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22231. TIMASSS. I.
ID:
ivo://CDS.VizieR/J/A+A/532/A23
Title:
TIMASSS. I.
Short Name:
J/A+A/532/A23
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
22232. Time and positions of coronal bright points
ID:
ivo://CDS.VizieR/J/A+A/587/A29
Title:
Time and positions of coronal bright points
Short Name:
J/A+A/587/A29
Date:
21 Oct 2021
Publisher:
CDS
Description:
It is possible to detect and track coronal bright points (CBPs) in Solar Dynamics Observatory / Atmospheric Imaging Assembly (SDO/AIA) images. A combination of high resolution and high cadence provides a wealth of data that can be used to determine velocity flows on the solar surface with very high accuracy. We derived a very accurate solar rotation profile and investigated meridional flows, torsional oscillations, and horizontal Reynolds stress based on ~6 months of SDO/AIA data. We used a segmentation algorithm to detect CBPs in SDO/AIA images. We also used invariance of the solar rotation profile with central meridian distance (CMD) to determine the height of CBPs in the 19.3nm channel. The best fit solar rotation profile is given by {omega}(b)=(14.4060+/-0.0051+(-1.662+/-0.050)sin^2^b+ (-2.742+/-0.081)sin^4^b){deg}/day. The height of CBPs in the SDO/AIA 19.3nm channel was found to be ~6500km. Meridional motion is predominantly poleward for all latitudes, while solar velocity residuals show signs of torsional oscillations. Horizontal Reynolds stress was found to be smaller than in similar works, but still showed transfer of angular momentum towards the solar equator. Most of the results are consistent with Doppler measurements rather than tracer measurements. The fairly small calculated value of horizontal Reynolds stress might be due to the particular phase of the solar cycle. Accuracy of the calculated rotation profile indicates that it is possible to measure changes in the profile as the solar cycle evolves. Analysis of further SDO/AIA CBP data will also provide a better understanding of the temporal behaviour of the rotation velocity residuals, meridional motions, and Reynolds stress.
22233. Time delays and H0 from WFI J2033-4723
ID:
ivo://CDS.VizieR/J/A+A/488/481
Title:
Time delays and H0 from WFI J2033-4723
Short Name:
J/A+A/488/481
Date:
21 Oct 2021
Publisher:
CDS
Description:
Gravitationally lensed quasars can be used to map the mass distribution in lensing galaxies and to estimate the Hubble constant H0 by measuring the time delays between the quasar images. Here we report the measurement of two independent time delays in the quadruply imaged quasar WFI J2033-4723 (z=1.66). Our data consist of R-band images obtained with the Swiss 1.2m EULER telescope located at La Silla and with the 1.3m SMARTS telescope located at Cerro Tololo. The light curves have 218 independent epochs spanning 3 full years of monitoring between March 2004 and May 2007, with a mean temporal sampling of one observation every 4th day. We measure the time delays using three different techniques, and we obtain Dt(B-A)=35.5+/-1.4days (3.8%) and Dt(B-C)=62.6^+4.1^_-2.3_days (^+6.5%^_-3.7%_), where A is a composite of the close, merging image pair. After correcting for the time delays, we find R-band flux ratios of FA/FB=2.88+/-0.04, FA/FC=3.38+/-0.06, and FA1/FA2=1.37+/-0.05 with no evidence for microlensing variability over a time scale of three years. However, these flux ratios do not agree with those measured in the quasar emission lines, suggesting that longer term microlensing is present. Our estimate of H0 agrees with the concordance value: non-parametric modeling of the lensing galaxy predicts H0=67^+13^_-10_km/s/Mpc, while the Single Isothermal Sphere model yields H0=63^+7^_-3_km/s/Mpc (68% confidence level). More complex lens models using a composite de Vaucouleurs plus NFW galaxy mass profile show twisting of the mass isocontours in the lensing galaxy, as do the non-parametric models. As all models also require a significant external shear, this suggests that the lens is a member of the group of galaxies seen in field of view of WFI J2033-4723.
22234. Time-dependent cooling in photoionized plasma
ID:
ivo://CDS.VizieR/J/ApJS/228/11
Title:
Time-dependent cooling in photoionized plasma
Short Name:
J/ApJS/228/11
Date:
21 Oct 2021
Publisher:
CDS
Description:
I explore the thermal evolution and ionization states in gas cooling from an initially hot state in the presence of external photoionizing radiation. I compute the equilibrium and nonequilibrium cooling efficiencies, heating rates, and ion fractions for low-density gas cooling while exposed to the ionizing metagalactic background radiation at various redshifts (z=0-3), for a range of temperatures (10^8^-10^4^K), densities (10^-7^-10^3^cm^-3^), and metallicities (10^-3^-2 times solar). The results indicate the existence of a threshold ionization parameter, above which the cooling efficiencies are very close to those in photoionization equilibrium (so that departures from equilibrium may be neglected), and below which the cooling efficiencies resemble those in collisional time-dependent gas cooling with no external radiation (and are thus independent of density).
22235. Time minima of EP Aur
ID:
ivo://CDS.VizieR/J/other/NewA/35.48
Title:
Time minima of EP Aur
Short Name:
J/other/NewA/35.
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new observations for the eclipsing binary EP Aurigae, which were performed by using three small telescopes in China from 2003 December to 2014 January. With the updated 2003 version of the Wilson-Devinney code, the photometric elements were deduced from three sets of light curves. Based on all available eclipsing times, the orbital period changes were investigated. It is discovered that the (O-C) curve may show an existence of light-time effect due to an unseen third body, which was weakly identified by the photometric solution. The modulated period and amplitude of the cyclic variation are P_3_=71.2(+/-8.0)yr and A=0.0101(+/-0.0008)day, respectively. In the co-planar orbit with the binary system, the mass of the third body is M_3_=0.18(+/-0.02)M_{sun}_. The photometric results imply that EP Aur is an Algol-type binary with a mass ratio of q=0.831(+/-0.004). Its primary component almost fills its Roche lobe. Therefore, EP Aur may consist of a normal main-sequence star and a cool Roche-lobe filling subgiant, which may be undergoing rapid mass transfer.
22236. Time of Maxima for the SX Phe star XX Cyg
ID:
ivo://CDS.VizieR/J/PASP/123/26
Title:
Time of Maxima for the SX Phe star XX Cyg
Short Name:
J/PASP/123/26
Date:
21 Oct 2021
Publisher:
CDS
Description:
XX Cyg is a High Amplitude {delta} Scuti star which has been extensively studied because of its changing period. We present 64 new times of maxima which have been combined with 174 times of maxima from literature, in order to give an updated ephemeris and O-C plot for XX Cyg. Its period, currently found to be 0.134865117(3) days, is shown to be increasing continuously, which has lead to a new calculated value of (1/P)(dP/dt)=(1.33+/-0.09)10^-8^yr^-1^
22237. Time of minima of BX Peg
ID:
ivo://CDS.VizieR/J/other/NewA/41.17
Title:
Time of minima of BX Peg
Short Name:
J/other/NewA/41.
Date:
21 Oct 2021
Publisher:
CDS
Description:
We presented BVRcIc light curves of BX Peg obtained by the Weihai Observatory 1.0m telescope of Shandong University. The W-D code was used to analyze the four color light curves, it is shown that BX Peg is a W-subtype shallow contact binary with a fill-out factor of f=14.6%. The asymmetric light curves were explained by a dark spot on the less massive hot component. A total of 328 times of minimum light were used to study the orbital period variation of BX Peg. We found that the orbital period of BX Peg was continuous decrease with a rate of dp/dt=-2.07x10^-7^d/yr superimposed on a cyclic oscillation with a period of 57.8yr. The secular period decrease should be caused by the angular momentum loss via magnetic stellar wind. The cyclic modulation is very likely to be produced by the light travel time effect due to a tertiary companion.
22238. Time of minima of eclipsing binaries
ID:
ivo://CDS.VizieR/J/other/JAVSO/38.183
Title:
Time of minima of eclipsing binaries
Short Name:
J/other/JAVSO/38
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper continues the publication of times of minima for eclipsing binary stars from observations reported to the AAVSO Eclipsing Binary section. Times of minima from observations made from September 2009 through February 2010 are presented.
22239. Time of minima of HD 181068
ID:
ivo://CDS.VizieR/J/MNRAS/428/1656
Title:
Time of minima of HD 181068
Short Name:
J/MNRAS/428/1656
Date:
21 Oct 2021
Publisher:
CDS
Description:
HD 181068 is the brighter of the two known triply eclipsing hierarchical triple stars in the Kepler field. It has been continuously observed for more than 2yr with the Kepler space telescope. Of the nine quarters of the data, three have been obtained in short-cadence mode, that is one point per 58.9s. Here we analyse this unique data set to determine absolute physical parameters (most importantly the masses and radii) and full orbital configuration using a sophisticated novel approach. We measure eclipse timing variations (ETVs), which are then combined with the single-lined radial velocity measurements to yield masses in a manner equivalent to double-lined spectroscopic binaries. We have also developed a new light-curve synthesis code that is used to model the triple, mutual eclipses and the effects of the changing tidal field on the stellar surface and the relativistic Doppler beaming. By combining the stellar masses from the ETV study with the simultaneous light-curve analysis we determine the absolute radii of the three stars. Our results indicate that the close and the wide subsystems revolve in almost exactly coplanar and prograde orbits. The newly determined parameters draw a consistent picture of the system with such details that have been beyond reach before.
22240. Times & durations in Kepler-80 planetary system
ID:
ivo://CDS.VizieR/J/AJ/162/114
Title:
Times & durations in Kepler-80 planetary system
Short Name:
J/AJ/162/114
Date:
16 Mar 2022 00:10:21
Publisher:
CDS
Description:
Since the launch of the Kepler space telescope in 2009 and the subsequent K2 mission, hundreds of multiplanet systems have been discovered. The study of such systems, both as individual systems and as a population, leads to a better understanding of planetary formation and evolution. Kepler-80, a K dwarf hosting six super-Earths, was the first system known to have four planets in a chain of resonances, a repeated geometric configuration. Transiting planets in resonant chains can enable us to estimate not only the planets' orbits and sizes but also their masses. Since the original resonance analysis and TTV fitting of Kepler-80, a new planet has been discovered whose signal likely altered the measured masses of the other planets. Here, we determine masses and orbits for all six planets hosted by Kepler-80 by direct forward photodynamical modeling of the light curve of this system. We then explore the resonant behavior of the system. We find that the four middle planets are in a resonant chain, but that the outermost planet only dynamically interacts in ~14% of our solutions. We also find that the system and its dynamic behavior are consistent with in situ formation and compare our results to two other resonant chain systems, Kepler-60 and TRAPPIST-1.

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