ABSTRACT
In this paper, we present observations of two high-resolution transit data sets obtained with ESPRESSO of the bloated sub-Saturn planet WASP-131 b. We have simultaneous photometric ...observations with NGTS and EulerCam. In addition, we utilized photometric light curves from TESS, WASP, EulerCam, and TRAPPIST of multiple transits to fit for the planetary parameters and update the ephemeris. We spatially resolve the stellar surface of WASP-131 utilizing the Reloaded Rossiter McLaughlin technique to search for centre-to-limb convective variations, stellar differential rotation, and to determine the star–planet obliquity for the first time. We find WASP-131 is misaligned on a nearly retrograde orbit with a projected obliquity of $\lambda = 162.4\substack{+1.3 \\
-1.2}^{\circ }$ . In addition, we determined a stellar differential rotation shear of α = 0.61 ± 0.06 and disentangled the stellar inclination ($i_* = 40.9\substack{+13.3 \\
-8.5}^{\circ }$ ) from the projected rotational velocity, resulting in an equatorial velocity of $v_{\rm {eq}} = 7.7\substack{+1.5 \\
-1.3}$ km s−1. In turn, we determined the true 3D obliquity of $\psi = 123.7\substack{+12.8 \\
-8.0}^{\circ }$ , meaning the planet is on a perpendicular/polar orbit. Therefore, we explored possible mechanisms for the planetary system’s formation and evolution. Finally, we searched for centre-to-limb convective variations where there was a null detection, indicating that centre-to-limb convective variations are not prominent in this star or are hidden within red noise.
Context . Long-period transiting exoplanets bridge the gap between the bulk of transit- and Doppler-based exoplanet discoveries, providing key insights into the formation and evolution of planetary ...systems. The wider separation between these planets and their host stars results in the exoplanets typically experiencing less radiation from their host stars; hence, they should maintain more of their original atmospheres, which can be probed during transit via transmission spectroscopy. Although the known population of long-period transiting exoplanets is relatively sparse, surveys performed by the Transiting Exoplanet Survey Satellite (TESS) and the Next Generation Transit Survey (NGTS) are now discovering new exoplanets to fill in this crucial region of the exoplanetary parameter space. Aims . This study aims to characterise a new long-period transiting exoplanet by following up on a single-transit candidate found in the TESS mission. Methods . The TOI-4862 system was monitored using a combination of photometric instruments (TESS, NGTS, and EulerCam) and spectroscopic instruments (CORALIE, FEROS, HARPS, and PFS) in order to determine the period, radius, and mass of the long-period transiting exoplanet NGTS-30 b/TOI-4862 b. These observations were then fitted simultaneously to determine precise values for the properties and orbital parameters of the exoplanet, as well as the refined stellar parameters of the host star. Results . We present the discovery of a long-period ( P = 98.29838 ± 0.00010 day) Jupiter-sized (0.928 ± 0.032 R J ; 0.960 ± 0.056 M J ) planet transiting a 1.1 Gyr old G-type star, one of the youngest warm Jupiters discovered to date. NGTS-30 b/TOI-4862 b has a moderate eccentricity (0.294 −0.010 +0.014 ), meaning that its equilibrium temperature can be expected to vary from 274 −46 +30 K to 500 −84 +55 K over the course of its orbit. Through interior modelling, NGTS-30 b/TOI-4862b was found to have a heavy element mass fraction of 0.23 −0.06 +0.05 and a heavy element enrichment ( Z p / Z ★ ) of 20 −6 +5 , making it metal-enriched compared to its host star. Conclusions . NGTS-30 b/TOI-4862 b is one of the youngest well-characterised long-period exoplanets found to date and will therefore be important in the quest to understanding the formation and evolution of exoplanets across the full range of orbital separations and ages.
The Transiting Exoplanet Survey Satellite (TESS) mission was designed to perform an all-sky search of planets around bright and nearby stars. Here we report the discovery of two sub-Neptunes orbiting ...around TOI 1062 (TIC 299799658), a V = 10.25 G9V star observed in the TESS Sectors 1, 13, 27, and 28. We use precise radial velocity observations from HARPS to confirm and characterize these two planets. TOI 1062b has a radius of 2.265(-0.091,+0.096) Rꚛ, a mass of 10.15 ± 0.8 Mꚛ, and an orbital period of 4.1130 ± 0.0015 days. The second planet is not transiting, has a minimum mass of 9.78(−1.18,+1.26) Mꚛ and is near the 2:1 mean motion resonance with the innermost planet with an orbital period of 7.972(−0.024,+0.018) days. We performed a dynamical analysis to explore the proximity of the system to this resonance, and to attempt further constraining the orbital parameters. The transiting planet has a mean density of 4.85(−0.74,+0.84) g/cu. cm and an analysis of its internal structure reveals that it is expected to have a small volatile envelope accounting for 0.35% of the mass at most. The star’s brightness and the proximity of the inner planet to what is know as the radius gap make it an interesting candidate for transmission spectroscopy, which could further constrain the composition and internal structure of TOI 1062b.
Ultra-hot Jupiters (UHJ) have emerged as ideal testbeds for new techniques for studying exoplanet atmospheres. Only a limited number of them are currently well studied, however. We search for ...atmospheric constituents for the UHJ with two ESPRESSO transits. Additionally, we show parallel photometry that we used to obtain updated and precise stellar, planetary, and orbital parameters. The two transits we obtained were analysed with narrow-band transmission spectroscopy and with the cross-correlation technique to provide detections at different altitude levels. We focused on searching for and lines in narrow-band data as well as and and attempted to confirm with the cross-correlation technique. We corrected for the Rossiter-McLaughlin effect and regions with a low signal-to-noise ratio due to absorption in the interstellar medium. We then verified our results via bootstrapping. We report the resolved line detections of and $5.4\ sigma$) and tentatively With a cross-correlation, we confirm the detection ($7.8\ and $5.8\ and we additionally report the detections of and $10\ and and $8.4\ on both nights separately. The detection of remains tentative, however, because the results on the two nights differ. The results also differ compared with the properties derived from the narrow-band data. None of our resolved spectral lines probing the middle to upper atmosphere shows significant shifts relative to the planetary rest frame. and exhibit a respective line broadening of $39.6 and $27.6 however indicating the onset of possible escape. differs from similar UHJ by its lack of strong atmospheric dynamics in the upper atmosphere. The broadening seen for and might indicate the presence of winds in the mid-atmosphere, however Future studies of the impact of the flux variability caused by the host star activity might shed more light on the subject Previous work indicated the presence of SiO cloud-precursors in the atmosphere of WASP-178 b and a lack of and However, our results suggest that a scenario in which the planetary atmosphere is dominated by and is more likely. In light of our results, we encourage future observations to further elucidate these atmospheric properties.
Context.
Long-period transiting planets provide the opportunity to better understand the formation and evolution of planetary systems. Their atmospheric properties remain largely unaltered by tidal ...or radiative effects of the host star, and their orbital arrangement reflects a different and less extreme migrational history compared to close-in objects. The sample of long-period exoplanets with well-determined masses and radii is still limited, but a growing number of long-period objects reveal themselves in the Transiting Exoplanet Survey Satellite (TESS) data.
Aims.
Our goal is to vet and confirm single-transit planet candidates detected in the TESS space-based photometric data through spectroscopic and photometric follow-up observations with ground-based instruments.
Methods.
We used high-resolution spectrographs to confirm the planetary nature of the transiting candidates and measure their masses. We also used the Next Generation Transit Survey (NGTS) to photometrically monitor the candidates in order to observe additional transits. Using a joint modeling of the light curves and radial velocities, we computed the orbital parameters of the system and were able to precisely measure the mass and radius of the transiting planets.
Results.
We report the discovery of two massive, warm Jupiter-size planets, one orbiting the F8-type star TOI-5153 and the other orbiting the G1-type star NGTS-20 (=TOI-5152). From our spectroscopic analysis, both stars are metal rich with a metallicity of 0.12 and 0.15, respectively. Only TOI-5153 presents a second transit in the TESS extended mission data, but NGTS observed NGTS-20 as part of its mono-transit follow-up program and detected two additional transits. Follow-up high-resolution spectroscopic observations were carried out with CORALIE, CHIRON, FEROS, and HARPS. TOI-5153 hosts a planet with a period of 20.33 days, a planetary mass of 3.26
−0.17
+0.18
Jupiter masses (
M
J
), a radius of 1.06
−0.04
+0.04
R
J
, and an orbital eccentricity of 0.091
−0.026
+0.024
. NGTS-20 b is a 2.98
−0.15
+0.16
M
J
planet with a radius of 1.07
−0.04
+0.04
R
J
on an eccentric 0.432
−0.023
+0.023
orbit with an orbital period of 54.19 days. Both planets are metal enriched and their heavy element content is in line with the previously reported mass-metallicity relation for gas giants.
Conclusions.
Both warm Jupiters orbit moderately bright host stars, making these objects valuable targets for follow-up studies of the planetary atmosphere and measurement of the spin-orbit angle of the system.
Context.
A large sample of long-period giant planets has been discovered thanks to long-term radial velocity surveys, but only a few dozen of these planets have a precise radius measurement. ...Transiting gas giants are crucial targets for the study of atmospheric composition across a wide range of equilibrium temperatures and, more importantly, for shedding light on the formation and evolution of planetary systems. Indeed, compared to hot Jupiters, the atmospheric properties and orbital parameters of cooler gas giants are unaltered by intense stellar irradiation and tidal effects.
Aims.
We aim to identify long-period planets in the Transiting Exoplanet Survey Satellite (TESS) data as single or duo-transit events. Our goal is to solve the orbital periods of TESS duo-transit candidates with the use of additional space-based photometric observations and to collect follow-up spectroscopic observations in order to confirm the planetary nature and measure the mass of the candidates.
Methods.
We use the CHaracterising ExOPlanet Satellite (CHEOPS) to observe the highest-probability period aliases in order to discard or confirm a transit event at a given period. Once a period is confirmed, we jointly model the TESS and CHEOPS light curves along with the radial velocity datasets to measure the orbital parameters of the system and obtain precise mass and radius measurements.
Results.
We report the discovery of a long-period transiting Neptune-mass planet orbiting the G7-type star TOI-5678. Our spectroscopic analysis shows that TOI-5678 is a star with a solar metallicity. The TESS light curve of TOI-5678 presents two transit events separated by almost two years. In addition, CHEOPS observed the target as part of its Guaranteed Time Observation program. After four non-detections corresponding to possible periods, CHEOPS detected a transit event matching a unique period alias. Follow-up radial velocity observations were carried out with the ground-based high-resolution spectrographs CORALIE and HARPS. Joint modeling reveals that TOI-5678 hosts a 47.73 day period planet, and we measure an orbital eccentricity consistent with zero at 2
σ
. The planet TOI-5678 b has a mass of 20 ± 4 Earth masses (
M
⊕
) and a radius of 4.91 ± 0.08
R
⊕
Using interior structure modeling, we find that TOI-5678 b is composed of a low-mass core surrounded by a large H/He layer with a mass of 3.2
±1.7
−1.3
M
⊕
.
Conclusions.
TOI-5678 b is part of a growing sample of well-characterized transiting gas giants receiving moderate amounts of stellar insolation (11
S
⊕
). Precise density measurement gives us insight into their interior composition, and the objects orbiting bright stars are suitable targets to study the atmospheric composition of cooler gas giants.
An ESPRESSO view of the HD 189733 system Cristo, E; E. Esparza Borges; Santos, N C ...
Astronomy and astrophysics (Berlin),
02/2024, Letnik:
682
Journal Article
Recenzirano
Odprti dostop
Context. The development of state-of-the-art spectrographs has ushered in a new era in the detection and characterization of exoplanetary systems. The astrophysical community now has the ability to ...gain detailed insights into the composition of atmospheres of planets outside our Solar System. In light of these advancements, several new methods have been developed to probe exoplanetary atmospheres using both broadband and narrowband techniques. Aims. Our objective is to utilize the high-resolution and precision capabilities of the ESPRESSO instrument to detect and measure the broadband transmission spectrum of HD 189733b’s atmosphere. Additionally, we aim to employ an improved Rossiter–McLaughlin (RM) model to derive properties related to the velocity fields of the stellar surface and to constrain the orbital architecture. Methods. The RM effect, which strongly depends on a planet’s radius, offers a precise means of measurement. To this end, we divided the observation range of ESPRESSO into wavelength bins, enabling the computation of radial velocities as a function of wavelength. By employing a robust model of the RM effect, we first determined the system’s color-independent properties across the entire spectral range of observations. Subsequently, we measured the planet’s radius from the radial velocities obtained within each wavelength bin, allowing us to extract the exoplanet’s transmission spectrum. Additionally, we employed a retrieval algorithm to fit the transmission spectrum and study the atmospheric properties. Results. Our results demonstrate a high degree of precision in fitting the radial velocities observed during transit using the improved modeling of the RM effect. We tentatively detect the effect of differential rotation, with a confidence level of 93.4% when considering a rotation period within the photometric literature values, and 99.6% for a broader range of rotation periods. For the former, the amplitude of the differential rotation ratio suggests an equatorial rotation period of 11.45 ± 0.09 days and a polar period of 14.9 ± 2. The addition of differential rotation breaks the latitudinal symmetry, enabling us to measure the true spin-orbit angle, ψ ≈ 13.6 ± 6.9°, and the stellar inclination axis angle, i* ≈ 71.87−5.55°+6.91°. Moreover, we determine a sub-solar amplitude of the convective blueshift velocity, VCB ≈ −211−61+69 m s−1, which falls within the expected range for a K-dwarf host star and is compatible with both runs. Finally, we successfully retrieved the transmission spectrum of HD 189733b from the high-resolution ESPRESSO data. We observe a significant decrease in radius with increasing wavelength, consistent with the phenomenon of super-Rayleigh scattering.
An ESPRESSO view of the HD 189733 system Cristo, E.; Esparza Borges, E.; Santos, N. C. ...
Astronomy and astrophysics (Berlin),
02/2024, Letnik:
682
Journal Article
Recenzirano
Odprti dostop
Context
. The development of state-of-the-art spectrographs has ushered in a new era in the detection and characterization of exoplanetary systems. The astrophysical community now has the ability to ...gain detailed insights into the composition of atmospheres of planets outside our Solar System. In light of these advancements, several new methods have been developed to probe exoplanetary atmospheres using both broadband and narrowband techniques.
Aims
. Our objective is to utilize the high-resolution and precision capabilities of the ESPRESSO instrument to detect and measure the broadband transmission spectrum of HD 189733b’s atmosphere. Additionally, we aim to employ an improved Rossiter–McLaughlin (RM) model to derive properties related to the velocity fields of the stellar surface and to constrain the orbital architecture.
Methods
. The RM effect, which strongly depends on a planet’s radius, offers a precise means of measurement. To this end, we divided the observation range of ESPRESSO into wavelength bins, enabling the computation of radial velocities as a function of wavelength. By employing a robust model of the RM effect, we first determined the system’s color-independent properties across the entire spectral range of observations. Subsequently, we measured the planet’s radius from the radial velocities obtained within each wavelength bin, allowing us to extract the exoplanet’s transmission spectrum. Additionally, we employed a retrieval algorithm to fit the transmission spectrum and study the atmospheric properties.
Results
. Our results demonstrate a high degree of precision in fitting the radial velocities observed during transit using the improved modeling of the RM effect. We tentatively detect the effect of differential rotation, with a confidence level of 93.4% when considering a rotation period within the photometric literature values, and 99.6% for a broader range of rotation periods. For the former, the amplitude of the differential rotation ratio suggests an equatorial rotation period of 11.45 ± 0.09 days and a polar period of 14.9 ± 2. The addition of differential rotation breaks the latitudinal symmetry, enabling us to measure the true spin-orbit angle,
ψ
≈ 13.6 ± 6.9°, and the stellar inclination axis angle,
i
*
≈ 71.87
−5.55°
+6.91°
. Moreover, we determine a sub-solar amplitude of the convective blueshift velocity,
V
CB
≈ −211
−61
+69
m s
−1
, which falls within the expected range for a K-dwarf host star and is compatible with both runs. Finally, we successfully retrieved the transmission spectrum of HD 189733b from the high-resolution ESPRESSO data. We observe a significant decrease in radius with increasing wavelength, consistent with the phenomenon of super-Rayleigh scattering.
TOI-5678 b Ulmer-Moll, S.; Olofsson, Göran; Brandeker, Alexis ...
Astronomy and astrophysics (Berlin),
06/2023, Letnik:
674
Journal Article
Recenzirano
Odprti dostop
Context. A large sample of long-period giant planets has been discovered thanks to long-term radial velocity surveys, but only a few dozen of these planets have a precise radius measurement. ...Transiting gas giants are crucial targets for the study of atmospheric composition across a wide range of equilibrium temperatures and, more importantly, for shedding light on the formation and evolution of planetary systems. Indeed, compared to hot Jupiters, the atmospheric properties and orbital parameters of cooler gas giants are unaltered by intense stellar irradiation and tidal effects. Aims. We aim to identify long-period planets in the Transiting Exoplanet Survey Satellite (TESS) data as single or duo-transit events. Our goal is to solve the orbital periods of TESS duo-transit candidates with the use of additional space-based photometric observations and to collect follow-up spectroscopic observations in order to confirm the planetary nature and measure the mass of the candidates. Methods. We use the CHaracterising ExOPlanet Satellite (CHEOPS) to observe the highest-probability period aliases in order to discard or confirm a transit event at a given period. Once a period is confirmed, we jointly model the TESS and CHEOPS light curves along with the radial velocity datasets to measure the orbital parameters of the system and obtain precise mass and radius measurements. Results. We report the discovery of a long-period transiting Neptune-mass planet orbiting the G7-type star TOI-5678. Our spectroscopic analysis shows that TOI-5678 is a star with a solar metallicity. The TESS light curve of TOI-5678 presents two transit events separated by almost two years. In addition, CHEOPS observed the target as part of its Guaranteed Time Observation program. After four non-detections corresponding to possible periods, CHEOPS detected a transit event matching a unique period alias. Follow-up radial velocity observations were carried out with the ground-based high-resolution spectrographs CORALIE and HARPS. Joint modeling reveals that TOI-5678 hosts a 47.73 day period planet, and we measure an orbital eccentricity consistent with zero at 2s. The planet TOI-5678 b has a mass of 20 +/- 4 Earth masses (M-circle plus) and a radius of 4.91 +/- 0.08 R-circle plus Using interior structure modeling, we find that TOI-5678 b is composed of a low-mass core surrounded by a large H/He layer with a mass of 3.2(-1.3)(+1.7) M-circle plus. Conclusions. TOI-5678 b is part of a growing sample of well-characterized transiting gas giants receiving moderate amounts of stellar insolation (11 S circle plus). Precise density measurement gives us insight into their interior composition, and the objects orbiting bright stars are suitable targets to study the atmospheric composition of cooler gas giants.
The detection and characterization of exoplanets and brown dwarfs (BDs) around massive AF-type stars is essential to investigate and constrain the impact of stellar mass on planet properties. ...However, such targets are still poorly explored in radial velocity (RV) surveys because they only feature a small number of stellar lines and those are usually broadened and blended by stellar rotation as well as stellar jitter. As a result, the available information about the formation and evolution of planets and BDs around hot stars is limited. We aim to increase the sample and precisely measure the masses and eccentricities of giant planets and BDs transiting AF-type stars detected by the Transiting Exoplanet Survey Satellite (TESS). We followed bright (V < 12 mag) stars with \(T_{\mathrm{eff}}\) > 6200 K that host giant companions (R > 7 \(\mathrm{R_{\rm \oplus}}\)) using ground-based photometric observations as well as high precision RV measurements from the CORALIE, CHIRON, TRES, FEROS, and MINERVA-Australis spectrographs. In the context, we present the discovery of three BD companions, TOI-629b, TOI-1982b, and TOI-2543b, and one massive planet, TOI-1107b. From the joint analysis we find the BDs have masses between 66 and 68 \(\mathrm{M_{\rm Jup}}\), periods between 7.54 and 17.17 days, and radii between 0.95 and 1.11 \(\mathrm{R_{\rm Jup}}\). The hot Jupiter TOI-1107b has an orbital period of 4.08 days, a radius of 1.30 \(\mathrm{R_{\rm Jup}}\), and a mass of 3.35 \(\mathrm{M_{\rm Jup}}\). As a by-product of this program, we identified four low-mass eclipsing components (TOI-288b, TOI-446b, TOI-478b, and TOI-764b). Both TOI-1107b and TOI-1982b present an anomalously inflated radius with respect to the age of these systems. TOI-629 is among the hottest stars with a known transiting brown dwarf. TOI-629b and TOI-1982b are among the most eccentric brown dwarfs.
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