- ID:
- ivo://CDS.VizieR/J/AJ/159/261
- Title:
- LC of microlensing event OGLE-2012-BLG-0838
- Short Name:
- J/AJ/159/261
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We present the discovery of a planet on a very wide orbit in the microlensing event OGLE-2012-BLG-0838. The signal of the planet is well separated from the main peak of the event and the planet-star projected separation is found to be twice the Einstein ring radius, which corresponds to a projected separation of ~4au. Similar planets around low-mass stars are very hard to find using any technique other than microlensing. We discuss microlensing model fitting in detail and discuss the prospects for measuring the mass and distance of the lens system directly.
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3442. LC of the TNO Varuna
- ID:
- ivo://CDS.VizieR/J/ApJ/883/L21
- Title:
- LC of the TNO Varuna
- Short Name:
- J/ApJ/883/L21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From CCD observations carried out with different telescopes, we present short-term photometric measurements of the large trans-Neptunian object Varuna in 10 epochs, spanning around 19 years. We observe that the amplitude of the rotational light curve has changed considerably during this period of time from 0.41 to 0.55mag. In order to explain this variation, we constructed a model in which Varuna has a simple triaxial shape, assuming that the main effect comes from the change of the aspect angle as seen from Earth, due to Varuna's orbital motion in the 19yr time span. The best fits to the data correspond to a family of solutions with axial ratios b/a between 0.56 and 0.60. This constrains the pole orientation in two different ranges of solutions presented here as maps. Apart from the remarkable variation of the amplitude, we have detected changes in the overall shape of the rotational light curve over shorter timescales. After the analysis of the periodogram of the residuals to a 6.343572hr double-peaked rotational light-curve fit, we find a clear additional periodicity. We propose that these changes in the rotational light-curve shape are due to a large and close-in satellite whose rotation induces the additional periodicity. The peak-to-valley amplitude of this oscillation is in the order of 0.04mag. We estimate that the satellite orbits Varuna with a period of 11.9819hr (or 23.9638hr), assuming that the satellite is tidally locked, at a distance of ~1300km (or ~2000km) from Varuna, outside the Roche limit.
- ID:
- ivo://CDS.VizieR/J/AJ/161/194
- Title:
- LCs and RVs of 5 exoplanets discovered by TESS
- Short Name:
- J/AJ/161/194
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- We present the discovery and characterization of five hot and warm Jupiters TOI-628b (TIC281408474; HD288842), TOI-640b (TIC147977348), TOI-1333b (TIC395171208, BD+473521A), TOI-1478b (TIC409794137), and TOI-1601b (TIC139375960)-based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (R_P_=1.01-1.77R_J_) and have masses that range from 0.85 to 6.33M_J_. The host stars of these systems have F and G spectral types (5595<~Teff<~6460K) and are all relatively bright (9.5<V<10.8, 8.2<K<9.3), making them well suited for future detailed characterization efforts. Three of the systems in our sample (TOI-640b, TOI-1333b, and TOI-1601b) orbit subgiant host stars (logg<4.1). TOI-640b is one of only three known hot Jupiters to have a highly inflated radius (R_P_>1.7R_J_, possibly a result of its host star's evolution) and resides on an orbit with a period longer than 5days. TOI-628b is the most massive, hot Jupiter discovered to date by TESS with a measured mass of 6.31_-0.30_^+0.28^M_J_ and a statistically significant, nonzero orbital eccentricity of e=0.074_-0.022_^+0.021^. This planet would not have had enough time to circularize through tidal forces from our analysis, suggesting that it might be remnant eccentricity from its migration. The longest-period planet in this sample, TOI-1478b (P=10.18days), is a warm Jupiter in a circular orbit around a near-solar analog. NASA's TESS mission is continuing to increase the sample of well-characterized hot and warm Jupiters, complementing its primary mission goals.
- ID:
- ivo://CDS.VizieR/J/ApJ/860/100
- Title:
- LCs of 26 hydrogen-poor superluminous SNe
- Short Name:
- J/ApJ/860/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the light-curve properties of a sample of 26 spectroscopically confirmed hydrogen-poor superluminous supernovae (SLSNe-I) in the Palomar Transient Factory survey. These events are brighter than SNe Ib/c and SNe Ic-BL, on average, by about 4 and 2mag, respectively. The peak absolute magnitudes of SLSNe-I in rest-frame g band span -22<~M_g_<~-20mag, and these peaks are not powered by radioactive ^56^Ni, unless strong asymmetries are at play. The rise timescales are longer for SLSNe than for normal SNe Ib/c, by roughly 10 days, for events with similar decay times. Thus, SLSNe-I can be considered as a separate population based on photometric properties. After peak, SLSNe-I decay with a wide range of slopes, with no obvious gap between rapidly declining and slowly declining events. The latter events show more irregularities (bumps) in the light curves at all times. At late times, the SLSN-I light curves slow down and cluster around the ^56^Co radioactive decay rate. Powering the late-time light curves with radioactive decay would require between 1 and 10M_{sun}_ of Ni masses. Alternatively, a simple magnetar model can reasonably fit the majority of SLSNe-I light curves, with four exceptions, and can mimic the radioactive decay of ^56^Co, up to ~400days from explosion. The resulting spin values do not correlate with the host-galaxy metallicities. Finally, the analysis of our sample cannot strengthen the case for using SLSNe-I for cosmology.
- ID:
- ivo://CDS.VizieR/J/AJ/161/293
- Title:
- LCs of OGLE-2018-BLG-0567 and OGLE-2018-BLG-0962
- Short Name:
- J/AJ/161/293
- Date:
- 10 Dec 2021
- Publisher:
- CDS
- Description:
- We present the analyses of two microlensing events, OGLE-2018-BLG-0567 and OGLE-2018-BLG-0962. In both events, the short-lasting anomalies were densely and continuously covered by two high-cadence surveys. The light-curve modeling indicates that the anomalies are generated by source crossings over the planetary caustics induced by planetary companions to the hosts. The estimated planet/host separation (scaled to the angular Einstein radius {theta}E) and mass ratio are (s, qx10^3^)=(1.81{+/-}0.02, 1.24{+/-}0.07) and (s, qx10^3^)=(1.25{+/-}0.03, 2.38{+/-}0.08), respectively. From Bayesian analyses, we estimate the host and planet masses as (M_h_, M_p_)=(0.25_-0.13_^+0.27^, M{odot}, 0.32_-0.17_^+0.34^, M_J_) and (M_h_, M_p_=(0.54_-0.28_^+0.33^, M{odot}, 1.34_-0.70_^+0.82^, M_J_), respectively. These planetary systems are located at a distance of 7.06_-1.15_^+0.93^kpc for OGLE-2018-BLG-0567 and 6.50_-1.75_^+1.06^kpc for OGLE-2018-BLG-0962, suggesting that they are likely to be near the Galactic bulge. The two events prove the capability of current high-cadence surveys for finding planets through the planetary-caustic channel. We find that most published planetary-caustic planets are found in Hollywood events in which the source size strongly contributes to the anomaly cross-section relative to the size of the caustic.
- ID:
- ivo://CDS.VizieR/J/ApJ/901/61
- Title:
- LCs of 4 superluminous SNe from the ZTF survey
- Short Name:
- J/ApJ/901/61
- Date:
- 17 Feb 2022 13:56:34
- Publisher:
- CDS
- Description:
- We present photometry and spectroscopy of four hydrogen-poor luminous supernovae discovered during the 2-month long science commissioning and early operations of the Zwicky Transient Facility (ZTF) survey. Three of these objects, SN 2018bym (ZTF18aapgrxo), SN 2018avk (ZTF18aaisyyp), and SN 2018bgv (ZTF18aavrmcg), resemble typical SLSN-I spectroscopically, while SN 2018don (ZTF18aajqcue) may be an object similar to SN 2007bi experiencing considerable host galaxy reddening, or an intrinsically long-lived, luminous, and red SN Ic. We analyze the light curves, spectra, and host galaxy properties of these four objects and put them in context of the population of SLSN-I. SN 2018bgv stands out as the fastest-rising SLSN-I observed to date, with a rest-frame g-band rise time of just 10 days from explosion to peak-if it is powered by magnetar spin-down, the implied ejecta mass is only ~1M_{sun}_. SN 2018don also displays unusual properties-in addition to its red colors and comparatively massive host galaxy, the light curve undergoes some of the strongest light-curve undulations postpeak seen in an SLSN-I, which we speculate may be due to interaction with circumstellar material. We discuss the promises and challenges of finding SLSNe in large-scale surveys like ZTF given the observed diversity in the population.
- ID:
- ivo://CDS.VizieR/J/ApJ/809/L19
- Title:
- LCs of the RR Lyrae stars V350 Lyr & KIC 7021124
- Short Name:
- J/ApJ/809/L19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent photometric space missions, such as CoRoT and Kepler, revealed that many RR Lyrae stars pulsate --beyond their main radial pulsation mode-- in low-amplitude modes. Space data seem to indicate a clear trend that, namely, overtone (RRc) stars and modulated fundamental (RRab) RR Lyrae stars ubiquitously show additional modes, while non-Blazhko RRab stars never do. Two Kepler stars (V350Lyr and KIC7021124), however, apparently seemed to break this rule: they were classified as non-Blazhko RRab stars showing additional modes. We processed Kepler pixel photometric data of these stars. We detected a small amplitude (but significant) Blazhko effect for both stars by using the resulting light curves and O-C diagrams. This finding strengthens the apparent connection between the Blazhko effect and the excitation of additional modes. In addition, it yields a potential tool for detecting Blazhko stars through the additional frequency patterns, even if we have only short but accurate time series observations. V350 Lyr shows the smallest amplitude multiperiodic Blazhko effect ever detected.
- ID:
- ivo://CDS.VizieR/J/ApJS/227/6
- Title:
- LCs re-analysis of Mira variables in ASAS
- Short Name:
- J/ApJS/227/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have developed an interactive PYTHON code and derived crucial ephemeris data of 99.4% of all stars classified as "Mira" in the ASAS database, referring to pulsation periods, mean maximum magnitudes, and whenever possible, the amplitudes among others. We present a statistical comparison between our results and those given by the International Variable Star Index (VSX) of the American Association of Variable Star Observers, as well as those determined with the machine learning automatic procedure of Richards et al. (2012, J/ApJS/203/32). Our periods are in good agreement with those of the VSX in more than 95% of the stars. However, when comparing our periods with those of Richards et al., the coincidence rate is only 76% and most of the remaining cases refer to aliases. We conclude that automatic codes still require more refinements in order to provide reliable period values. Period distributions of the target stars show three local maxima around 215, 275, and 330 days, apparently of universal validity; their relative strength seems to depend on galactic longitude. Our visual amplitude distribution turns out to be bimodal, however, 1/3 of the targets have rather small amplitudes (A<2.5^m^) and could refer to semiregular variables (SR). We estimate that about 20% of our targets belong to the SR class. We also provide a list of 63 candidates for period variations and a sample of 35 multiperiodic stars that seem to confirm the universal validity of typical sequences in the double period and in the Petersen diagrams.
- ID:
- ivo://CDS.VizieR/J/ApJ/836/14
- Title:
- LCs & spectra of SDSS J1515+1511 lens system
- Short Name:
- J/ApJ/836/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze new optical observations of the gravitational lens system SDSS J1515+1511. These include a 2.6-year photometric monitoring with the Liverpool Telescope (LT) in the r band, as well as a spectroscopic follow-up with the LT and the Gran Telescopio Canarias (GTC). Our r-band LT light curves cover a quiescent microlensing period of the doubly imaged quasar at z_s_=2.049, which permits us to robustly estimate the time delay between the two images A and B: 211+/-5d (1{sigma} confidence interval; A is leading). Unfortunately, the main lensing galaxy (G1) is so faint and close to the bright quasar that it is not feasible to accurately extract its spectrum through the GTC data. However, assuming the putative redshift z_G1_=0.742, the GTC and LT spectra of the distant quasar are used to discuss the macrolens magnification, and the extinction and microlensing effects in G1. The new constraints on the time delay and macrolens magnification ratio essentially do not change previous findings on the mass scale of G1 and external shear, while the redshift of the lensing mass is found to be consistent with the assumed value of z_G1_. This is clear evidence that G1 is indeed located at z_G1_=0.742. From the GTC data, we also obtain the redshift of two additional objects (the secondary galaxy G2 and a new absorption system) and discuss their possible roles in the lens scenario.
- ID:
- ivo://CDS.VizieR/J/A+A/611/A9
- Title:
- LDN 183 and LDN 169 Vilnius photometry
- Short Name:
- J/A+A/611/A9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The interstellar extinction is investigated in a 2x2deg area containing the dust and molecular clouds LDN 183 (MBM 37) and LDN 169, centered at RA=15h54m, DEC=-3{deg}. The study is based on photometric classification in spectral and luminosity classes of 782 stars selected from the catalogs of 1299 stars down to V=20mag observed in the Vilnius seven-color system. For control, the MK types for 18 brightest stars with V between 8.5 and 12.8mag were determined spectroscopically. For 14 stars, located closer than 200pc, distances were calculated from trigonometric parallaxes taken from the Gaia Data Release 1. For about 70% of the observed stars, two-dimensional spectral types, interstellar extinctions Av and distances were determined. Using 57 stars closer than 200pc we estimate that the front edge of the clouds begins at 105+/-8pc. The extinction layer in the vicinities of the clouds can be about 20pc thick. In the outer parts of the clouds and between the clouds the extinction is 2.0-2.5mag. Behind the Serpens/Libra clouds the extinction range does not increase; this means that the dust layer at 105pc is a single extinction source.
