KELT-9 as an Eclipsing Double-lined Spectroscopic Binary: A Unique and Self-consistent Solution to the System

Transiting hot Jupiters present a unique opportunity to measure absolute planetary masses due to the magnitude of their radial velocity signals and known orbital inclination. Measuring planet mass is critical to understanding atmospheric dynamics and escape under extreme stellar irradiation. Here we present the ultrahot Jupiter system KELT-9 as a double-lined spectroscopic binary. This allows us to directly and empirically constrain the mass of the star and its planetary companion without reference to any theoretical stellar evolutionary models or empirical stellar scaling relations. Using data from the PEPSI, HARPS-N, and TRES spectrographs across multiple epochs, we apply least-squares deconvolution to measure out-of-transit stellar radial velocities. With the PEPSI and HARPS-N data sets, we measure in-transit planet radial velocities using transmission spectroscopy. By fitting the circular orbital solution that captures these Keplerian motions, we recover a planetary dynamical mass of 2.17 ± 0.56 M J and stellar dynamical mass of 2.11 ± 0.78 M ⊙, both of which agree with the discovery paper. Furthermore, we argue that this system, as well as systems like it, are highly overconstrained, providing multiple independent avenues for empirically cross-validating model-independent solutions to the system parameters. We also discuss the implications of this revised mass for studies of atmospheric escape.

Modeling the High-resolution Emission Spectra of Clear and Cloudy Nontransiting Hot Jupiters

The advent of high-resolution spectroscopy (R ≳ 25,000) as a method for characterization of exoplanet atmospheres has expanded our capability to study nontransiting planets, vastly increasing the number of planets accessible for observation. Many of the most favorable targets for atmospheric characterization are hot Jupiters, where we expect large spatial variation in physical conditions such as temperature, wind speed, and cloud coverage, making viewing geometry important. Three-dimensional models have generally simulated observational properties of hot Jupiters assuming edge-on viewing, which can be compared to observations of transiting planets, but neglected the large fraction of planets without nearly edge-on orbits. As the first investigation of how orbital inclination manifests in high-resolution emission spectra from three-dimensional models, we use a general circulation model to simulate the atmospheric structure of Upsilon Andromedae b, a typical nontransiting hot Jupiter with high observational interest, due the brightness of its host star. We compare models with and without clouds, and find that cloud coverage intensifies spatial variations by making colder regions dimmer and relatedly enhancing emission from the clear, hotter regions. This increases both the net Doppler shifts and the variation of the continuum flux amplitude over the course of the planet’s orbit. In order to accurately capture scattering from clouds, we implement a generalized two-stream radiative transfer routine for inhomogeneous multiple scattering atmospheres. As orbital inclination decreases, four key features of the high-resolution emission spectra also decrease in both the clear and cloudy models: (1) the average continuum flux level, (2) the amplitude of the variation in continuum with orbital phase, (3) net Doppler shifts of spectral lines, and (4) Doppler broadening in the spectra. Models capable of treating inhomogeneous cloud coverage and different viewing geometries are critical in understanding results from high-resolution emission spectra, enabling an additional avenue to investigate these extreme atmospheres.

THE CHALLENGES OF MODELLING THE ACTIVITIES OCCURRING ON ECLIPSING BINARIES V1130 CYG AND V461 LYR

We present the findings for the magnetic activities seen on V1130 Cyg and V461 Lyr. In the case of V1130 Cyg, the secondary component's temperature was found to be 3891±50 K, while the mass ratio was computed as 0.689±0.001, and the orbital inclination as 90°.00±0°.01. The temperature of V461 Lyr's secondary component was found to be 4206±50 K, and the mass ratio was calculated as 0.999±0.001 with 89°.58±0°.01 of orbital inclination. The analyses exhibit the effects of the stellar spots on the light curves. The models indicate that there are two types of flares in the case of V1130 Cyg, and three types of flares for V461 Lyr. The Plateau parameters have been found as 2.1997 s for Group 1 and 1.0068 s for Group 2 in the case of V1130 Lyr. They have been computed as 1.9015 s for Group 1, 2.7943 s for Group 2, and 3.4324 s for Group 3 of V461 Lyr.

The intermediate polar cataclysmic variable GK Persei 120 years after the nova explosion: a first dynamical mass study

We present a dynamical study of the intermediate polar and dwarf nova cataclysmic variable GK Per (Nova Persei 1901) based on a multi-site optical spectroscopy and R-band photometry campaign. The radial velocity curve of the evolved donor star has a semi-amplitude K2 = 126.4 ± 0.9 km s−1 and an orbital period P = 1.996872 ± 0.000009 d. We refine the projected rotational velocity of the donor star to vrotsin i = 52 ± 2 km s−1 which, together with K2, provides a donor star to white dwarf mass ratio q = M2/M1 = 0.38 ± 0.03. We also determine the orbital inclination of the system by modelling the phase-folded ellipsoidal light curve and obtain i = 67○ ± 5○. The resulting dynamical masses are $M_{1}=1.03^{+0.16}_{-0.11} \, \mathrm{M}_{\odot }$ and $M_2 = 0.39^{+0.07}_{-0.06} \, \mathrm{M}_{\odot }$ at 68 per cent confidence level. The white dwarf dynamical mass is compared with estimates obtained by modelling the decline light curve of the 1901 nova event and X-ray spectroscopy. The best matching mass estimates come from the nova light curve models and an X-ray data analysis that uses the ratio between the Alfvén radius in quiescence and during dwarf nova outburst.

Strong scatterings of cold jupiters and their influence on inner low-mass planet systems: theory and simulations

Recent observations have indicated a strong connection between compact (a ≲ 0.5 au) super-Earth and mini-Neptune systems and their outer (a ≳ a few au) giant planet companions. We study the dynamical evolution of such inner systems subject to the gravitational effect of an unstable system of outer giant planets, focussing on systems whose end configurations feature only a single remaining outer giant. In contrast to similar studies which used on N-body simulations with specific (and limited) parameters or scenarios, we implement a novel hybrid algorithm which combines N-body simulations with secular dynamics with aims of obtaining analytical understanding and scaling relations. We find that the dynamical evolution of the inner planet system depends crucially on Nej, the number of mutual close encounters between the outer planets prior to eventual ejection/merger. When Nej is small, the eventual evolution of the inner planets can be well described by secular dynamics. For larger values of Nej, the inner planets gain orbital inclination and eccentricity in a stochastic fashion analogous to Brownian motion. We develop a theoretical model, and compute scaling laws for the final orbital parameters of the inner system. We show that our model can account for the observed eccentric super-Earths/mini-Neptunes with inclined cold Jupiter companions, such as HAT-P-11, Gliese 777 and π Men.

Properties of the Transfers from LEO to the Retrograde-GEO using Lunar Swing-by in a Three-Body Model

A monitor-satellite on a retrograde geostationary earth orbit (retro-GEO) gives the GEO-assets debris-warnings per 12 hour. The properties of the transfers from a low earth orbit to the retro-GEO using lunar swing-by without middle-way maneuver are exhibited in a three-body model. Based on the Poincaré-section methodology, the proof of the existence of this transfer is proven in the planar circular restricted three-body problem (CR3BP) model. Then, the maximum altitude of the perilune of this transfer is solved using the sequence quadratic programming optimization algorithm. Besides, the orbital inclination changeable capacity of this transfer is calculated in the spatial CR3BP model by the continuation of the orbital design values in the planar CR3BP model. The numerical results show that the maximum altitude of the perilune is 892 km and the maximum orbital inclination changeable capacity is 138 degree relative to the plane of the Moon’s path. Further analysis show that the minimum sum of the two-impulse velocity increments (i.e., departure from LEO and insert into the retro-GEO) is 4.224 km/s, the change of the orbital inclination is 107 degree relative to the plane of the Moon’s path in this case. Due to the maximum angle of the plane of the Moon’s path on the equator is 28.6 degree per Metonic cycle (i.e., 18.6 years), everyday has a month window to match the longitude of the launch-site for trans-lunar injection.

Enhanced algorithms to ensure the success of rendezvous maneuvers using aerodynamic forces

A common practice in the field of differential lift and drag controlled satellite formation flight is to analytically design maneuver trajectories using linearized relative motion models and the constant density assumption. However, the state-of-the-art algorithms inevitably fail if the initial condition of the final control phase exceeds an orbit and spacecraft-dependent range, the so-called feasibility range. This article presents enhanced maneuver algorithms for the third (and final) control phase which ensure the overall maneuver success independent of the initial conditions. Thereby, all maneuvers which have previously been categorized as infeasible due to algorithm limitations are rendered feasible. An individual algorithm is presented for both possible control options of the final phase, namely differential lift or drag. In addition, a methodology to precisely determine the feasibility range without the need of computational expensive Monte Carlo simulations is presented. This allows fast and precise assessments of possible influences of boundary conditions, such as the orbital inclination or the maneuver altitude, on the feasibility range.

Mission Planning for Optical Satellite’s Constant Surveillance to Geostationary Spacecraft

For a mission to constantly watch geostationary (Orbital inclination isn’t 0, GEO) spacecraft by an optical satellite during a whole fly-around cycle, study the relative position relationship between the two and sun during fly-around mission; design the trajectory of the optical satellite, on which, the optical satellite keeps facing to the spacecraft in the direction opposite the Sun. Firstly, for constant surveillance to geosynchronous (Orbital inclination is 0) spacecraft, study from the Keplerian orbit elements, analyze its geometric relationship with the sun and the optical satellite. Then calculate the initial phase interval that meets the requirements of the mission. Compared with Clohessy-Wiltshire equation (CW equation), this method is more concise and the spatial physical meaning is clearer. However, the orbital inclination of GEO spacecraft is usually not 0. Secondly, taking GEO spacecraft with 1° inclination as an example, calculate the initial phase interval of the mission. Thirdly, select an initial phase in the initial phase interval, and design the fly-around trajectory based on CW equation. Lastly, the optical satellite’s position when it receives the mission is initial position, and the position when the fly-around mission starts is final position. The optical satellite’s approach trajectory is summarized as spacecraft's Lambert trajectory optimization. Take the time of two orbital maneuvers as optimization variables, and the fuel consumption as optimization objective. Optimize the plan of orbital maneuvering. The total pulse thrust velocity required for orbital maneuver after optimization in the example is 18.2514m/s, which is highly feasible in engineering. This method can be used for space situational awareness and in-orbit services of GEO spacecraft.

Evaluation the quality of FORMOSAT-7/COSMIC-2 Observation Data and its application for ionospheric monitoring during the extreme space weather

<p>Owing to the advantages of high vertical resolution, global coverage, high precision, and all-weather operation, GNSS occultation has been widely used for ionospheric weather monitoring and meteorological forecast. Aiming to obtain the meteorological, climatic, and ionospheric information, FORMOSAT-7/COSMIC-2, the successor constellation of COSMIC-1, is jointly launched by the United States and Taiwan on June 25, 2019. As a new generation occultation constellation, COSMIC-2 consists of six low-latitude satellites with an orbital inclination of 24 degrees and an altitude of 520km. In contrast, COSMIC1 consists of the high-latitude satellites with an orbital inclination of 72 degrees and an orbital altitude of 720km. These differences in constellation structure, orbital altitude, and inclination inevitably lead to the difference in observation quality.</p><p> </p><p>Firstly, in this contribution, the qualities of satellite-based GNSS observations from COSMIC-2 and COSMIC-1 are both analyzed and compared. The result shows that the satellite-based observation data of COSMIC-2 are improved significantly compared with COSMIC-1. The multipath effect reduced by more than 40%, and the probability of cycle slip decreased by three times. Then the occultation observations of the two constellations are also analyzed. Next, using the observations of COSMIC-2 satellites in 2020, an ionospheric total electron content (TEC) model was established. Finally, the TEC model was adopted for investigating the ionospheric disturbances under extreme space weather in 2020.</p><p> </p><p><strong>Keywords</strong>: COSMIC-2; Ionospheric TEC Model; Extreme Space Weather</p>

Strong inclination pacing of climate in Late Triassic low latitudes revealed by the Earth-Saturn tilt cycle

<p>Gravitational interactions among masses in the solar system are recorded in Earth’s paleoclimate history because variations in the geometry of Earth’s orbit and axial orientation modulate solar insolation. However, astronomical models prior to ca. 60 Ma are unreliable due to the unpredictable nature of orbital chaos in the solar system, and therefore such models must be constrained using geological data. Here, we use natural gamma radioactivity and other environmental proxies from paleo-tropical Late Triassic lake deposits of the Newark Rift Basin of eastern North America, previously shown to be paced by variations in axial precession and orbital eccentricity and stratigraphically constrained by U-Pb dating, to explore hitherto undescribed strong variations in orbital inclination in the 201–206 Ma interval (lacustrine, upper Passaic Formation), where lake level variations are particularly muted. We identify the Earth-Saturn 173 kyr orbital inclination cycle and use it to tune the sequence because it exhibits high theoretical stability and metronomic behavior due to the very large mass of Saturn. We tune separately to long-eccentricity as well, with similar effect. Slight, complimentary offsets in the other inclination and eccentricity periods revealed by the Earth-Saturn (s3-s6) and Venus-Jupiter (g2-g5) tunings are apparent that may be due to chaotic variations of the secular fundamental frequencies in the nodal and perihelion orbital precessions of Earth and Venus, respectively. The surprising strength of the inclination cycles in this specific sequence suggest an additional modulating effect of the Earth System on expression of the components of orbital pacing of climate, as well a mechanism to more fully constrain the secular fundamental frequencies of the solar system beyond the ca. 60 Myr limit of predictability that chaos imposes on astronomical solutions.</p>