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At least 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

THE OCCURRENCE OF WIDE-ORBIT PLANETS IN BINARY STAR SYSTEMS

The occurrence of planets in binary star systems has been investigated via a variety of techniques that sample a wide range of semi-major axes, but with a preponderance of such results applicable to planets with semi-major axes less than a few astronomical units. We utilize a new method—the presence or absence of heavy elements in the atmospheres of white dwarf stars—to elucidate the frequency in main sequence binary star systems of planets with semi-major axes greater than a few astronomical units. We consider only binaries where a putative planetary system orbits one member (no circumbinary planets). For main sequence binaries where the primary star is of spectral type A or F, data in the published literature suggests that the existence of a secondary star with a semi-major axis less than about 1000 AU suppresses the formation and/or long-term stability of an extended planetary system around the primary. For these spectral types and initial semi-major axis ≥1000 AU, extended planetary systems appear to be as common around stars in binary systems as they are around single stars.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

DETERMINING THE AGE OF THE KEPLER OPEN CLUSTER NGC 6819 WITH A NEW TRIPLE SYSTEM AND OTHER ECLIPSING BINARY STARS

As part of our study of the old (∼2.5 Gyr) open cluster NGC 6819 in the Kepler field, we present photometric (Kepler and ground-based BVR{sub C}I{sub C}) and spectroscopic observations of the detached eclipsing binary WOCS 24009 (Auner 665; KIC 5023948) with a short orbital period of 3.6 days. WOCS 24009 is a triple-lined system, and we verify that the brightest star is physically orbiting the eclipsing binary using radial velocities and eclipse timing variations. The eclipsing binary components have masses M{sub B} = 1.090 ± 0.010 M{sub ⊙} and M{sub C} = 1.075 ± 0.013 M{sub ⊙}, and radii R{sub B} = 1.099 ± 0.006 ± 0.005 R{sub ⊙} and R{sub C} = 1.069 ± 0.006 ± 0.013 R{sub ⊙}. The bright non-eclipsing star resides at the cluster turnoff, and ultimately its mass will directly constrain the turnoff mass: our preliminary determination is M{sub A} = 1.251 ± 0.057 M{sub ⊙}. A careful examination of the light curves indicates that the fainter star in the eclipsing binary undergoes a very brief period of total eclipse, which enables us to precisely decompose the light of the three stars and place them in the color–magnitude diagram (CMD). We also present improved analysis of two previously discussed detached eclipsing stars in NGC 6819 (WOCS 40007 and WOCS 23009) en route to a combined determination of the cluster’s distance modulus (m − M){sub V} = 12.38 ± 0.04. Because this paper significantly increases the number of measured stars in the cluster, we can better constrain the age of the CMD to be 2.21 ± 0.10 ± 0.20 Gyr. Additionally, using all measured eclipsing binary star masses and radii, we constrain the age to 2.38 ± 0.05 ± 0.22 Gyr. The quoted uncertainties are estimates of measurement and systematic uncertainties (due to model physics differences and metal content), respectively.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

Photometric and period investigation of the late F-type overcontact binary II UMa

II UMa is a late F-type (F5) contact binary with a close-in tertiary and a distant visual companion. According to the four-color (B V R{sub c}I{sub c}) light curves’ solutions of II UMa, it is a high fill-out (f = 86.6%) and low-mass ratio (q = 0.172) contact binary system, which indicates that it is at the late evolutionary stage of late-type tidal-locked binary stars. The masses of the primary star and secondary star are calculated to be M{sub 1}=1.99M{sub ⊙} and M{sub 2}=0.34M{sub ⊙}. The primary star has evolved from the zero-age main sequence, but it still appeared before the terminal-age main sequence, and the secondary star is even more evolved. Considering the mass ratio (M{sub 3}/M{sub 1}=0.67) obtained by spectroscopic observations, the mass of the close-in tertiary is estimated to be M{sub 3}=1.34M{sub ⊙}. The period variations of the binary system are investigated for the first time. According to the observed–calculated (O−C) curve analysis, a continuous period increase at a rate of dP/dt=4.88×10{sup −7} day yr{sup −1} is determined. The parabolic variation in the O−C curve may be part of a cyclic period of change, or the combined period of change of a parabolic variation and a cyclic one. More instances of minimum light are needed to confirm this. The presence of the tertiary component may play an important role in the formation and evolution of this binary system by drawing angular momentum from the central system during the pre-contact stage.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

IRAS 16253–2429: THE FIRST PROTO-BROWN DWARF BINARY CANDIDATE IDENTIFIED THROUGH THE DYNAMICS OF JETS

The formation mechanism of brown dwarfs (BDs) is one of the long-standing problems in star formation because the typical Jeans mass in molecular clouds is too large to form these substellar objects. To answer this question, it is crucial to study a BD in the embedded phase. IRAS 16253–2429 is classified as a very low-luminosity object (VeLLO) with an internal luminosity of <0.1 L {sub ⊙}. VeLLOs are believed to be very low-mass protostars or even proto-BDs. We observed the jet/outflow driven by IRAS 16253–2429 in CO (2–1), (6–5), and (7–6) using the IRAM 30 m and Atacama Pathfinder Experiment telescopes and the Submillimeter Array (SMA) in order to study its dynamical features and physical properties. Our SMA map reveals two protostellar jets, indicating the existence of a proto-binary system as implied by the precessing jet detected in H{sub 2} emission. We detect a wiggling pattern in the position–velocity diagrams along the jet axes, which is likely due to the binary orbital motion. Based on this information, we derive the current mass of the binary as ∼0.032 M{sub ⊙}. Given the low envelope mass, IRAS 16253–2429 will form a binary that probably consist of one or two BDs. Furthermore, we found that the outflow force as well as the mass accretion rate are very low based on the multi-transition CO observations, which suggests that the final masses of the binary components are at the stellar/substellar boundary. Since IRAS 16253 is located in an isolated environment, we suggest that BDs can form through fragmentation and collapse, similar to low-mass stars.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

A Double-line M-dwarf Eclipsing Binary from CSS × SDSS

Eclipsing binaries offer a unique opportunity to determine basic stellar properties. With the advent of wide-field camera and all-sky time-domain surveys, thousands of eclipsing binaries have been charted via light curve classification, yet their fundamental properties remain unexplored mainly due to the extensive efforts needed for spectroscopic follow-ups. In this paper, we present the discovery of a short-period ( P = 0.313 day), double-lined M-dwarf eclipsing binary, CSSJ114804.3+255132/SDSSJ114804.35+255132.6, by cross-matching binary light curves from the Catalina Sky Survey and spectroscopically classified M dwarfs from the Sloan Digital Sky Survey. We obtain follow-up spectra using the Gemini telescope, enabling us to determine the mass, radius, and temperature of the primary and secondary component to be M {sub 1} = 0.47 ± 0.03(statistic) ± 0.03(systematic) M {sub ⊙}, M {sub 2} = 0.46 ± 0.03(statistic) ± 0.03(systematic) M {sub ⊙}, R {sub 1} = 0.52 ± 0.08(statistic) ± 0.07(systematic) R {sub ⊙}, R {sub 2} =0.60 ± 0.08(statistic) ± 0.08(systematic) R {sub ⊙}, T {sub 1} = 3560 ± 100 K, and T {sub 2} = 3040 ± 100 K, respectively. The systematic error was estimated using the difference between eccentric and non-eccentric fits. Our analysis also indicates that there is definitively third-light contamination (66%) in the CSS photometry. The secondary star seems inflated, probably due to tidal locking of the close secondary companion, which is common for very short-period binary systems. Future spectroscopic observations with high resolution will narrow down the uncertainties of stellar parameters for both components, rendering this system as a benchmark for studying fundamental properties of M dwarfs.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

Photometric Solutions of Three Eclipsing Binary Stars Observed from Dome A, Antarctica

Based on spectroscopic observations for the eclipsing binaries CSTAR 036162 and CSTAR 055495 with the WiFeS/2.3 m telescope at SSO and CSTAR 057775 with the Mage/Magellan I at LCO in 2017, stellar parameters are derived. More than 100 nights of almost-continuous light curves reduced from the time-series photometric observations by CSTAR at Dome A of Antarctic in i in 2008 and in g and r in 2009, respectively, are applied to find photometric solutions for the three binaries with the Wilson–Devinney code. The results show that CSTAR 036162 is a detached configuration with the mass ratio q = 0.354 ± 0.0009, while CSTAR 055495 is a semi-detached binary system with the unusual q = 0.946 ± 0.0006, which indicates that CSTAR 055495 may be a rare binary system with mass ratio close to one and the secondary component filling its Roche Lobe. This implies that a mass-ratio reversal has just occurred and CSTAR 055495 is in a rapid mass-transfer stage. Finally, CSTAR 057775 is believed to be an A-type W UMa binary with q = 0.301 ± 0.0008 and a fill-out factor of f = 0.742(8).

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

WIYN Open Cluster Study. LXXXII. Radial-velocity Measurements and Spectroscopic Binary Orbits in the Open Cluster NGC 7789

We present an extensive time-series radial-velocity (RV) survey of stars in the rich open cluster NGC 7789 (1.6 Gyr, [Fe/H] = +0.02). The stellar sample lies within an 18′ circular radius from the cluster center (10 pc in projection, or about 2 core radii), and includes giants, red clump stars, blue stragglers, red stragglers, sub-subgiants, and main-sequence stars down to 1 mag below the turnoff. Our survey began in 2005 and comprises more than 9000 RV measurements from the Hydra Multi-Object Spectrograph on the WIYN 3.5 m telescope. We identify 624 likely cluster members and present the orbital solutions for 81 cluster binary stars with periods between 1.45 and 4200 days. From the main-sequence binary solutions we fit a circularization period of 7.2{sub −1.1}{sup +0.6} days. We calculate an incompleteness-corrected main-sequence binary frequency of 31% ± 4% for binaries with periods less than 10{sup 4} days, similar to other WIYN Open Cluster Survey (WOCS) open clusters of all ages. We detect a blue straggler binary frequency of 33% ± 17%, consistent with the similarly aged open cluster NGC 6819. We also find one secure, rapidly rotating sub-subgiant and one red straggler candidate in our sample.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Tidal Circularization of Binaries by Resonance Locking. I. The Importance of the Pre-main Sequence

Although tidal dissipation in binary stars has been studied for over a century, theoretical predictions have yet to match the observed properties of binary populations. This work quantitatively examines the recent proposal of tidal circularization by resonance locking, where tidal dissipation arises from resonances between the star’s natural oscillation frequencies and harmonics of the orbital frequency, and where resonances are “locked” for an extended period of time due to concurrent stellar evolution. We focus on tidal resonances with axi-symmetric gravity modes, and examine binaries with primary masses from one to two solar masses. We find that orbital evolution via resonance locking occurs primarily during the star’s pre-main-sequence phase, with the main-sequence phase contributing negligibly. Resonance locking, ignoring nonlinearity, can circularize binaries with peri-center distances out to ∼10 stellar radii, corresponding to circular periods of ∼4–6 days. However, we find resonantly excited gravity modes will become nonlinear in stellar cores, which prevents them from reaching their full, linear amplitudes. We estimate that such a “saturated resonance lock” reduces the circularization period by about a third, but resonance locking remains much more effective than the cumulative actions of equilibrium tides. In a companion paper, we examine recent binary data to compare against theory.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

ACCRETION AND MAGNETIC RECONNECTION IN THE CLASSICAL T TAURI BINARY DQ TAU

The theory of binary star formation predicts that close binaries ( a < 100 au) will experience periodic pulsed accretion events as streams of material form at the inner edge of a circumbinary disk (CBD), cross a dynamically cleared gap, and feed circumstellar disks or accrete directly onto the stars. The archetype for the pulsed accretion theory is the eccentric, short-period, classical T Tauri binary DQ Tau. Low-cadence (∼daily) broadband photometry has shown brightening events near most periastron passages, just as numerical simulations would predict for an eccentric binary. Magnetic reconnection events (flares) during the collision of stellar magnetospheres near periastron could, however, produce the same periodic, broadband behavior when observed at a one-day cadence. To reveal the dominant physical mechanism seen in DQ Tau’s low-cadence observations, we have obtained continuous, moderate-cadence, multiband photometry over 10 orbital periods, supplemented with 27 nights of minute-cadence photometry centered on four separate periastron passages. While both accretion and stellar flares are present, the dominant timescale and morphology of brightening events are characteristic of accretion. On average, the mass accretion rate increases by a factor of five near periastron, in good agreement with recent models. Large variability is observed in the morphology and amplitude of accretion events from orbit to orbit. We argue that this is due to the absence of stable circumstellar disks around each star, compounded by inhomogeneities at the inner edge of the CBD and within the accretion streams themselves. Quasiperiodic apastron accretion events are also observed, which are not predicted by binary accretion theory.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

The Evolution of Accreting Binaries: From Brown Dwarfs to Supermassive Black Holes

Circumbinary accretion occurs throughout the universe, from the formation of stars and planets to the aftermath of major galactic mergers. We present an extensive investigation of circumbinary accretion disks, studying circular binaries with mass ratios (q ≡ M 2 /M 1 ) from 0.01 to 1 and at each mass ratio probing the effects of disk thickness and viscosity. We study disks with aspect ratios H/r ϵ {0.1, 0.05, 0.03} and vary both the magnitude and spatial dependence of viscosity. Although thin accretion disks have previously been found to promote rapid inspirals of equal-mass binaries, we find that gravitational torques become weaker at lower mass ratios and most binaries with 0.01 ≤ q ≤ 0.04 outspiral, which may delay the coalescence of black hole binaries formed from minor mergers and cause high-mass exoplanets to migrate outward. However, in a number of cases, the disks accreting onto binaries with mass ratios ~0.07 fail to develop eccentric modes, leading to extremely rapid inspirals. Variability in black hole accretion correlates with disk eccentricity, and we observe variability above the ~10% level even for mass ratios of 0.01. We demonstrate that the spatial dependence of the viscosity (e.g., α vs. constant ν) significantly affects the degree of preferential accretion onto the secondary, resolving discrepancies between previous studies. Colder circumbinary disks remain eccentric even at q ~ 0.01 and sustain deep, asymmetric cavities.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2016

Distinguishing between formation channels for binary black holes with LISA

The recent detections of GW150914 and GW151226 imply an abundance of stellar-mass binary black hole (BBH) mergers in the local universe. While ground-based gravitational wave detectors are limited to observing the final moments before a binary merges, space-based detectors, such as the Laser Interferometer Space Antenna (LISA), can observe binaries at lower orbital frequencies where such systems may still encode information about their formation histories. In particular, the orbital eccentricity and mass of BBHs in the LISA frequency band can be used together to discriminate between binaries formed in isolation in galactic fields and those formed in dense stellar environments such as globular clusters. In this letter, we explore the orbital eccentricity and mass of BBH populations as they evolve through the LISA frequency band. Overall we find that there are two distinct populations discernible by LISA. We show that up to ∼90% of binaries formed either dynamically or in isolation have eccentricities that are measurable with LISA. Finally, we note how measured eccentricities of low-mass BBHs evolved in isolation could provide detailed constraints on the physics of black hole natal kicks and common-envelope evolution.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Revealing the Formation of Stellar-mass Black Hole Binaries: The Need for Deci-Hertz Gravitational-wave Observatories

The formation of compact stellar-mass binaries is a difficult, but interesting problem in astrophysics. There are two main formation channels: in the field via binary star evolution, or in dense stellar systems via dynamical interactions. The Laser Interferometer Gravitational-wave Observatory (LIGO) has detected black hole binaries (BHBs) via their gravitational radiation. These detections provide us with information about the physical parameters of the system. It has been claimed that when the Laser Interferometer Space Antenna (LISA) is operating, the joint observation of these binaries with LIGO will allow us to derive the channels that lead to their formation. However, we show that for BHBs in dense stellar systems dynamical interactions could lead to high eccentricities such that a fraction of the relativistic mergers are not audible to LISA. A non-detection by LISA puts a lower limit of about 0.005 on the eccentricity of a BHB entering the LIGO band. On the other hand, a deci-Hertz observatory, like DECIGO or Tian Qin, would significantly enhance the chances of a joint detection and shed light on the formation channels of these binaries.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Formation of Black Hole X-Ray Binaries with Non-degenerate Donors in Globular Clusters

In this Letter, we propose a formation channel for low-mass X-ray binaries with black hole accretors and non-degenerate donors via grazing tidal encounters with subgiants. We estimate that in a typically dense globular cluster with a core density of 10{sup 5} stars pc{sup −3}, the formation rates are about one binary per Gyr per 50–100 retained black holes. The donors—stripped subgiants—will be strongly underluminous when compared to subgiant or giant branch stars of the same colors. The products of tidal stripping are underluminous by at least one magnitude for several hundred million years when compared to normal stars of the same color, and differ from underluminous red stars that could be produced by non-catastrophic mass transfer in an ordinary binary. The dynamically formed binaries become quiescent LMXBs, with lifetimes of about a Gyr. The expected number of X-ray binaries is one per 50–200 retained black holes, while the expected number of strongly underluminous subsubgiant is about half this. The presence of strongly underluminous stars in a GC may be indicative of the presence of black holes.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

Colloidal Binary Supracrystals with Tunable Structural Lattices

Here, colloidal binary supracrystals (SCs) possessing tunable and ordered assembly of two different types of functional nanoparticles (NPs) represent a unique class of artificial materials for both fundamental study and technological applications, but related study has been limited due to substantial challenges in materials growth. Here we report the controlled growth of colloidal binary SCs consisting of Au and Fe 3 O 4 NPs via an oil-in-water emulsion process. The size, stoichiometry, and lattice structure of the SCs can be broadly tuned by the growth parameters. Furthermore, our growth method is general and applicable to other NP building blocks to achieve various functional binary SCs. These as-grown free-standing binary SCs should therefore enable new test beds for exploring different nanoscale interactions ranging from the formation and stability of nanoscale binary phase to the emerging magneto-plasmonic coupling physics.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Largely enhanced dielectric properties of carbon nanotubes/polyvinylidene fluoride binary nanocomposites by loading a few boron nitride nanosheets

The ternary nanocomposites of boron nitride nanosheets (BNNSs)/carbon nanotubes (CNTs)/polyvinylidene fluoride (PVDF) are fabricated via a combination of solution casting and extrusion-injection processes. The effects of BNNSs on the electrical conductivity, dielectric behavior, and microstructure changes of CNTs/PVDF binary nanocomposites are systematically investigated. A low percolation value (f{sub c}) for the CNTs/PVDF binary system is obtained due to the integration of solution and melting blending procedures. Two kinds of CNTs/PVDF binary systems with various CNTs contents (f{sub CNTs}) as the matrix are discussed. The results reveal that compared with CNTs/PVDF binary systems at the same f{sub CNTs}, the ternary BNNSs/CNTs/PVDF nanocomposites exhibit largely enhanced dielectric properties due to the improvement of the CNTs dispersion state and the conductive network. The dielectric constant of CNTs/PVDF binary nanocomposite with 6 vol. % CNTs (f{sub CNTs} < f{sub c}) shows a 79.59% enhancement from 49 to 88 after the incorporation of 3 vol. % BNNSs. For the other CNTs/PVDF system with 8 vol. % CNTs (f{sub CNTs} > f{sub c}), it displays a 43.32% improvement from 1325 to 1899 after the addition of 3 vol. % BNNSs. The presence of BNNSs facilitates the formation of the denser conductive network. Meanwhile, the ternary BNNSs/CNTs/PVDF systems exhibit a low dielectric loss. The adjustable dielectric properties could be obtained by employing the ternary systems due to the microstructure changes of nanocomposites.

36 MATERIALS SCIENCE↗
DOE OSTI2014

WIYN open cluster study. LX. Spectroscopic binary orbits in NGC 6819

We present the current state of the WOCS radial-velocity (RV) survey for the rich open cluster NGC 6819 (2.5 Gyr) including 93 spectroscopic binary orbits with periods ranging from 1.5 to 8000 days. These results are the product of our ongoing RV survey of NGC 6819 using the Hydra Multi-Object Spectrograph on the WIYN 3.5 m telescope. We also include a detailed analysis of multiple prior sets of optical photometry for NGC 6819. Within a 1° field of view, our stellar sample includes the giant branch, the red clump, and blue straggler candidates, and extends to almost 2 mag below the main sequence (MS) turnoff. For each star observed in our survey we present all RV measurements, the average RV, and velocity variability information. Additionally, we discuss notable binaries from our sample, including eclipsing binaries (WOCS 23009, WOCS 24009, and WOCS 40007), stars noted in Kepler asteroseismology studies (WOCS 4008, WOCS 7009, and WOCS 8007), and potential descendants of past blue stragglers (WOCS 1006 and WOCS 6002). We find the incompleteness-corrected binary fraction for all MS binaries with periods less than 10{sup 4} days to be 22% ± 3% and a tidal circularization period of 6.2{sub −1.1}{sup +1.1} days for NGC 6819.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

Photometric study and period analysis of the contact binary XZ Leonis

We present multi-color CCD photometry of the neglected contact binary XZ Leo. Completely covered VRI band light curves and four times of minimum light were obtained. Combining the photometric and previously published radial-velocity data, a revised photometric analysis was carried out for the binary system by applying the Wilson–Devinney code. With a hot spot placed on the massive primary component near the neck region of the common envelope, the light curves were satisfactorily modeled. The photometric solution combined with the radial-velocity solution reveals that XZ Leo is an A-type contact binary with a degree of contact of 24(±1)%. The absolute parameters of the components were determined to be M{sub 1} = 1.74(±0.06)M{sub ⊙}, M{sub 2} = 0.61(±0.02)M{sub ⊙}, R{sub 1} = 1.69(±0.01)R{sub ⊙}, R{sub 2} = 1.07(±0.01)R{sub ⊙}, L{sub 1} = 6.73(±0.08) L{sub ⊙}, and L{sub 2} = 2.40(±0.04)L{sub ⊙}. Based on all the available data, the long-term orbital period behavior of the system was investigated. It indicates that the binary system was undergoing a continuous orbital period increase in the past three decades with a rate of dP/dt =+6.12×10{sup −8} days yr{sup −1}, which suggests a probable mass transfer from the secondary to the primary component at a rate of dM/dt=3.92×10{sup −8}M{sub ⊙} yr{sup −1}. The binary system is expected to evolve into the broken-contact stage in 1.56×10{sup 6} years. This could be evidence supporting the thermal relaxation oscillation theory.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

The outcome of supernovae in massive binaries; removed mass, and its separation dependence

The majority of massive stars are formed in binary systems. It is hence reasonable to expect that most core-collapse supernovae (CCSNe) take place in binaries and the existence of a companion star may leave some imprints in observed features. Having this in mind, we have conducted two-dimensional hydrodynamical simulations of the collisions of CCSNe ejecta with the companion star in an almost-equal-mass (∼10 M {sub ☉}) binary to find out possible consequences of such events. In particular we pay attention to the amount of mass removed and its dependence on the binary separation. In contrast to the previous surmise, we find that the companion mass is stripped not by momentum transfer but by shock heating. Up to 25% of the original mass can be removed for the closest separations and the removed mass decreases as M {sub ub}∝a {sup –4.3} with the binary separation a. By performing some experimental computations with artificially modified densities of incident ejecta, we show that if the velocity of ejecta is fixed, the density of incident ejecta is the single important parameter that actually determines the removed mass as M{sub ub}∝ρ{sub ej}{sup 1.4}. On the other hand, another set of simulations with modified velocities of incident ejecta demonstrate that the strength of the forward shock, which heats up the stellar material and causes the mass loss of the companion star, is actually the key parameter for the removed mass.

79 ASTRONOMY AND ASTROPHYSICS↗