scholarly journals Physical Properties of 29 sdB+dM Eclipsing Binaries in Zwicky Transient Facility

2022 ◽  
Author(s):  
Min Dai ◽  
Xiaodian Chen ◽  
Kun WANG ◽  
Yangping Luo ◽  
Shu Wang ◽  
...  
Keyword(s):  
Physical Properties ◽  
Large Scale ◽  
Probability Distributions ◽  
Brown Dwarfs ◽  
Eclipsing Binaries ◽  
Mass Ratio ◽  
Light Curve Analysis ◽  
Short Period ◽  
Orbital Periods ◽  
The Masses

Abstract The development of large-scale time-domain surveys provides an opportunity to study the physical properties as well as the evolutionary scenario of B-type subdwarfs (sdB) and M-type dwarfs (dM). Here, we obtained 33 sdB+dM eclipsing binaries based on the Zwicky Transient Facility (ZTF) light curves and {\sl Gaia} early data release 3 (EDR3) parallaxes. By using the PHOEBE code for light curve analysis, we obtain probability distributions for parameters of 29 sdB+dM. $R_1$, $R_2$, and $i$ are well determined, and the average uncertainty of mass ratio $q$ is 0.08. Our parameters are in good agreement with previous works if a typical mass of sdB is assumed. Based on parameters of 29 sdB+dM, we find that both the mass ratio $q$ and the companion's radius $R_2$ decrease with the shortening of the orbital period. For the three sdB+dMs with orbital periods less than 0.075 days, their companions are all brown dwarfs. The masses and radii of the companions satisfy the mass--radius relation for low-mass stars and brown dwarfs. Companions with radii between $0.12R_\odot$ and $0.15R_\odot$ seem to be missing in the observations. As more short-period sdB+dM eclipsing binaries are discovered and classified in the future with ZTF and {\sl Gaia}, we will have more information to constrain the evolutionary ending of sdB+dM.

Tidal Interactions Between Planets and Host Stars

2020 ◽  
Author(s):  
Gordon Ogilvie
Keyword(s):  
Angular Momentum ◽  
Large Scale ◽  
Solid Mechanics ◽  
Hydrodynamic Instability ◽  
The Body ◽  
Tidal Dissipation ◽  
Tidal Interactions ◽  
Exoplanetary Systems ◽  
Short Period ◽  
Orbital Periods

Hundreds of planets are already known to have orbits only a few times wider than the stars that host them. The tidal interaction between a planet and its host star is one of the main agents shaping the observed distributions of properties of these systems. Tidal dissipation in the planet tends make the orbit circular, as well as synchronizing and aligning the planet’s spin with the orbit, and can significantly heat the planet, potentially affecting its size and structure. Dissipation in the star typically leads to inward orbital migration of the planet, accelerating the star’s rotation, and in some cases destroying the planet. Some essential features of tidal evolution can be understood from the basic principles that angular momentum and energy are exchanged between spin and orbit by means of a gravitational field and that energy is dissipated. For example, most short-period exoplanetary systems have too little angular momentum to reach a tidal equilibrium state. Theoretical studies aim to explain tidal dissipation quantitatively by solving the equations of fluid and solid mechanics in stars and planets undergoing periodic tidal forcing. The equilibrium tide is a nearly hydrostatic bulge that is carried around the body by a large-scale flow, which can be damped by convection or hydrodynamic instability, or by viscoelastic dissipation in solid regions of planets. The dynamical tide is an additional component that generally takes the form of internal waves restored by Coriolis and buoyancy forces in a rotating and stratified fluid body. It can lead to significant dissipation if the waves are amplified by resonance, are efficiently damped when they attain a very short wavelength, or break because they exceed a critical amplitude. Thermal tides are excited in a planetary atmosphere by the variable heating by the star’s radiation. They can oppose gravitational tides and prevent tidal locking, with consequences for the climate and habitability of the planet. Ongoing observations of transiting exoplanets provide information on the orbital periods and eccentricities as well as the obliquity (spin–orbit misalignment) of the star and the size of the planet. These data reveal several tidal processes at work and provide constraints on the efficiency of tidal dissipation in a variety of stars and planets.

scholarly journals A survey for high-mass eclipsing binaries

2019 ◽  
Vol 490 (4) ◽  
pp. 5147-5173
Author(s):  
F Pozo Nuñez ◽  
R Chini ◽  
A Barr Domínguez ◽  
Ch Fein ◽  
M Hackstein ◽  
...  
Keyword(s):  
Eclipsing Binaries ◽  
Light Curves ◽  
High Mass ◽  
System Component ◽  
Fundamental Parameters ◽  
Average Value ◽  
Short Period ◽  
Orbital Periods ◽  
Photometric Monitoring ◽  
Period System

ABSTRACT We report results from a search for Galactic high-mass eclipsing binaries. The photometric monitoring campaign was performed in Sloan r and i with the robotic twin refractor RoBoTT at the Universitätssternwarte Bochum in Chile and complemented by Johnson UBV data. Comparison with the SIMBAD data base reveals 260 variable high-mass stars. Based on well-sampled light curves, we discovered 35 new eclipsing high-mass systems and confirm the properties of six previously known systems. For all objects, we provide the first light curves and determine orbital periods through the Lafler–Kinman algorithm. Apart from GSC 08173-0018 and Pismis 24-13 ($P = 19.47\, d$ and $20.14\, d$) and the exceptional short-period system TYC 6561-1765-1 ($P = 0.71\, d$), all systems have orbital periods between 1 and 9 d. We model the light curves of 26 systems within the framework of the Roche geometry and calculate fundamental parameters for each system component. The Roche lobe analysis indicates that 14 systems have a detached geometry, while 12 systems have a semidetached geometry; seven of them are near-contact systems. The deduced mass ratios q = M2/M1 reach from 0.4 to 1.0 with an average value of 0.8. The similarity of masses suggests that these high-mass binaries were created during the star formation process rather than by tidal capture.

scholarly journals Synthetic Light-Curve Analysis of a Short Period Binary System YY Eri

2021 ◽  
Vol 58 (1) ◽  
pp. 5454-5456
Author(s):  
Warisa Pancharoen, Wiraporn Maithong
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Effective Temperature ◽  
Curve Analysis ◽  
Photometric System ◽  
Mass Ratio ◽  
Light Curve Analysis ◽  
The Public ◽  
Secondary Star ◽  
Short Period

YY Eri, the short-period binary system, is a W UMa type of the eclipsing binary system. This study using a 0.7-meter telescope with CCD photometric system in B V and R filters. It was observed at the Regional Observatory for the Public, Chachoengsao, Thailand on December 5, 2018, UT. The MaxIm DL software was used to analyzed the images photometry to produce the light curve. The Wilson-Devinney technique was computed the synthetic light curve that prefer to the physical properties of the YY Eri. The results show that the effective temperature of the primary and secondary star was 5533 and 5598 K, respectively. The inclination is 81.450 and the mass ratio is 0.55. The degree of contact was calculated as 16.64%  

scholarly journals Differential rotation in convective envelopes: constraints from eclipsing binaries

2019 ◽  
Vol 491 (1) ◽  
pp. 690-707 ◽  
Author(s):  
Adam S Jermyn ◽  
Jamie Tayar ◽  
Jim Fuller
Keyword(s):  
Differential Rotation ◽  
Orbital Period ◽  
Binary Systems ◽  
Rotation Period ◽  
Eclipsing Binaries ◽  
Rotation Periods ◽  
Short Period ◽  
Orbital Periods ◽  
The Difference ◽  
Surface Convection

ABSTRACT Over time, tides synchronize the rotation periods of stars in a binary system to the orbital period. However, if the star exhibits differential rotation, then only a portion of it can rotate at the orbital period, so the rotation period at the surface may not match the orbital period. The difference between the rotation and orbital periods can therefore be used to infer the extent of the differential rotation. We use a simple parametrization of differential rotation in stars with convective envelopes in circular orbits to predict the difference between the surface rotation period and the orbital period. Comparing this parametrization to observed eclipsing binary systems, we find that in the surface convection zones of stars in short-period binaries there is very little radial differential rotation, with |r∂rln Ω| < 0.02. This holds even for longer orbital periods, though it is harder to say which systems are synchronized at long periods, and larger differential rotation is degenerate with asynchronous rotation.

scholarly journals Time-Resolved Spectroscopy of Short Period RS CVn Systems

1993 ◽  
Vol 137 ◽  
pp. 392-394
Author(s):  
C. Lázaro ◽  
M.J. Arévalo
Keyword(s):  
Spectral Type ◽  
Main Sequence ◽  
Eclipsing Binaries ◽  
Time Resolved ◽  
Binary Model ◽  
Short Period ◽  
First Results ◽  
Orbital Phase ◽  
Phase Resolution ◽  
Orbital Periods

AbstractWe have initiated a programme of spectroscopic observations of RS CVn short-period group, with orbital phase resolution. The systems of this group are all eclipsing binaries with both components at the Main Sequence, and most of them have similar spectral type components. The high rotational velocities and their short orbital periods (less than 1 day) hinder the spectroscopic study of these stars. We presents the first results yielded by Hα line observations of the systems XY UMa and WY Cnc. Both systems were observed during 1991 with reasonably wide orbital phase coverage. The analysis of the spectra is made by comparison with a binary model, constructed from the observed spectra of normal stars of the same spectral type as the RS CVn system components. The model accounts for the partial contribution of each component at any orbital phase within eclipses.

scholarly journals Orbital Migration and the Brown Dwarf Desert

2003 ◽  
Vol 211 ◽  
pp. 31-34
Author(s):  
Philip J. Armitage ◽  
Ian A. Bonnell
Keyword(s):  
Extrasolar Planets ◽  
Brown Dwarfs ◽  
Circumstellar Disks ◽  
Mass Ratio ◽  
Orbital Elements ◽  
Brown Dwarf ◽  
Migration Model ◽  
Short Period ◽  
Solar Type ◽  
Orbital Migration

The orbital elements of extreme mass ratio binaries will be modified by interactions with surrounding circumstellar disks. For brown dwarf companions to Solar-type stars the resulting orbital migration is sufficient to drive short period systems to merger, creating a brown dwarf desert at small separations. We highlight the similarities and the differences between the migration of brown dwarfs and massive extrasolar planets, and discuss how observations can test a migration model for the brown dwarf desert.

Companion(s) of the Eclipsing Binary KIC 3832716

2017 ◽  
Vol 14 (S339) ◽  
pp. 331-334
Author(s):  
Š. Parimucha ◽  
M. Fedurco ◽  
P. Gajdoš
Keyword(s):  
Eclipsing Binaries ◽  
Secondary Component ◽  
Centre Of Mass ◽  
Mass Ratio ◽  
Time Effects ◽  
Eclipsing Binary ◽  
Long Term Changes ◽  
Different Types ◽  
Orbital Periods

AbstractDetailed analyses of observations by the Kepler satellite may reveal unknown facts about objects that were previously regarded as eclipsing binaries. We present results of our analysis of such an object, KIC 3832716. We show that the system actually contains two eclipsing binaries (EB1 and EB2), with orbital periods of 1.14 and 2.17 days, orbiting around their common centre of mass with period of at least 1400 days and with an estimated mass ratio of 0.7 ± 0.3. Analyses of the (O–C) diagrams of both eclipsing pairs show three different types of variation: (i) long-term changes probably due to light-time effects, (ii) spikes caused by the superposition of the eclipses of both binaries, and (iii) semi-regular variations in EB1 with a period of 57 days, presumably caused by the presence of spots on its secondary component.

scholarly journals News From The Erebos Project

2017 ◽  
Vol 26 (1) ◽  
Author(s):  
Veronika Schaffenroth ◽  
Brad Barlow ◽  
Stephan Geier ◽  
Maja Vučković ◽  
Dave Kilkenny ◽  
...  
Keyword(s):  
Binary Systems ◽  
Brown Dwarfs ◽  
Eclipsing Binaries ◽  
Current Status ◽  
Red Giants ◽  
Large Program ◽  
Low Mass ◽  
Orbital Periods ◽  
Red Giant

AbstractPlanets and brown dwarfs in close orbits will interact with their host stars, as soon as the stars evolve to become red giants. However, the outcome of those interactions is still unclear. Recently, several brown dwarfs have been discovered orbiting hot subdwarf stars at very short orbital periods of 0.065 - 0.096 d. More than 8% of the close hot subdwarf binaries might have sub-stellar companions. This shows that such companions can significantly affect late stellar evolution and that sdB binaries are ideal objects to study this influence. Thirty-eight new eclipsing sdB binary systems with cool low-mass companions and periods from 0.05 to 0.5 d were discovered based on their light curves by the OGLE project. In the recently published catalog of eclipsing binaries in the Galactic bulge, we discovered 75 more systems. We want to use this unique and homogeneously selected sample to derive the mass distribution of the companions, constrain the fraction of sub-stellar companions and determine the minimum mass needed to strip off the red-giant envelope. We are especially interested in testing models that predict hot Jupiter planets as possible companions. Therefore, we started the EREBOS (Eclipsing Reflection Effect Binaries from the OGLE Survey) project, which aims at analyzing those new HW Vir systems based on a spectroscopic and photometric follow up. For this we were granted an ESO Large Program for ESO-VLT/FORS2. Here we give an update on the the current status of the project and present some preliminary results.

scholarly journals Observations and light curve solutions of the eclipsing binaries USNO-B1.0 1395-0370184 and USNO-B1.0 1395-0370731

2016 ◽  
pp. 27-32 ◽  
Author(s):  
D. Kjurkchieva ◽  
V.A. Popov ◽  
D. Vasileva ◽  
N. Petrov
Keyword(s):  
Light Curve ◽  
Eclipsing Binaries ◽  
Eclipsing Stars ◽  
System P ◽  
Photometric Observations ◽  
Short Period ◽  
Orbital Periods ◽  
Period System

We present follow-up photometric observations in Sloan filters g', i' of the newly discovered eclipsing stars USNO-B1.0 1395-0370184 and USNO-B1.0 1395-0370731. Our data revealed that their orbital periods are considerably bigger than the previous values. This result changed the classification of USNO-B1.0 1395-0370184 from ultrashort-period binary (P=0.197 d) to short-period system (P=0.251 d). The light curve solutions of our observations revealed that USNOB1.0 1395-0370184 and USNO-B1.0 1395-0370731 are overcontact binaries in which components are K dwarfs, close in masses and radii. The light curve distortions were reproduced by cool spots with angular radius of around 20?.

From the Oort cloud to Halley-type comets

1999 ◽  
Vol 173 ◽  
pp. 327-338 ◽  
Author(s):  
J.A. Fernández ◽  
T. Gallardo
Keyword(s):  
Total Population ◽  
Complex Function ◽  
Dynamical Evolution ◽  
Oort Cloud ◽  
Capture Process ◽  
Influx Rate ◽  
Short Period ◽  
Dynamical Properties ◽  
Orbital Periods ◽  
Probability Of Capture

AbstractThe Oort cloud probably is the source of Halley-type (HT) comets and perhaps of some Jupiter-family (JF) comets. The process of capture of Oort cloud comets into HT comets by planetary perturbations and its efficiency are very important problems in comet ary dynamics. A small fraction of comets coming from the Oort cloud − of about 10−2− are found to become HT comets (orbital periods < 200 yr). The steady-state population of HT comets is a complex function of the influx rate of new comets, the probability of capture and their physical lifetimes. From the discovery rate of active HT comets, their total population can be estimated to be of a few hundreds for perihelion distancesq <2 AU. Randomly-oriented LP comets captured into short-period orbits (orbital periods < 20 yr) show dynamical properties that do not match the observed properties of JF comets, in particular the distribution of their orbital inclinations, so Oort cloud comets can be ruled out as a suitable source for most JF comets. The scope of this presentation is to review the capture process of new comets into HT and short-period orbits, including the possibility that some of them may become sungrazers during their dynamical evolution.

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