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3531. Lightcurves of Near-Earth Asteroid 162173 (1999 JU3)
ID:
ivo://CDS.VizieR/J/A+A/550/L11
Title:
Lightcurves of Near-Earth Asteroid 162173 (1999 JU3)
Short Name:
J/A+A/550/L11
Date:
21 Oct 2021
Publisher:
CDS
Description:
Near-Earth asteroid (hereafter NEA) 162173 (1999 JU3) is a potential target of two asteroid sample return missions not only because of its accessibility but also because of the first C-type asteroid for exploration missions. The lightcurve related physical properties of this object were investigated during the 2011-2012 apparition. We aim to confirm the physical parameters useful for JAXAs Hayabusa 2 mission such as rotational period, absolute magnitude and phase function. Our data complement previous studies which did not cover low phase angles. With optical imagers and 1-2m class telescopes, we acquired the photometric data at different phase angles. We independently derived the rotational lightcurve and the phase curve of the asteroid.
3532. Lightcurves of Near-Earth Asteroid 3200 Phaethon
ID:
ivo://CDS.VizieR/J/A+A/619/A123
Title:
Lightcurves of Near-Earth Asteroid 3200 Phaethon
Short Name:
J/A+A/619/A123
Date:
21 Oct 2021
Publisher:
CDS
Description:
The near-Earth asteroid 3200 Phaethon (1983 TB) is an attractive object not only from a scientific viewpoint but also because of JAXA's DESTINY+ target. The rotational lightcurve and spin properties were investigated based on the data obtained in the ground-based observation campaign of Phaethon. We aim to refine the lightcurves and shape model of Phaethon using all available lightcurve datasets obtained via optical observation, as well as our time-series observation data from the 2017 apparition. Using eight 1-2-m telescopes and an optical imager, we acquired the optical lightcurves and derived the spin parameters of Phaethon. We applied the lightcurve inversion method and SAGE (Shaping Asteroids with Genetic Evolution) algorithm to deduce the convex and non-convex shape model and pole orientations.
3533. Lightcurves of 12 NEAs
ID:
ivo://CDS.VizieR/J/A+A/511/A49
Title:
Lightcurves of 12 NEAs
Short Name:
J/A+A/511/A49
Date:
21 Oct 2021
Publisher:
CDS
Description:
Very small asteroids (VSAs) are thought to be the building blocks of larger asteroids and, as such, are interesting to study. Many of these monolithic or deeply fractured objects display rapid rotations with periods as short as several minutes. Observations of such asteroids can reveal their spin limits, which can be related to the tensile strength of their interiors. The evolution of the spins of these objects is primarily shaped by the YORP effect, the theory of which needs comparison with observations. With the 10m SALT telescope, we observed VSAs belonging to near-Earth asteroids. The obtained lightcurves were used to derive synodical periods of rotation, amplitudes, and elongations of these bodies. Results for 14 rapidly rotating asteroids were reported in the first paper in this series. Here we show lightcurves of 2 fast rotators, 9 objects with periods >=1h, and a possible non-principal axis rotator. We also list negative detections that most probably indicate asteroids with long periods and/or low amplitudes. Combining our results with the data from the literature, we obtain a set of 79 near-Earth VSAs with a median period of 0.25h (15min). By adjusting the spin limits predicted by theory to those observations, we find tentative evidence that the tensile strengths of VSAs, after scaling them to the same size, are of the same order as the minimum tensile strengths of stony meteoroids that undergo fragmentation under the atmospheric load.
3534. Lightcurves of 14 NEAs
ID:
ivo://CDS.VizieR/J/A+A/509/A94
Title:
Lightcurves of 14 NEAs
Short Name:
J/A+A/509/A94
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report first results from our extensive survey of the very small (H>21.5mag) near-Earth asteroids. Our aim was to obtain photometric lightcurves for these faint, fast moving objects and to measure their rotation periods and amplitudes of light variations. These parameters can be used to make statistical analysis of the still little known population of the smallest asteroids, test present theories of the YORP effect as well as to study their spin limits, which are connected with their internal structure. Due to the faintness of the targets and the expected short periods of rotation, observations were performed with the large, 10-m SALT telescope in SAAO (South Africa). For most asteroids, V filter images with exposure times of 5-60 seconds were obtained with the instrument's SALTICAM's CCD camera. Even though the non-sidereal tracking was not available, the SALTICAM's relatively large field-of-view of 8'x8' helped to perform the relative photometry of the fast-moving targets. The presented asteroids have synodic periods ranging from 77s to 44min, effective diameters from 21 to 94m, and significantly elongated shapes.
3535. Light curves of NGC 6910 pulsating stars
ID:
ivo://CDS.VizieR/J/A+A/632/A95
Title:
Light curves of NGC 6910 pulsating stars
Short Name:
J/A+A/632/A95
Date:
21 Oct 2021
Publisher:
CDS
Description:
The aim of this study is to obtain the age of the open cluster NGC 6910 by means of ensemble asteroseismology of the early-type pulsating members, to derive their stellar parameters, and to classify the excited modes. We used time-series analysis, performed photometric and spectroscopic mode identification, and calculated grids of evolutionary and seismic models to apply the procedure of ensemble asteroseismology for nine pulsating members of NGC 6910. With two iterations of the procedure of ensemble asteroseismology we derived an age of 10.6^+0.9^_-0.8_Myr for NGC 6910. We also identified the degree l for 8 of 37 modes detected in these stars and classified all modes in terms of p, g, and mixed-mode pulsations. Of the nine pulsating stars examined in the paper, eight are {beta} Cep stars, including three that are hybrid {beta} Cep and slowly pulsating B-type (SPB) pulsators, and one is an SPB star. Interestingly, the least massive {beta} Cep star, NGC 6910-38, has a mass of about 5.6 solar masses. The present theory does not predict unstable p modes in B-type stars with such a low mass. The g modes with relatively high frequencies (>3.5d^-1^), observed in three members of the cluster, are also stable according to seismic modelling. Both findings pose a challenge for theoretical calculations and prompt a revision of the opacities. The procedure of ensemble asteroseismology was found to be successful for NGC 6910 and {chi} Per on the basis of pulsating B-type stars and can therefore be applied to other young open clusters that are rich in such stars.
3536. 21 light curves of OGLE-TR-56b
ID:
ivo://CDS.VizieR/J/ApJ/741/102
Title:
21 light curves of OGLE-TR-56b
Short Name:
J/ApJ/741/102
Date:
21 Oct 2021
Publisher:
CDS
Description:
Although OGLE-TR-56b was the second transiting exoplanet discovered, only one light curve, observed in 2006, has been published besides the discovery data. We present 21 light curves of 19 different transits observed between 2003 July and 2009 July with the Magellan Telescopes and Gemini South. The combined analysis of the new light curves confirms a slightly inflated planetary radius relative to model predictions, with R_p_=1.378+/-0.090R_J_. However, the values found for the transit duration, semimajor axis, and inclination values differ significantly from the previous result, likely due to systematic errors. The new semimajor axis and inclination, a=0.01942+/-0.00015AU and i=73.72+/-0.18{deg}, are smaller than previously reported, while the total duration, T_14_=7931+/-38s, is 18 minutes longer. The transit midtimes have errors from 23s to several minutes, and no evidence is seen for transit midtime or duration variations. Similarly, no change is seen in the orbital period, implying a nominal stellar tidal decay factor of Q_*_=10^7^, with a 3{sigma} lower limit of 10^5.7^.
3537. Light curves of Qatar-2 transit events
ID:
ivo://CDS.VizieR/J/MNRAS/443/2391
Title:
Light curves of Qatar-2 transit events
Short Name:
J/MNRAS/443/2391
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 17 high-precision light curves of five transits of the planet Qatar-2 b, obtained from four defocused 2m-class telescopes. Three of the transits were observed simultaneously in the Sloan g'r'i'z' passbands using the seven-beam Gamma Ray Burst Optical and Near-Infrared Detector imager on the MPG/ESO 2.2m telescope. A fourth was observed simultaneously in Gunn grz using the Centro Astronomico Hispano Aleman 2.2m telescope with Bonn University Simultaneous Camera, and in r using the Cassini 1.52m telescope. Every light curve shows small anomalies due to the passage of the planetary shadow over a cool spot on the surface of the host star. We fit the light curves with the prism+gemc model to obtain the photometric parameters of the system and the position, size and contrast of each spot. We use these photometric parameters and published spectroscopic measurements to obtain the physical properties of the system to high precision, finding a larger radius and lower density for both star and planet than previously thought. By tracking the change in position of one star-spot between two transit observations, we measure the orbital obliquity of Qatar-2b to be lambda=4.3{deg}+/-4.5{deg}, strongly indicating an alignment of the stellar spin with the orbit of the planet. We calculate the rotation period and velocity of the cool host star to be 11.5+/-0.2d and 3.28+/-0.04km/s at a colatitude of 74{deg}. We assemble the planet's transmission spectrum over the 386-976 nm wavelength range and search for variations of the measured radius of Qatar-2 b as a function of wavelength. Our analysis highlights a possible H_2_/He Rayleigh scattering in the blue.
3538. Light curves of ROTSE-I delta Scuti type stars
ID:
ivo://CDS.VizieR/J/A+A/404/621
Title:
Light curves of ROTSE-I delta Scuti type stars
Short Name:
J/A+A/404/621
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present multi-passband CCD photometry of 20 ROTSE-I {delta} Scuti type pulsating stars and 1 RR Lyrae star to re-classify their variable types using the comparison of amplitudes between V and I passbands. For the re-classification, we used a criterion that pulsating stars have larger amplitude differences between passbands than eclipsing binaries because brightness changes of pulsating stars are mainly due to the temperature variations. As a result, only six stars were re-confirmed as {delta} Scuti variables and thirteen stars turned out to be W UMa type eclipsing binaries. The other two stars were identified as one cataclysmic variable and one non-variable, respectively. Our results suggest that a number of ROTSE-I {delta} Scuti type stars, which do not show typical pulsating light curves of high amplitude {delta} Scuti stars, are W UMa type eclipsing binaries.
3539. Light curves of RR Lyrae stars in M3 (NGC5272)
ID:
ivo://CDS.VizieR/J/ApJS/219/25
Title:
Light curves of RR Lyrae stars in M3 (NGC5272)
Short Name:
J/ApJS/219/25
Date:
21 Oct 2021
Publisher:
CDS
Description:
The overtone and multi-mode RR Lyrae stars in the globular cluster M3 are studied using a 200 day long, B,V, and l_c_ time-series photometry obtained in 2012. 70% of the 52 overtone variables observed show some kind of multi-periodicity (with additional frequency at f_0.61_=f_1O_/0.61 frequency ratio, Blazhko effect, double/multi-mode pulsation, and period doubling). A signal at the 0.587 frequency ratio to the fundamental-mode frequency is detected in the double-mode star, V13, which may be identified as the second radial overtone mode. If this mode identification is correct, then V13 is the first RR Lyrae star showing triple-mode pulsation of the first three radial modes. Either the Blazhko effect or the f_0,61_ frequency (or both of these phenomena) appears in seven double-mode stars. The P_1O_/P_F_ period ratio of RRd stars showing the Blazhko effect are anomalous. A displacement of the main frequency component at the fundamental mode with the value of modulation frequency (or its half), is detected in three Blazhko RRd stars that are parallel with the appearance of the overtone-mode pulsation. The f_0.61_ frequency appears in RRc stars that lie at the blue side of the double-mode region and in RRd stars, raising the suspicion that its occurrence may be connected to double-mode pulsation. The changes of the Blazhko and double-mode properties of the stars are also reviewed using the recent and archive photometric data.
3540. Light curves of RR Lyrae variables in M31
ID:
ivo://CDS.VizieR/J/MNRAS/478/4590
Title:
Light curves of RR Lyrae variables in M31
Short Name:
J/MNRAS/478/4590
Date:
10 Dec 2021 13:45:59
Publisher:
CDS
Description:
We present an analysis of M31 RR Lyrae stars in six different fields using archival imaging from the Hubble Space Telescope. Published data for M31, M33, and several M31 dwarf spheroidal galaxies are also used to study the global properties of RR Lyrae in these systems. From the properties of RR Lyrae stars, we found that the majority of M31 and M33 RRLs are of Oosterhoff I (OoI),while those in M31 dSphs are of Oosterhoff intermediate. The main parameter affecting these Oosterhoff types is likely to be metallicity. Metallicity also plays a role in the lack of RRLs in the high amplitude short period(HASP, defined as those with P<=0.48 and A_V_>=0.75mag) variables in M31 dSphs. This difference in the properties of RRLs between their parent galaxy and satellites, as well as the lack of RRLs in the HASP region in dSphs can also be observed in the Milky Way (MW). Therefore, systems like these dSphs are unlikely to be the main building blocks of the M31 and MW halo.