirmation of two planets orbiting the metal-poor Sun-like star HD 35843 (TOI 4189). HD 35843 c is a temperate sub-Neptune transiting planet with an orbital period of 46.96 days that was first identified by Planet Hunters TESS. We combine data from TESS and follow-up observations to rule out false-positive scenarios and validate the planet. We then use ESPRESSO radial velocities (RVs) to confirm the planetary nature and characterize the planet{\textquoteright}s mass and orbit. Further analysis of these RVs reveals the presence of an additional planet, HD 35843 b, with a period of 9.90 days and a minimum mass of 5.84 ± 0.84 M⊕. For HD 35843 c, a joint photometric and spectroscopic analysis yields a radius of 2.54 ± 0.08 R⊕, a mass of 11.32 ± 1.60 M⊕, and an orbital eccentricity of e = 0.15 ± 0.07. With a bulk density of 3.80 ± 0.70 g cm−3, the planet might be rocky with a substantial H2 atmosphere or it might be a “water world.” With an equilibrium temperature of ∼480 K, HD 35843 c is among the coolest ∼5\% of planets discovered by TESS. Combined with the host star{\textquoteright}s relative brightness (V = 9.4), HD 35843 c is a promising target for atmospheric characterization that will probe this sparse population of temperate sub-Neptunes.",

author = "Katharine Hesse and Ismael Mireles and Fran{\c c}ois Bouchy and Diana Dragomir and Sol{\`e}ne Ulmer-Moll and Eisner, \{Nora L.\} and Stassun, \{Keivan G.\} and Quinn, \{Samuel N.\} and Osborn, \{Hugh P.\} and Sousa, \{Sergio G.\} and Watkins, \{Cristilyn N.\} and Collins, \{Karen A.\} and Bryant, \{Edward M.\} and Irwin, \{Jonathan M.\} and Coel Hellier and Johnson, \{Marshall C.\} and Carl Ziegler and Howell, \{Steve B.\} and Anderson, \{David R.\} and Daniel Bayliss and Allyson Bieryla and C{\'e}sar Brice{\~n}o and Butler, \{R. Paul\} and David Charbonneau and Ryan Cloutier and Jeffrey Crane and Jason Dittmann and Eastman, \{Jason D.\} and Freigeiro, \{Sebasti{\'a}n A.\} and Fulton, \{Benjamin J.\} and Samuel Gill and Maximilian G{\"u}nther and Haedam Im and Jenkins, \{Jon M.\} and Michelle Kunimoto and Baptiste Lavie and Monika Lendl and Lund, \{Michael B.\} and Mann, \{Andrew W.\} and Belinda Nicholson and David Osip and Martin Paegert and Santos, \{Nuno C.\} and Schwarz, \{Richard P.\} and Sara Seager and Stephen Shectman and Johanna Teske and Twicken, \{Joseph D.\} and St{\'e}phane Udry and \{Van Eylen\}, Vincent and Jos{\'e} Vin{\'e}s and Wang, \{Sharon X.\} and Wheatley, \{Peter J.\} and Winn, \{Joshua N.\} and Zuidema, \{Edward E.\}",

note = "Publisher Copyright: {\textcopyright} 2025. The Author(s). Published by the American Astronomical Society.",

year = "2025",

month = aug,

day = "4",

doi = "10.3847/1538-3881/add7d7",

language = "English (US)",

volume = "170",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "American Astronomical Society",

number = "2",

}

Hesse, K, Mireles, I, Bouchy, F, Dragomir, D, Ulmer-Moll, S, Eisner, NL, Stassun, KG, Quinn, SN, Osborn, HP, Sousa, SG, Watkins, CN, Collins, KA, Bryant, EM, Irwin, JM, Hellier, C, Johnson, MC, Ziegler, C, Howell, SB, Anderson, DR, Bayliss, D, Bieryla, A, Briceño, C, Butler, RP, Charbonneau, D, Cloutier, R, Crane, J, Dittmann, J, Eastman, JD, Freigeiro, SA, Fulton, BJ, Gill, S, Günther, M, Im, H, Jenkins, JM, Kunimoto, M, Lavie, B, Lendl, M, Lund, MB, Mann, AW, Nicholson, B, Osip, D, Paegert, M, Santos, NC, Schwarz, RP, Seager, S, Shectman, S, Teske, J, Twicken, JD, Udry, S, Van Eylen, V, Vinés, J, Wang, SX, Wheatley, PJ, Winn, JN & Zuidema, EE 2025, 'HD 35843: A Sun-like Star Hosting a Long-period Sub-Neptune and Inner Super-Earth', Astronomical Journal, vol. 170, no. 2, 108. https://doi.org/10.3847/1538-3881/add7d7

TY - JOUR

T1 - HD 35843

T2 - A Sun-like Star Hosting a Long-period Sub-Neptune and Inner Super-Earth

AU - Hesse, Katharine

AU - Mireles, Ismael

AU - Bouchy, François

AU - Dragomir, Diana

AU - Ulmer-Moll, Solène

AU - Eisner, Nora L.

AU - Stassun, Keivan G.

AU - Quinn, Samuel N.

AU - Osborn, Hugh P.

AU - Sousa, Sergio G.

AU - Watkins, Cristilyn N.

AU - Collins, Karen A.

AU - Bryant, Edward M.

AU - Irwin, Jonathan M.

AU - Hellier, Coel

AU - Johnson, Marshall C.

AU - Ziegler, Carl

AU - Howell, Steve B.

AU - Anderson, David R.

AU - Bayliss, Daniel

AU - Bieryla, Allyson

AU - Briceño, César

AU - Butler, R. Paul

AU - Charbonneau, David

AU - Cloutier, Ryan

AU - Crane, Jeffrey

AU - Dittmann, Jason

AU - Eastman, Jason D.

AU - Freigeiro, Sebastián A.

AU - Fulton, Benjamin J.

AU - Gill, Samuel

AU - Günther, Maximilian

AU - Im, Haedam

AU - Jenkins, Jon M.

AU - Kunimoto, Michelle

AU - Lavie, Baptiste

AU - Lendl, Monika

AU - Lund, Michael B.

AU - Mann, Andrew W.

AU - Nicholson, Belinda

AU - Osip, David

AU - Paegert, Martin

AU - Santos, Nuno C.

AU - Schwarz, Richard P.

AU - Seager, Sara

AU - Shectman, Stephen

AU - Teske, Johanna

AU - Twicken, Joseph D.

AU - Udry, Stéphane

AU - Van Eylen, Vincent

AU - Vinés, José

AU - Wang, Sharon X.

AU - Wheatley, Peter J.

AU - Winn, Joshua N.

AU - Zuidema, Edward E.

PY - 2025/8/4

Y1 - 2025/8/4

N2 - We report the discovery and confirmation of two planets orbiting the metal-poor Sun-like star HD 35843 (TOI 4189). HD 35843 c is a temperate sub-Neptune transiting planet with an orbital period of 46.96 days that was first identified by Planet Hunters TESS. We combine data from TESS and follow-up observations to rule out false-positive scenarios and validate the planet. We then use ESPRESSO radial velocities (RVs) to confirm the planetary nature and characterize the planet’s mass and orbit. Further analysis of these RVs reveals the presence of an additional planet, HD 35843 b, with a period of 9.90 days and a minimum mass of 5.84 ± 0.84 M⊕. For HD 35843 c, a joint photometric and spectroscopic analysis yields a radius of 2.54 ± 0.08 R⊕, a mass of 11.32 ± 1.60 M⊕, and an orbital eccentricity of e = 0.15 ± 0.07. With a bulk density of 3.80 ± 0.70 g cm−3, the planet might be rocky with a substantial H2 atmosphere or it might be a “water world.” With an equilibrium temperature of ∼480 K, HD 35843 c is among the coolest ∼5% of planets discovered by TESS. Combined with the host star’s relative brightness (V = 9.4), HD 35843 c is a promising target for atmospheric characterization that will probe this sparse population of temperate sub-Neptunes.

AB - We report the discovery and confirmation of two planets orbiting the metal-poor Sun-like star HD 35843 (TOI 4189). HD 35843 c is a temperate sub-Neptune transiting planet with an orbital period of 46.96 days that was first identified by Planet Hunters TESS. We combine data from TESS and follow-up observations to rule out false-positive scenarios and validate the planet. We then use ESPRESSO radial velocities (RVs) to confirm the planetary nature and characterize the planet’s mass and orbit. Further analysis of these RVs reveals the presence of an additional planet, HD 35843 b, with a period of 9.90 days and a minimum mass of 5.84 ± 0.84 M⊕. For HD 35843 c, a joint photometric and spectroscopic analysis yields a radius of 2.54 ± 0.08 R⊕, a mass of 11.32 ± 1.60 M⊕, and an orbital eccentricity of e = 0.15 ± 0.07. With a bulk density of 3.80 ± 0.70 g cm−3, the planet might be rocky with a substantial H2 atmosphere or it might be a “water world.” With an equilibrium temperature of ∼480 K, HD 35843 c is among the coolest ∼5% of planets discovered by TESS. Combined with the host star’s relative brightness (V = 9.4), HD 35843 c is a promising target for atmospheric characterization that will probe this sparse population of temperate sub-Neptunes.

UR - https://www.scopus.com/pages/publications/105011679629

UR - https://www.scopus.com/pages/publications/105011679629#tab=citedBy

U2 - 10.3847/1538-3881/add7d7

DO - 10.3847/1538-3881/add7d7

M3 - Article

AN - SCOPUS:105011679629

SN - 0004-6256

VL - 170

JO - Astronomical Journal

JF - Astronomical Journal

IS - 2

M1 - 108

ER -

HD 35843: A Sun-like Star Hosting a Long-period Sub-Neptune and Inner Super-Earth

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