A5100731387- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- History and Developments in Astronomy
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Geological formations and processes
- Chinese history and philosophy
- Astrophysics and Cosmic Phenomena
- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Australian History and Society
- Galaxies: Formation, Evolution, Phenomena
- Geology and Paleoclimatology Research
- Historical Astronomy and Related Studies
- African history and culture studies
- Adaptive optics and wavefront sensing
- Global Maritime and Colonial Histories
- Irish and British Studies
- Social Work Education and Practice
- Spacecraft Design and Technology
- Space Science and Extraterrestrial Life
Universidad de La Laguna
2016-2025
Instituto de Astrofísica de Canarias
2016-2025
Nordic Optical Telescope
2023-2025
Auckland University of Technology
2025
Virginia Tech
2024
University of Iowa
2018-2019
Mathematica Policy Research
2018-2019
National Bureau of Economic Research
2018-2019
Policy Analysis (United States)
2018-2019
Cornell University
2018-2019
In this paper we present a catalog of 4584 eclipsing binaries observed during the first two years (26 sectors) TESS survey. We discuss selection criteria for binary candidates, detection hither-to unknown systems, determination ephemerides, validation and triage process, derivation heuristic estimates ephemerides. Instead keeping to widely used discrete classes, propose star morphology classification based on dimensionality reduction algorithm. Finally, statistical properties sample,...
PHOEBE 2 is a Python package for modeling the observables of eclipsing star systems, but until now has focused entirely on forward-model -- that is, generating synthetic model given fixed values large number parameters describing system and observations. The inverse problem, obtaining orbital stellar observational data, more complicated computationally expensive as it requires set forward-models to determine which uncertainties best represent available data. process determining solution also...
Stars are generally spherical, yet their gaseous envelopes often appear non-spherical when ejected near the end of lives. This quirk is most notable during planetary nebula phase these become ionized. Interactions among stars in a binary system suspected to cause asymmetry. In particular, precessing accretion disk around companion believed launch point-symmetric jets, as seen prototype Fleming 1. Our discovery post common-envelope nucleus 1 confirms that this scenario highly favorable....
ABSTRACT A current issue in the study of planetary nebulae with close binary central stars (CSs) is extent to which binaries affect shaping nebulae. Recent studies have begun show a high coincidence rate between large-scale axial or point symmetries and stars. In addition, combined binary-star spatiokinematic modeling demonstrated that all systems studied date appear their axis aligned primary nebula. Here we add two more list, CSs NGC 6337 Sp 1. We both be low inclination, nearly our line...
It has recently been noted that there seems to be a strong correlation between planetary nebulae with close binary central stars, and highly enhanced recombination line abundances. We present new deep spectra of seven objects known have find the heavy element abundances derived from lines exceed those collisionally excited by factors 5-95, placing several these among most extreme abundance discrepancies. This study nearly doubles number star an discrepancy. A statistical analysis all...
Traditionally, the effects of interstellar extinction on binary star light curves have been treated as a uniform reduction in observed brightness system that is independent orbital phase. However, unless plane coincides with sky, or if two stars are completely identical and present minimal mutual irradiation tidal/rotational distortions, then this unlikely to be an accurate representation effect extinction. Here, we updated treatment incorporated PHOEBE 2.2 release (publicly available from...
An analytical EHL model suitable for highly loaded point contacts operating in mixed and boundary regimes of lubrication is presented. The results are compared validated with the experimental measurements friction coefficient from an MTM tribometer. Measurements carried out upon a PAO40 oil at medium to high temperatures. In general, good agreement trend magnitude over wide range conditions observed. Both findings predictions show inverse relationship between contact load lubrication, effect...
IPHASX J194359.5+170901 is a new high-excitation planetary nebula with remarkable characteristics. It consists of knotty ring expanding at speed 28 km s−1, and fast collimated outflow in the form faint lobes caps along direction perpendicular to ring. The expansion polar ∼100 their kinematical age twice as large Time-resolved photometry central star reveals sinusoidal modulation period 1.16 d. This interpreted evidence for binarity star, brightness variations being related orbital motion an...
The discrepancy between abundances computed using optical recombination lines (ORLs) and collisionally excited (CELs) is a major unresolved problem in nebular astrophysics. We show here that the largest abundance discrepancies are reached planetary nebulae with close binary central stars. This illustrated by deep spectroscopy of three post common-envelope (CE) star. Abell 46 Ou5 have O++/H+ factors larger than 50, as high 300 inner regions 46. 63 has smaller factor around 10, but still above...
We present new optical spectra of the nearby, bright, planetary nebula NGC 6778. The has been known to emit strong recombination lines for more than 40 years but this is first detailed study its abundances. Heavy element abundances derived from are found exceed those collisionally excited by a factor ~20 in an integrated spectrum nebula, which among largest abundance discrepancy factors. Spatial analysis shows that strongly, centrally peaked, reaching ~40 close central star. star 6778 be...
We present X-ray spectral analysis of 20 point-like sources detected in Chandra Planetary Nebula Survey observations 59 planetary nebulae (PNe) the solar neighborhood. Most these detections are associated with luminous central stars within relatively young, compact nebulae. The vast majority X-ray-emitting at PN cores display "hard" (⩾0.5 keV) emission components that unlikely to be due photospheric from hot (CSPN). Instead, we demonstrate well modeled by optically thin thermal plasmas. From...
We present a study of Hen 2-155 and 2-161, two planetary nebulae which bear striking morphological similarities to other known host close-binary central stars. Both stars are revealed be photometric variables while spectroscopic observations confirm that is double-eclipsing, post-common-envelope system with an orbital period 3h33m making it one the shortest binary known. The 2-161 found consistent ~1 day. A detailed model star 2-155, produced, showing nebular progenitor hot, post-AGB remnant...
ABSTRACT CO Cam (TIC 160268882) is the second ‘single-sided pulsator’ to be discovered. These are stars where one hemisphere pulsates with a significantly higher amplitude than other side of star. binary star comprised an Am δ Sct primary Teff = 7070 ± 150 K, and spectroscopically undetected G main-sequence secondary The dominant pulsating centred on L1 point. We have modelled spectral energy distribution combined radial velocities, independently TESS light curve velocities. Both these give...
Abstract Luminous red novae (LRNe) are transients characterized by low luminosities and expansion velocities, they associated with mergers or common-envelope ejections in stellar binaries. Intermediate-luminosity (ILRTs) an observationally similar class unknown origins, but generally believed to be either electron-capture supernovae super-asymptotic giant branch stars outbursts dusty luminous blue variables (LBVs). In this paper, we present a systematic sample of eight LRNe ILRTs detected as...
We present observations proving the close binary nature of central stars belonging to planetary nebulae (PNe) NGC 6326 and 6778. Photometric monitoring reveals irradiated lightcurves with orbital periods 0.372 0.1534 days, respectively, constituting firm evidence that they passed through a common-envelope (CE) phase. Unlike most surveys for (CSPN) however, was first revealed spectroscopically only later did photometry obtain an period. Gemini South large 160 km s-1 shift between nebula...
We present results from the most recent set of observations obtained as part Chandra X-ray observatory Planetary Nebula Survey (ChanPlaNS), first comprehensive survey planetary nebulae (PNe) in solar neighborhood (i.e., within ~1.5 kpc Sun). The is designed to place constraints on frequency appearance and range spectral characteristics X-ray-emitting PN central stars evolutionary timescales wind-shock-heated bubbles PNe. ChanPlaNS began with a combined Cycle 12 archive 35 continued via 14...
We searched for extrasolar planets around pulsating stars by examining $\textit{Kepler}$ data transit-like events hidden in the intrinsic variability. All Short Cadence observations targets with 6000 K $< T_{\rm eff} <$ 8500 were visually inspected following removal of pulsational signals sinusoidal fits. Clear detected KIC 5613330 and 8197761. is a confirmed exoplanet host (Kepler-635b), where transit period determined here consistent literature value. 8197761 $\gamma$ Doradus - $\delta$...
ABSTRACT We present the first direct image of high-metallicity gas component in a planetary nebula (NGC 6778), taken with OSIRIS Blue Tunable Filter centered on O ii λ 4649+50 Å optical recombination lines (ORLs) at 10.4 m Gran Telescopio Canarias. show that emission these faint ORLs is concentrated central parts and not spatially coincident either coming from bright [O iii ] 5007 collisionally excited line (CEL) or H α line. From monochromatic maps VIMOS 8.2 Very Large Telescope, we find...