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1901. Light-curve and radial velocities of BD+42 2782
ID:
ivo://CDS.VizieR/J/AJ/133/255
Title:
Light-curve and radial velocities of BD+42 2782
Short Name:
J/AJ/133/255
Date:
21 Oct 2021
Publisher:
CDS
Description:
BD+42 2782 was recently discovered to be a variable star with a W UMa-type, eclipsing-binary light curve. We have obtained the first photoelectric light curves (R_C_, I_C_) and also the first radial velocity curves for this binary.
1902. Light-curve data for GRB 050319
ID:
ivo://CDS.VizieR/J/ApJ/654/L25
Title:
Light-curve data for GRB 050319
Short Name:
J/ApJ/654/L25
Date:
21 Oct 2021
Publisher:
CDS
Description:
Multiwavelength observations of the optical afterglow of GRB 050319 were performed from 1.31 to 9.92hr after the burst. Our R-band light curves, combined with other published data, can be described by the smooth broken power-law function, with {alpha}_1_=-0.84+/-0.02 to {alpha}_2_=-0.48+/-0.03, 0.04 days after the gamma-ray burst. The optical light curves are characterized by shallow decays as was also observed in the X-rays which may have a similar origin, related to energy injection. However, our observations indicate that there is still a puzzle concerning the chromatic breaks in the R-band light curve (at 0.04 days) and the X-ray light curve (at 0.004 days) that remains to be solved.
1903. Light curve of OGLE-2018-BLG-0677
ID:
ivo://CDS.VizieR/J/AJ/159/256
Title:
Light curve of OGLE-2018-BLG-0677
Short Name:
J/AJ/159/256
Date:
08 Dec 2021
Publisher:
CDS
Description:
We report the analysis of the microlensing event OGLE-2018-BLG-0677. A small feature in the light curve of the event leads to the discovery that the lens is a star-planet system. Although there are two degenerate solutions that could not be distinguished for this event, both lead to a similar planet-host mass ratio. We perform a Bayesian analysis based on a Galactic model to obtain the properties of the system and find that the planet corresponds to a super- Earth/sub-Neptune with a mass of M_planet_=3.96_-2.66_^+5.88^M_{Earth}_. The host star has a mass of M_host_=0.12_-0.08_^+0.14^M_{odot}_. The projected separation for the inner and outer solutions are 0.63_-0.17_^+0.20^au and 0.72_-0.19_^+0.23^au respectively. At {Delta}{chi}^2^={chi}^2^(1L1S-{chi}^2^(2L1S)=46, this is by far the lowest {Delta}{chi}^2^ for any securely detected microlensing planet to date, a feature that is closely connected to the fact that it is detected primarily via a "dip" rather than a "bump."
1904. Light curve of the dwarf nova AT 2020iko
ID:
ivo://CDS.VizieR/J/AJ/161/15
Title:
Light curve of the dwarf nova AT 2020iko
Short Name:
J/AJ/161/15
Date:
08 Dec 2021
Publisher:
CDS
Description:
The ongoing Zwicky Transient Facility (ZTF) survey is generating a massive alert rate from a variety of optical transients and variable stars, which are being filtered down to subsets meeting user-specified criteria by broker systems such as the Arizona-NOIRLab Temporal Analysis and Response to Events System (ANTARES). In a beta implementation of the algorithm of Soraisam et al. on ANTARES, we flagged AT 2020iko from the ZTF real-time alert stream as an anomalous source. This source is located close to a red extended Sloan Digital Sky Survey source. In the first few epochs of detection, it exhibited a V-shaped brightness profile, preceded by nondetections both in ZTF and in the All-Sky Automated Survey for Supernovae extending to 2014. Its full light curve shows a precursor event, followed by a main superoutburst and at least two rebrightenings. A low-resolution spectrum of this source points to a dwarf nova (DN) nature. Although some of the features of AT 2020iko indicate an SU UMa-type DN, its large amplitude, presence of rebrightenings, and inferred supercycle period of >~6yr are in favor of AT 2020iko being a new WZ Sge- type DN candidate, a subset of rare DNe consisting of extreme mass-ratio (<0.1) binaries with an orbital period around the period minimum. The precusor event of AT 2020iko brightened by 6.5mag, while its decay spanned 3-5mag. We speculate this superoutburst is associated with a less expanded accretion disk than in typical superoutbursts in WZ Sge systems, with the large depth of the precursor decay implying an extremely small mass ratio. To the best of our knowledge, such a precursor event has not been recorded for any DN. This result serves to demonstrate the efficacy of our real-time anomaly search algorithm.
1905. Light curve of T Pyx from 1890 to 2011
ID:
ivo://CDS.VizieR/J/ApJ/773/55
Title:
Light curve of T Pyx from 1890 to 2011
Short Name:
J/ApJ/773/55
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery by M. Linnolt on JD 2455665.7931 (UT 2011 April 14.29) of the sixth eruption of the recurrent nova T Pyxidis. This discovery was made just as the initial fast rise was starting, so with fast notification and response by observers worldwide, the entire initial rise was covered (the first for any nova), and with high time resolution in three filters. The speed of the rise peaked at 9mag/day, while the light curve is well fit over only the first two days by a model with a uniformly expanding sphere. We also report the discovery by R. Stubbings of a pre-eruption rise starting 18 days before the eruption, peaking 1.1mag brighter than its long-time average, and then fading back toward quiescence 4 days before the eruption. This unique and mysterious behavior is only the fourth known (with V1500 Cyg, V533 Her, and T CrB) anticipatory rise closely spaced before a nova eruption. We present 19 timings of photometric minima from 1986 to 2011 February, where the orbital period is fast increasing with P/dot{P}=+313000yr. From 2008 to 2011, T Pyx had a small change in this rate of increase, so that the orbital period at the time of eruption was 0.07622950+/-0.00000008 days. This strong and steady increase of the orbital period can only come from mass transfer, for which we calculate a rate of (1.7-3.5)x10^-7^M_{sun}_/yr. We report 6116 magnitudes between 1890 and 2011, for an average B=15.59+/-0.01 from 1967 to 2011, which allows for an eruption in 2011 if the blue flux is nearly proportional to the accretion rate. The ultraviolet-optical-infrared spectral energy distribution is well fit by a power law with f_{nu}_{prop.to}{nu}^1.0^, although the narrow ultraviolet region has a tilt with a fit of f_{nu}_{prop.to}{nu}^1/3^.
1906. Light curve of V945 Cen in Geneva photometry
ID:
ivo://CDS.VizieR/J/A+A/520/A73
Title:
Light curve of V945 Cen in Geneva photometry
Short Name:
J/A+A/520/A73
Date:
21 Oct 2021
Publisher:
CDS
Description:
A detailed analysis of multicolour Geneva photometry and high-resolution echelle spectroscopy of the B8.5V star V945 Cen (HD 112409, V=5.2mag) whose short-term periodic variability was first detected from the HIPPARCOS data, led to the finding that the object is an ellipsoidal variable and a close double-lined spectroscopic binary with a 0.6496d orbital period and a circular orbit. The components have spectral types B7 and B8.5 and are both main-sequence objects. The system is detached but close to a contact configuration and is observed at an inclination of ~23-24{deg}. A notable finding is that the optical spectrum also contains a third system of spectral lines corresponding to a late B spectral type that remained stationary during the 5 days of spectral observations. From several independent lines of reasoning, we tentatively conclude that the third spectrum belongs to a real third body in the system. However, the possibility that it instead originates in circumbinary gas cannot be excluded completely, and additional spectral and interferometric observations are required to help us determine its origin conclusively.
1907. Light curve segments of 22 host stars with TESS
ID:
ivo://CDS.VizieR/J/AJ/160/155
Title:
Light curve segments of 22 host stars with TESS
Short Name:
J/AJ/160/155
Date:
10 Dec 2021
Publisher:
CDS
Description:
We present a systematic phase curve analysis of known transiting systems observed by the Transiting Exoplanet Survey Satellite (TESS) during year one of the primary mission. Using theoretical predictions for the amplitude of the planetary longitudinal atmospheric brightness modulation, stellar ellipsoidal distortion and Doppler boosting, as well as brightness considerations to select targets with likely detectable signals, we applied a uniform data processing and light-curve modeling framework to fit the full-orbit phase curves of 22 transiting systems with planet-mass or brown dwarf companions, including previously published systems. Statistically significant secondary eclipse depths and/or atmospheric brightness modulation amplitudes were measured for HIP65A, WASP-18, WASP-19, WASP-72, WASP-100, WASP-111, WASP-121, and WASP-122/KELT-14. For WASP-100b, we found marginal evidence that the brightest region of the atmosphere is shifted eastward away from the substellar point. We detected significant ellipsoidal distortion signals in the light curves of HIP65A, TOI-503, WASP-18, and WASP-30, with HIP65A, TOI-503 and WASP-18 also exhibiting Doppler boosting. The measured amplitudes of these signals agree with the predictions of theoretical models. Combining the optical secondary eclipse depths with previously published Spitzer 3.6 and 4.5{mu}m measurements, we derived dayside brightness temperatures and visible-light geometric albedos for a subset of the analyzed systems. We also calculated updated transit ephemerides combining the transit timings from the TESS light curves with previous literature values.
1908. Light curves for the eclipsing binary V1094 Tau
ID:
ivo://CDS.VizieR/J/A+A/578/A25
Title:
Light curves for the eclipsing binary V1094 Tau
Short Name:
J/A+A/578/A25
Date:
21 Oct 2021
Publisher:
CDS
Description:
V1094 Tau is a bright eclipsing binary star with an orbital period close to 9 days containing two stars similar to the Sun. Our aim is to test models of Sun-like stars using precise and accurate mass and radius measurements for both stars in V1094 Tau. We present new spectroscopy of V1094 Tau which we use to estimate the effective temperatures of both stars and to refine their spectroscopic orbits. We also present new, high-quality photometry covering both eclipses of V1094 Tau in the Stroemgren uvby system and in the Johnson V-band. The masses, radii and effective temperatures of the stars in V1094 Tau are found to be M_A_=1.0965+/-0.0040M_{sun}_, R_A_=1.4109+/-0.0058R_{sun}_, T_eff,A_=5850+/-100K, and M_B_=1.0120+/-0.0028M_{sun}_, R_B_=1.1063+/-0.0066R_{sun}_, T_eff,B_=5700+/-100K. An analysis of the times of mid-eclipse and the radial velocity data reveals apsidal motion with a period of 14500+/-3700-years. The observed masses, radii and effective temperatures are consistent with stellar models for an age ~6Gyr if the stars are assumed to have a metallicity similar to the Sun. This estimate is in reasonable agreement with our estimate of the metallicity derived using Stroemgren photometry and treating the binary as a single star ([Fe/H]=-0.09+/-0.11). The rotation velocities of the stars suggest that V1094 Tau is close to the limit at which tidal interactions between the stars force them to rotate pseudo-syncronously with the orbital motion.
1909. Light curves of AL Gem and BM Mon
ID:
ivo://CDS.VizieR/J/AJ/143/13
Title:
Light curves of AL Gem and BM Mon
Short Name:
J/AJ/143/13
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the CCD photometry of two Algol-type binaries, AL Gem and BM Mon, observed from 2008 November to 2011 January. With the updated Wilson-Devinney program, photometric solutions were deduced from their EA-type light curves. The mass ratios and fill-out factors of the primaries are found to be q_ph_=0.090(+/-0.005) and f_1_=47.3%(+/-0.3%) for AL Gem, and q_ph_=0.275(+/-0.007) and f_1_=55.4%(+/-0.5%) for BM Mon, respectively. By analyzing the O-C curves, we discovered that the periods of AL Gem and BM Mon change in a quasi-sinusoidal mode, which may possibly result from the light-time effect via the presence of a third body. Periods, amplitudes, and eccentricities of light-time orbits are 77.83(+/-1.17)yr, 0.0204(+/-0.0007)d, and 0.28(+/-0.02) for AL Gem and 97.78(+/-2.67)yr, 0.0175(+/-0.0006)d, and 0.29(+/-0.02) for BM Mon, respectively. Assumed to be in a coplanar orbit with the binary, the masses of the third bodies would be 0.29M_{sun}_ for AL Gem and 0.26M_{sun}_ for BM Mon. This kind of additional companion can extract angular momentum from the close binary orbit, and such processes may play an important role in multiple star evolution.
1910. Light curves of Algol-type binaries. VI. FR Ori
ID:
ivo://CDS.VizieR/J/AJ/147/35
Title:
Light curves of Algol-type binaries. VI. FR Ori
Short Name:
J/AJ/147/35
Date:
21 Oct 2021
Publisher:
CDS
Description:
New photometry of the neglected eclipsing binary FR Orionis was obtained in 2012 November and December. Using the updated Wilson-Devinney program, the photometric elements were deduced from two-color light curves. The results indicate that this system is a semi-detached binary, with a mass ratio of 0.325(+/-0.002) and a fill-out factor of the primary of f_p_=73.5(+/-0.2)%. The oscillating light curves imply that FR Ori may be an oscillating EA (oEA)-type star with a rapidly pulsating, mass-accreting primary component. After we removed the theoretical light curves from the observations, Fourier analysis revealed that the more massive component possibly shows a {delta} Scuti type pulsation with four detected frequencies. The dominant frequency is f_1_=38.6c/day (i.e., P_puls_=37.3minutes), and the pulsation constant is Q=0.014days. Based on all available eclipsing times, the orbital period is undergoing a secular period increase with a rate of dP/dt=+8.85(+/-0.66)x10^-8^day/yr, which may be interpreted by mass transfer from the secondary to the primary. We expect that the more massive component will fill its Roche lobe due to mass transfer of the secondary. Therefore, the oEA star FR Ori may evolve into a contact configuration.