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Topic: Contact binaries

	Eclipsing Binaries with MONS
		Particular aspects of eclipsing binaries are studied within the context of MONS (eccentric systems, systems with pulsating components, second order light curve effects).
		The most interesting fact about eclipsing binaries is that all kinds of stars are found as members of binaries: from normal main sequence stars, variable stars, evolved giants and supergiants, to collapsed objects.
		The main asset of MONS with respect to eclipsing binaries is its capability of obtaining stable, long time series photometry of moderately bright stars with millimagnitude-level accuracy.
	astro4.ast.villanova.edu /MONS/binaries.htm (875 words)

	ESA Science & Technology: Binary Stars
		Resolved binaries will be studied in different populations of stars: nearby star-forming regions, open clusters and associations as well as field binaries of different ages.
		Large fractions of astrometric binaries with periods in the range 0.03 to 30 years will be immediately recognized by their poor fit to the standard 5 parameter single star astrometric model.
		The surprising number of new eclipsing and contact binaries discovered by Hipparcos at magnitudes as bright as 7 mag demonstrates that even bright binary systems are not well surveyed.
	sci.esa.int /science-e/www/object/index.cfm?fobjectid=31441 (874 words)

	Eclipsing Binaries with MONS
		The most interesting fact about eclipsing binaries is that all kinds of stars are found as members of binaries: from normal main sequence stars, variable stars, evolved giants and supergiants, to collapsed objects.
		The main asset of MONS with respect to eclipsing binaries is its capability of obtaining stable, long time series photometry of moderately bright stars with millimagnitude-level accuracy.
		This is a yellow light curve of the 5.5-mag eclipsing binary V380 Cyg.
	astro4.ast.vill.edu /MONS/binaries.htm (875 words)

	Research Magazine :: Fall 1998 : Twinkle, Twinkle, Double Star
		Binary stars are a foreign concept to most earthlings, who expect to see just one rising star in the morning.
		Binary star research is journeyman work - nothing so flashy that would land it on the cover of a major news magazine.
		One clue: Contact binary stars appear to live in clusters that are at least a billion years old.
	www.ovpr.uga.edu /researchnews/fall98/star.html (501 words)

	Chapter 21: Companions To Stars: Binaries, Multiples, andPossible Planetary Systems
		Visual binary: is a physical binary in which the orbiting pair can be resolved with the eye, telescope, or camera.
		Spectroscopic binary: orbital motion is revealed by periodic Doppler shifts in the spectral lines, but the individual stars cannot be resolved.
		Eclipsing binary: a binary pair whose orbit is seen nearly edgewise.
	mywebpage.netscape.com /GWBlaylock/Astr1010/Chapter21.html (475 words)

	Reference Library - RedOrbit (Site not responding. Last check: 2007-10-29)
		Binary stars may be found with any conceivable separation, from pairs orbiting so closely that they are practically in contact with each other, to pairs so distantly separated that their connection is indicated only by their common proper motion through space.
		In the case of a visual binary star, after the orbit has been determined and the stellar parallax of the system obtained, the combined mass of the two stars may be obtained by a direct application of the Keplerian harmonic law.
		In the case of eclipsing binaries which are also spectroscopic binaries it is possible to make a complete solution for the specifications (mass, density, size, luminosity, and approximate shape) of both members of the system.
	www.redorbit.com /education/reference_library?article_id=173 (481 words)

	Binary starsystems - Visual, optical and spectroscopic binary starsystems, eclipsing binaries, cataclysmic binaries, ...
		Optical binaries: Two stars that falsely appear to be binary stars, judging from their closeness on the sky are called optical binaries.
		Spectroscopic binaries: Stars that orbit so close to each other (or are so far away), that both components can't be resolved through telescopes are called spectroscopic binaries, because they require a method of studying called spectroscopy to distinguish the stars.
		Contact binary: In this case, both stars will have filled their Roche lobe, and may have become slightly egg-shaped.
	www.novacelestia.com /space_art_binary/kinds_of_binaries.html (998 words)

	Binary Stars
		Notice that an eclipsing binary is the only direct method to measure the radius of a star, both the primary and the secondary from the time for the light curve to reach and rise from minimum.
		Most binary stars are too close to separate the components, yet their existence can be deduced from Doppler shifts.
		Thus we say the binaries are in contact, even if their surfaces are not touching directly.
	abyss.uoregon.edu /~js/ast122/lectures/lec10.html (997 words)

	SkyandTelescope.com - News from Sky & Telescope - Kissing in the Kuiper Belt
		Astronomers may have identified the third known contact binary, a system in which two minor planets either nearly or actually touch each other.
		"We believe 2001 QG is a contact binary," said Sheppard, as he reported the team's findings at the November meeting of the American Astronomical Society’s Division of Planetary Sciences in Louisville, Kentucky.
		Given the number of KBOs they have observed, and the fact that other KBO contact binaries might be viewed pole-on (which makes them harder to categorize), Sheppard and Jewitt estimate that at least 10 to 20 percent of all large KBOs might be contact binaries with similarly-sized components.
	www.skyandtelescope.com /news/3309751.html?page=1&c=y (692 words)

	Astronomy - Study yields new variable stars - Provided by Luther College
		Among the variables are seven eclipsing binaries, in which the light from one star periodically blocks the light from the second star as viewed from earth.
		If these contact binaries prove to be members of the star cluster instead of foreground or background stars, Wilkerson said, they will be useful as part of a study of how the systems evolve.
		LCV22 and LCV24 are eclipsing binaries with stellar surfaces in contact.
	www.astronomy.com /asy/default.aspx?c=a&id=5670&r=rss (1077 words)

	Toutatis (minor planet 4179)
		These images revealed two irregularly shaped, cratered objects about 4 and 2.5 km in average diameter which are probably in contact with each other.
		Such contact binaries may be fairly common since another one, Castalia, was observed in 1989.
		Numerous surface features on Toutatis, including a pair of large craters, side by side, and a series of three prominent ridges – a type of asteroid mountain range - are presumed to result from a complex history of impacts.
	www.daviddarling.info /encyclopedia/T/Toutatis.html (379 words)

	Doctoral research pr Study of the structure and evolution of contact binaries and ...
		Study of the structure and evolution of contact binaries and of binaries in stellar clusters.
		We will concentrate in particular on contact binaries, which are system for which the two stellar components are in contact with each other and that share a common envelope.
		The latter will be classified and follow-up observations of the new binaries among them will be organised and analysed, again with the aim to derive their stellar properties.
	www.kuleuven.ac.be /research/researchdatabase/project/3E04/3E040699.htm (170 words)

	Multiple Systems
		The life history of close binary systems is quite complicated; variations arise from the initial masses and separation of the components, and from the transfer of mass from one component to the other.
		Symbiotic Binaries - Long period (~200 to 1500 days) interacting binaries comprising a cool type M giant (sometimes a pulsating Mira-type variable) and a hot accreting companion such as a white dwarf, sub-dwarf, or low-mass main sequence star.
		Barium and S-Star Binaries - Long period binaries in which the originally more massive component evolved into a white dwarf, transferring some of its nuclear-processed gas to a giant type K or M companion.
	www.peripatus.gen.nz /Astronomy/MulSys.html (421 words)

	Blue Stragglers in Globular Clusters
		Empirical evidence for stellar collisions is found in the crowded core of 47 Tucanae, which is full of unusual compact binary star systems (where a normal star is paired with a white dwarf, neutron star, or a fl hole) in unusually large numbers rarely found outside of globular cores.
		Rex A. Saffer of Villanova University and colleagues have found a blue stragger in globular cluster NGC 6397 to be three times as massive as any ordinary star in that cluster, which they and other astronomers believe must have formed from a collisional merger (Sepinsky et al, 2000; and more information and images at APOD).
		BSS 19 is rotating rapidly, which means that it probably formed from the coalescence of a contact binary pair of old, smaller and dimmer stars -- instead of from a collision of previous unrelated stars (Shara et al, 1997).
	www.solstation.com /x-objects/bluestrag.htm (1264 words)

	Dave Jewitt: Binary Kuiper Belt Objects
		With strong observational biases against the detection of very close binaries, and against binaries in which the brightness difference between components is large, we can be sure that the binary fraction amongst these objects is much larger than 1%.
		Binaries produced collisionally are most usually highly asymetric in the masses of their components.
		Petit and collaborators have shown that the stability of wide binaries is marginal on timescales comparable to the age of the solar system.
	www.ifa.hawaii.edu /faculty/jewitt/kb/binaries.html (616 words)

	SkyandTelescope.com - News from SkyandTelescope - Kissing in the Kuiper Belt
		Astronomers may have identified the third known contact binary, a system in which two minor planets either nearly or actually touch each other.
		"We believe 2001 QG is a contact binary," said Sheppard, as he reported the team's findings at the November meeting of the American Astronomical Society’s Division of Planetary Sciences in Louisville, Kentucky.
		Given the number of KBOs they have observed, and the fact that other KBO contact binaries might be viewed pole-on (which makes them harder to categorize), Sheppard and Jewitt estimate that at least 10 to 20 percent of all large KBOs might be contact binaries with similarly-sized components.
	skyandtelescope.com /news/article_1394_1.asp (663 words)

	Centauri Dreams » Blog Archive » Terrestrial Planets and Close Binaries
		An additional beneﬁt of understanding the differences between planet formation around single stars and that around close binaries is that for eclipsing binaries, the contrast ratio between brightness of the stars and that of the planet(s) is reduced during the eclipse.
		I often wonder if a binary red-dwarf pair wouldn’t be a better place for long-term civilisations, as the binary arrangement could allow a planet to avoid the tide lock issue, while the stars would last for 100 billion years.
		Contact binaries have large orbital kinetic energy (a significant fraction of the gravitational binding energy of the stars).
	www.centauri-dreams.org /?p=742 (1041 words)

	[No title]
		This is different from the situations of the late-type (W UMa-type) contact binaries where both secular period increase and decrease are usually encountered, indicating that magnetic field may play an important role in causing the long-term period decrease of W UMa-type contact binary stars.
		The tertiary components in the seven binaries, BH Cen, V382 Cyg, AW Lac, TU Mus, RZ Pyx, V701 Sco and CT Tau, may be invisible, while those in LY Aur and V729 Cyg may be the fainter visual companions in the two systems.
		It is possible that the tertiary components in those binaries played an important role for the formations and evolutions of the contact configurations by bringing angular momentum out from the central systems.
	iau.conference-services.net /viewfile.asp?abstractID=85463&conferenceID=609 (356 words)

	UGA Physics and Astronomy \| People \| Faculty \| Shaw
		Binary stars are the means to determine the fundamental properties of all stars.
		My research on binary stars has ranged from many ground-based telescopes to the IUE and ROSAT space observatories.
		Most recently we have used the SARA 0.9m telescope to search for eclipsing binary stars and other variable stars in old open clusters.
	www.physast.uga.edu /people/fac-jss.html (205 words)

	./ch02.html
		First of all, such binaries are formed in the core, where the density is highest.
		Take two stars in a binary with a semi-major axis that is much larger than the sum of their radii while they are on the main sequence.
		It is clear that the vast majority of those X-ray binaries in clusters are formed through dynamical effects, as a result of the high density of stars.
	www.artcompsci.org /kali/vol/vision/ch02.html (2915 words)

	Iowa Robotic Telescope Facilities
		Many such binaries are bright (V<12), have orbital periods less than one day and have deep eclipse minima (DV>0.1), making them easy targets for modestly equipped observatories.
		A particularly interesting class of eclipsing binaries is the W Ursa-Majoris or contact binary.
		Contact binaries are so close that they are ‘touching’, i.e.
	phobos.physics.uiowa.edu /curriculum/eclbin.html (1128 words)

	Radial Velocities of Short Period Binaries
		Bright, nearby, short-period binary systems, mostly from the Hipparcos list, are systematically observed at David Dunlap Observatory with the 1.88m telescope and the Cassegrain spectrograph.
		The program has dealt mostly with contact binaries, which are the most abundant at periods below one day, but does include related (short-period EB and EA) systems.
		Contact binaries of the W UMa-type appear to be very numerous in space, with the relative spatial frequency of about 1/500 of FGK dwarfs in the solar vicinity (Rucinski 2002).
	www.astro.toronto.edu /DDO/research/binaries_prog.html (745 words)

	High Resolution Image of Toutatis
		The image reveals two irregularly shaped, cratered objects about 4 and 2.5 kilometers (2.5 and 1.6 miles) in average diameter which are probably in contact with each other.
		These "contact binaries" may be fairly common since another one, 4769 Castalia, was observed in 1989 when it passed near the Earth.
		Numerous surface features on Toutatis, including a pair of half-mile-wide craters, side by side, and a series of three prominent ridges -- a type of asteroid mountain range -- are presumed to result from a complex history of impacts.
	www.solarviews.com /cap/ast/toutathi.htm (147 words)

	Astronomy Labratory : Eclipsing Binaries (Site not responding. Last check: 2007-10-29)
		Eclipsing binaries are variable stars, in which th light variations are caused by mutual eclipses and transits of binary star.
		Contact binary, Semi detached binary and detached binaries.
		Usualy contact binary has the smallest periods, and for that reason they will be the choise for observations.
	www.tau.ac.il /~lab3/TELESCOPE/EB.html (75 words)

	Contact SB-Software
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	www.sb-software.com /contact.html (167 words)

	Tables of amplitudes for contact binaries
		The tables here are sampled at very small intervals, delq=0.01, dela=0.01, and take too much space for printing.
		The names of files signify the respective values of the degree of contact f: f=0.00, f=0.25, f=0.50, and "F" in the name is for the "fine" spacing:
		The distributions A_q are tabulated in 100 columns formatted (f8.5) for the mass-ratio decreasing from q=1.0 to 0.01 in steps of 0.01.
	www.astro.utoronto.ca /~rucinski/tables/TabFexpl.html (165 words)

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