Tranquility Science Duty Logs

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230119.0330
Reporting Officer: Lt Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions

Nitrogen = 77.1 percent
Oxygen = 21.8 percent
Argon = 0.88 percent
Neon, Helium, Krypton = 0.0008 percent
Carbon dioxide = 0.22 percent
Water vapor = 0 - 4 percent

Daystar condition = Thermal radiation within acceptable margins. Two sunspot-groupings detected with growing flares. Moderately elevated interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with 0.04 magnitude.

Today's project : Space environment and magnetospheric Poynting fluxes of the exoplanet τ Boötis b.

Context: The first tentative detection of a magnetic field on the Hot Jupiter type exoplanet τ Boötis b was recently reported by Turner et al. (2421). The magnetic field was inferred from observations of circularly-polarized radio emission obtained with the LOFAR telescopes. The radio emission is possibly a consequence of the interaction of the surrounding stellar wind with the planet's magnetic field. Methods: We perform magnetohydrodynamic simulations of the space environment around τ Boötis b and its interaction with the stellar wind using the PLUTO code. We study the magnetospheric energy fluxes and effects of different magnetic field orientations in order to understand the physical processes which cause energy fluxes leading to the observed radio emission given the proposed magnetic field strength in Turner et al. (2421). Furthermore we study the effect of stellar wind density and pressure on magnetospheric energy fluxes given the uncertainty of extrasolar stellar wind predictions. Results: We find in our simulations that the interaction is most likely super--Alfvénic and energy fluxes generated by the stellar wind--planet interaction are consistent with the observed radio powers. Magnetospheric Poynting fluxes are of the order of 1-8 ×1018 W for open, semi-open and closed magnetospheres. The Poynting fluxes are energetically consistent with the radio powers in Turner et al. (2421) for a magnetospheric Poynting flux-to-radio efficiency >10−3 when the magnetic fields of the planet and star are aligned. In case of lower efficiency factors the magnetospheric emission scenario is according to the parameter space modeled in this study not powerful enough. In case of a magnetic polarity reversal of the host star towards an anti-aligned field configuration, expected radio powers in the magnetospheric emission scenario fall below the observable threshold.

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Lt Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230124.0110
Reporting Officer: Lt Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions

Nitrogen = 77.4 percent
Oxygen = 21.2 percent
Argon = 0.88 percent
Neon, Helium, Krypton = 0.0008 percent
Carbon dioxide = 0.26 percent
Water vapor = 0 - 4 percent

Daystar condition = Thermal radiation within acceptable margins. Two sunspot-groupings detected with growing flares. Moderately elevated interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with 0.02 magnitude.

Today's project : A Mixed Stirring Mechanism for Debris Discs with Giant and Dwarf Planetary Perturbations

Debris discs consist of belts of bodies ranging in size from dust grains to planetesimals; these belts are visible markers of planetary systems around other stars that can reveal the influence of extrasolar planets through their shape and structure. Two key stirring mechanisms -- self-stirring by planetesimals and secular perturbation by an external giant planet -- have been identified to explain the dynamics of planetesimal belts; their relative importance has been studied independently, but are yet to be considered in combination. In this work we perform a suite of 286 N-body simulations exploring the evolution of debris discs over 1~Gyr, combining the gravitational perturbations of both dwarf planets embedded in the discs, and an interior giant planet. Our systems were somewhat modeled after the architecture of the outer Solar system: a Solar mass star, a single massive giant planet at 30~au (MGP= 10 to 316~M⊕), and a debris disc formed by 100 massive dwarf planets and 1000 massless particles (MDD= 3.16 to 31.6~M⊕). We present the evolution of both the disc and the giant planet after 1~Gyr. The time evolution of the average eccentricity and inclination of the disc is strongly dependent on the giant planet mass as well as on the remaining disc mass. We also found that efficient stirring is achieved even with small disc masses. In general, we find that a mixed mechanism is more efficient in the stirring of cold debris discs than either mechanism acting in isolation.

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Lt Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230125.0010
Reporting Officer: Lt Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions

Nitrogen = 77.2 percent
Oxygen = 21.2 percent
Argon = 0.88 percent
Neon, Helium, Krypton = 0.0008 percent
Carbon dioxide = 0.28 percent
Water vapor = 0 - 4 percent

Daystar condition = Thermal radiation within acceptable margins. Two sunspot-groupings detected with growing flares. Moderately elevated interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with 0.07 magnitude.

Today's project : KMT-2022-BLG-0440Lb: A New q<10−4 Microlensing Planet with the Central-Resonant Caustic Degeneracy Broken

We present the observations and analysis of a high-magnification microlensing planetary event, KMT-2422-BLG-0440, for which the weak and short-lived planetary signal was covered by both the KMTNet survey and follow-up observations. The binary-lens models with a central caustic provide the best fits, with a planet/host mass ratio, q=0.75--1.00×10−4 at 1σ. The binary-lens models with a resonant caustic and a brown-dwarf mass ratio are both excluded by Δχ2>70. The binary-source model can fit the anomaly well but is rejected by the ``color argument'' on the second source. From Bayesian analyses, it is estimated that the host star is likely a K or M dwarf located in the Galactic disk, the planet probably has a Neptune-mass, and the projected planet-host separation is 1.9+0.6−0.7 or 4.6+1.4−1.7 au, subject to the close/wide degeneracy. This is the third q<10−4 planet from a high-magnification planetary signal (A≳65). Together with another such planet, KMT-2421-BLG-0171Lb, the ongoing follow-up program for the KMTNet high-magnification events has demonstrated its ability in detecting high-magnification planetary signals for q<10−4 planets, which are challenging for the current microlensing surveys.

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Lt Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 23012.0030
Reporting Officer: Lt Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions

Nitrogen = 77.3 percent
Oxygen = 21.1 percent
Argon = 0.88 percent
Neon, Helium, Krypton = 0.0008 percent
Carbon dioxide = 0.24 percent
Water vapor = 0 - 4 percent

Daystar condition = Thermal radiation within acceptable margins. Three sunspot-groupings detected with growing flares. Moderately elevated interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with 0.4 magnitude (that is more than average).

Today's project : A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b

Close-in giant exoplanets with temperatures greater than 2,000 K (''ultra-hot Jupiters'') have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble and Spitzer Space Telescopes. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS instrument on JWST. The data span 0.85 to 2.85 μm in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at >6σ confidence) and evidence for optical opacity, possibly due to H−, TiO, and VO (combined significance of 3.8σ). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy element abundance (''metallicity'', M/H = 1.03+1.11−0.51 × solar), and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the sub-stellar point that decreases steeply and symmetrically with longitude toward the terminators.

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Lt Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230127.0230
Reporting Officer: Lt Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions

Nitrogen = 77.2 percent
Oxygen = 21.2 percent
Argon = 0.87 percent
Neon, Helium, Krypton = 0.0008 percent
Carbon dioxide = 0.22 percent
Water vapor = 0 - 4 percent

Daystar condition = Thermal radiation within acceptable margins. Three sunspot-groupings detected with growing flares. Moderately elevated interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with 0.02 magnitude
Today's project : Biosignature Line Ratios of [P II] in Exoplanetary and Nebular Environments

Being the backbone element of DNA, phosphorus is a key component in the search for life in the Universe. To aid in its detection, we present line emissivity ratios for the five lowest-lying forbidden [P~II] transitions, namely those among the levels 3s23p2(3P0,3P1,3P2,1D2,1S0). The wavelengths range between 0.44-70 \mum, and several lie within the spectroscopic domain observable with the UFS Telescope (UFST). These line ratios have been calculated using a new collisional-radiative-recombination (CRR) model combining calculated collision strengths and level-specific recombination rate coefficients; with both datasets computed using the accurate Breit-Pauli R-Matrix method. The CRR model includes a new scheme for \eion recombination to emission line formation. We compare its effect to models incorporating only electron impact excitation and spontaneous radiative decay. We find that electron-ion recombination has a significant impact on all line ratios, and represents a major improvement in physical accuracy of emission line models.

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Lt Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230129.0310
Reporting Officer: LtCmdr Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions

Nitrogen = 77.1 percent
Oxygen = 21.3 percent
Argon = 0.88 percent
Neon, Helium, Krypton = 0.0008 percent
Carbon dioxide = 0.24 percent
Water vapor = 0 - 4 percent

Daystar condition = Thermal radiation within acceptable margins. Two sunspot-groupings detected with growing flares. Minor interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with 0.07 magnitude

Today's project : Study of the non-thermal atmospheric loss for exoplanet π Men c.

We have studied the input of the exothermic photochemistry into the formation of the non-thermal escape flux in the transition H 2 − H region of the extended upper atmosphere of the hot exoplanet - the sub-neptune π Men c. The formation rate and the energy spectrum of hydrogen atoms formed with an excess of kinetic energy due to the exothermic photochemistry forced by the stellar XUV radiation were calculated using a numerical kinetic Monte Carlo model of a hot planetary corona. The escape flux was estimated to be equal to 2.5×1012 cm−2s−1 for the mean level of stellar activity in the XUV radiation flux. This results in the mean estimate of the atmospheric loss rate due to the exothermic photochemistry equal to 6.7×108 g s−1. The calculated estimate is close to the observational estimates of the possible atmospheric loss rate for the exoplanet π Men c in the range less than 1.0×109 gs−1.

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LtCmdr Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230130.0035
Reporting Officer: LtCmdr Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions

Nitrogen = 77.2 percent
Oxygen = 21.3 percent
Argon = 0.88 percent
Neon, Helium, Krypton = 0.0008 percent
Carbon dioxide = 0.23 percent
Water vapor = 0 - 4 percent

Daystar condition = Thermal radiation within acceptable margins. Two sunspot-groupings detected with growing flares. Minor interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with 0.01 magnitude

Today's project : Examining the orbital decay targets KELT-9 b, KELT-16 b, and WASP-4b, and the transit-timing variations of HD 97658 b

Context. Tidal orbital decay is suspected to occur for hot Jupiters in particular, with the only observationally confirmed case of this being WASP-12b. By examining this effect, information on the properties of the host star can be obtained using the so-called stellar modified tidal quality factor Q*′, which describes the efficiency with which the kinetic energy of the planet is dissipated within the star. This can provide information about the interior of the star.

Aims. In this study, we aim to improve constraints on the tidal decay of the KELT-9, KELT-16, and WASP-4 systems in order to find evidence for or against the presence of tidal orbital decay. With this, we want to constrain the Q*′ value for each star. In addition, we aim to test the existence of the transit timing variations (TTVs) in the HD 97658 system, which previously favoured a quadratic trend with increasing orbital period.

Methods. Making use of newly acquired photometric observations from CHEOPS (CHaracterising ExOplanet Satellite) and TESS (Transiting Exoplanet Survey Satellite), combined with archival transit and occultation data, we use Markov chain Monte Carlo (MCMC) algorithms to fit three models to the data, namely a constant-period model, an orbital-decay model, and an apsidal-precession model.

Results. We find that the KELT-9 system is best described by an apsidal-precession model for now, with an orbital decay trend at over 2 σ being a possible solution as well. A Keplerian orbit model with a constant orbital period provides the best fit to the transit timings of KELT-16 b because of the scatter and scale of their error bars. The WASP-4 system is best represented by an orbital decay model at a 5 σ significance, although apsidal precession cannot be ruled out with the present data. For HD 97658 b, using recently acquired transit observations, we find no conclusive evidence for a previously suspected strong quadratic trend in the data.

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LtCmdr Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230131.0045
Reporting Officer: LtCmdr Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions

Nitrogen = 77.1 percent
Oxygen = 21.5 percent
Argon = 0.88 percent
Neon, Helium, Krypton = 0.0008 percent
Carbon dioxide = 0.21 percent
Water vapor = 0 - 4 percent

Daystar condition = Thermal radiation within acceptable margins. Two sunspot-groupings detected with growing flares. Minor interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with 0.02 magnitude

Today's project : Measuring the variability of directly imaged exoplanets using vector Apodizing Phase Plates combined with ground-based differential spectrophotometry.

Clouds and other features in exoplanet and brown dwarf atmospheres cause variations in brightness as they rotate in and out of view. Ground-based instruments reach the high contrasts and small inner working angles needed to monitor these faint companions, but their small fields-of-view lack simultaneous photometric references to correct for non-astrophysical variations. We present a novel approach for making ground-based light curves of directly imaged companions using high-cadence differential spectrophotometric monitoring, where the simultaneous reference is provided by a double-grating 360° vector Apodizing Phase Plate (dgvAPP360) coronagraph. The dgvAPP360 enables high-contrast companion detections without blocking the host star, allowing it to be used as a simultaneous reference. To further reduce systematic noise, we emulate exoplanet transmission spectroscopy, where the light is spectrally-dispersed and then recombined into white-light flux. We do this by combining the dgvAPP360 with the infrared ALES integral field spectrograph on the Large Binocular Telescope Interferometer. To demonstrate, we observed the red companion HD 1160 B (separation ∼780 mas) for one night, and detect 8.8% semi-amplitude sinusoidal variability with a ∼3.24 h period in its detrended white-light curve. We achieve the greatest precision in ground-based high-contrast imaging light curves of sub-arcsecond companions to date, reaching 3.7% precision per 18-minute bin. Individual wavelength channels spanning 3.59-3.99 µm further show tentative evidence of increasing variability with wavelength. We find no evidence yet of a systematic noise floor, hence additional observations can further improve the precision. This is therefore a promising avenue for future work aiming to map storms or find transiting exomoons around giant exoplanets.

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LtCmdr Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230201.0050
Reporting Officer: LtCmdr Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions

Nitrogen = 77.3 percent
Oxygen = 21.1 percent
Argon = 0.88 percent
Neon, Helium, Krypton = 0.0008 percent
Carbon dioxide = 0.24 percent
Water vapor = 0 - 4 percent

Daystar condition = Thermal radiation within acceptable margins. One sunspot-grouping detected with less active flares. No interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Unchanged for the last 24 Hrs.
Today's project : The Dynamics of Co-orbital Giant Exomoons -- Applications for the Kepler-1625 b and Kepler-1708 b Satellite Systems.

Exomoons are a missing piece of exoplanetary science. Recently, two promising candidates were proposed, Kepler-1625 b-I and Kepler-1708 b-I. While the latter still lacks a dynamical analysis of its stability, Kepler-1625 b-I has already been the subject of several studies regarding its stability and origin. Moreover, previous works have shown that this satellite system could harbour at least two stable massive moons. Motivated by these results, we explored the stability of co-orbital exomoons using the candidates Kepler-1625 b-I and Kepler-1708 b-I as case studies. To do so, we performed numerical simulations of systems composed of the star, planet, and the co-orbital pair formed by the proposed candidates and another massive body. For the additional satellite, we varied its mass and size from a Mars-like to the case where both satellites have the same physical characteristics. We investigated the co-orbital region around the Lagrangian equilibrium point L4 of the system, setting the orbital separation between the satellites from θmin=30∘ to θmax=90∘. Our results show that stability islands are possible in the co-orbital region of Kepler-1708 b-I as a function of the co-orbital companion's mass and angular separation. Also, we identified that resonances of librational frequencies, especially the 2:1 resonance, can constrain the mass of the co-orbital companion. On the other hand, we found that the proximity between the host planet and the star makes the co-orbital region around Kepler-1625 b-I unstable for a massive companion. Finally, we provide TTV profiles for a planet orbited by co-orbital exomoons.

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LtCmdr Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230202.0250
Reporting Officer: LtCmdr Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions

Nitrogen = 77.4 percent
Oxygen = 21.2 percent
Argon = 0.88 percent
Neon, Helium, Krypton = 0.0008 percent
Carbon dioxide = 0.27 percent
Water vapor = 0 - 4 percent

Daystar condition = Thermal radiation within acceptable margins. One sunspot-grouping detected with less active flares. No interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Unchanged for the last 48 Hrs.

Today's project : The First Circumbinary Planet Discovered with Radial Velocities.

We report the detection of a gas-giant planet in orbit around both stars of an eclipsing binary star system that also contains the smaller, inner transiting planet TOI-1338b. The new planet, called TOI-1338/BEBOP-1c, was discovered using radial-velocity data collected with the HARPS and ESPRESSO spectrographs. Our analysis reveals it is a 65.2 sol 1 masses circumbinary planet with a period of 215.5 days. This is the first detection of a circumbinary planet using radial-velocity observations alone, and makes TOI-1338/BEBOP-1 only the second confirmed multiplanet circumbinary system to date. We do not detect the smaller inner transiting planet with radial-velocity data, and can place an upper limit on the inner planet's mass at 21.8 M⊕ with 99% confidence. The inner planet is the first circumbinary planet amenable for atmospheric characterisation, using the UFS Telescope.

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LtCmdr Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230203.0700
Reporting Officer: LtCmdr Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions

Nitrogen = 77.3 percent
Oxygen = 21.2 percent
Argon = 0.88 percent
Neon, Helium, Krypton = 0.0008 percent
Carbon dioxide = 0.26 percent
Water vapor = 0 - 4 percent

Daystar condition = Thermal radiation within acceptable margins. One sunspot-grouping detected with less active flares. No interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with a whopping 0.6 magnitude.

Today's project : A kinematically detected planet candidate in a transition disk.

Context. Transition disks are protoplanetary disks with inner cavities possibly cleared by massive companions. Observing them at high resolution is ideal for mapping their velocity structure and probing companion–disk interactions.

Aims. We present Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 dust and gas observations of the transition disk around RXJ1604.3–2130 A, known to feature nearly symmetric shadows in scattered light, and aim to search for non-Keplerian features.

Methods. We studied the 12CO line channel maps and moment maps of the line-of-sight velocity and peak intensity. We fitted a Keplerian model of the channel-by-channel emission to study line profile differences and produced deprojected radial profiles for all velocity components.

Results. The 12CO emission is detected out to R ∼ 1.8″ (265 au). It shows a cavity inward of 0.39″ (56 au) and within the dust continuum ring (at ∼0.56″, i.e., 81 au). Azimuthal brightness variations in the 12CO line and dust continuum are broadly aligned with the shadows detected in scattered-light observations. We find a strong localized non-Keplerian feature toward the west within the continuum ring (at R = 41 ± 10 au and PA = 280 ± 2°). It accounts for Δvϕ/vkep ∼ 0.4 or Δvz/vkep ∼ 0.04, depending on if the perturbation is in the rotational or vertical direction. A tightly wound spiral is also detected and extends over 300° in azimuth, possibly connected to the localized non-Keplerian feature. Finally, a bending of the iso-velocity contours within the gas cavity indicates a highly perturbed inner region, possibly related to the presence of a misaligned inner disk.

Conclusions. While broadly aligned with the scattered-light shadows, the localized non-Keplerian feature cannot be solely due to changes in temperature. Instead, we interpret the kinematical feature as tracing a massive companion located at the edge of the dust continuum ring. We speculate that the spiral is caused by buoyancy resonances driven by planet–disk interactions. However, this potential planet at ∼41 au cannot explain the gas-depleted cavity, the low accretion rate, and the misaligned inner disk, which suggests the presence of another companion closer in.

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LtCmdr Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230206.0700
Reporting Officer: LtCmdr Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

When entering Ops Red Alert was activated. Everything was checked and a overloaded subcircuit was discovered. The malfunction was immediately repaired by Engineering.

Surface environmental conditions : since we no longer orbit Pinastri it's impossible for us to follow up the atmospheric situation around Pinastri HQ. For all further information and analysis reports please contact the hight qualified Pinastri HQ Science team. Replacement reports and surveys will replace previous observations at a later date .

Daystar condition = Thermal radiation within acceptable margins. One sunspot-grouping detected with less active flares. No interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with 0.13 magnitude.

Today's project : Binary microlensing with plasma environment -- Star and planet

Galactic microlensing has been widely used to study the star and planet. The stellar wind plays an important role in the formation, environment and habitability of the planet. In this work we study a binary microlensing system including the stellar wind, i.e. a star with plasma environment plus a planet. Plasma surrounding the main lens causes chromatic deflection of the light rays, in addition to the gravitational one. As a result, such a lensing system can generate complicated caustics which depends on the different lensing parameters. In this work we study the magnification curves for different traces of the background source and compare the transitions of the formation of ``hill and hole'' in the magnification curves. We find that the plasma will cause extra caustic, shrink the central caustics generated by the star and push the caustic by the planet outwards. Observations and modelling of binary microlensing curves with taking plasma effect into account can provide a potential method to study plasma environment of the stars. In case of a high plasma density of the stellar wind, the plasma lensing effects will be observable in the sub-mm band.

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LtCmdr Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230207.0012
Reporting Officer: LtCmdr Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Surface environmental conditions : since we no longer orbit Pinastri it's impossible for us to follow up the atmospheric situation around Pinastri HQ. For all further information and analysis reports please contact the highly qualified Pinastri HQ Science team. Replacement reports and surveys will replace previous observations at a later date when all configurations are properly calibrated.

Daystar condition = Thermal radiation within acceptable margins. One sunspot-grouping detected with less active flares. No interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with 0.04 magnitude.

Today's project : The TIME Table: Rotation and Ages of Cool Exoplanet Host Stars

Age is a stellar parameter that is both fundamental and difficult to determine. Among middle-aged M dwarfs, the most prolific hosts of close-in and detectable exoplanets, gyrochronology is the most promising method to assign ages, but requires calibration by rotation-temperature sequences (gyrochrones) in clusters of known ages. We curated a catalog of 249 late K- and M-type ((Teff=3200-4200K) exoplanet host stars with established rotation periods, and applied empirical, temperature-dependent rotation-age relations based on relevant published gyrochrones, including one derived from observations of the 4 Gyr-old open cluster M67. We estimated ages for 227 of these stars, and upper limits for 8 others, excluding 14 which have too rapidly rotating or are otherwise outside the valid parameter range of our gyrochronology. We estimated uncertainties based on observed scatter in rotation periods in young clusters, error in the gyrochrones, and uncertainties in temperature and non-solar metallicity. For those stars with measured metallicities, we provide but do not incorporate a correction for the effects of deviation from solar metallicity. The age distribution of our sample declines to near zero at 10 Gyr, the age of the Galactic disk, with the handful of outliers explainable by large uncertainties. Continued addition or extension of cluster rotation sequences to more thoroughly calibrate the gyrochronology in time and temperature space, more precise and robust measurement of rotation periods, and more accurate stellar parameter measurements will enable continued improvements in the age estimates of these important exoplanet host stars.

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LtCmdr Ferre Flamand

[Ferre Flamand]

Tranquility Station/Ops + Tranquility Science Lab - Stardate 230208.0015
Reporting Officer: LtCmdr Ferre Flamand
Other Officers on Duty: 6 NPC's

Duty Log - Daily Scientific and Observation Report

Daystar condition = Thermal radiation within acceptable margins. One sunspot-grouping detected with less active flares. No interference can be expected. Warming-up sequence at normal rate within range.

Betelgeuse (Alpha Orionis) its variable magnitude intervals within range. Brightened with 0.12 magnitude.

Today's project : The tidal excitation of r modes in a solar type star orbited by a giant planet companion and the effect on orbital evolution I: The aligned case.

It has been suggested that tidal interaction is important for shaping the orbital configurations of close orbiting giant planets. The excitation of propagating waves and normal modes (dynamical tide) will be important for estimating time scales for orbital evolution. We consider the tidal interaction of a Jupiter mass planet orbiting a solar type primary. Tidal and rotational frequencies are assumed comparable making the effect of rotation important. Although centrifugal distortion is neglected, Coriolis forces are fully taken into account. We focus in detail on the potentially resonant excitation of r modes associated with spherical harmonics of degrees three and five. These are mostly sited in the radiative core but with a significant response in the convective envelope where dissipation occurs. Away from resonance significant orbital evolution over the system lifetime is unlikely. However, tidal interaction is enhanced near resonances and the orbital evolution accelerated as they are passed through. This speed up may be sustained if near resonance can be maintained. For close orbits with primaries rotating sufficiently rapidly, this could arise from angular momentum loss and stellar spin down through a stellar wind bringing about significant orbital evolution over the system lifetime.

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LtCmdr Ferre Flamand