Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTESSVisibility -- When was my favorite star or asteroid observed by TESS?
106
0
0.0
(
0
)
Authors
Andras Pal Konkoly Observatory
Ask ChatGPT about the research
No Arabic abstract
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 portable code implemented in both C an UNIX shell, providing functionalities for such bulk retrievals at the accuracy of a TESS pixel. This accuracy includes the gaps between the focal plane CCDs, the gaps between the cameras as well as at the sector-level treatment to obtain visibility information.
rate research
Read More
$gamma$ Doradus is the prototype star for the eponymous class of pulsating stars that consists of late A-early F main-sequence stars oscillating in low-frequency gravito-inertial modes. Being among the brightest stars of its kind (V = 4.2), $gamma$ Dor benefits from a large set of observational data that has been recently completed by high-quality space photometry from the TESS mission. With these new data, we propose to study $gamma$ Dor as an example of possibilities offered by synergies between multi-technical ground and space-based observations. Here, we present the preliminary results of our investigations.
We glance back at the short period of the great discoveries between 1970 and 1974 that led to the restablishment of Quantum Field Theory and the discovery of the Standard Model of Elementary Particles, in particular Quantum Chromodynamics, and ask ourselves where we stand now.
We present photometric and spectroscopic observations of the unusual Type Ia supernova ASASSN-18tb, including a series of SALT spectra obtained over the course of nearly six months and the first observations of a supernova by the Transiting Exoplanet Survey Satellite (TESS). We confirm a previous observation by Kollmeier et al. (2019) showing that ASASSN-18tb is the first relatively normal Type Ia supernova to exhibit clear broad ($sim1000$ km s$^{-1}$) H$alpha$ emission in its nebular phase spectra. We find that this event is best explained as a sub-Chandrasekhar mass explosion with $M_{Ni} approx 0.3; rm{M}_odot$. Despite the strong H$alpha$ signature at late times, we find that the early rise of the supernova shows no evidence for deviations from a single-component power-law and is best fit with a moderately shallow power-law of index $1.69pm0.04$. We find that the H$alpha$ luminosity remains approximately constant after its initial detection at phase +37 d, and that the H$alpha$ velocity evolution does not trace that of the Fe~III$~lambda4660$ emission. These suggest that the H$alpha$ emission arises from circumstellar medium (CSM) rather than swept up material from a non-degenerate companion. However, ASASSN-18tb is strikingly different from other known CSM-interacting Type Ia supernovae in a number of significant ways. Those objects typically show an H$alpha$ luminosity two orders of magnitude higher than what is seen in ASASSN-18tb, pushing them away from the empirical light-curve relations that define normal Type Ia supernovae. Conversely, ASASSN-18tb exhibits a fairly typical light curve and luminosity for an underluminous or transitional SN Ia, with $M_R approx -18.1$ mag. Moreover, ASASSN-18tb is the only SN Ia showing H$alpha$ from CSM interaction to be discovered in an early-type galaxy.
The Adaptive Optics (AO) performance significantly depends on the available Natural Guide Stars (NGSs) and a wide range of atmospheric conditions (seeing, Cn2, windspeed,...). In order to be able to easily predict the AO performance, we have developed a fast algorithm - called TIPTOP - producing the expected AO Point Spread Function (PSF) for any of the existing AO observing modes (SCAO, LTAO, MCAO, GLAO), and any atmospheric conditions. This TIPTOP tool takes its roots in an analytical approach, where the simulations are done in the Fourier domain. This allows to reach a very fast computation time (few seconds per PSF), and efficiently explore the wide parameter space. TIPTOP has been developed in Python, taking advantage of previous work developed in different languages, and unifying them in a single framework. The TIPTOP app is available on GitHub at: https://github.com/FabioRossiArcetri/TIPTOP, and will serve as one of the bricks for the ELT Exposure Time Calculator.
KIC 10685175 (TIC 264509538) was discovered to be a rapidly oscillating Ap star from {it Kepler} long cadence data using super-Nyquist frequency analysis. It was re-observed by TESS with 2-min cadence data in Sectors 14 and 15. We analyzed the TESS light curves, finding that the previously determined frequency is a Nyquist alias. The revised pulsation frequency is $191.5151 pm 0.0005$d$^{-1}$ ($P = 7.52$min) and the rotation frequency is $0.32229 pm 0.00005$d$^{-1}$ ($P_{rm rot} = 3.1028$d). The star is an oblique pulsator with pulsation amplitude modulated by the rotation, reaching pulsation amplitude maximum at the time of the rotational light minimum. The oblique pulsation generates a frequency quintuplet split by exactly the rotation frequency. The phases of sidelobes, the pulsation phase modulation, and a spherical harmonic decomposition all show this star to be pulsating in a distorted quadrupole mode. Following the oblique pulsator model, we calculated the rotation inclination $i$ and magnetic oblique $beta$ of this star, which provide detailed information of pulsation geometry. The $i$ and $beta$ derived by the best fit of pulsation amplitude and phase modulation through a theoretical model differ from those calculated for a pure quadrupole, indicating the existence of strong magnetic distortion. The model also predicts the polar magnetic field strength is as high as about 6kG which is predicted to be observed in a high resolution spectrum of this star.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
