HARPS-N, TESS, and CHEOPS∗ discover a transiting sub-Neptune and two outer companions around the bright solar analogue HD 85426
(2026) In Monthly Notices of the Royal Astronomical Society 545(3).- Abstract
- We provide a detailed characterization of the planetary system orbiting HD 85426 (TOI-1774). This bright G-type star (: 0.99;: 1.13; age: 7.4 Gyr; V mag: 8.25) hosts a transiting sub-Neptune, HD 85426 b, with an orbital period of 16.71 d and a blackbody equilibrium temperature of K. By jointly analysing HARPS-N RVs, TESS, and CHEOPS photometric data and using two different stellar activity mitigation techniques, we constrain planet b's mass to and, depending on the mitigation technique. We investigate the dependence of these results on the priors, data selection, and inclusion of other Keplerians in the modelling. Using this approach, we identify the presence of two non-transiting planetary companions with minimum masses near 10 and... (More)
- We provide a detailed characterization of the planetary system orbiting HD 85426 (TOI-1774). This bright G-type star (: 0.99;: 1.13; age: 7.4 Gyr; V mag: 8.25) hosts a transiting sub-Neptune, HD 85426 b, with an orbital period of 16.71 d and a blackbody equilibrium temperature of K. By jointly analysing HARPS-N RVs, TESS, and CHEOPS photometric data and using two different stellar activity mitigation techniques, we constrain planet b's mass to and, depending on the mitigation technique. We investigate the dependence of these results on the priors, data selection, and inclusion of other Keplerians in the modelling. Using this approach, we identify the presence of two non-transiting planetary companions with minimum masses near 10 and orbital periods of 35.7 and 89 d. Additionally, we reject the initial hypothesis that the 35.7-d periodic signal was due to stellar activity. We also determine HD 85426 b's radius to be and compute a transmission spectroscopy metric in the range of 82 to 115, making this planet a highly valuable target for atmospheric characterization. © 2025 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. (Less)
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- author
- Lienhard, F. ; Davies, M.B. LU and Zingales, T.
- author collaboration
- organization
- publishing date
- 2026
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- planets and satellites: composition, planets and satellites: fundamental parameters, stars: individual (HD 85426), techniques: photometric, techniques: radial velocities, techniques: spectroscopic, Astrophysics, Gravitation, Planets, Satellites, Stars, Neptune, Orbital periods, Planets and satellites: compositions, Planets and satellites: fundamental parameters, Star: individual (HD 85426), Stars: individual: proxima Centauri, Stellars, Techniques: photometric, Techniques: radial velocities, Techniques: spectroscopic, Orbits
- in
- Monthly Notices of the Royal Astronomical Society
- volume
- 545
- issue
- 3
- article number
- staf1934
- publisher
- Oxford University Press
- external identifiers
-
- scopus:105026662182
- ISSN
- 0035-8711
- DOI
- 10.1093/mnras/staf1934
- language
- English
- LU publication?
- yes
- id
- af81a67f-a6cc-4819-889a-c021298b89f4
- date added to LUP
- 2026-04-01 08:37:11
- date last changed
- 2026-04-01 08:37:49
@article{af81a67f-a6cc-4819-889a-c021298b89f4,
abstract = {{We provide a detailed characterization of the planetary system orbiting HD 85426 (TOI-1774). This bright G-type star (: 0.99;: 1.13; age: 7.4 Gyr; V mag: 8.25) hosts a transiting sub-Neptune, HD 85426 b, with an orbital period of 16.71 d and a blackbody equilibrium temperature of K. By jointly analysing HARPS-N RVs, TESS, and CHEOPS photometric data and using two different stellar activity mitigation techniques, we constrain planet b's mass to and, depending on the mitigation technique. We investigate the dependence of these results on the priors, data selection, and inclusion of other Keplerians in the modelling. Using this approach, we identify the presence of two non-transiting planetary companions with minimum masses near 10 and orbital periods of 35.7 and 89 d. Additionally, we reject the initial hypothesis that the 35.7-d periodic signal was due to stellar activity. We also determine HD 85426 b's radius to be and compute a transmission spectroscopy metric in the range of 82 to 115, making this planet a highly valuable target for atmospheric characterization. © 2025 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.}},
author = {{Lienhard, F. and Davies, M.B. and Zingales, T.}},
issn = {{0035-8711}},
keywords = {{planets and satellites: composition; planets and satellites: fundamental parameters; stars: individual (HD 85426); techniques: photometric; techniques: radial velocities; techniques: spectroscopic; Astrophysics; Gravitation; Planets; Satellites; Stars; Neptune; Orbital periods; Planets and satellites: compositions; Planets and satellites: fundamental parameters; Star: individual (HD 85426); Stars: individual: proxima Centauri; Stellars; Techniques: photometric; Techniques: radial velocities; Techniques: spectroscopic; Orbits}},
language = {{eng}},
number = {{3}},
publisher = {{Oxford University Press}},
series = {{Monthly Notices of the Royal Astronomical Society}},
title = {{HARPS-N, TESS, and CHEOPS∗ discover a transiting sub-Neptune and two outer companions around the bright solar analogue HD 85426}},
url = {{http://dx.doi.org/10.1093/mnras/staf1934}},
doi = {{10.1093/mnras/staf1934}},
volume = {{545}},
year = {{2026}},
}