Constraints on the variation of the gravitational constant G have been obtained by many observers using different methods, the most reliable and stringent being those based on the orbital timing of bodies in the solar system and binary pulsars. We show that the constraints determined from orbital timing are on rather than on when the speed of light c is also considered to be varying. Increasingly tighter

The Trojan asteroids of Mars and Jupiter are long-term stable, those of Earth are expected to be just transient companions. The first Trojan of our planet, 2010 TK7, was discovered in 2010 and its resonant state was found to be transient. Here, we provide a preliminary assessment of the current dynamical status and short-term orbital evolution of 2020 XL5, a recently discovered near-Earth asteroid

The absorbed soft X-ray (<1 keV) emission from Compton thin type-II active galactic nuclei (AGNs) with neutral absorption columns in the range N H = 1021−23 cm−2 may contain emission from star formation or scattered photons from the primary X-ray emission in Compton-thin circumnuclear gas extending out to ∼1 kpc, or leaky-absorbers along the line of sight allowing a part of the primary AGN emission

Recently Jiang et al. reported the discovery of a possible short duration transient, detected in a single image, spatially associated with a z∼11 galaxy. Jiang et al. and Kann et al. suggested the transient originates from a γ-Ray Burst (GRB), while Padmanabhan & Loeb argued the flash is consistent with a supernova shock breakout event of a 300 M ⊙ Population III star. Jiang et al. argued against the

We report resolved optical spectroscopy for the nearby low-mass stellar system BD-08 2582AB. We confirm prior unpublished reports of the existence of the secondary, and the spectral data indicate a secondary type of M6 Ve, consistent with spectrophotometric estimates from Gaia astrometry. The secondary exhibits Hα emission at a level equivalent to other M6 dwarfs, and has a metallicity index in line

Highly accreting quasars show fairly distinctive properties in their optical, UV, and X spectra, and are easy to recognize because of their specific location in the quasar main sequence: they are the strongest optical FeII emitters. They show a surprisingly high rate of radio detections and, at variance with the classical radio-loud (jetted) sources, the origin of their radio emission is probably “thermal

I combine duplicate spectroscopic stellar parameter estimates in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Data Release 6 Low Resolution Spectral Survey A, F, G, and K Type stellar parameter catalog. Combining repeat measurements results in a factor of two improvement in the precision of the spectroscopic stellar parameter estimates. Moreover, this trivializes the process

The dark matter halo masses of galaxies can be estimated from their stellar masses via abundance matching (AM). For both the Milky Way and M31, the AM mass is higher than the mass inferred from kinematics. The higher AM masses exacerbate the missing satellite problem. The difference is especially pronounced for M31, for which but . This is more than expected from scatter in the AM relation, and may

E+A galaxies are post-starburst galaxies that have recently undergone complete quenching of their star formation, making them a valuable source for studying the evolution of galaxies and their environments. Using the Extended Virgo Cluster Catalog, we manually identified 125 “green” and 24 “blue” E+A galaxy candidates within the Virgo Cluster based on their spectral shape, u − r color, lack of Hα emission

We have reprocessed a set of observations of 75 bright, unidentified, steep-spectrum polarized radio sources taken with the Green Bank 43 m telescope to find previously undetected sub-millisecond pulsars and radio bursts. The (null) results of the first search of these data were reported by Schmidt et al.. Our reprocessing searched for single pulses out to a dispersion measure (DM) of 1000 pc cm−3

I searched for the ground state 6.8 and 9.2 GHz hyperfine transitions of rubidium and cesium toward M- and L-dwarfs that show Rb and Cs optical resonance lines. The optical lines can pump the hyperfine transitions, potentially forming masers. These spin-flip transitions of Rb and Cs are the principal transitions used in atomic clocks (the 133Cs hyperfine transition defines the second). If they are

We present the discovery of CWISE J203546.35–493611.0, a peculiar M8 companion to the M4.5 star APMPM J2036−4936 discovered through the citizen science project Backyard Worlds: Planet 9. Given CWISE J203546.35–493611.0's proper motion (μ α , μ δ ) = (−126 22, −478 23) and angular separation of 34.″2 from APMPM 2036−4936, we calculate a chance alignment probability of 1.15 10−6. Both stars in this system

Since the first signal in 2015, the gravitational-wave detections of merging binary black holes (BBHs) by the LIGO and Virgo collaborations (LVC) have completely transformed our understanding of the lives and deaths of compact object binaries, and have motivated an enormous amount of theoretical work on the astrophysical origin of these objects. We show that the phenomenological fit to the redshift-dependent

We report polarization properties for eight narrowband bursts from FRB 121102 that have been re-detected in a high-frequency (4–8 GHz) Breakthrough Listen observation with the Green Bank Telescope, originally taken on 2017 August 26. The bursts were found to exhibit nearly 100% linear polarization, Faraday rotation measures bordering 9.3נ104 rad m−2, and stable polarization position angles, all of

The comparison of all unpublished archival IUE spectra of the bright spectroscopic binary α Draconis shows that the far-ultraviolet flux has remained constant over the 18 yr of the mission, except possibly for one spectrum which shows significantly less flux below 1800 Å. The Si ii lines undergo large radial velocity variations which are due to the orbital motion of α Draconis around the center of

I report a tentative (∼4σ) emission line at ν = 100.84 GHz from “COS-3mm-1,” a 3 mm selected galaxy reported by Williams et al. that is undetected at optical and near-infrared wavelengths. The line was found in the ALMA Science Archive after re-processing ALMA band 3 observations targeting a different source. Assuming the line corresponds to the CO(6 → 5) transition, this tentative detection implies

Much of the information about the magnetic field in the Milky Way and other galaxies comes from measurements which are path integrals, such as Faraday rotation and the polarization of synchrotron radiation of cosmic ray electrons. The measurement made at the radio telescope results from contributions of volume elements along a long line of sight (LOS). A magnetic field measurement at a given spatial

Using Gaia Early Data Release 3 (EDR3) parallaxes and Bayesian inference, we infer a parallax of the Westerlund 1 (Wd1) cluster. We find a parallax of 0.34 0.05 mas corresponding to a distance of kpc. The new Gaia EDR3 distance is consistent with our previous result using Gaia Data Release 2 (DR2) parallaxes. This confirms that Wd1 is less massive and older than previously assumed. Compared to DR2

The goal of this Research Note is to provide the theoretical calculations of the limb-darkening coefficients and gravity-darkening coefficients (GDC) for the space mission CHEOPS. We use two stellar atmosphere models: ATLAS (plane-parallel) and PHOENIX with spherical symmetry covering a wide range of effective temperatures, local gravities, and hydrogen/metal. These grids cover 19 metallicities ranging

The star 2MASS J07363415+6538548 (hereafter 2M0736) was previously classified as a possible symbiotic binary, a cataclysmic variable, an H ii region, a massive star cluster, a supernova remnant, or a high-mass X-ray binary. In the previous research, while analyzing disputable symbiotic candidates in our New Online Database of Symbiotic Variables, we employed multi-frequency photometric observations

In this work, I present the effects of single passing stars on planetary disks and explore the orbital modification of their components. I analyze the effects of passing stars and look for differences between flyby masses of 0.25 M ⊙, 0.5 M ⊙, 0.75 M ⊙, and 1 M ⊙. Resultant eccentricities and inclinations of disk particles are fit to mathematical equations to estimate values for them as a function

We present our Keck/OSIRIS observations of the Paβ emission line (1.282 μm) to investigate accretion mechanisms of PDS 70 planetary system. Our spectral differential imaging reduction to remove the stellar PSF resulted in null detection of Paβ at the locations of PDS 70b and c. The 5σ detection limit of Paβ compared with the theoretical model of Aoyama & Ikoma (2019) indicates the gas velocity onto

We compared high-resolution spectra of Betelgeuse observed before and during the Great Dimming. Atomic lines are shallow and broad during the Great Dimming presumably because of molecular veiling and increased macroturbulence, ν macro ≳ 23 km s−1. The best fit for TiO bands was found for the MARCS model atmosphere with T eff = 3500 K.

Stellar models often use relations between the temperature T and optical depth τ to evaluate the structure of their optically thin outer layers. We fit a novel analytic function to the Hopf function q(τ) of a radiation-coupled hydrodynamics simulation of near-surface convection with solar parameters by Trampedach et al. The fit is accurate to within 0.82% for the solar simulation and to within 13%

A research project on the activities of solar-type stars based on the LAMOST sky survey was initiated recently. We describe the data processing workflow of the project and perspective on scientific yields.

We report the discovery of a one magnitude increase in the optical brightness of the 59.63 minutes orbital period AM CVn binary SDSS J113732.32+405458.3. Public g, r, and i band data from the Zwicky Transient Facility exhibit a subsequent decline over a 300 days period, while a few data points from commissioning show that the peak was likely seen. Such an outburst is likely due to a change in the state

We combine different measurements of the polytropic index of the proton plasma in the heliosphere: (i) near-adiabatic index in the inner heliosphere ∼1 au, (ii) subadiabatic indices in the outer heliosphere ∼20–40 au, and (iii) near-zero indices in the inner heliosheath. These observations are unified by a single theoretical model of the polytropic index throughout its radial extent in the heliosphere;

I report the detection of linear X-ray features associated with PSR B2224+65, based on a new Chandra observation, plus two obtained ∼6 and 12 yr earlier. This mid-aged pulsar is known for its extreme proper motion and its associated guitar-shaped optical nebula in the opposite direction. The main jet-like feature with the same proper motion is long and directed 62 away from the nebula, which is associated

The black hole in the quasar SDSS J140821.67+025733.2 has been reported to have a mass of 1.96 1011 M ⊙ based on measurements from the SDSS DR12 Quasar Catalog. As a result, references to this object as the most massive known black hole in the universe have recently appeared in scientific articles and in popular media including Wikipedia. We show that this extremely high mass estimate is incorrect

The cometary globule CG 12 and its associated young cluster NGC 5367 is located at a Galactic latitude of b=21, and the origin of this high-latitude star formation event has been unclear. Getman et al. identified a nearby group of B stars and suggested they could be the remnant of a group of massive stars of which one exploded as a supernova. We here use Gaia EDR3 data to measure the accurate distance

We investigate how measurements of differential chromatic refraction might influence choices for survey strategy in the Legacy Survey of Space and Time.

We describe calibrated TESS images that serve as the input to the MIT Quick Look Pipeline, which we are releasing as a High Level Science Product (HLSP). We also outline the python package tica, which we use to fully calibrate the raw pixels and apply astrometric registration in the form of World Coordinate Solutions. This HLSP could serve as a means for delivering calibrated Full Frame Images to the

The Gemini Near-infrared Integral Field Spectrograph (NIFS) reduction pipeline is widely used to reduce NIFS data. However, there are critical known limitations. A new NIFS reduction pipeline has recently been developed and solves several of these problems. We present a comparison of stellar kinematics derived from the new and old data reduction pipelines, as well as recommendations for optimal NIFS

The high-speed solar wind is typically the simplest and least stochastic type of large-scale plasma flow in the heliosphere. For much of the solar cycle, it is connected magnetically to large polar coronal holes on the Sun’s surface. Because these features are relatively well-known (and less complex than the multiple source-regions of the slow wind), the fast wind is often a useful testing-ground for

The recently discovered rapid transient GN-z11-flash has been suggested to be the prompt-emission ultraviolet (UV) flash associated with a gamma-ray burst (GRB) serendipitously exploding in the ultra-high-z galaxy GN-z11. We here place the flash into the context of the early UV emission of GRBs, and find it is in agreement with the luminosity distribution of these events.

We present here a list of 25 bright stars (G < 8) that are possible members of Gaia-Enceladus, a system that merged with the Milky Way approximately 10 Gyr ago, and whose debris dominates the halo near the Sun. These stars were therefore born beyond the edges of the Milky Way and are visible with binoculars. We expect the list to be of interest for public outreach and amateur astronomers. These bright

I report outcomes of the analysis of the A + parameter, which measures the level of radial segregation of blue straggler stars in old star clusters, commonly known as the dynamical clock for the long-term internal dynamical evolution. I used A + values available in the literature for 48 Milky Way globular clusters. I found that the relationship of A + and the number of central relaxation times which

Correcting the tip and tilt modes of optical aberrations can mitigate a large proportion of distortions in adaptive optics (AO) systems. We describe a method to greatly improve tip/tilt correction for the Keck telescopes, using a Kalman filter with a physics model conditioned by the expected tip/tilt power spectrum and vibration peaks. The model builds on similar implementations, such as that of the

The exoplanet candidate around the white dwarf WD 1856+534 is of special interest for exoplanet atmosphere characterization because of its very cool temperature and potentially large spectral signal in transmission spectroscopy. Here we present ground-based transit follow-up to verify the transit depth and refine the orbital ephemeris allowing for a more accurate scheduling of future transit observations

Here I describe 184 mid-infrared detections of supernovae (SNe) in co-added images of the NEOWISE mission. 15 of the SNe had previously unknown long-lasting mid-IR detections with durations of more than a year. I find 7 SNe which have previously unknown SN 2010jl-like mid-infrared evolution. There are also long detections around one type IIb (SN 2016gkg), type IIP (SN 2016X) and type IIL (SN 2016iot)

Here I report the appearance of a new nebula in the constellation Puppis. The nebula was discovered in archived DECam images from 2017 January. Additionally the central source shows an outburst between 2015 February and 2015 April in archived unWISE images. The outburst reached the current brightness in 2016 November (W1∼3.6 mag, W2∼1.5 mag). The pre-outburst images from the VST (2012 March) and PanSTARRS

Magnetic fields are a critical component of interior and atmospheric models of low-mass stars. Additionally, stellar activity associated with magnetic fields may make exoplanets around K and M stars uninhabitable. Here we describe the measurement of the magnetic fields of K and M dwarfs from high-resolution spectra, and discuss the impact of projected rotational velocity (v sin i) on these measurements

Hoadley et al. present an exceptional star system hosting orbiting dust and gas and a detached shell of material presumably generated in a stellar merger event. While they claim it to be “the only known merger system not enshrouded by dust,” the reality is that this system is a new addition to a remarkable collection of stars first recognized decades ago as likely post-merger stellar remnants. In this

Kepler, K2, and Transiting Exoplanet Survey Satellite (TESS) have demonstrated the power of high-precision uninterrupted photometry. Combining data sets from these two observatories can extend the baseline of high precision photometry on a target. In addition, for some investigations, the differing passbands of the two telescopes may provide additional information about the causes of the observed variability

The two and three body mean motion resonances with Jupiter and Mars (and possible with Earth) may have a significant effect on the dynamics of very young close asteroid pairs and families. The best known example is the influence 9:16 resonance with Mars to some members of Datura family. It is evident, that the evolution of this family can be properly reconstructed only when this fact has been taken

The Observed-minus-Calculated diagram shows a stability of a period being analyzed. In case of binary system, any nonlinear O − C variation indicates an orbital period variation that can be caused by e.g., mass loss or mass transfer between components (physical change), additional component(s) to the system (apparent change only). Baran et al. reported a sinusoidal variation of the O − C of 2M 1938+4603

Via numerical experiments, we show that the ∼10%–20% passive fraction seen at z ≳ 3 is consistent with galaxy star formation histories being maximally correlated stochastic processes. If so, this fraction should reflect a time-independent baseline that holds at any epoch or mass regime where mean star formation rates are rising. Data at and z ≲ 0.5 bear this out, as should future James Webb Space Telescope

We present the first coordinated soft and hard 0.3–80 keV X-ray campaign of the extragalactic supernova SN2014C in the first ∼2307 days of its evolution. SN2014C initially appeared to be an ordinary type Ib explosion but evolved into a strongly-interacting hydrogen-rich SN IIn over ∼1 yr. We observed signatures of interaction with a dense medium across the X-ray spectrum, which revealed the presence

As part of the Transient UV Objects project, we have discovered a new outburst (at the beginning of 2020 October) of the candidate cataclysmic variable (CV) ASASSN-18eh using the UV/Optical Telescope aboard the Neil Gehrels Swift Observatory. During the outburst its brightness increased by about 6 mag in UV compared to its brightness in the quiescent state. The properties of this outburst are consistent

Evidence is presented in this Note for the presence of twice ionized praseodymium and neodymium in the upper atmosphere of HD 99803 A, which turns out to be a newly discovered cool HgMn star in a binary system.

The He i 10830 Å absorption line in transit spectra traces the upper atmospheres of exoplanets and their mass loss, which in turn is important in determining their evolution and demographics. We use archival VLT/X-Shooter data to set new, more sensitive limits on the extended helium atmosphere of GJ 1214 b, a sub-Neptune orbiting an M-dwarf. We determine limits for the excess absorption at 10830 Å

The results of LIGO/Virgo S200302c (O3) error-box optical inspection by MASTER are presented. We observed 4242 square degrees square degrees inside 3σ error box during 1 month. We present MASTER OT J141401.39–483305.7, MASTER OT J215856.95–392909.6, MASTER OT J061642.05+435617.9, MASTER OT J052817.95+672801.4—optical transients found by the MASTER auto-detection system during this inspection as the

Future stellar encounters with the Sun might disturb the outskirts of the solar system, for close-enough passages. Such encounters may send small bodies toward the inner regions of the solar system. In the near future and among known stars, none will pass closer to the Sun than Gliese710. Here, we present an updated analysis of this topic using GaiaEDR3 data. Our new estimate confirms, within errors

The Bajamar Star is an early O star that ionizes the North America/Pelican Nebulae. In projection, it is near the geometric center of the H ii region, but appears to lie outside any of the main stellar subgroups. Furthermore, in Gaia DR2, there were slight discrepancies between this star and the rest of the system in parallax (2σ larger) and relative tangential velocity (∼6 km s−1). Using Gaia EDR3

We perform a linear analysis of the stability of isothermal, rotating, magnetic, self-gravitating sheets that are weakly ionized. We include a self-consistent treatment of thermal pressure, gravitational, rotational, and magnetic (pressure and tension) forces together with two nonideal magnetohydrodynamic (MHD) effects: Ohmic dissipation and ambipolar diffusion. Our results show that there is always

The launch of the James Webb Space Telescope (JWST) in 2021 will revolutionize exoplanetary science by providing detailed characterizations of exoplanets within the infrared range of 3–13 microns. This is of particular interest to the field of direct imaging, where empirical models that remove excess starlight from imaged extrasolar systems have proven vital to the discovery of exoplanets. pyKLIP is

In 2015 June, the symbiotic binary star AG Pegasi underwent a period of outburst. SkyCam T, mounted onboard the 2 m Liverpool Telescope, collected over 650 unfiltered images of this event, and several thousand images from before and after. This note presents Sloan r′ band light curves obtained from these images. In addition, a color–magnitude diagram (CMD) using AAVSO data is included to infer parameters

While Transiting Exoplanet Survey Satellite (TESS) covers a considerable area of the sky during routine observations and the pointing schedule is easy to follow, it is not obvious to retrieve the current and/or predicted visibility of a bulk amount of objects, considering both stationary and moving Solar System targets like asteroids or comets. The program tessvisibility is a small piece of highly

The Early Gaia Data Release 3 (EDR3) provides precise astrometry for nearly 1.5 billion sources across the entire sky. A few tens of these are associated with neutron stars in the Milky Way and Magellanic Clouds. Here, we report on a search for EDR3 counterparts to known rotation-powered pulsars using the method outlined in Antoniadis. A cross-correlation between EDR3 and the ATNF pulsar catalog identifies

We present the results of MASTER Global Robotic Net optical observations of LIGO/Virgo S200224ca error-box (O3 set). We observed 380 square degrees inside the 3σ error box during 1 month. We present optical transients found by MASTER auto-detection system during this inspection. They are not the optical counterparts, but the result of MASTER observation strategy, that is is briefly discussed. Also