ABSTRACT
We report the period, eccentricity, and mass determination for the Transiting Exoplanet Survey Satellite (TESS) single-transit event candidate TOI-222, which displayed a single 3000 ppm ...transit in the TESS 2-min cadence data from Sector 2. We determine the orbital period via radial velocity measurements (P = 33.9 d), which allowed for ground-based photometric detection of two subsequent transits. Our data show that the companion to TOI-222 is a low-mass star, with a radius of $0.18_{-0.10}^{+0.39}$ R⊙ and a mass of 0.23 ± 0.01 M⊙. This discovery showcases the ability to efficiently discover long-period systems from TESS single-transit events using a combination of radial velocity monitoring coupled with high-precision ground-based photometry.
Context.
Planets around stars in the solar neighbourhood will be prime targets for characterisation with upcoming large space- and ground-based facilities. Since large-scale exoplanet searches will ...not be feasible with such telescopes, it is crucial to use currently available data and instruments to find possible target planets before next-generation facilities come online.
Aims.
We aim to detect new extrasolar planets around stars in the solar neighbourhood via blind radial velocity (RV) searching with ESPRESSO. Our target sample consists of nearby stars (
d
< 11 pc) with few (<10) or no previous RV measurements.
Methods.
We used 31 radial velocity measurements obtained with ESPRESSO at the VLT between December 2020 and February 2022 of the nearby M dwarf star (
M
★
= 0.21
M
⊙
,
d
= 10.23 pc) L 363-38 to derive the orbital parameters of the newly discovered planet. In addition, we used TESS photometry and archival VLT/NaCo high-contrast imaging data to put further constraints on the orbit inclination and the possible planetary system architecture around L 363-38.
Results.
We present the detection of a new extrasolar planet orbiting the nearby M dwarf star L 363-38. L 363-38 b is a planet with a minimum mass of
m
p
sin(
i
) = 4.67 ± 0.43
M
⊕
orbiting its star with a period of
P
= 8.781 ± 0.007 days, corresponding to a semi-major axis of
a
= 0.048 ± 0.006 AU, which is smaller than the inner edge of the habitable zone. We further estimate a minimum radius of
r
p
sin(
i
) ≈ 1.55–2.75
R
⊕
and an equilibrium temperature of
T
eq
≈ 330 K.
Conclusions.
With this study, we further demonstrate the potential of the state-of-the-art spectrograph ESPRESSO in detecting and investigating planetary systems around nearby M dwarf stars, which were inaccessible to previous instruments such HARPS.
We report the discovery of NGTS-11 b (=TOI-1847b), a transiting Saturn in a 35.46 day orbit around a mid K-type star ( = 5050 80 K). We initially identified the system from a single-transit event in ...a TESS full-frame image light curve. Following 79 nights of photometric monitoring with an NGTS telescope, we observed a second full transit of NGTS-11 b approximately one year after the TESS single-transit event. The NGTS transit confirmed the parameters of the transit signal and restricted the orbital period to a set of 13 discrete periods. We combined our transit detections with precise radial-velocity measurements to determine the true orbital period and measure the mass of the planet. We find NGTS-11 b has a radius of , a mass of , and an equilibrium temperature of just K, making it one of the coolest known transiting gas giants. NGTS-11 b is the first exoplanet to be discovered after being initially identified as a TESS single-transit event, and its discovery highlights the power of intense photometric monitoring in recovering longer-period transiting exoplanets from single-transit events.
We report the discovery of the planets WASP-20b and WASP-28b along with measurements of their sky-projected orbital obliquities. WASP-20b is an inflated, Saturn-mass planet (0.31 MJup; 1.46 RJup) in ...a 4.9-day, near-aligned (λ = 12.7 ± 4.2°) orbit around CD-24 102 (V = 10.7; F9). Due to the low density of the planet and the apparent brightness of the host star, WASP-20 is a good target for atmospheric characterisation via transmission spectroscopy. WASP-28b is an inflated, Jupiter-mass planet (0.91 MJup; 1.21 RJup) in a 3.4-day, near-aligned (λ = 8 ± 18°) orbit around a V = 12, F8 star. As intermediate-mass planets in short orbits around aged, cool stars (7+ 2-1 Gyr and 6000 ± 100 K for WASP-20; 5+ 3-2 Gyr and 6100 ± 150 K for WASP-28), their orbital alignment is consistent with the hypothesis that close-in giant planets are scattered into eccentric orbits with random alignments, which are then circularised and aligned with their stars’ spins via tidal dissipation.
ABSTRACT
We set out to explore how best to mitigate the number of period aliases for a transiting Transiting Exoplanet Survey Satellite (TESS) system with two identified transits separated by a large ...time period on the order of years. We simulate a realistic population of doubly transiting planets based on the observing strategy of the TESS primary and extended missions. We next simulate additional observations using photometry (NGTS) and spectroscopy (HARPS and CORALIE) and assess its impact on the period aliases of systems with two TESS transits. We find that TESS will detect around 400 exoplanets that exhibit one transit in each of the primary and extended missions. Based on the temporal coverage, each of these systems will have an average of 38 period aliases. We find that, assuming a combination of NGTS and CORALIE over observing campaigns spanning 50 d, we can find the true alias, and thus solve the period, for up to 207 of these systems with even more being solved if the observing campaigns are extended or we upgrade to HARPS over CORALIE.
The EBLM Project von Boetticher, Alexander; Triaud, Amaury H. M. J.; Queloz, Didier ...
Astronomy and astrophysics (Berlin),
05/2019, Letnik:
625
Journal Article, Web Resource
Recenzirano
Odprti dostop
Measurements of the physical properties of stars at the lower end of the main sequence are scarce. In this context we report masses, radii and surface gravities of ten very-low-mass stars in ...eclipsing binary systems, with orbital periods of the order of several days. The objects probe the stellar mass-radius relation in the fully convective regime,
M
⋆
≲ 0.35
M
⊙
, down to the hydrogen burning mass-limit,
M
HB
∼ 0.07
M
⊙
. The stars were detected by the WASP survey for transiting extra-solar planets, as low-mass, eclipsing companions orbiting more massive, F- and G-type host stars. We use eclipse observations of the host stars, performed with the TRAPPIST,
Leonhard Euler
and SPECULOOS telescopes, and radial velocities of the host stars obtained with the CORALIE spectrograph, to determine the physical properties of the low-mass companions. Surface gravities of the low-mass companions are derived from the eclipse and orbital parameters of each system. Spectroscopic measurements of the host star effective temperature and metallicity are used to infer the host star mass and age from stellar evolution models for solar-type stars. Masses and radii of the low-mass companions are then derived from the eclipse and orbital parameters of the binary systems. The objects are compared to stellar evolution models for low-mass stars, to test for an effect of the stellar metallicity and orbital period on the radius of low-mass stars in close binary systems. Measurements are found to be in good agreement with stellar evolution models; a systematic inflation of the radius of low-mass stars with respect to model predictions is limited to 1.6 ± 1.2%, in the fully convective low-mass regime. The sample of ten objects indicates a scaling of the radius of low-mass stars with the host star metallicity. No correlation between stellar radii and the orbital periods of the binary systems is determined. A combined analysis with thirteen comparable objects from the literature is consistent with this result.
The EBLM project von Boetticher, Alexander; Triaud, Amaury H. M. J.; Queloz, Didier ...
Astronomy and astrophysics (Berlin),
8/2017, Letnik:
604
Journal Article, Web Resource
Recenzirano
Odprti dostop
We report the discovery of an eclipsing binary system with mass-ratio q ˜ 0.07. After identifying a periodic photometric signal received by WASP, we obtained CORALIE spectroscopic radial velocities ...and follow-up light curves with the Euler and TRAPPIST telescopes. From a joint fit of these data we determine that EBLM J0555-57 consists of a sun-like primary star that is eclipsed by a low-mass companion, on a weakly eccentric 7.8-day orbit. Using a mass estimate for the primary star derived from stellar models, we determine a companion mass of 85 ± 4 MSUBJup/SUB (0.081 MSUB⊙/SUB) and a radius of 0.84SUP+ 0.14/SUPSUB-0.04/SUBRSUBJup/SUB (0.084 RSUB⊙/SUB) that is comparable to that of Saturn. EBLM J0555-57Ab has a surface gravity log gSUB2/SUB =5.50SUP+ 0.03/SUPSUB-0.13/SUB and is one of the densest non-stellar-remnant objects currently known. These measurements are consistent with models of low-mass stars. The photometry tables and radial velocities are only available at the CDS and on demand via anonymous ftp to http://cdsarc.u-strasbg.fr ( http://130.79.128.5 ) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/604/L6
ABSTRACT
We present the discovery of NGTS-19b, a high-mass transiting brown dwarf discovered by the Next Generation Transit Survey. We investigate the system using follow-up photometry from the South ...African Astronomical Observatory, as well as sector 11 Transiting Exoplanet Survey Satellite data, in combination with radial velocity measurements from the CORALIE spectrograph to precisely characterize the system. We find that NGTS-19b is a brown dwarf companion to a K-star, with a mass of $69.5 ^{+5.7}_{-5.4}$ MJup and radius of $1.034 ^{+0.055}_{-0.053}$RJup. The system has a reasonably long period of 17.84 d, and a high degree of eccentricity of $0.3767 ^{+0.0061}_{-0.0061}$. The mass and radius of the brown dwarf imply an age of $0.46 ^{+0.26}_{-0.15}$ Gyr, however, this is inconsistent with the age determined from the host star spectral energy distribution, suggesting that the brown dwarf may be inflated. This is unusual given that its large mass and relatively low levels of irradiation would make it much harder to inflate. NGTS-19b adds to the small, but growing number of brown dwarfs transiting main-sequence stars, and is a valuable addition as we begin to populate the so-called brown dwarf desert.
Context. The detection and characterization of exoplanets and brown dwarfs 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 brown dwarfs around hot stars is limited.
Aims. We aim to increase the sample and precisely measure the masses and eccentricities of giant planets and brown dwarfs transiting early-type stars detected by the Transiting Exoplanet Survey Satellite (TESS).
Methods. We followed bright (V < 12 mag) stars with Teff > 6200 K that host giant companions (R > 7 R⊕) using ground-based photometric observations as well as high precision radial velocity measurements from the CORALIE, CHIRON, TRES, FEROS, and MINERVA-Australis spectrographs.
Results. In the context of the search for exoplanets and brown dwarfs around early-type stars, we present the discovery of three brown dwarf companions, TOI-629b, TOI-1982b, and TOI-2543b, and one massive planet, TOI-1107b. From the joint analysis of TESS and ground-based photometry in combination with high precision radial velocity measurements, we find the brown dwarfs have masses between 66 and 68 MJup, periods between 7.54 and 17.17 days, and radii between 0.95 and 1.11 RJup. The hot Jupiter TOI-1107b has an orbital period of 4.08 days, a radius of 1.30 RJup, and a mass of 3.35 MJup. As a by-product of this program, we identified four low-mass eclipsing components (TOI-288b, TOI-446b, TOI-478b, and TOI-764b).
Conclusions. 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. The massive planet and the three brown dwarfs add to the growing population of well-characterized giant planets and brown dwarfs transiting AF-type stars and they reduce the apparent paucity.
We present the discovery of a transiting massive giant planet around TOI-4603, a sub-giant F-type star from NASA’s Transiting Exoplanet Survey Satellite (TESS). The newly discovered planet has a ...radius of 1.042
−0.035
+0.038
R
J
and an orbital period of 7.24599
−0.00021
+0.00022
days. Using radial velocity measurements with the PARAS and TRES spectrographs, we determined the planet’s mass to be 12.89
−0.57
+0.58
M
J
, resulting in a bulk density of 14.1
−1.6
+1.7
g cm
−3
. This makes it one of the few known massive giant planets with an extreme density. It lies in the transition mass region of massive giant planets and low-mass brown dwarfs, an important addition to the population of fewer than five known objects in this mass range. The eccentricity of 0.325 ± 0.020 and an orbital separation of 0.0888 ± 0.0010 AU from its host star suggest that the planet is likely undergoing high-eccentricity tidal migration. We find a fraction of heavy elements of 0.13
−0.06
+0.05
and metal enrichment of the planet (
Z
P
/
Z
star
) of 4.2
−2.0
+1.6
. Detection of such systems will enable us to gain valuable insights into the governing mechanisms of massive planets and improve our understanding of their dominant formation and migration mechanisms.
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