scholarly journals Systematic KMTNet Planetary Anomaly Search. II. Six New q < 2 × 10−4 Mass-ratio Planets

2022 ◽  
Vol 163 (2) ◽  
pp. 43
Author(s):  
Kyu-Ha Hwang ◽  
Weicheng Zang ◽  
Andrew Gould ◽  
Andrzej Udalski ◽  
Ian A. Bond ◽  
...  
Keyword(s):  
Light Curve ◽  
Light Curves ◽  
The Other ◽  
Mass Ratio ◽  
Mass Ratios ◽  
Prime Fields ◽  
Einstein Radius ◽  
Ratio Range

Abstract We apply the automated AnomalyFinder algorithm of Paper I to 2018–2019 light curves from the ≃13 deg2 covered by the six KMTNet prime fields, with cadences Γ ≥ 2 hr−1. We find a total of 11 planets with mass ratios q < 2 × 10−4, including 6 newly discovered planets, 1 planet that was reported in Paper I, and recovery of 4 previously discovered planets. One of the new planets, OGLE-2018-BLG-0977Lb, is in a planetary caustic event, while the other five (OGLE-2018-BLG-0506Lb, OGLE-2018-BLG-0516Lb, OGLE-2019-BLG-1492Lb, KMT-2019-BLG-0253, and KMT-2019-BLG-0953) are revealed by a “dip” in the light curve as the source crosses the host-planet axis on the opposite side of the planet. These subtle signals were missed in previous by-eye searches. The planet-host separations (scaled to the Einstein radius), s, and planet-host mass ratios, q, are, respectively, (s, q × 105) = (0.88, 4.1), (0.96 ± 0.10, 8.3), (0.94 ± 0.07, 13), (0.97 ± 0.07, 18), (0.97 ± 0.04, 4.1), and (0.74, 18), where the “ ± ” indicates a discrete degeneracy. The 11 planets are spread out over the range − 5 < log q < − 3.7 . Together with the two planets previously reported with q ∼ 10−5 from the 2018–2019 nonprime KMT fields, this result suggests that planets toward the bottom of this mass-ratio range may be more common than previously believed.

scholarly journals New Data on the Eclipsing Binary V1848 Ori and Improved Orbital and Light Curve Solutions

2020 ◽  
Vol 29 (1) ◽  
pp. 72-80 ◽  
Author(s):  
Fatemeh Davoudi ◽  
Atila Poro ◽  
Fahri Alicavus ◽  
Afshin Halavati ◽  
Saeed Doostmohammadi ◽  
...  
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Mass Function ◽  
Light Curves ◽  
Complete Analysis ◽  
Physical Parameters ◽  
Mass Ratio ◽  
Third Body ◽  
Eclipsing Binary

AbstractNew observations of the eclipsing binary system V1848 Ori were carried out using the V filter resulting in a determination of new times of minima and new ephemeris were obtained. We presented the first complete analysis of the system’s orbital period behavior and analysis of O-C diagram done by the GA and MCMC approaches in OCFit code. The O-C diagram demonstrates a sinusoidal trend in the data; this trend suggests a cyclic change caused by the LITE effect with a period of 10.57 years and an amplitude of 7.182 minutes. It appears that there is a third body with mass function of f (m3) = 0.0058 M⊙ in this binary system. The light curves were analyzed using the Wilson-Devinney code to determine some geometrical and physical parameters of the system. These results show that V1848 Ori is a contact W UMa binary system with the mass ratio of q = 0.76 and a weak fillout factor of 5.8%. The O’Connell effect was not seen in the light curve and there is no need to add spot.

scholarly journals UBVRI Photometric Analysis of the Solar-Type Eclipsing Binary TYC 3034-299-1

2012 ◽  
Vol 2012 ◽  
pp. 1-11
Author(s):  
Ronald G. Samec ◽  
Adam Jaso ◽  
Jesse White ◽  
Danny R. Faulkner ◽  
Nicholas Blum ◽  
...  
Keyword(s):  
Light Curve ◽  
Massive Star ◽  
Light Curves ◽  
Dark Spot ◽  
Mass Ratio ◽  
Photometric Analysis ◽  
Contact Binary ◽  
Solar Type ◽  
Curve Solution ◽  
Light Curve Solution

TYC 3034-0299-1 (CVn) is a magnetically active, contact binary, ROTSE variable. UBVRcIc light curves are presented along with a period study and a simultaneous UBVRI light curve solution. Our light curves show eclipse amplitudes of 0.72 and 0.62 mags (V) in the primary and secondary eclipses. Modeled results include a dark spot region, found at longitude 51°, a 24% Roche lobe fill-out, and a mass ratio of 0.48. A total eclipse is found to occur in the secondary eclipse making TYC 3034-0299-1 a W-type (less massive star is hotter) W UMa variable.

scholarly journals TU Muscae and the Early-type Overcontact Binaries

2002 ◽  
Vol 187 ◽  
pp. 319-323
Author(s):  
Dirk Terrell
Keyword(s):  
Light Curve ◽  
Stellar Evolution ◽  
Spectroscopic Analysis ◽  
Light Curves ◽  
Early Type ◽  
Mass Ratio ◽  
Reflection Effect ◽  
Detailed Treatment

AbstractA simultaneous photometric and spectroscopic analysis of the purported early-type overcontact binary TU Muscae is presented. With a well-behaved light curve and a mass ratio far from unity, if TU Mus is indeed an overcontact system, it presents an interesting challenge for 3-D stellar evolution codes, like the Djehuty code, that will be applied to early-type overcontact binaries. The analysis shows TU Mus is slightly overcontact and that a detailed treatment of the reflection effect is important for modeling the light curves.

scholarly journals Mass-Ratio Determination in Contact Binaries

1974 ◽  
Vol 59 ◽  
pp. 199-199
Author(s):  
J. B. Hutchings
Keyword(s):  
Spectroscopic Data ◽  
Theoretical Work ◽  
Light Curves ◽  
Line Profiles ◽  
Mass Ratio ◽  
Recent Theoretical Work ◽  
Mass Ratios ◽  
Contact Binaries ◽  
Ratio Determination ◽  
The Masses

In the wake of recent theoretical work on contact systems (e.g. Whelan, 1972; Biermann and Thomas, 1972; Lucy, 1968), it is of importance to determine fundamental data from observations. This has been done recently by several groups in analysing light curves (Mochnacki and Doughty, 1972; Hutchings and Hill, 1973; Wilson and Devinney, 1973), and it is found that shapes, temperature differences and distributions, and mass-ratios, can be determined in many cases. However, where spectroscopic data are also available, the mass-ratios are not always in agreement. Using the photometric models, it is possible (Hutchings, 1973) to calculate the distortion of line profiles resulting (primarily) from the non-uniform brightness over the component stars in these systems. This distortion leads to the characteristically observed ‘square’ velocity curves for the systems (e.g. Binnendijk, 1967). Correction for the effect in most cases (a) resolves the mass-ratio discrepancy and (b) leads to better estimates for the masses. The faintness of most contact systems makes detailed spectroscopy difficult, but there appears to be a need for further work in the directions outlined here to improve the fundamental data available on them. These results should also be borne in mind in inspecting previous work on contact binaries.

scholarly journals Search for Dormant Black Holes in Ellipsoidal Variables I. Revisiting the Expected Amplitudes of the Photometric Modulation

2020 ◽  
Author(s):  
Roy Gomel ◽  
Simchon Faigler ◽  
Tsevi Mazeh
Keyword(s):  
Light Curve ◽  
Compact Object ◽  
Large Data ◽  
Light Curves ◽  
Large Data Sets ◽  
Data Sets ◽  
Mass Ratio ◽  
Stellar Radius ◽  
Short Period ◽  
Stellar Temperature

Abstract Ellipsoidal variables present light-curve modulations caused by stellar distortion, induced by tidal interaction with their companions. An analytical approximated model of the ellipsoidal modulation is given as a discrete Fourier series by Morris and Naftilan 1993 (MN93). Based on numerical simulations using the PHOEBE code we present here updated amplitudes of the first three harmonics of the model. The expected amplitudes are given as a function of the mass ratio and inclination of the binary system and the fillout factor of the primary—the ratio between the stellar radius and that of its Roche lobe. The corrections can get up to 30% relative to the MN93 model for fillout factors close to unity. The updated model can be instrumental in searching for short-period binaries with compact-object secondaries in large data sets of photometric light curves. As shown in one OGLE light-curve example, the minimum mass ratio can be obtained by using only the amplitudes of the three harmonics and an estimation of the stellar temperature. High enough amplitudes can help to identify binaries with mass ratios larger than unity, some of which might have compact companions.

scholarly journals A Search for Companions to L Dwarfs

2003 ◽  
Vol 211 ◽  
pp. 303-304
Author(s):  
P. R. Allen ◽  
D. W. Koerner ◽  
M. W. McElwain ◽  
G. R. Murphy ◽  
I. Neill Reid ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
The Other ◽  
Evolutionary Models ◽  
Mass Ratio ◽  
Upper Limits ◽  
Mass Ratios ◽  
L Dwarfs

We present the results of two imaging surveys for companions to low-luminosity dwarfs, one with Keck to a limiting magnitude of K = 20, and the other with HST to a limiting magnitude of I = 23. No companions were found at separations of 0″.5 to 20″.0, but seven companions were found within 0″.5. Based on sub-stellar evolutionary models, we estimate the companion detection efficiency as a function of mass ratio. This modeling, coupled with the data, place strong upper limits on the mass ratios of unobserved companions. We conclude that no companions exist in the optimal sensitivity regions of both surveys for q > 0.85 (HST), and q > 0.4 (Keck).

SPECTRAL FUNCTION SUM RULES IN SU(3) × SU(3)

1967 ◽  
Vol 45 (12) ◽  
pp. 3901-3902 ◽  
Author(s):  
J. W. Moffat ◽  
P. J. O'Donnell
Keyword(s):  
Spectral Function ◽  
Sum Rules ◽  
The Other ◽  
Mass Ratio ◽  
Spectral Functions ◽  
Other Hand ◽  
Mass Ratios

Recently derived spectral function sum rules have been used to obtain mass ratios, assuming that the spectral functions are dominated by certain low-lying states. The strangeness-carrying resonance mass ratio is investigated and the predicted value is found to depend critically upon the ratio FK/Fπ. Using the experimental value FK/Fπ = 1.28 ± 0.02, it is found that [Formula: see text]. On the other hand, from the input value [Formula: see text] we get [Formula: see text].

scholarly journals Star Spots on AR Lac Type Stars

1977 ◽  
Vol 4 (2) ◽  
pp. 397-403 ◽  
Author(s):  
D. M. Popper
Keyword(s):  
Main Sequence ◽  
Light Curves ◽  
Close Binaries ◽  
Good Precision ◽  
Mass Ratio ◽  
Considerable Uncertainty ◽  
Rs Cvn Stars ◽  
Mass Ratios ◽  
Definition Of

There is no generally accepted definition of AR Lac Stars, and the term RS CVn stars is used interchangeably or to refer to a particular subgroup. For the purposes of this discussion I use the term AR Lac stars to refer to detached close binaries showing Ca II emission in at least the cooler component outside eclipse, the hotter component being a main-sequence or subgiant star of spectral type F or G. Most of the systems show irregularities in their light curves as well as period changes. In order to determine whether a system is detached, one must know both the mass ratio and the relative radii. The determination of minimum masses is a fairly straightforward spectroscopic task, and provisional values are available for 22 of the systems, two or possibly three of them being non-eclipsing. All but 3 (AD Cap, RT Lac, RV Lib) have masses of the two components within 30% of each other. Because of appreciable irregularities in the light curves, the radii are subject to considerable uncertainty even when photometry of good precision is available. Nevertheless the 9 systems with very provisional radii all appear to be detached. These all have mass ratios near unity. We may assume, as a working hypothesis, that the other systems with mass ratios near unity are also detached and hence also belong in the AR Lac group. Most of the data referred to are to be found in IBVS 1083.

Light curve analysis of six totally eclipsing W UMa binaries

2020 ◽  
Author(s):  
Olivera Latković ◽  
Atila Čeki
Keyword(s):  
Light Curve ◽  
Parameter Space ◽  
Curve Analysis ◽  
Light Curves ◽  
Evolutionary Status ◽  
Search Procedure ◽  
Light Curve Analysis ◽  
Short Period ◽  
Mass Ratios ◽  
First Time

Abstract We analyze multicolor light curves of six totally eclipsing, short-period W UMa binaries and derive, for the first time, their orbital and stellar parameters. The mass ratios are established robustly through an automated q-search procedure that performs an heuristic survey of the parameter space. Five stars belong to the W and one to the A subtype. The mass ratios range from 0.23 to 0.51 and the fillouts from $10\%$ to $15\%$. We estimate the ages and discuss the evolutionary status of these objects in comparison with a sample of other short-period W UMa binaries from the literature.

scholarly journals Photometric and spectroscopic study of candidate Be stars in the Magellanic Clouds

2010 ◽  
Vol 6 (S272) ◽  
pp. 294-295
Author(s):  
Paul KT ◽  
Annapurni Subramaniam ◽  
Blesson Mathew ◽  
Ronald E. Mennickent ◽  
Beatriz Sabogal
Keyword(s):  
Light Curve ◽  
Magellanic Clouds ◽  
Light Curves ◽  
The Other ◽  
Be Stars ◽  
Curve Variation ◽  
Be Star ◽  
Type 3

Mennickent et al. (2002) presented a catalogue of 1056 Be star candidates in the Small Magellanic cloud (SMC) by studying light curve variation using OGLE II data base. They classified these Be star candidates of the SMC in four categories: Type 1 stars showing outbursts (139 stars); Type 2 stars showing sudden luminosity jumps (154 stars); Type 3 stars showing periodic or near periodic variations (78 stars); Type 4 stars showing light curves similar to Galactic Be stars (658 stars). They suggested that Type 4 could be Be stars. On the other hand, they suggested that Type-3 stars may not be linked to the Be star phenomenon at all.

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