J/A+A/701/A173 HIP 4178 f radial velocity curves (Grouffal+ 2025)
The star HIP 41378 potentially misaligned with its cohort of long-period
planets.
Grouffal S., Santerne A., Bourrier V., Kunovac V., Dressing C.,
Akinsanmi B., Armstrong C., Baliwal S., Balsalobre-Ruza O., Barros S.C.C.,
Bayliss D., Crossfield I.J.M., Demangeon O., Dumusque X., Giacalone S.,
Harada C.K., Isaacson H., Kellermann H., Lillo-Box J., Llama J., Mortier A.,
Palle E., Rajpurohit A.S., Rice M., Santos N.C., Seidel J.V., Sharma R.,
Sousa S.G., Thomas L., Turtelboom E.V., Udry S., Wheatley P.J.
<Astron. Astrophys. 701, A173 (2025)>
=2025A&A...701A.173G 2025A&A...701A.173G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Radial velocities ;
Optical
Keywords: techniques: spectroscopic -
planets and satellites: individual: HIP41378 - stars: rotation
Abstract:
The obliquity between the stellar spin axis and the planetary orbit,
detected via the Rossiter-McLaughlin (RM) effect, is a tracer of the
formation history of planetary systems. While obliquity measurements
have been extensively applied to hot Jupiters and short-period
planets, they remain rare for cold and long-period planets due to
observational challenges, particularly their long transit durations.
We report the detection of the RM effect for the 19-hour-long transit
of HIP 41378 f, a temperate giant planet on a 542-day orbit, observed
through a worldwide spectroscopic campaign. We measure a slight
projected obliquity of 21±8° and a significant 3D spin-orbit
angle of 52±6°, based on the measurement of the stellar rotation
period. HIP 41378 f is part of a 5-transiting planetary system with
planets close to mean motion resonances. The observed misalignment
likely reflects a primordial tilt of the stellar spin axis relative to
the protoplanetary disk, rather than dynamical interactions.
HIP 41378 f is the first non-eccentric long-period (P>100 days) planet
observed with the RM effect, opening new constraints on planetary
formation theories. This observation should motivate the exploration
of planetary obliquities across a longer range of orbital distances
through international collaboration.
Description:
Observations of the Rossiter-McLaughlin effect of HIP 41378 f with
CARMENES, ESPRESSO, EXPRES, HARPS-N, HIRES, MaHPS, HERMES, NEID and
PARAS instruments during the night of 12-13 November 2022.
Objects:
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RA (2000) DE Designation(s)
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08 26 27.84 +10 04 49.3 HIP 41378 = TIC 366443426
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
rv.dat 68 138 CARMEMES, ESPRESSO, EXPRES, MERCATOR, NEID
and PARAS radial velocities of HIP 41378
drv.dat 69 182 HARPSN, HIRES and MaHPS relative radial
velocities of HIP 41378
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See also:
J/A+A/686/L18 : HIP 41378 velocity curve (Sulis+, 2024)
Byte-by-byte Description of file: rv.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Inst Instrument
10- 27 F18.10 d BJD Baricentric Julian date (BJD)
29- 48 F20.14 m/s RV Radial Velocity
50- 68 F19.16 m/s e_RV Radial Velocity error
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Byte-by-byte Description of file: drv.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Inst Instrument
10- 27 F18.10 d BJD Baricentric Julian date (BJD)
29- 49 F21.17 m/s dRV Relative radial Velocity
51- 69 F19.16 m/s e_dRV Relative radial Velocity error
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Acknowledgements:
Salome Grouffal, salome.grouffal(at)lam.fr
(End) Patricia Vannier [CDS] 31-Jul-2025