New Perspectives on AX Monocerotis

Elias, N. M.; Wilson, R. E.; Olson, Edward C.; Aufdenberg, J. P.; Guinan, E. F.; Güdel, M.; Hamme, W. Van; Stevens, and Heather L.

doi:10.1086/304299

Cited by 20 publications

(25 citation statements)

References 34 publications

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“…However, one can also appeal to an almost entirely nonconservative model in which the starting parameters might have been (14 þ 13 M , $200 days) and presumably to a range of possibilities in between. Elias et al (1997) point to a rate of period decrease, significant at the 3 level, on a timescale of 1:7 Â 10 4 yr. The sign is unexpected whichever of the above two models one attempts to support.…”

Section: Mechanisms For Rapid Envelope Ejectionmentioning

confidence: 82%

“…Alias Spectra Gies et al 1998; (5) Plets et al 1995;(6) Burki & Mayor 1983, Parsons & Ake 1990; (7) Gordon et al 1998;(8) Dudley & Jeffery 1990;(6) Kaspi et al 1994Kaspi et al , 1996Bell et al 1995;(10) Bolton & Rogers 1978;(11) Evans 1990;(12) Elias et al 1997 includes tidal friction and the interaction of the intrinsic spin of star 1 with orbital eccentricity and orbital angular momentum. The effect of the spin of star 1 on its internal structure is included, though only as uniform rotation.…”

Section: Namementioning

confidence: 99%

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Envelope Ejection: An Alternative Evolutionary Process for Some Early Case B Binaries

Eggleton

2002

ApJ

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We discuss the evolution of binaries with moderately high masses ($10-30 M ) and with periods of $3-300 days, corresponding mostly to early case B. These are usually thought to evolve either by reasonably conservative Roche lobe overflow, if the initial mass ratio is fairly mild, or else by highly nonconservative common-envelope evolution, with spiral-in to short periods (hours, typically), if the initial mass ratio is rather extreme. We discuss here a handful of binaries from part of this period range ($50-250 days), which appear to have followed a different path: we argue that they must have lost a large proportion of initial mass ($70%-80%) but without shortening their periods at all. We suggest that their behavior may be due to the fact that stars of such masses, when evolved also to rather large radii, are not far from the Humphreys-Davidson limit, where single stars lose their envelopes spontaneously in P Cygni winds, and so have envelopes that are only lightly bound to the core. These envelopes therefore may be relatively easily dissipated by the perturbing effect of a companion. In addition, some or all of the stars considered here may have been close to the Cepheid instability strip when they filled their Roche lobes. One or the other, or both, of high luminosity and Cepheid instability, in combination with an appropriately close binary companion, may be implicated.

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Section: Mechanisms For Rapid Envelope Ejectionmentioning

confidence: 82%

Section: Namementioning

confidence: 99%

Envelope Ejection: An Alternative Evolutionary Process for Some Early Case B Binaries

Eggleton

2002

ApJ

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“…An alternative to ephemerides from eclipse timings is ephemerides from whole curves (Hadrava 1990, 2004, Elias et al 1997, Wilson 2005, Van Hamme & Wilson 2007, Mikulasek et al 2011. Relations for conversion of time interval to phase interval are in Wilson (2005) (including series approximations needed when dP/dt is close to zero) and in Kallrath & Milone (2009).…”

Section: Whole Light and Velocity Curvesmentioning

confidence: 99%

“…Attenuation along the line of sight to each surface element of each star is computed, and results are combined for any line of sight that passes through more than one cloud. So far the circumstellar matter feature has been applied only to AX Mon (Elias et al 1997), which seems to have a stationary accumulation of material where a mass transfer stream selfintersects after having passed around the hotter star.…”

Section: Attenuation By Circumstellar Mattermentioning

confidence: 99%

Under-Developed and Under-Utilized Eclipsing Binary Model Capabilities

Wilson¹

2012

Journal of Astronomy and Space Sciences

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Existing but largely unused binary star model capabilities are examined. An easily implemented scheme is parameterization of starspot growth and decay that can stimulate work on outer convection zones and their dynamos. Improved precision in spot computation now enhances analysis of very precise data. An existing computational model for blended spectral line profiles is accurate for binary system effects but needs to include damping, thermal Doppler, and other intrinsic broadening effects. Binary star ephemerides had been found exclusively from eclipse timings until recently, but now come also from whole light and radial velocity curves. A logical further development will be to expand these whole curve solutions to include eclipse timings. An attenuation model for circumstellar clouds, with several absorption and scattering mechanisms, has been applied only once, perhaps because the model clouds have fixed locations. However the clouds could be made to move dynamically and be combined into moving streams and disks. An area of potential interest is polarization curve analysis, where incentive for modeling could follow from publication of observed polarization curves. Other recent advances include direct single step solutions for temperatures of both stars of an eclipsing binary and third body kinematics from combined light and velocity curves.Keywords: binaries, starspots, line profiles, ephemerides, circumstellar attenuation, polarization INTERACTION OF UNDER-DEVELOPMENT AND UNDER-UTILIZATIONA binary star story of some years hence might begin: "once upon a time there was a model feature that needed further work (UD for under-developed), and another that could have been applied but was not (UU for under-utilized). UD was not dressed for the science scene and UU was all dressed up with no place to go." We have experienced both situations in the early growing pains of high definition television and 3D TV, where few promoters were covering production costs for lack of in-home receivers (UD) and few persons bought receivers for lack of on-air productions (UU)-an iterative loop with very slow convergence at startup. So development and utilization can interact, as in the modeling and analysis capabilities now to be discussed. GROWTH AND DECAY OF MAGNETIC STARSPOTS AND SPOT GROUPSAn observational pursuit in need of analytic progress is growth and decay (briefly aging) of magnetic starspots for tests of theoretical work on outer convection zones and their dynamos. A realistic aim is to establish the statistics of spot (and spot group) area versus time over ranges of star mass, composition, envelope rotation, and age, without attempts to assess configurational details. Many parameters compete for attention, so spot temperature variation can be disregarded to reduce the parameter count, given that magnetic spots are nearly black in the first approximation.This is an open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/) w...

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“…HD 45910. -Elias et al (1997) present velocities for the cool component only. HD 50846.-Peters k Polidan (1998) discuss the disk and FUV spectrum.…”

mentioning

confidence: 99%

Glimpses of Be Binary Evolution

Gies

2000

International Astronomical Union Colloquium

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Abstract. Models of close binary evolution predict that mass gainers will be spun up to speeds close to the critical rotational velocity while the mass donors will appear as stripped down He stars, white dwarfs, or neutron stars. I argue here that the mass gainers are closely related to the Be stars. I present a list of the known Be binary systems which consists of those with bright, Roche-filling companions and those with faint or undetected companions. Notably absent are Be + B systems which are expected if the Be phase is a stage in the life of a single star. We now have the first example of a Be + He star system in the binary, Per, and taken together with the well known Be X-ray binaries, there is clear evidence that some fraction of Be stars are created in binaries; whether all such rapid rotators are so formed remains unknown.

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New Perspectives on AX Monocerotis

Cited by 20 publications

References 34 publications

Envelope Ejection: An Alternative Evolutionary Process for Some Early Case B Binaries

Envelope Ejection: An Alternative Evolutionary Process for Some Early Case B Binaries

Under-Developed and Under-Utilized Eclipsing Binary Model Capabilities

Glimpses of Be Binary Evolution

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