JuanCastillo29/space-mission-intelligence-data huggingface dataset:
3.1. Spectroscopic stellar parameters We characterized the host stars of the two planet candidates by combining spectroscopic stellar parameters with the available broadband photometry. We used the Python code SpecMatch-Emp (Yee et al. 2017) to extract Teff, log g, and [Fe/H] from the MaHPS spectra. The MaHPS templates of the stars that were used for the RV extraction are compared orderwise to a library of 404 spectra in the wavelength range between 500 nm and 640 nm. The five best-fitting library spectra are then combined through linear interpolation to derive the final stellar parameters. We found Teff = 5917 ± 110 K, log g = 4.23 ± 0.12 and [Fe/H] = −0.28±0.09 for TOI-2147 and Teff = 5635±110 K, and log g = 4.01 ± 0.12 and [Fe/H] = 0.02 ± 0.09 for TOI-6019. These values are compatible with the stellar parameters that were derived using the stellar parameter classification tool (SPC; Buchhave et al. 2012; Buchhave et al. 2014) on the TRES reconnaissance spectra. The spectroscopic parameters are used as priors in the following analysis of the stellar properties.
3.2. Bulk stellar parameters To derive the bulk stellar parameters, we performed a combination of spectral energy distribution (SED) and isochrone fitting. The SED fitting is done with the Python package ARIADNE (Vines & Jenkins 2022), which uses Bayesian model averaging to combine the results of fitting different stellar atmosphere models. We fit stellar atmosphere models from PHOENIX V2 (Husser et al. 2013), BT-Settl (Hauschildt et al. 1999; Allard et al. 2012), Kurucz (Kurucz 1993), and Castelli & Kurucz (Castelli & Kurucz 2003) to broadband photometric data from the filters TYCHO B, V, Johnson B, V, Gaia DR3 G, RP, and BP, 2MASS JHK, and ALL-WISE W1 and W2. We used Gaussian priors on Teff, log g, and log [Fe/H] from our spectroscopic analysis. For the distance, D, we used a normally distributed prior around the Bailer-Jones distance estimate from Gaia EDR3 (Bailer-Jones et al. 2021). The stellar radius, R∗and extinction, Av are given uniform priors ranging from 0.05 to 20 R⊙and 0 to the maximum line-of-sight extinction calculated from the updated SFD galactic dust map (Schlegel et al. 1998; Schlafly & Finkbeiner 2011) through the dustmaps Python package (Green 2018). To derive the mass and age of the two stars, we fit the results of the SED analysis to interpolated MESA Isochrones and Stellar Tracks (MIST, Dotter 2016; Choi et al. 2016), using the isoclassify package (Huber et al. 2017). The final stellar parameters are summarized in Table 1. For the projected rotational velocity, we adopted the values from the TRES specuniform priors.
legel et al. 1998; Schlafly & Finkbeiner 2011) through the dustmaps Python package (Green 2018). To derive the mass and age of the two stars, we fit the results of the SED analysis to interpolated MESA Isochrones and Stellar Tracks (MIST, Dotter 2016; Choi et al. 2016), using the isoclassify package (Huber et al. 2017). The final stellar parameters are summarized in Table 1. For the projected rotational velocity, we adopted the values from the TRES specuniform priors.

[Table: Table 1. Stellar parameters of TOI 2147 and TOI 6019.
Parameters TOI 2147 TOI 6019 Ref.
Identifiers TIC ID TIC 341630071 TIC 125520907 3 2MASS ID J10223416+8305013 J23402193+3556271 2 GAIA DR3 ID 1146601241188708608 2879320137933766912 1
Astrometric properties α (J2000) 10:22:33.98 23:40:21.92 1 δ (J2000) 83:05:01.41 35:56:27.02 1 Parallax (mas) 3.5201 ± 0.014 3.7829 ± 0.015 1 RUWE 0.98 0.90 1
Photometric properties TESS (mag) 10.705 ± 0.007 10.065 ± 0.006 3 B (mag) 11.76 ± 0.15 11.64 ± 0.16 3 V (mag) 11.10 ± 0.01 10.791 ± 0.012 3 GaiaBP (mag) 9.928 ± 0.003 10.402 ± 0.003 1 Gaia (mag) 9.612 ± 0.003 10.142 ± 0.003 1 GaiaRP (mag) 9.132 ± 0.004 9.715 ± 0.004 1 J (mag) 10.131 ± 0.022 9.391 ± 0.021 2 H (mag) 9.880 ± 0.029 9.043 ± 0.021 2 KS (mag) 9.835 ± 0.022 8.94 ± 0.016 2 W1 (mag) 9.764 ± 0.023 8.884 ± 0.023 4 W2 (mag) 9.789 ± 0.02 8.945 ± 0.02 4 W3 (mag) 9.729 ± 0.035 8.875 ± 0.031 4 W4 (mag) 9.11 8.116 4
Derived properties Teff [K] 5983 ± 50 5561 ± 70 5 log g [cgs] 4.2 ± 0.1 4.00 ± 0.1 5 [Fe/H] [dex]
−0.29+0.07
−0.08
0.04+0.07
−0.08
5 R∗[R⊙] 1.39+0.03
−0.02
2.02 ± 0.03 5 M∗[M⊙] 0.99 ± 0.04 1.13 ± 0.04 5 v sin i [km/s] 4.4 ± 0.5 3.5 ± 0.5 5 Prot/ sin i [d] 16 ± 2 29 ± 4 5 Age [Gyr] 8.0 ± 1.0 6.4 ± 0.6 5 Distance [pc]
283.4+1.6
−1.4
265.2+1.9
−1.5
5]
To derive the final properties of the two planet candidates, we
modeled all available photometry together with the RV data from
MaHPS using juliet. Again, we fit a circular and an eccentric
model to compare their Bayesian evidence. A full list of the fitted
parameters and their priors for TOI-2147 and TOI-6019 is given
in Tables 2 and 3.
For TOI-2147, the eccentric model is preferred with a ∆ ln(z)
of 5 in the combined RV and transit fits. As shown in Figure 2,
the solution for e and ω in our joint fit matches one of the ex-
plored areas in the posterior distribution of e and ω in the transit-
only fits. Additionally, our results for the eccentricity satisfy the
criterion from Lucy & Sweeney (1971) for the eccentricity to be
significant. Therefore, we adopted the values from the eccentric
model for the final parameters of TOI-2147 b.
In the case of TOI-6019, we find very strong evidence for
eccentricity in the combined data with a ∆ ln(z) of 35. While the
combination of ω and e from the combined fit of TOI-6019 is
at the edge of the transit-only posteriors, the values agree within
their uncertainties (see Figure 2). Given the large difference in
the Bayesian evidence, we again adopt our results from the ec-
centric fit. The RV time-series and phase-folded data with the
Keplerian model for both planets are shown in Figure 3. All the
light curves are shown in Appendix A.

References: 1) Gaia DR3 (Gaia Collaboration 2020); 2) 2MASS (Cutri et al. 2003); 3) TICv8 (Paegert et al. 2022); 4) WISE (Wright et al. 2010); 5) This work.
2147 b and TOI-6019 b. TOI-2147 b is a planet with a radius of
it orbits every 14.5 days. The radius of TOI-6019 b is among
the largest of the warm (P > 10 days) planet population. Both
although their densities are not as low as some of the very puffy
HJs (e.g., WASP-107 b; Anderson et al. 2017). The densities of
the known giant planet population are shown in Figure 4. While
our two planets are too far away from their host stars and too ma-
ture to have significant thermal inflation, they could be subject
to tidal heating and inflation given their moderate eccentricities.

v sin i.
We first analyzed the photometric data from TESS to identify the
transit signals and looked for signs of stellar activity. We also ex-
plored whether the photometric data warrant the use of nonzero
eccentricity in the modeling via the photo-eccentric effect (Daw-
son & Johnson 2012). Our analysis of the TESS data using
generalized-Lomb-Scargle periodograms (GLS, Zechmeister &
Kürster 2009) shows no significant signs of the stellar rotation
periods, indicating the quiet nature of the two stars. For the
transit fitting, we used the Python package juliet (Espinoza
et al. 2019), which employs a nested sampling algorithm via
dynesty (Speagle 2020), enabling a comparison of different mod-
els through their Bayesian evidence ratios ∆ ln(z).
Both planets were modeled with a circular orbit and a model
where the eccentricity and the argument of periastron (ω) were
ping 2013) calculated via the ExoCTK package (Bourque et al.
2021) from our stellar modeling in Section 3. The rest of the pa-
excited WJs, potentially offering insights into their formation
and subsequent evolution. Overall, WJs exhibit a wider range
of orbital eccentricities than their hot Jupiter counterparts (Daw-
son & Johnson 2018; Morgan et al. 2026), where the majority
are found on low eccentricity orbits. Figure 5 shows all known
Article number, page 5 of 14 measured eccentricities (σe < 0.2).

[Table: Table 2. Priors and final parameter values (median and 1σ confidence intervals) from the juliet fit to the RVs and photometry of TOI-2147.
Parameter name Prior Derived values
Fitting parameters
P [d] U[26.0, 26.4] 26.20518 ± 0.00003 T0 (BJDTDB −2457000) U[2389.45, 2389.6]
2389.5349+0.0006
−0.0007
Rp/R∗ U[0.001, 1]
0.0694+0.0009
−0.0008
b U[0, 1]
0.33+0.14
−0.17
e U[0, 0.99] 0.29 ± 0.07 ω [◦] U[0, 360] 121 ± 30 K [m s−1] U[0, 200] 26 ± 5 ρ∗[kg/m3] N[520, 40.] 520 ± 40
Instrumental parameters
q1,TES S
N[0.28, 0.1]
0.27+0.08
−0.07 q2,TES S
N[0.26, 0.1] 0.24 ± 0.09 µMaHPS (m s−1) U[−100, 100] 5 ± 4 σMaHPS (m s−1) L[0.001, 100]
25.7+3.0
−2.9
a/R∗ 26.6+0.6
−0.7
a [au] 0.172 ± 0.006 T14 [hours] 5.85 ± 0.12 i [◦] 89.3 ± 0.4 Rp [R⊕] 10.5 ± 0.3 Mp [M⊕] 116 ± 22 ρp [kg/m3] 550 ± 110 Teq [K] 820 ± 20
Notes: U indicates a uniform prior, while N and L indicate normal and log-normal priors, respectively.
of nearby companions. Giant planets in single-planet systems are colored in blue in Figure 5, while multiplanet giants are plotted with red markers. The giant planets that only have one, massive outer companion (Mp > 0.3 MJ and Porb > 1000 d for the companion) are indicated by the red crosses. The majority of the HJs are found in single-planet systems and the ones that are in multiplanet systems tend to have a long-period giant companion. This is consistent with the high-eccentricity formation channel, where the outer giant scatters the hot Jupiter, clearing any close companion planets during the migration. Again, WJs tend to show more diverse system architectures, with many of the low to medium eccentricity planets (e < 0.6) residing in multiplanet systems, indicating a more dynamically quiet evolution. To further investigate possible formation channels of our two planets, we searched for signals of additional planets in the spectroscopic and photometric data. A periodogram analysis of the RV datasets of TOI-2147 b and TOI-6019 b finds no significant periodicities apart from the known planets. To quantify the significance of the absence of such signals, we performed an injection recovery test to check the sensitivity of our RV data. Using the RVSearch python package (Rosenthal et al. 2021) to inject 3000 synthetic planets drawn from a log-uniform period (1-1000 days) and RV amplitude (1-500 m/s) distribution into our RV data. We then used the ∆BIC periodogram search implemented in RVSearch to see if we could recover these planets. The resulting completeness maps are shown in Appendix B. Based on these completeness maps, we can only rule out the existence of giant planet companions
Article number, page 6 of 14]
and TTV) data, we cannot rule out the existence of smaller companions, which would imply a more quiescent migration.

[Figure: Fig. 4. Density as a function of period for giant planets (Mp > 0.3 MJ) with mass and radius measured to a precision of 33% or better, taken from the NASA Exoplanet Archive (Christiansen et al. 2025). TOI-6019 b and TOI-2147 b are highlighted in black. The vertical dotted line indicates the separation between the hot and warm Jupiter populations.]

Article number, page 7 of 14

[Table: Table 3. Priors and final parameter values (median and 1σ confidence intervals) from the juliet fit to the RVs and photometry of TOI-6019.
Parameter name Prior Derived values
Fitting parameters
P [d] U[14.4, 14.6]
14.547952+0.000036
−0.000035
T0 (BJDTDB −2457000) U[2862.1, 2862.5] 2862.3434 ± 0.0015 Rp/R∗ U[0.001, 1] 0.0560 ± 0.0011 b U[0, 1]
0.72+0.05
−0.07
e U[0, 0.99] 0.48 ± 0.04 ω [◦] U[0, 360]
171+9 −8
K [m s−1] U[0, 200] 41 ± 4 ρ∗[kg/m3] N[190, 10.] 191 ± 10
Instrumental parameters
q1,TESS
N[0.34, 0.1]
0.32+0.09
−0.08 q2,TESS
N[0.32, 0.1] 0.3 ± 0.1 µMaHPS (m s−1) U[−100, 100]
8.6+2.8
−2.6
σMaHPS (m s−1) L[0.001, 100]
17.6+2.4
−2.2
a/R∗ 12.9 ± 0.3 a [au] 0.1212 ± 0.0033 T14 [hours] 5.5 ± 0.1 i [◦] 86.80 ± 0.32 Rp [R⊕] 12.3 ± 0.3 Mp [M⊕] 149 ± 15 ρp [kg/m3] 440 ± 60 Teq [K] 1095 ± 30
Notes: U indicates a uniform prior while N and L indicate normal and log-normal priors respectively.]
on Q′ p for our two planets, we took the range Q′ p = 103 −106 to estimate the minimum and maximum expected temperature from tidal heating. For TOI-2147 b this results in a tidal temperature of Ttide = 40 −230 K and for TOI-6019 b, we estimated Ttide = 140 −800 K. With this, we run another set of interior retrievals where we put a prior on the internal temperature from the tidal heating. The total internal temperature is calculated as Tint = (T 4 tide + T 4 age)1/4 with Tage

[Figure: Fig. 5. Population of giant planets (Mp > 0.3 MJ) with true mass measurements and measured eccentricities (σe/e < 0.33) taken from NASA Exoplanet Archive (Christiansen et al. 2025). Planets where the eccentricity was set as 0 without an associated uncertainty are also included. The gray region shows constant angular momentum tracks of planets expected to end up as HJs (adopted from Dawson & Johnson 2018). Planets without known companions are colored in blue markers, while giant planets in multiplanet systems are plotted with red markers. Giant planets with exactly one detected outer giant companion (Mp > 0.3 MJ and Porb > 1000 d for the companion) are indicated by the red cross. TOI-2147 b and TOI-6019 b are highlighted in black.]

taken from the previous internal structure retrievals (∼60 K for TOI2147 b and ∼70 K for TOI-6019 b). This results in a prior on the internal temperature of TOI-2147 b between 65 K and 230 K and between 145 K and 800 K for TOI-6019 b. The results of this retrieval are summarized in Table 4. Comparing the results of this interior retrieval with the previous run highlights the importance of including tidal heating even for longer-period
Article number, page 8 of 14 using Gemini-N/IGRINS2 (Lee et al.

[Table: Table 4. Results of the interior retrievals for TOI-2147 b and TOI-6019 b.]
2022; Oh et al. 2024),
which simultaneously covers the H and K bands at a spectral
resolving power of R ∼ 45, 000. Based on the stellar parameters
in Table 1, we adopted exposure times of 300 s with a readout
time of 39.5 s, yielding a signal-to-noise ratio (S/N) of ≈ 150 per
nodding position, as predicted using the integration time calcu-
(Prinoth 2024; Prinoth et al. 2024), which wraps tayph (Hoeij-
makers et al. 2024), petitRADTRANS (Mollière et al. 2019), and
FastChem Cond (Kitzmann et al. 2023) into an end-to-end sim-
ulator to generate time-series observations of exoplanets for a
variety of instruments. We assumed the planetary atmospheres
to be in chemical and hydrostatic equilibrium, with an isother-
mal temperature-pressure profile at the equilibrium temperatures
listed in Table 3 and metallicity of the host stars listed in Table 1.
The pressure at the bottom of the atmosphere was set to 10 bar.
continuum-opacities through collisionally-induced absorption of
free. We modeled the stellar spectra with a PHOENIX spec-
trum (Husser et al. 2013) adopting the stellar parameters in Ta-
ble 1, including telluric contamination using telfit (Gullikson
et al. 2014), and assuming a precipitable water vapor of 2.0 mm,
which is slightly worse than average for Mauna Kea (Otárola
et al. 2015). For an extensive description of the simulator and
radial velocities of the components, see Prinoth et al. (2024).

−0.04
−0.03
−0.01
−0.01
The James Webb Space Telescope (JWST) observed the ultrahot Jupiter WASP-121 b starting 145 minutes before the beginning of the planet’s eclipse behind the star on October 14, 2022 (UTC), and finishing the observation 105 minutes after the end of the eclipse on October 15, 2022 (UTC). This observation was carried out as the telescope’s observing program GO 1729 (PIs: Evans-Soma, Kataria) using the Near Infrared Spectrograph (NIRSpec) with the G395H grating and naturally included the transit of the planet in front of the star between these two eclipses. The observations were conducted using NIRSpec’s SUB2048 subarray and NRSRAPID readout pattern with 42 groups per integration and were reduced using the Fast Infrared Exoplanet Fitting Lightcurve (Firefly [38–40]) and Eureka! [41] pipelines. The details of the two data reductions performed with the two different pipelines are listed in ref. [21, 22].
ing, both planets are inferred to have large envelope mass frac-
into account the additional heat from tidal effects, the inferred
velope mass fraction, which is in line with the measured masses
of the two planets being closer to Saturn’s than Jupiter’s. Mea-
surements of the atmospheric composition, particularly the bulk
atmospheric metallicity, would allow us to improve the accuracy
of the interior modeling and give a more detailed picture of the
nature of these two planets.
ulated transits with POSEIDON (MacDonald & Madhusudhan
2017; MacDonald 2023; Wang et al. 2025), applying three, five,
and ten principal components using its SYSREM implementa-
tion. As POSEIDON assumes circular orbits by default, we mod-
ified the code to handle eccentric orbits using radvel (Fulton
et al. 2018) and PyAstronomy’s modelsuite (Czesla et al. 2019)
to compute expected radial velocities.
important constraints on their formation pathways, as it traces
the relative contributions of solid and gas accretion at differ-
ent locations in the protoplanetary disc (e.g. Öberg et al. 2011;
Madhusudhan et al. 2011). The relatively low bulk densities of
for atmospheric follow-up to probe their chemical composition.
However, their transmission spectroscopy metrics are 44 and 40,
respectively, which makes them not ideal targets for follow-up
using transmission spectroscopy where the threshold for favor-
able targets is assumed to be 90 (Kempton et al. 2018). However,
this threshold does depend on the telescope aperture and instru-
ment capabilities. Future facilities such as the ELT are expected
to be able to probe targets with substantially lower TSM values
(Palle et al. 2025).
For the ground-based follow-up, the feasibility for character-
ization strongly depends on the sky position and orbital config-
uration. Both planets are on eccentric orbits with favorable tran-
sit geometry (ω < 180 deg) for the transmission spectroscopy
(Prinoth et al. 2024). However, the TOI-2147 system is circum-
polar with a declination of +83:05:01.41 (see Table 1) and con-
sequently never reaches sufficiently low airmass (≤ 2.8) for ex-
tended periods from major Northern Hemisphere observatories
equipped with ≥ 8m mirrors. This limits its accessibility for
high-precision ground-based time-series observations.
In contrast, TOI-6019 b is well suited for atmospheric
follow-up from the ground and is overall the more favourable
system given its shorter orbital period and brighter host star.
With an equilibrium temperature of ≈ 1100 K, its atmosphere
is expected to be H/He-dominated with prominent molecular ab-
for near-infrared spectroscopy.
ination remains the dominant limitation. Even when combining
five transits (ten simulated observations), the atmospheric signal
remains far below the 3σ-level (Figure 6). However, when artifi-
cally increasing the resolving power to R ∼ 100, 000, we predict
that this would give us the ability to detect the atmosphere at
≳ 4σ with only two transits (via four simulated observations).
This demonstrates the need for higher resolving powers when
probing these kinds of planetary atmospheres. It also shows that
detectability is not necessarily limited by the sensitivity and, in-
stead, it could be affected by the spectral resolution and how
successfully telluric contamination can be removed.
We present the detection and characterization of two new eccentric WJs, TOI-2147 b and TOI-6019 b, using TESS photometry and high-resolution spectroscopy from MaHPS.
1. We confirm the planetary nature of TOI-2147 b and TOI-6019 b via a joint modeling of the TESS light curves and MaHPS radial velocities. TOI-2147 b has a radius of 10.5 ± 0.3 R⊕and a mass of 116 ± 22 M⊕, orbiting its host star every 26.2 days. TOI-6019 b has a radius of 12.3 ± 0.3 R⊕and a mass of 149 ± 15 M⊕, orbiting a mildly evolved sub-giant host star with a period of 14.5 days. Both planets have bulk densities slightly below that of Jupiter, placing them among the population of mildly inflated WJs. 2. Both planets have significantly nonzero eccentricities, e = 0.29±0.07 for TOI-2147 b and e = 0.48+0.05 −0.04 for TOI-6019 b,
as evidenced by strong Bayesian evidence in favour of eccentric solutions in the combined photometric and RV fits. TOI-6019 b is a proto-hot Jupiter whose orbit is expected to circularize to a final semi-major axis of 0.093 ± 0.007 au. 3. No additional planetary companions have been detected in the RV periodograms or from transit timing variations. The elevated eccentricities combined with the absence of nearby companions are consistent with a high-eccentricity migration origin for both planets, although the limited sensitivity of our RV data cannot rule out smaller companions that would be consistent with a more quiescent migration scenario. 4. Interior structure modeling using GASTLI shows that the observed masses and radii of both planets are inconsistent with high atmospheric metallicity, when only considering internal heat based on the ages of the systems. However, when tidal heating is taken into account, the inferred envelope mass fractions are reduced significantly and even higher atmospheric metallicities produce results that are consistent with the observed masses and radii.
Neuenheimer Feld 226, Heidelberg, D-69120, Germany.
l’Observatoire, CS 34229, Nice, 06304, France.
Baltimore, MD, USA.
Baltimore, MD, USA.
Lucia, QLD 4072, Australia.
d’Azur, Nice, 06903, France.
Geoffroy Saint-Hilaire, Pessac, 33615, France.
Close-in exoplanets are tidally locked to their host star and thus exhibit extreme atmospheric temperature gradients. It has been theorized that the fraction of star light absorbed by such planets during transit changes as a function of orbital phase as progressively hotter or colder atmospheric gas rotates into view, but this effect has not been observed so far. Here, we show that two transits of the ultrahot Jupiter WASP-121 b, acquired with JWST/NIRSpec and NIRISS, exhibit asymmetric transit light curves caused by the planet’s rotation during transit.

We observe increasing CO absorption and slightly decreasing H2O absorption in the transmission spectrum, as the planet rotates. These results are indicative of a stronger longitudinal temperature gradient across the evening than across the morning terminator, consistent with higher temperatures in the eastern half than in the western half of the dayside. The observed changes of the transmission spectrum with orbital phase are in line with the temperature increase causing thermal dissociation of H2O, while CO remains abundant. The observation of longitudinal gradients of atmospheric temperature and chemistry from the planet’s rotational transit provides a new probe for constraining atmospheric heterogeneity using JWST beyond differences between morning and evening terminators from limb asymmetries.
Keywords: Exoplanet atmospheric composition, Transmission spectroscopy, Infrared spectroscopy