J/AJ/169/26 Radial velocities of HD 119130 b (Murphy+, 2025)
HD 119130 b is not an "ultradense" sub-Neptune.
Murphy J.M.A., Luque R., Batalha N.M., Carleo I., Palle E., Brady M.,
Fulton B., Handley L.B., Isaacson H., Lacedelli G., Murgas F., Nowak G.,
Orell-Miquel J., Osborne H.L.M., Van Eylen V., Zapatero Osorio M.R.
<Astron. J., 169, 26 (2025)>
=2025AJ....169...26M 2025AJ....169...26M
ADC_Keywords: Radial velocities; Exoplanets; Spectroscopy; Infrared; Optical
Keywords: Exoplanets ; Radial velocity
Abstract:
We present a revised mass measurement for HD 119130 b (aka K2-292 b),
a transiting planet (P=17days, Rp={2.63}{-0.10}{+0.11}R⊕)
orbiting a chromospherically inactive G dwarf, previously thought to
be one of the densest sub-Neptunes known. Our follow-up Doppler
observations with HARPS, HARPS-N, and HIRES reveal that HD 119130 b
is, in fact, nearly one-third as massive as originally suggested by
its initial confirmation paper. Our revised analysis finds
Mp=8.8±3.2M⊕ (Mp<15.4M⊕ at 98% confidence) compared
to the previously reported Mp=24.5±4.4M⊕. While the
true cause of the original mass measurement's inaccuracy remains
uncertain, we present the plausible explanation that the planet's
radial velocity (RV) semiamplitude was inflated due to constructive
interference with a second, untreated sinusoidal signal in the data
(possibly rotational modulation from the star). HD 119130 b
illustrates the complexities of interpreting the RV orbits of small
transiting planets. While RV mass measurements of such planets may be
precise, they are not necessarily guaranteed to be accurate. This
system serves as a cautionary tale as observers and theorists alike
look to the exoplanet mass-radius diagram for insights into the
physics of small-planet formation.
Description:
Luque+2019 (J/A+A/623/A114), hereafter L19, obtained 18 RVs from
CARMENES (Calar Alto high-Resolution search for M dwarfs with
Exoearths with Near-infrared and optical Echelle Spectrographs)
between UT 2018 June 14 and 2018 July 18. CARMENES is a two-channel
spectrograph covering the wavelength range from 520 to 1710nm which is
mounted on the 3.5m telescope at the Calar Alto Observatory in Spain.
The CARMENES RVs have a median internal uncertainty of 3.1m/s and an
rms of 7.1m/s about the mean value.
The High-accuracy Radial Velocity Planetary Searcher (HARPS) is an
ultraprecise optical echelle spectrograph with sub-meter-per-second
precision installed at the European Southern Observatory (ESO) 3.6m
telescope at La Silla Observatory in Chile. We obtained
31 high-resolution spectra between UT 2023 April 2 and 2023 July 9
under program 0111.C-0138 (PI: E. Palle). The RVs have a median
internal uncertainty of 2.3m/s and an rms of 5.6m/s about the mean
value.
The High-accuracy Radial Velocity Planetary Searcher-North (HARPS-N)
spectrograph is mounted at the 3.6m Telescopio Nazionale Galileo of
Roque de los Muchachos Observatory in La Palma, Spain. We obtained
16 high-resolution spectra between UT 2023 April 13 and 2024 May 13
under the observing programs CAT23A_52 and CAT23B_74 (PI: I. Carleo).
The RVs have a median internal precision of 1.9m/s and an rms of
4.3m/s about the mean value.
The High Resolution Echelle Spectrometer (HIRES) is mounted on the 10m
Keck I Telescope at the W. M. Keck Observatory on Maunakea, Hawai'i.
We obtained 10 high-resolution spectra of HD 119130 between
UT 2023 April 10 and 2023 June 25 under observing program 2023A_U156
(PI: N. Batalha). To measure precise RVs using the iodine method, a
high-resolution, high-signal-to-noise ratio (S/N), iodine-free
"template" spectrum must also be obtained to create a deconvolved
stellar spectral template of the host star. We obtained the
iodine-free template of HD 119130 on UT 2023 June 24. The RVs have a
median internal precision of 1.5m/s and an rms of 2.5m/s about the
mean value.
Objects:
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RA (2000) DE Designation(s) (Period)
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13 41 30.30 -09 56 45.8 HD 119130 b = K2-292b (Period=16.98d)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 35 75 HD 119130 RVs
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See also:
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
I/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)
III/286 : APOGEE-2 DR17 final allStar catalog (Abdurro'uf+, 2022)
VII/233 : 2MASS All-Sky Extended Src Cat. (XSC) (IPAC/UMass, 2003-2006)
J/ApJ/787/80 : 139 Kepler planets transit time variations (Hadden+, 2014)
J/AJ/148/81 : APASS BVgri photometry of RAVE stars. I. Data (Munari+, 2014)
J/ApJS/224/2 : K2 EPIC stellar properties for 138600 targets (Huber+, 2016)
J/AJ/154/107 : California-Kepler Surv. (CKS). I. 1305 stars (Petigura+, 2017)
J/A+A/623/A114 : Light curve of K2-292 (HD 119130) (Luque+, 2019)
J/AJ/159/57 : HST spectr. LCs of Kepler 51b & 51d (Libby-Roberts+, 2020)
J/ApJS/254/39 : Exoplanet candidates from TESS first 2yr obs (Guerrero+, 2021)
J/AJ/161/47 : Radial velocity & phot. of HD106315 & GJ9827 (Kosiarek+, 2021)
J/AJ/162/184 : APOGEE: Properties & RVs of binaries (Kounkel, 2021)
J/other/Sci/377.1211 : RV and LC of 8 M dwarf stars with planets (Luque+, 2022)
J/AJ/166/62 : New HIRES radial velocity data for V1298 Tau (Blunt+, 2023)
J/other/RAA/23.K5026 : APOGEE DR17 standard stars radial velocities (Li, 2023)
J/ApJS/274/35 : California Legacy Survey. V. Activity cycles (Isaacson+, 2024)
J/AJ/167/282 : TESS/HIRES radial velocity follow up of TOI-1824 (Lange+, 2024)
J/A+A/701/A100 : Cluster Members in the APOGEE DR17. I. (Guerco, 2025)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d BJD [2458284/2460445] Barycentric Julian Date (1)
16- 21 F6.2 m/s RVel [-15.55/16.63] Radial velocity (2)
23- 26 F4.2 m/s e_RVel [1.08/7.13] Uncertainty in RVel (2)
28- 35 A8 --- Inst Instrument identifier (3)
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Note (1): BJD is reported using the TDB standard (e.g.,
Eastman+, 2010PASP..122..935E 2010PASP..122..935E).
Note (2): Model-specific instrumental offsets have not been applied to the
RVel values listed here. The RVel errors listed here represent
measurement uncertainty and have not been added in quadrature with
the corresponding instrument jitter values resulting from our
models of the data.
Note (3): Instruments as follows:
CARMENES = Calar Alto high-Resolution search for M dwarfs with Exoearths
with Near-infrared and optical Echelle Spectrographs, mounted on
the 3.5m telescope at the Calar Alto Observatory in Spain
(18 occurrences)
HARPS = High-Accuracy Radial velocity Planetary Searcher at the
3.6m telescope at La Silla Observatory in Chile
(31 occurrences)
HARPS-N = High-Accuracy Radial velocity Planetary Searcher-North at the
3.6m Telescopio Nazionale Galileo of Roque de los Muchachos
observatory in La Palma, Spain (16 occurrences)
HIRES = High Resolution Echelle Spectrometer at the 10m Keck I telescope
at the W. M. Keck Observatory on Maunakea, Hawaii
(10 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 05-Nov-2025