Update on WASP-19 Korth, Judith; Parviainen, Hannu
Universe (Basel),
01/2024, Letnik:
10, Številka:
1
Journal Article
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Tidal interaction between a star and a close-in massive exoplanet causes the planetary orbit to shrink and eventually leads to tidal disruption. Understanding orbital decay in exoplanetary systems is ...crucial for advancing our knowledge of planetary formation and evolution. Moreover, it sheds light on the broader question of the long-term stability of planetary orbits and the intricate interplay of gravitational forces within stellar systems. Analyzing Transiting Exoplanet Survey Satellite (TESS) data for the ultra-short period gas giant WASP-19, we aim to measure orbital period variations and constrain the stellar tidal quality parameter. For this, we fitted the TESS observations together with two WASP-19 transits observed using the Las Cumbres Observatory Global Telescope (LCOGT) and searched for orbital decay in combination with previously published transit times. As a result, we find a deviation from the constant orbital period at the 7σ level. The orbital period changes at a rate of P˙=−3.7±0.5msyear−1, which translates into a tidal quality factor of Q★′=(7±1)×105. We additionally modeled WASP-19 b’s phase curve using the new TESS photometry and obtained updated values for the planet’s eclipse depth, dayside temperature, and geometric albedo. We estimate an eclipse depth of 520±60 ppm, which is slightly higher than previous estimates and corresponds to a dayside brightness temperature of 2400±60 K and geometric albedo of 0.20±0.04.
We report on the discovery of three transiting planets around GJ 9827. The planets have radii of 1.75 0.18, 1.36 0.14, and R⊕, and periods of 1.20896, 3.6480, and 6.2014 days, respectively. The ...detection was made in Campaign 12 observations as part of our K2 survey of nearby stars. GJ 9827 is a V = 10.39 mag K6V star at a distance of 30.3 1.6 parsecs and the nearest star to be found hosting planets by Kepler and K2. The radial velocity follow-up, high-resolution imaging, and detection of multiple transiting objects near commensurability drastically reduce the false positive probability. The orbital periods of GJ 9827 b, c, and d planets are very close to the 1:3:5 mean motion resonance. Our preliminary analysis shows that GJ 9827 planets are excellent candidates for atmospheric observations. Besides, the planetary radii span both sides of the rocky and gaseous divide, hence the system will be an asset in expanding our understanding of the threshold.
We present the discovery of three small planets transiting K2-136 (LP 358 348, EPIC 247589423), a late K dwarf in the Hyades. The planets have orbital periods of 7.9757 0.0011, , and , and radii of ...1.05 0.16, 3.14 0.36, and , respectively. With an age of 600-800 Myr, these planets are some of the smallest and youngest transiting planets known. Due to the relatively bright (J = 9.1) host star, the planets are compelling targets for future characterization via radial velocity mass measurements and transmission spectroscopy. As the first known star with multiple transiting planets in a cluster, the system should be helpful for testing theories of planet formation and migration.
ABSTRACT We report the discovery of K2-31b, the first confirmed transiting hot Jupiter detected by the K2 space mission. We combined K2 photometry with FastCam lucky imaging and FIES and HARPS ...high-resolution spectroscopy to confirm the planetary nature of the transiting object and derived the system parameters. K2-31b is a 1.8-Jupiter-mass planet on a 1.26-day orbit around a G7 V star ( M , R ). The planetary radius is poorly constrained (0.7 < Rp < 1.4 RJup),15 owing to the grazing transit and the low sampling rate of the K2 photometry.16
TWO HOT JUPITERS FROM K2 CAMPAIGN 4 Johnson, Marshall C.; Gandolfi, Davide; Fridlund, Malcolm ...
The Astronomical journal,
06/2016, Letnik:
151, Številka:
6
Journal Article
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ABSTRACT We confirm the planetary nature of two transiting hot Jupiters discovered by the Kepler spacecraft's K2 extended mission in its Campaign 4, using precise radial velocity measurements from ...FIES@NOT, HARPS-N@TNG, and the coudé spectrograph on the McDonald Observatory 2.7 m telescope. K2-29 b (EPIC 211089792b) transits a K1V star with a period of 3.2589263 0.0000015 days; its orbit is slightly eccentric ( e = 0.084 − 0.023 + 0.032 ). It has a radius of R P = 1.000 − 0.067 + 0.071 RJ and a mass of M P = 0.613 − 0.026 + 0.027 MJ. Its host star exhibits significant rotational variability, and we measure a rotation period of P rot = 10.777 0.031 days. K2-30 b (EPIC 210957318 b) transits a G6V star with a period of 4.098503 0.000011 days. It has a radius of R P = 1.039 − 0.051 + 0.050 RJ and a mass of M P = 0.579 − 0.027 + 0.028 MJ. The star has a low metallicity for a hot Jupiter host, Fe / H = − 0.15 0.05 .
We report the characterization and independent detection of K2-60b, as well as the detection and characterization of K2-107b, two transiting hot gaseous planets from the K2 space mission. We confirm ...the planetary nature of the two systems and determine their fundamental parameters combining the K2 time-series data with FIES@NOT and HARPS-N@TNG spectroscopic observations. K2-60b has a radius of 0.683 0.037 RJup and a mass of 0.426 0.037 MJup and orbits a G4 V star with an orbital period of 3.00267 0.00006 days. K2-107b has a radius of 1.44 0.15 RJup and a mass of 0.84 0.08 MJup and orbits an F9 IV star every 3.31392 0.00002 days. K2-60b is among the few planets at the edge of the so-called "desert" of short-period sub-Jovian planets. K2-107b is a highly inflated Jovian planet orbiting an evolved star about to leave the main sequence.
ABSTRACT We report the discovery of K2-98b (EPIC 211391664b), a transiting Neptune-size planet monitored by the K2 mission during its Campaign 5. We combine the K2 time-series data with ground-based ...photometric and spectroscopic follow-up observations to confirm the planetary nature of the object and derive its mass, radius, and orbital parameters. K2-98b is a warm Neptune-like planet in a 10 day orbit around a V = 12.2 mag F-type star with M = 1.074 0.042 M , R = R , and age of . We derive a planetary mass and radius of Mp = 32.2 8.1 M⊕ and Rp = R⊕. K2-98b joins the relatively small group of Neptune-size planets whose mass and radius have been derived with a precision better than 25%. We estimate that the planet will be engulfed by its host star in ∼3 Gyr, due to the evolution of the latter toward the red giant branch.
TESS’s first planet Gandolfi, D.; Barragán, O.; Livingston, J. H. ...
Astronomy and astrophysics (Berlin),
11/2018, Letnik:
619
Journal Article
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We report on the confirmation and mass determination of
π
Men c, the first transiting planet discovered by NASA’s TESS space mission.
π
Men is a naked-eye (V = 5.65 mag), quiet G0 V star that was ...previously known to host a sub-stellar companion (
π
Men b) on a longperiod (
P
orb
= 2091 days), eccentric (
e
= 0.64) orbit. Using TESS time-series photometry, combined with
Gaia
data, published UCLES at AAT Doppler measurements, and archival HARPS at ESO-3.6m radial velocities, we found that
π
Men c is a close-in planet with an orbital period of
P
orb
= 6.27 days, a mass of
M
c
= 4.52 ± 0.81
M
⊕
, and a radius of
R
c
= 2.06 ± 0.03
R
⊕
. Based on the planet’s orbital period and size,
π
Men c is a super-Earth located at, or close to, the radius gap, while its mass and bulk density suggest it may have held on to a significant atmosphere. Because of the brightness of the host star, this system is highly suitable for a wide range of further studies to characterize the planetary atmosphere and dynamical properties. We also performed an asteroseismic analysis of the TESS data and detected a hint of power excess consistent with the seismic values expected for this star, although this result depends on the photometric aperture used to extract the light curve. This marginal detection is expected from pre-launch simulations hinting at the asteroseismic potential of the TESS mission for longer, multi-sector observations and/or for more evolved bright stars.
Large Interferometer For Exoplanets (LIFE) Quanz, S. P.; Ottiger, M.; Fontanet, E. ...
Astronomy and astrophysics (Berlin),
08/2022, Letnik:
664
Journal Article, Web Resource
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Context.
One of the long-term goals of exoplanet science is the atmospheric characterization of dozens of small exoplanets in order to understand their diversity and search for habitable worlds and ...potential biosignatures. Achieving this goal requires a space mission of sufficient scale that can spatially separate the signals from exoplanets and their host stars and thus directly scrutinize the exoplanets and their atmospheres.
Aims.
We seek to quantify the exoplanet detection performance of a space-based mid-infrared (MIR) nulling interferometer that measures the thermal emission of exoplanets. We study the impact of various parameters and compare the performance with that of large single-aperture mission concepts that detect exoplanets in reflected light.
Methods.
We have developed an instrument simulator that considers all major astrophysical noise sources and coupled it with Monte Carlo simulations of a synthetic exoplanet population around main-sequence stars within 20 pc of the Sun. This allows us to quantify the number (and types) of exoplanets that our mission concept could detect. Considering single visits only, we discuss two different scenarios for distributing 2.5 yr of an initial search phase among the stellar targets. Different apertures sizes and wavelength ranges are investigated.
Results.
An interferometer consisting of four 2 m apertures working in the 4–18.5 μ.m wavelength range with a total instrument throughput of 5% could detect up to ≈550 exoplanets with radii between 0.5 and 6
R
⊕
with an integrated
S
/
N
≥ 7. At least ≈160 of the detected exoplanets have radii ≤1.5
R
⊕
. Depending on the observing scenario, ≈25–45 rocky exoplanets (objects with radii between 0.5 and 1.5
R
⊕
) orbiting within the empirical habitable zone (eHZ) of their host stars are among the detections. With four 3.5 m apertures, the total number of detections can increase to up to ≈770, including ≈60–80 rocky eHZ planets. With four times 1 m apertures, the maximum detection yield is ≈315 exoplanets, including ≤20 rocky eHZ planets. The vast majority of small, temperate exoplanets are detected around M dwarfs. The impact of changing the wavelength range to 3–20 μm or 6–17 μm on the detection yield is negligible.
Conclusions.
A large space-based MIR nulling interferometer will be able to directly detect hundreds of small, nearby exoplanets, tens of which would be habitable world candidates. This shows that such a mission can compete with large single-aperture reflected light missions. Further increasing the number of habitable world candidates, in particular around solar-type stars, appears possible via the implementation of a multi-visit strategy during the search phase. The high median S/N of most of the detected planets will allow for first estimates of their radii and effective temperatures and will help prioritize the targets for a second mission phase to obtain high-S/N thermal emission spectra, leveraging the superior diagnostic power of the MIR regime compared to shorter wavelengths.
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