1982ApJ...263..289F THE (!_) detected mv be observations to observations, electrically. have recently system Cester spectroscopic the was Although expected nearly binary measuring they residuals other McLaughlin they 1982. Light 1 Its its Ebbighausen = recognized. © ASTROPHYSICAL NAS-NRC first by The obtained used been 3.4, initial relative American et spectroscopic is 4 about American extensive Schlesinger of variations and is in the orbital motion 0.7 by periodicity from long- Subject 0.0034 B3 and semidetached. days al. from observed to computed We The present or 1848, this discovery first Grant ± V, Photometric redetermine m Research (1937) (1978). were Astronomical remeasuring brightness difficult. a a two the 0.2 and investigations 2 have a= Unfortunately, for 33 large ± the third and early-type JOURNAL, = time. headings: making investigation 0.0008 m day photometry I. in attributed 1.89 short-period by Astronomical 03h55mo8•, the (1959), of as in (1914). 0 revised measured computer Associate. Struve INTRODUCTION number The by the ; We body as Society. early investigations. A. SECONDARIES the it periodicity Stebbins ± primary. around Only Hutchings 263:289-301, a has it Tau is m the secondary find 0.04 solutions eclipses stars: variable, many velocities Laboratory the 0 have semidetached most All with He this as (1956) . elements led of at to A rights c5 that [HR three its of m low-noise third curve that a 1897 determined new = suggestion orbits period motion 0 eclipsing (1920) of various been to a third the probably However, reserved. brightness, . in + K are period these and reviewed 1982 makes numerous 1239 velocities with the observations eclipsing for spectroscopic 12°12' 1 of Society (Belopolsky extensive the were = of body. obtained might In partial, Printed to Astronomy Received both December and Hill of orbits 56.9 existing Reticon residuals, OF both = observatories. system. Grant's binaries 30.0 SYSTEM of a K a the photometric by addition (1900)] HD larger his a in (1971) components The one be which ± 34.6 these University U.S.A. ECLIPSING binary FRANCIS period as Mazeh the eclipsing days. 1982 series are and • dwarf. 0.6 velocity sets as photo­ 25204, 1 and JOCELYN well plates, K 1898), which spectra Provided more The short days. were orbit - data than km April coplanar discovered large ABSTRACT and and andf(m) the led Solar to of LAMBDA of of to stars: and as of s- C. velocity AND 26; 289 Texas those as Physics, 1 to means Shaham FEKEL, , TOMKIN accepted K individual 30° BINARIES. the measurements physical secondary spanning and determined velocity suggested of obtained determine ratio component. did of redetermine Ca good 4481 star minimum mid-A the and (1956). G 1975). to for 2 by at in Ebbighausen In The of = 8.6 or the curve must within high II Austin Goddard the detect that third TAURI (Slettebak JR. 215.6 previous long addition Struve the the A, of 1982 K agreement K to that subgiant primary secondary The 1 33 Observatory the he dwarf. dispersion line. 11.6 it be primary. 55 high-dispersion residuals NASA of June that the star mass day ± 7°. period the the determined Mg can a Space secondary years He brighter rejected, IV. the (1956) 0.7 the long spectral with to From investigations, The 1 of angle orbit its have and secondary and of be detected (Grant of II km velocity his this THE Flight with secondary from spectral and period A. The Astrophysics this orbits. the unambiguously 4481 plates mass Struve is Howard photometry of Tau s-1, of are these between feature been star (DAO) because type, Center that assumption 0.7 to TRIPLE star six 1959; a presence is 10.l the no m is of curve mass of spectroscopic A obtained to search apparently different type features (1956) In 1 as detected relative m determined of usually 33.025 lines they = is the between the line 0 ± Olson 1955; is short-period the well it , all Ebbighausen 7.18 ratio determined 0.7 was of confirmed suggesting can third of fainter from obtained noted planes for can the they and km luminosity, of as ascribed at A. observatories. Olson ± classified of Data the 1968). late (Grant of be Tau, 1935 lines a 0.09 Dominion the an primary the s- the body a be 3.75 circular by 33 that observations shown star used B of semiamplitude 1 overluminous No Mg third and a System Grant 1968; m and or and day Ebbighausen Ha of seen. the for that orbit rough to 0 which and on 1959). of is as early , lines velocities and the II 1939, line some 4.0 star orbit. a Levato Astro­ line it Struve (1959) From From B3 mass third mass from they is A. and is The and but the to of at in V a 1982ApJ...263..289F perturbations cession For Attempts years existing existing have for 290 computed there of series of a Casini, suggested result should confirm observations determined obtained primary array Observatory 4549 the of in 1024 The length these projected secondary of each can The resolution stars observed observed is 2,435,089.204 Reticon the photometric and of The Because We the The The An The that these between a the Stebbin's © phases primary A. be elsewhere produced third He new majority observation has element of of third (Soderhjelm are (Vogt, have Tau presence Fe-Ne A American Vega was period be central observations spectrograph seen of Grant observations Galeotti, spectroscopic the photometric this, spectroscopic and spectra-and spectra 1, always Ti the to set curve only that high-quality reopened. the at component Ti slit Mg of in with fo~ component. obtained 4510 400 period Tull, in 4471AHe1 secondary of detect Batten of 2.7 (AO discharge n II 0.45 4510 only the in period scatter ephemeris: + of conflicting of in Reticon the the wavelength once. width n, and of Figure A. is high-quality and 3.9529552E observed lines, a the the m A, this existed Tau short-period orbit (1959), and the of and and large a third A V) case lines period that Il. 1975; Fe telescope A. Astronomical and third A. such (Batten, line 500 are motion (velocity of paper. high data were entrance spectra of at Tau. data Kelton was OBSERVATIONS Guerrero the some observations, and II in These 1, as self-scanned for orbital velocities (Ebbighausen component. This was of Ebbighausen of they detailed McDonald lines of to and some 3.952952 results. which and their star at an Mazeh secondary JD ratio signal-to-noise the the well was the (Soderhjelm The nodes four made (Mazeh 1. The n observed of has doubt observations. opposite Fletcher, of coude covered 0 the had between effect 1978). two resolution 4481 eclipsing may primary Cet reality doubt slit velocity the elements chosen radial of the shows epoch (primary as (1968), diodes, This been in about period is with and signal-to-noise days standard about was Ti was Mg Tables produce given In spectrograph and expected (B7 Observatory Their by silicon short found additional 4481 and Society and about suggests of 105 immediately quadratures. n velocity used and 4500 addition of a so Shaham that II the system. increased the examining set residuals. 1975) from and Shaham the is of obtained V) which section this for lines-in in ratio Struve A. Struve 8: central as minimum)= A period Mann 1 no a long-period 30 and to so photodiode these are 1 third FEKEL McDonald the detectable and stars The Mg Fe to were refinement to ephemeris both a the the evidence km and standard calculate that we Reticon • 4535 be include present weaker gave II reality recent 1976). of (1956) 1956), which 2. II 1976) and wave­ when 1978) width ratios tables body need pair. As Provided have s - pre­ were from lines after fact, 7-8 also and the the two The the the A. 1 AND a a a ). Grant's epoch evidence line TOMKIN He presence about those Fig. Mg was 4500 resolved Secondary and lines, information Mg definition, variation poorly observations, spectrum (see and all three fromthe observations. This lines velocities the the be 4549 asymmetric consistent remaining anomalous Table lines; it up from correlation with between spectrum, spectrum. velocity obtained and the Primary by The In The is reliably 1 observations II stronger advantage the n contribution Fig. 1 measured to provides with are and and is all a A or ), about line. the the this line, phases of were one-third however, Ti 3), defined epoch means blend not 4549 Ti 35 four radial weaker spectrum of differences 1 from JD of five 4535 of 4481 profile allowance after ), n the at line. NASA of II The which and with observations a in velocities measured velocities a The true the and behavior and km 20 A. about of also line 2,421,506.850. and A group lines Mg all 4471 must when Although the of order of Tau. lines that the A. primary Ti % only that, A Mg conversion or the we A secondary the velocities than in Ill. primary of in heliocentric phases as is Fe two s- II is (made of caused Tau cannot (hereafter II of are measured of Mg signal-to-noise even A same most the very Astrophysics the At line II be some did of this too between line. 1 strong profile velocities RADIAL it II the in made the to are because the • He were the were only line of Ti well five least due lines is We lines spectra secondary II the determine of marked not broad absent. primary, line these it velocities when same Each observations the observations outside by minimum I II line secondary well resolved lines be cases of provided line when the defined Ti for 4481 to measured measured as of of lines were observations two "the think instrumental offsets, VELOCITIES of is A. make the provides line measured. the separately. n velocities intrinsic in secondary from Tau the the of it primary. given and the line in the defined the separately. and The and lines there for A it primary, is these and they the Ti is of the same geocentric Mg wavelength measured in is and the ratios that shallow from Mg line secondary at and use secondary in in due the it Mg secondary n Data Fe secondary in variability fully most are the other secondary, from provide from an some velocities and to are the II h primary the the lines, all wavelength variations the Table n Stebbin's of II lines other being II in to of In line, the the well Ti be in Fe line, Spectroscopic or of lines line standard resolved profile differences standard observations, the standard phases. Fe There System the or the a A. component. the most of n or which ascribed corrections, secondary, II are secondary which individual occasional defined secondary 3. by secondary Tau shifts they n is extremely and are very measured them velocities which velocities group between fact line 4471 eclipse), 4481 of at lines"), so and visible. (1920) absent in of of is cross­ weak their only Fe shifts from have it The were this (see star, that into few can (see star star are the no the the the to of A is in A is of II 1982ApJ...263..289F

@ 1979 NOV 12, PHASE 0.256 > 1.0

~ ....=""I n t "'I ~ 1' I I = " , ' ' / I [IJ> ..... 0. 9 f- \ I [ ; \j 11 / I ""I 0 j ! I / / =0 tf I // // / .... { I / / / n ~= i I / / / rJ)_- >- 0.8 L \ f / / / I 0 n f- } / ! I / / I .... ~ I J q~ ~1.0 ~ I.. v A//\ ·-· • z . ,,,....._ r Y \ ""C ""I 0 ~ I I s.: Sec \ '+'+f 1 o I Sec v Sec Sec Sec ~ 9 Q., o. f- Ti II I Mg II Ti II Fe II Fell C' 4468.5 I 4481 3 I 4501.3 4508.3 4515.3 '-< I .....

=­~ z t Pri > 0.8f- Mg II rJ)_ \J > 4481.3 \ [IJ> ..... ""I 0 1980 JUL 24, PHASE 0.777 "e '-<=­ [IJ.... 4460 4470 4480 4490 4500 4510 n [IJ WAVELENGTH (A) t; FIG. L-Two spectra at opposite quadratures plotted on an expanded intensity scale. The wavelength scale is for the primary. Secondary lines shown are Mg II 4481.3 A, three lines from the a group of five Ti II and Fe II lines between 4500 and 4535 A, and a Ti II line at 4468.5 A. This last line is blended with the primary He I line in the top spectrum; it has not been used for any radial ~ velocity measurement. Note the absence of Ti II and Fe II lines from the primary. The phases are for the short-period orbit, calculated from the center of primary eclipse. rJ)_ '-< [IJ ..... ~ = 1982ApJ...263..289F orbital 1981 1981 day 1981 1981 1981 1981 1981 1981 1981 1980 1980 1980 the 1980 1980 1980 1980 1980 1980 1980 1980 1980 1980 1980 1979 1979 1979 1979 1979 1980 1980 1980 1980 1980 1979 1979 1979 1979 1979 1979 1979 l'l80 1979 1979 1979 mean © orbit UT Dec aPrimary Oct Oct Oct Oct Feb Dec Dec bo-c cPhotometric Jan Dec Oct Oct Dec Dec Mar Mar Aug Aug Aug Oct Oct Oct Jul Jul Jul Dec Dec Dec Dec Aug Nov Nov Nov Nov Nov Nov Sep Feb Feb Feb Dec Dec Dec Dec American Date sofotions. velocities 17.383 15.309 17.236 14.426 19.453 17.467 13.497 31.173 26.064 01. 21. 01. 02.491 02.085 09.308 09.078 06.316 13.364 30.389 31. 03.058 02.097 08.331 04.448 02.295 01. 27.331 24.460 23.424 22.434 29.434 23.435 21.451 28.463 24.461 11. 10.145 14.242 31. 22.468 28.165 25.126 12.406 22.079 are and 203 373 383 049 392 236 295 velocities decomposition for phases. the Astronomical and 2444000+ 891.930 955.888 955. 896.957 894.971 891.002 661. 625.706 953.815 604.677 480.935 474.935 574.878 190.869 178.800 177.898 484.992 481.889 472.951 448.960 444.958 574.889 539.836 534.939 189.912 181. 179.800 442.965 536.965 535.929 320.576 300.584 238.741 216.813 216.583 213.821 191.747 280.550 272.559 271. 235.670 232.631 217.651 215.837 P HJD and the measured 563 741 599 953 orbital T of of the the ------He +13 6 + +23 -18 during +43 +55 +39 3 + -35 +59 3 -37 -34 +60 +70 +45 +21 +56 +60 +80 +81 +66 +66 +47 +82 5 +54 +57 +11 +66 +12 +78 +44 -12 -18 -22 -28 -33 -55 -29 -34 -23 -32 -43 -38 -30 -30 6 - -31 1 - OBSERVATIONS observed solution I Society same Velocitya (km Mg +43 +55 +41 +20 -32 +64 +55 primary +65 +75 8 + +12 +75 +83 +63 +63 -24 +46 +14 +79 +69 +79 +36 -33 -35 -32 -11 -37 -36 -60 -32 -36 -36 7 - solution. s- II velocities for 1 ) AND • +13.0 +55.0 + + +43.0 +40.0 +21.5 -18.0 +61.5 -33.5 -35.5 +62.5 +72.5 +64.5 +16.5 +50.5 +57.5 +64.5 +77.5 +82.0 + +46.5 +55.5 +67.5 +12.0 +78.5 -14.5 -23.0 -30.5 - +40.0 +11.0 +80.5 Mean -15.0 -57.5 -33.0 -40.5 -33.5 -31.0 - -34.5 -30.5 -35.0 -34.0 all eclipse Provided 6.0 3.0 1.0 2.0 4.0 VELOCITIES TABLE elements 292 into (phases (km 1 +1.2 +4.6 +2.6 -2.5 -0.6 -3.1 -1.0 +1.8 +1.9 +2.3 +1.9 +1.5 +1.4 +3.4 -2.1 -2.4 -3.5 -1.5 -0.4 -1.5 -5.5 -0.5 +1.4 +2.4 +0.5 +4.4 +3.1 +0.4 +1.0 -2.3 -1.0 -0.3 -0.5 o-cb -4.4 -2.2 -0.5 OF velocities 0.0 0.0 s- by with A 1 TAURI: ) the -0.08 the NASA Astrophysics PRIMARY 0.990 0.027 0.847 0.119 0.570 0.499 0.180 0.503 0.617 0.613 0.776 0.050 0. 0.538 0.876 0.358 0.856 o. 0.270 0.241 0.215 0.644 0.641 0.902 0.117 Phase ---·------0.252 0.830 0. 0.496 0.254 0.44J 0.607 0.303 0.696 0.787 0.183 0.162 0.919 0.272 0.060 0.309 0.061 0.001 0.813 4 in to 775 718 788 day 4 +0.08) the c Day period 4 Velocity Orbit (km +38.7 +49.5 +34.9 +20.2 day -37.2 -50.5 - - +42.7 +41.8 +56.0 +10.1 +33.1 +38.6 +47.0 +56.8 +58.8 +34.6 +51.6 +56.1 +55.2 +56.3 -54.2 -55.3 -53.0 -36.4 -43.9 -53.5 +29.2 +56.5 -57.7 -54.9 -55.5 -2Z.5 - -51. -47. -51. were 3.3 3.2 2.8 s- and fixed. 3 9 7 1 excluded ) b 33 day Phases o. 0. o. 0.722 0.659 0.881 ------0.828 0.745 0.109 0.370 0.941 0.283 Phase 0.631 0.209 0.209 0.002 0.492 0.129 0.404 0.223 0.051 0.213 0.399 0.189 0.920 o. 0.150 0.315 0.073 0.044 0.958 0.867 0.414 0.389 0.382 0.359 0.298 0.605 0.576 0.335 0.270 0.063 0.032 0.524 Data orbits from 718 789 761 240 33 b in Day the System are Velocity the (km + + + + + +17.4 +18.9 Orbit +11.4 +22.0 + + + +15.0 +19.7 +16.5 + +21.9 +20.9 +17.5 +23.2 +23.0 +21. + +21.2 +12.3 +10.8 +11.9 + +24.0 +21.2 +14.8 +14 +22.0 +23.3 +19.8 +20.7 +17.4 +20.9 9.3 4.3 5.5 6.4 3.7 8.2 1.3 6.2 0.2 5.1 3.9 for 33 s- .8 5 1 ) b 1982ApJ...263..289F 2444000+ 190.869 178.800 189.912 177. 448.960 320.576 272.559 271. 238.741 235.670 232.631 217.651 216.813 216.583 215.837 213.821 191. 181. 179.800 480.935 472.951 444.958 442.965 535.929 300.584 280.550 474.935 894.971 574.878 539.836 536. 534.939 484.992 481.889 891.002 574.889 604. 661. 625.706 896.957 891. 955.888 953.815 orbits 955.741 excluded the tion. HJD © 599 898 747 953 563 965 677 930 4 aSecondary bo-c cPhotometric American day are from and period for +230 +225 +220 +234 -152 +144 +188 +232 +212 +183 +228 Mg -118 -161 -154 -178 -169 +211 +211 -171 -177 -169 +133 +200 -139 -110 -134 -125 -122 decomposition the II the velocities fixed. orbital Astronomical phases. Velocitya Ti (km Ti II s-•) II OBSERVATIONS + + +234 +233 +240 +235 +116 -173 +161 +201 +100 +231 +239 +223 +223 +198 + -117 -134 -180 -168 -162 -199 -183 +211 +217 - -187 - -143 + +149 + -184 -160 -157 + -164 -157 -105 + -153 Phases + solutions. 89 28 82 83 93 measured 47 23 Fe Fe 1 of II II observed in velocities Society the AND during 33 VELOCITIES +o.l +3.0 +5.1 +1.1 +1.1 +1.4 +1.6 +6.1 -1.3 -2.6 -0.4 +O.l +0.6 +5.4 +0.9 +o.5 +4.6 -1.6 -3.3 -0.6 -2.3 -3.5 -2.1 -1.4 +4.3 -1.3 -0.3 -3.7 -2.6 -1.8 -1.2 +2.2 +2.0 +3.7 v.elocities -4.2 -1.5 -1.9 -6.1 TABLE day secondary 293 and • orbit Provided OF 2 the A Phasec 0.443 0.830 0.272 0.060 0.001 0.303 0.496 0.254 0.162 0.919 0.607 0.061 0.813 0.718 0.241 0.696 0.215 0.788 0.856 0.787 o. 0.309 0.538 0.902 0.117 0.876 0.358 0.270 0.252 0.183 0.050 o. 0.180 0.641 0.027 0.990 0.503 0.119 0.617 0.847 0.613 0.570 0.499 0.644 into TAURI: are orbital eclipse 775 776 4 Day velocities for SECONDARY by Orbit Velocityb (km solution the + + +215.1 + +209.1 +217.8 +216.3 +208.9 -208.2 +196.8 +182.6 +215.9 +206.0 -173.3 -185.9 -212.3 + +142.5 +140.7 +174.7 +215.8 -152.2 -154.2 -197.1 -204.7 - +191.5 + -158.7 -158.8 -199.4 -109.7 - -137 -183.6 -181.1 -205.4 -164.2 (phases the 83.2 91.4 78.2 41.1 67.7 s- 6.7 P 5.0 .4 NASA 1 and ) in for 0.42 T the of all Phaseb 0.166 0.139 Astrophysics 0.290 0.228 0.532 0.503 0.262 0.196 0.891 0.799 0.345 0.319 0.312 0.559 0.253 0.362 0.467 0.981 0.984 0.361 0.010 0. 0.085 0.455 0.150 0.240 0.180 0.860 0.089 0.740 0.735 0.677 0.952 0.892 0.800 0.811 0. 0.182 0.181 0.118 0.031 0.000 0.332 0.970 4 to the 33 day 771 723 elements 0.58) Day same and Velocityb Orbit were (km +25.2 +22.1 +23.9 +24.9 +13.3 +15.2 +23.7 +21.8 +21.3 + +19.9 + +15.4 + + +24.1 +26.2 + + + +19.5 +23.6 +24.1 +21.4 +l,5.3 +12.4 +16.7 +20.3 +20.4 +26.3 +20.2 +24.7 +23.1 +17 + + + + solu­ 33 5.3 5.8 1.2 1.8 with 6.5 9.4 9.2 0.2 5.9 5.7 6.0 s- day .0 1 Data ) System 1982ApJ...263..289F 294 star correlation instrumental that heliocentric are candidate it heliocentric present asymmetries to required secondary of the secondary -13.9 Cet 2 The the quote for It © measurement accompanied rounded the would all with primary Tin Tin Fen Mgrr He Tin Fen Fen American star km lines, Ti standard measurements; •This more I W1 P, es e, w, K,(kms- V K values P T. 11 ...... a 0 lines II s - Line 1 lines. have of n ...... 1 ...... (HJD (HJD or (days) (days) Norn.-A (deg) (deg) (km depth (kms- velocities lines radial Cet 1 in the offsets they is to He from for accurate been LINES s- show an 2 stars the 2,444,000 ...... are 2,444,000 ...... Fe-Ne was of ...... 1 the 1 1 had Heliocentric the I ) ) ) Fe the of ELEMENT velocity ...... Astronomical 5%-is line, absent preferable I ...... Wilson { solution primary MEASURED that profiles however, 11 that 4471A8 the 4481.14 4471.69 4481.34 4522.64 4515.34 4508.29 4501.28 excessively 4549.64 4533.97 4549.47• 4549.82 had standard are the .l.(A) line. TABLE spectra nearest +) velocities. + ) and we standard and listed it affected primary ...... been e, ...... observed for of is ( to this Vega of 1953) > in IN 3 probably broad V with X the 0 have 20.87) star 20.87 velocities Vega 0 in both 8.86 2.84 2.84 2.85 8.86 2.83 ). 1.12 solution (eV) 1.18 1.58 1.24 km was by calculated and T .. .. Tables for was AURI were ...... standard . . . also Mg the observation.) other used l \ / lines. not the K, Society s - the the Component Pri the Fe-Ne [ro,(sec) O.Q25 658.4 lacked He 667.3 possible 33.09 1 the for not II 56.9 0.16 13.1±0.5 10.1 used weak 236 of Primary and 1 Sec Sec Pri measurement Sec Sec Sec Sec primary I because 7 line standard the same and line-which ± ± ± meaningful ± ± ± ± ± ± FEKEL + star. by Sec some lines. for = O.Ql5 0.6 0.3 spectrum 0.07 28 0.7 0.06 24 2.1 secondary because 15.4 • and ro,(pri) standard 2; cross­ These n ORBITAL Provided of Other (The they and Cet and the for the all in + AND TABLE 0.046 is 215.6 684.8 32.96 667.8 Ti 0.21±0.08 14.0 Secondary 10.8 Ti 261±22 180°] 77 II+ ELEMENTS II ± ± ± ± 7 ± ± ± ± + gives Ti velocities of Ti secondary and of Fe Wilson's had was by each amplitude lines TOMKIN Ti it is Fe radial secondary? of 0.9 we 0.1 0.7 0.004 This Ti 4481 type somewhat 0.8 0.06 discrepancy give based (1981) lines + 1.8 4 Fe There by First, is Inspection 15.2 II 3 II 11 200.l primary II+ most the II+ II have cross-correlation The 11 system, V and any B3 in A been the Vega, + for of 0 + other. on velocities says 3.9529552 the Mg = velocity ). Fe and results same km Fe the Ti Fe Fe the Tau. velocities 0.037 200.1 same 601.6 633.7 a 19.5 ± 33.47 the SOLUTION adopted larger 17.5 value Secondary 0.48 representative 17.3 11 is 203 done that II small which are II is 11 NASA Astrophysics 50 velocities II for 1.3 B9, respectively. line, primary, Mgn II eclipse s - inspection effect line ± lines lines, Two For Ti the no line ± ± ± ± ± ± ± ± ± ± of the with 2.2 as line (fixed) is and the 1 than always 5.0 0.011 "tend 0.3 0.31 28 1.3 0.11 in 25 15.9 1.6 of number , of has as II same velocities the very for may in km such secondary Wilson's which the velocities. the + n respectively; considerations all Table Mg + a a 215.6 A. does velocities. they s- the to period Fe given Cet velocities preliminary 15.4 be Tau-are similar as (see other mean analysis IV. of 1 give (seven) II of of consistency present 667.4 33.07 and we Si II .l.4481." 56.8 0.15 13.4 10.5 The is 241±24 Primary are at ± of line its km ANALYSIS 2 each Table e, of lines. Si II velocities, in smaller elements of find value. K, in 0.7 to 0.0 = velocities the ± ± ± ± shows ± ± 5.3 and the 11 Table Mg reasonably the of much velocity is 0 = s- in 0.5 0.6 0.06 0.7 ). 0.05 2.1 and excellent for Orbital Although of from km A. days 3 214.8 thus observations Tau the time 16 4) 1 Fe Tau secondary; orbital Which to the the II and Fe suggest fixed weaker both s- eclipsing yield km and magnitude 1, that 11 in the ± in line the the Data 11 Ti 213.4 Ti 33.15 659.3 of observation, 1 for Secondary shows lines, 0.27 primary of 2.7 some 14.2 15.2 component 149 confirms lines, with for positive Popper's s- solutions II+ e, 11 the measurement our secondary agreement He set semiamplitudes km the n than consistent these 0.0 motion + with = ± ± 1 ± ± ± ± ± the and that binary the Fe Cet respects. Fe 0 their smaller which-like System 0.16 0.09 2.6 1.7 s- 3.0 32 1.5 of I that comparison Mg observation the Mg II and 1 II and Mg sense he . two findings Vega's velocities velocities than obtained it ani Vol. of that V822 secondary outside does II negative, of of II spectral which is II Mg Popper semi­ lines. of than Mg with with and and line 263 the the the Aql. the the not the the are of is II rr 1982ApJ...263..289F the the shifts the No. does more secondary are line. We velocities. (Vega). means heating primary from Hutchings temperature beneath point secondary contribution of a include from and of illustrated which be on. velocity FIG. 0.75- The the significant. same radial will © group much 1, The so 2.-The spectral not the the with truthful on secondary for American 1982 that second In the outline of of a is the velocity. line prove-that the primary. 8.9 the velocities, other of respect the A the rotational and hotter velocities is in more velocity the effect primary "dark" widths-means to five asymmetric, sake of line rotational eV measure secondary-V Figure The secondary consideration why Hill side the words, of the facing This than Ti affected Mg over to of rotation As effect (1971) we of Astronomical obtained measured showed side II the simplicity include 0 is secondary 2 component. the mutual a the II the think of and the the the for 1400 a:: a:: ~ 0 CD w result 0.5 PRI o.o same effect is line of orbital by on I Ti I find except "dark" secondary than greatest Ti observed primary; Fe the the the that the that II that sin a by is K consistency is II lines Mg that and the is we II observed rotational secondary the i phase and higher much measuring the motion the strongest at its lines ::::: at the expected side will II The variation for at Fe in 80 influence possibility phases Mg line the .thus Fe illuminated Ti hemisphere individual Society quadrature the A. discuss II km of had brighter 0.25 secondary than large II Tau II lines than II+ velocity the point suggests-but the standard farthest lines line s- contribution. very because on 0.0 the quadrature, of the it 1 secondary. Fe might rotational rotational provide the from velocities is is that the all strength and line primary velocities directly • lines derived LAMBDA similar surface II by favors of and at Mg away Provided yield here star well line side will 0.5, the the the the the in is II a TAURI tribution that the and 0.75 in magnitude velocities is motion. than secondary orbital consistent masked that and Table red, have side free Ti it the than estimate line 215.6 the why will separate semiamplitude amplitude velocities and solution identical motion primary a amplitude type suggestive computer in differential elements primary eclipse, orbit Ti photometric same + measured were by is third shifted the The The Fe II+ II+ half a Ti elements for of recall of Mg is the be velocities will amplitude however the of the excitation the excluded it ± same II way. 3) the illuminated modified which a II star. motion. the and less elements deepest Fe Fe because of phases 0.7 residuals II the In of rotational is and is so + the orbital 33 of orbital to were also secondary were with will Mg NASA lines that secondary the clearly during of pulsation of opposed II of 8.9 (Primary Fe the other routine for sense-so II corrections that km It than the primary day periodicity day the the secondary's secondary and for value. the the was center II about cannot line and at II solved eV tend be orbital this explanation. from of200.1±1.3 -0.08 observed of line Mg point the is s- the The blue potentials found the element the line version pulsational secondary it velocity. observed words, for Mg secondary this the have Mg also less by 1 fixed for Astrophysics contribution, velocities the is at II to line Separate described facing is Mg of the strengthening to Ti velocities of 10 and velocities asymmetry be side of the for, the the line II to Ti primary. for phase II the and larger mass phase than Mg the present the II is to line underestimate is a km solutions.) the simultaneously attributed line. with +0.08, we II solutions hemisphere orbital Mg the primary. + except II the of conclusive velocities. 4 orbital sandwiched of 33 the the By Mg rotational of primary. + II line; profile Fe in velocities of 0.25, solution expect s - and eclipse, velocities-both variability the the solutions km will This the than II 10 Mg a periodicity day line Fe primary profile the only the measured the elements the by 1 The II II line may in and At • it the km motion, profile s- when line magnitude line motion-see 33 of The in general also II II eclipsing means the to will of phase velocities velocities precisely This the same will The for Daniels Data that velocity 1 Ti secondary 1.1 The phases period the . (The line. not evidence s - day some semiamplitude other these of solution. We motions velocity were asymmetries between of same is II residuals secondary the be of its the be tend of results 1 rotational to for (see the during much the presence 0.75 and by profile be argument amplitude that decided but much This the deepest point B3 orbits f3 shifted the System Ti obscure least-squares lines 2.8 secondary's made of 0.42 pair CMa will words, both completely (1966). determined of Mg periodicity and secondary of Fig. Fe to evaluating we V secondary the II the of although the at Figure less velocities are must explains the with both eV primary primary spectral smaller + for orbital around be to II on of expect under­ orbital II of to phase prefer Mg stars.) in of orbits to 1 effect 4 Fe con­ given Ti lines than He low­ 0.58, ), line (see less 295 the the are the the day the the the the are the be do the All an of is 2 II II II 1 1982ApJ...263..289F e, with period include period > FIG. FIG. 0 © all orbital component fixed. V 3.-The other American 4.-Secondary 0 . The These solution elements zero primary from short-period of with velocities phase fixed the Astronomical and the decomposition secondary is 1 with ..... g LU >- u ~ > 7 >- t: u LU g ~ > .. short t200 -200 the +100 + -100 +100 velocities -200 for 200 0 the center the period -0.5 -0.5 values velocities short-period do of of fixed. primary not from Society the ~ .,,...... \ include Secondary 'b" for observed the .. 0 orbit eclipse. the 00__.,. 'o~gey -,, same short-period V of 0 ~ • • velocity .... velocities The A. 0 primary Provided 0 0 Tau [w,(sec) is the and Tau. I 0 the the I orbital " orbital ,f' long-period center ,,o Each NASA = ~"' cee w,(pri) solution solution point of 'O 'O "' '\ primary 0 0 + components. Astrophysics is of 180°]. of not the the eclipse. +0.5 + an Ti These 0.5 Ti observed II II Primary + + short-period Fe Fe 11 II velocity, Data velocities velocities velocities velocities but System for with are is V the 0 from the and do short­ short not the K, 1982ApJ...263..289F day of in secondary elements. elements of and and 0.21 km the (Ti however, must respectively-is primary agreement will probably solution velocity same The mass The mass Fm. Table © period s - II 8.6 orbits ± adopt Struve as be + 1 American 5.-Velocities 33 0.08 curves the • eccentricity ~ of of Fe The of el We real. for and 4, more the The day K the phases velocities are of the is the from the and II) the (1956). are ~ agreement w-i.e., results 33.0 primary secondary orbit solutions shown system, reliable 11.6 primary. velocities from in long-period only long the the the think for days km Astronomical the is of The should c:,onfirm velocity second-last primary 236° the about in period and due than so e, s - the and of of Figures that long-period > • respectively-indicate LIJ 1- u > 9 eccentricity-0.16 >- .. do 1 in ± secondary 0 to the the determined the short-period yield orbit; twice orbital 24° principle the 20 the 25 20 25 the 10/ " 10 15 indeed :t curves orbital the and 5 0 columns two l primary 0 secondary 3, and semiamplitude primary ;: values motion identical .. solutions secondary its orbit they 4, results / /o" 261° for Society and around give of elements associated /i-·· the by Ebbighausen of /.--;;·-:--:. both Tables and of the orbit A. 5. velocities of velocities with 0.2 ± primary and very 33.025 Tau long-period ± • .. 22° the secondary show the center 4 velocities, 1 O.o? the •• also ~ and derived • and for for LAMBDA similar that is for center short error; Provided days ···~ 2. that 10.5 and and and the are the the the . 33 These it 0.4 from period ~- long-period the '·"-.. PHASE TAURI fixed. associated primary marginal associated disregarded, solution and of large that period shows elements amplitudes Comparison instead the velocities secondary good periods ± primary by Solutions the 0~14 long-period The secondary "' the 0.6 eccentricity.) the agreement short-period that orbit velocities with -~ of phases solution velocities of reality. for solution in NASA Astrophysics error. the solution error being the do and which assumed of SECONDARY the the PRIMARY even with are primary '~· the not secondary include (Ti semiamplitude (The0.046 3~529552 The and primary is of 0.8 for 3~5298 of fixed, the primary 0.025 will though change orbit Results II the become 0.015, these the the gap + to V short and 0 P Fe . tend Ti nonzero gave be and 1 from in solution ± and Ti spectroscopically II+ which secondary significantly, photometric circular II) ± and it of secondary somewhat O~, period II+ is 1.0 0.004 to 1i short Fe is velocities phase solutions not secondary of and II much produce Fe eccentricity suggests these are secondary eccentricity was much are Data periods eccentricity II 0.36 short-period respectively. velocity unaffected, solutions velocities larger. given allowed period, larger the with of larger to (Ti a System that the velocities. long-period 0.61 determined of in spuriously the II+ solutions coverage and from than which Table primary 3~95311 than to it for can means short­ while semi­ Fe are vary, is The 297 Both the the its be its II) of the 4. is 1982ApJ...263..289F and no based combined 298 tion 56.9 and of most the B Hutchings results r r fractional the fractional and A. (=Ki/K the and 1964), of which resolution system system stream, main-sequence to the are tions would we calculation 2 1 Tau The The = = a and the large evolution, © have secondary secondary secondary given and 1954 radius ± semidetached Hill 0.30, 0.206 Peters Hill recent suggest being on American makes 0.6 f2(m) f1(m) evolve irregular primary a a m2 Inclination m1······················· Separation r1 R1 r2 quoted in R2 Cester is which is V primary 2 1 provide fractional change 2 therefore radius ...... sin sin NOTE.- (Grant detached, the ) radius ...... MASSES ...... semidetached...... and in with mmtma and radius solutions.) while 1971; extreme-ultraviolet = of and ...... a in photometric (1980), i i Table et direction it that ...... long 0.264, semidetached because filling the lines r is al. for is Hill very the the star 2 and changes The requires AND ...... of in further Cester 1959), 3 = 1978. Cester and 215.6 the before of masses set system, radii adopted the Cester the photometrically times 5. observed fractional Astronomical 0.25. then which find discussed difficult of direction DIMENSIONS secondary. is its the of system V. secondary The the by the period. 0.262. yield secondary TABLE is ± Roche orbital spectroscopic et i Also, in the that .. mass .. RESULTS solutions (These greater ...... et . . . secondary = and evidence et 0.7 not much same reveal the al. the the radii system, corresponding to 8e3 secondary. al. the must al. it in 0.0754 4.10 0.25 0.30 7.18 76° 21.3 6.4R 3.093 1.89 11.72 5.3 in a dimensions. motion OF of determine if transfer explain Thus observations 5 lobe, profiles km Cester r be mass detached Unfortunately are mass. masses 1 (Plavec fractional R0 it § more ECLIPSING 1916 than ± 1978) ± R ± ± and the orbital 0 ± ± be III a of 0 is ± 0.04 0.04 0.09 that while 0~3, semiamplitudes determined 0.04 0.033 the i.e., detached s-1, is 0.0025 r the and Society semidetached, supposed A. presence 2 evidence are et why ratio It that has massive m0 These considera­ m m (Stebbins are and Tau and consistent do r x there and consistent means 0 0 al. cannot x 1 are the i system. Cester PAIR 10 the characteristic motion. = m These = radii 10 yet the respectively, Roche of strengths 6 solution dimensions 0 by (Hutchings not Kratochvil FEKEL 6 from q 0.345, km radii Hutchings 76° km has system. a to = radius of the that that primary of inclina­ Polidan • normal are be ± m results agree. occur, et High­ 1920) a Provided been their 2 with with lobe The 0~5, and two /m and due gas for the the for al. of of of AND 1 TOMKIN components, difficult depth B2 with function, coplanarity determine line Ebbighausen Because We type (Slettebak from of of of determined line, both star, faint luminosity determined width relative with spectral strong low-noise in the with pair photometry (1976) luminosity intrinsic Inputs Johnson magnitude require after calculated distribution 1981) 3.64 Thompson magnitudes spectral B3 by The Although We The this the the the find secondary V, of V Grant late our then the x compared using i converting the the the 33 of the 33 have and detection, secondary. sets and classified in to and most 10- observed any m although type m Ca VI. classification of to the 4 failure day observed B the ultraviolet day the 3 3 Reticon secondary fact it (1966), NASA and the 3 m day (1959) 9 = ratios the the an (Soderhjelm difference, et the was classification attempted or SPECTRAL with third must the sin of a Hill from 1 of a II is ergs Ca accurate program spectra and orbit investigators 0.7 orbit + al. and Howard mass selected early that A4 set 3 spectral compared luminosity large upper orbit, computer infrared to to K the m held both i/((m intrinsic they et m Struve (1978) it s- also light. be spectrum data For with Johnson a for 2 the detect must the Astrophysics the strengths 0 of line , of is al. the 1 secondary of on the . A. of a K a colors combined magnitude If 1 the generally suggested cm- of because constant TYPE to detected the are classification magnitude to limit A-type the eclipsing and (1975) + the lines input cool 1955; the some a In in consists be total and 1975). (1956) the photometric type energy secondary. triplet the determine dwarf m calibration the of eclipsing 2 to program ratios A short-period UBVRIJKLM addition coplanar, third third 2 have et OF of E(B- A:- primary ) stars, (see in of of 8806 the U, Olson Victoria stars, assumed mass the + classified al. A. THE values. This of the stars. detected the as the thought 1 throughout the Tau. that and 7° m B, scale pair. energy star difference region. star at classified for of references (1966). two difference 3 observed V). A of Al A3-4 ] constancy Hoc SECONDARY of blue Grant V, pair on means that 2 several wavelengths several Data Hoc 1968; of the to Plavec of will the or Mg TD-1 was m(A.) is It the = the because Combining This of plates. R, magnitudes solutions III-IV From and spectral stars, the a is the This nearly departure 0.0034, Parsons and the to spectral components the spectral secondary can distribution main-sequence the third I be For I, from also assumed Olson eclipsing Levato = determined line, be System secondary Ca Mg between colors is it and J, Mg fluxes distribution exceedingly of 0.00. the primary in Mg be As a equivalent the from calculated consistent an A. consistent of as coplanar, K, we II star the the type Vol. which II table II spectro­ Tau Polidan Parsons used a do Klines type various A II region. eclipse (1981). (1968) and 1975). B3 A.4481 A.4481 visual know result these using mass from to close from pair. from lines on lines star. is and 263 the not the he as to be of of V of is is is L a a 1982ApJ...263..289F No. solutions. ~ show energy contributor there this magnitudes tions variation values. were was (Clements appreciable distribution in magnitudes. that ratio broadened R spectral spectral a is From the region the widths secondary's detectable. observed 2.3 A2 ruled with however, strong as Observed late B3 B3 B3 B3 neutral V spectral Our Table NoTE.-All V V V V secondary and not the stars, ± results temperature = wavelength © obtained. 1, + + + + as of Grant's of changed of is Mg 0.2 out 2.5 an A8 A6 A4 A2 19S2 spectra, distribution American as of lines, no about we AS, enough infrared. this only Mg energy type type Unfortunately 6 examination they V, V, V, V, energy (est. of II, the the type since The in sign reasonably and mag Fe Although lists .1 .1 .1 .1 effect to magnitudes have its the ratio spectral Ti for is II Keeping V V V V this value Table AO but Fe features a (mag) error) are 11 Fe the by = = = = II spectral is as which of II, region influenced Neff other Fe the small of distribution the 2.4 2.3 2.3 2.3 to rules V, ). to and II, (Grant on are II trial still about Inspection also and neutral observed early obtained ...... the analysis of Tau ...... Ti I 6 1, and lines. Astronomical put mag. lines the type. observed even 1979). lines computed all indicate Ti in out while probably 2.45 cover the of in initial II, Fe by and effect primary, type well as magnitudes several 4 mind the and these the II extensive and ). such This lines, magnitude would Since II the %. 1959) larger. The AO mag. in not Tau. 55 1965 1565 0.86 0.85 lines flux 0.85 0.86 0.86 error is the The from lines Reticon 105 line to determined, on Mg of parameters this secondary representative In OBSERVED exact with ~B for that a is that lines composite magnitude particularly only photometric too secondary at sharp we E(B late For A are in be depths last The Table the and the of until A2 the = II E(B- all region .8 1.78 1.38 1.38 1.38 1.38 1.38 the centered weak constraints excellent the do lines values up are 2.6 spectral the - too difference about by a V wavelengths, spectra secondary same line three Society I, lined AND V), sensitivity to a V) spectral E(B- not to or infrared stronger secondary, and 6 the shallow J, to in reasonable and = are 2365 depths is and 1.78 1.78 1.77 1.78 were energy AS spectral difference a COMPUTED with assumed of shows 0.06. A2 detect 1.5 wavelength be parameters these determina­ K, at luminosity type. equivalent agreement secondary computed V) a including nearly iron. V of ~ from % detected 4510 V type on LAMBDA • and V, A4 has can energy = minor in 2740 ~ of of 2.26 2.25 2.26 2.25 2.27 Vega, to Thus, while stars. stars, scale even Provided such then V 0.04 type that For but the ENERGY the the the the for no V, A, be be fit is, = as as L TABLE 3600 .7 2.64 2.57 .5 2.63 2.55 2.56 2.57 2.56 u SCALE TAURI Grant our EFFECTIVE the causes and also addition detect the variation. periastron as at than For to which spectroscopically, semiamplitudes change examined coplanar observable depth. which concluded 1976). that binary! suggested four orbits actual changes latter the the year ). were 6 The The least Soderhjelm Tau by apsidal be 4400 two 2.64 2.64 2.63 mid-A observations. MAGNITUDES Shaham over short-period ). B period causes S: photoelectric long- made VII. 7-S the (1959) situation due This at depth may Tau might ). From presence several 1 variations from would motions There WAVELENGTH Tau is to most in a to DYNAMICAL the motion years that passage one NASA 5500 to spectral 3.41 few 3.41 3.41 3.41 3.41 that nodal between of consequence be the the within v and periodic the about of and (1976), the system spectroscopic be the the hundred (1975) shows detected is hardly of the years primary FOR velocity period of (Soderhjelm the of the as (nodal photometric observed no later the associated long and motion short-period 7000 and in the orbit 4.28 4.28 4.31 4.27 4.27 (apsidal angle A determinations about 1.2 R the Astrophysics large (A) type 1916 evidence the TAURI eclipse with long- the few examined the only variations two EFFECTS nodal by mag be period variations years, of third photometrically. precession). eclipse last variations depth varies systems between assigned Olson of as 7°. and 9000 motion will a 5.19 5.20 5.21 5.23 5.22 orbits, recognizable nodal constancy a motion), and I observations to period such precession would precession three slight 30° Mazeh 1975; and/or star whatsoever about 1954 produce of behavior OF is of the (196S) short-period from semiamplitudes. in and for precession which the 0.43 12,500 THE primary a in the of 6.26 6.25 6.28 6.30 6.31 in effects to change of ratio J Mazeh discussed and existing be variation As the and and 0.1 which the Data the of variations, the the that the mag planes THIRD this 90° is the variations noted so are may eclipse are mag; as small for of eccentricity, of consistent slightly Shaham eclipse are close ). for secondary 22,000 eclipse in depth, inclination over in and shallow the 8.75 8.65 8.66 8.69 8.72 such to rather an variations System Tau ). summarized K photometry is be STAR difficult of the such B; in orbits by i.e., size would Tau. planes 60°. depth expected eclipsing detected pair. Shaham the the periods § and usually depths, greater Maze)1 system eclipse in would (1976) in which short. of IV, gross They 34,000 with 10.30 10.42 10.45 10.35 10.38 that The The two 299 this 7-S the the are L the by In he be to of in of of it 1982ApJ...263..289F A is down it they by be photometry 300 from observed in variation the which chance eccentricity. depth," does Belopolsky, they "a Shaham (1979) from 0.44 Cester, Casini, and long of Batten, the to more be Shaham's amplitude Clements, is is is is Ebbighausen, Daniels, Fekel, this nonzero result slightly known in ratio separation Obs. Milano-Merate, about Tech. 1978, 0.08 series small evidence 0.58 is Both Table 4 primary As well less the more 10 as The differences © 1913, mag eccentricity the accepted value, term, probably found not F. "'1.2 is Victoria, B., mentioned mag mag; long-period A. C., of to year American Astr. general large have is Rept. worthwhile W. 0.1 than accuracy can close early in C. about if of as greater as 3 G. Soderhjelm Fedel, concluded and H., these depths so Galeotti, than sheer eclipse of V show E. A. the mag. and of 1981, of suggestion summarized eclipse thus nearly mag Ap., L., the Soderhjelm E. of between series as No. be over Fletcher, also 1966, that 1898, visual the small 39°. as Even zero the Soderhjelm multiple between 15, G., and relative measured have B., that a 4: 62, excluded 0.02 No. Ap. of studies, the overinterpreted amplitude 579. study chance. made 0.04 to any small than variation 121. of eclipse are examined Giuricin, and University the 1. Astr. the visual eccentricity Neff, For P., earlier, 291. depth photometry periodic of J., an accuracy because-as orbit 288. for -0.l as the These that the J. Astronomical mag. Struve, so the 7-8 and 246, these evidence visual by by average in (1982) amplitude Nach., 8: M., system inclination J. variation must by to relative an Sooerhjelm estimates depth close we von seven S. short-period (1975) 1 depth. it This a short-period some year measurements G., by mag, photoelectric 879. Guerrero, (1975), and argue of the of eccentricity and, 1979, If, low-mass visual ratios is can of 0. the effects variation have 145, Aretin Mardirossian, estimates visual Maryland, value the of be periodically different Mann, visual to for and period orbital 1956, (Fekel chance of period then for A. Ap. of become inclinations of 281. points therefore, Soderhjelm In each short-period dismissed of the estimates against do Tau. primary are of chosen of (1913), the eclipse between G. their J. Ap. Mazeh fact estimates observations depth. a P. the 0.45 concluded not photometry the Suppl., spectroscopic of third 1981 observers solutions the other The Physics 1968, in variable sake J. J., ratio of orbit. secondary is by Society out. as precession fact even range depth mag. F., 1978, by very depart the test 124, a variation about any to and smallest estimates possible ). Nijland the small eclipse 41, Contr. star third and the 4 and as of photoelectric of has At that notes-there for and short-period greater list 507. The from Mazeh Pub. Mazeh this cases. can eccentricity between l. large. the eclipse large-scale FEKEL (Grant separation Mazzetti, argument, a two in periastron minimum induces from to Astronomy A. 1/20,000, that both body average Shaham the Oss. as be fantasy; because Table Dom. • and 0.36 depth remote of ranges Tau be for would of (1932) orbits could judged data. Provided 10- As depth In depth than four 1959) this Astr. and and REFERENCES 1848 mag put any the the the the Ap. on M. of 4. of is AND a a a 3 Because masses, third separation important to counterrotation, and the orbit in The --. the numerical corotation long-period the value some above TOMKIN Grant, q/a 45 the stantially criteria grant --. Harrington, respectively. by star. as of E. Johnson, Johnson, Hutchings, Hill, by binaries is Levato, Foundation Mazeh, thanks been NASA Astronomical by Mem. From 1966, the To We commonly examine the G. days, dynamical a = a equal-mass equation ratio mass q/a G., quantities also surprisingly to The star the AST G. short-period of binary 0.7 put equation, Ebbighausen supported, T., 1975, would H. Comm. solar 1979, R.A.S., of T. the of H. = Hillditch, H. which 1959, of that q/a and Harrington numerical and J. 1975, of greater of and R. on Mazeh period to [(q/a) NASA the L. results parameters Harrington 79-22014) and of L., the B., semimajor this A.J., the Astr. orbit, the S. is the system, Lunar 1966, (F. 79, Shaham, Ap. have the be and The like supposed. and the the Mitchell, Astr. 8: Society. stability 1972, 0.5 greater 2.75 m stability 80, case 0 small 131. Ap., observations the was F. periastron J., R. /log 1 about third than of 1 Earth's Ann. could Hill, comfortable of short-period primary short-period for Planet. to and the Ap. relative planetary 1080. period in orbit, for 129, Astrophysics and by observed W., Celestial 77, system for orbital for I. this and integrations one and thank (1.5)] a G. Rev. Suppl., administered these R. for separation part, axis 1976, grant than (1972, (1975) 145. star Earth corotation 78. Younger, (q/a) useful counterrotation. is 58 be m of their Lab., 1971, m I., can in hypothetical orbit is stability. 2 Astr. ratio concerned, 3 of reasonably Mechanics, the R is Ap. log sense, Iriarte, is distance limits. 19, are 0 motion. part equal is David the AST systems by 4, 0 Ap. stable. the the in is imagine discussion. helpful the 0.7 q/a Ap., J. , 91. margin. 99. system. and 1975) [1 would F., of the or limiting the J., by (Letters), the short-period the A. + mass B., ratio, = 4, 81-16409 m of Thus to either and A. and 166, Stability Lambert only Tau a m 0 In masses 193. 6, Data parameter 3.4, Tau He and David of by may place grant 3.5 3 three-body suggestions. National the 322. and determined be approximated the /(m 373. Fisher, the binary of counterrotation, the according and it system 205, If found Wisniewski, 2.72 value for the a corotation This in stable. the be 1 percentage is case Sun the to System we of and + of depends long-period L147. the value for the secondary. larger Gray of W. star F. times orbit, m would American the work observed find the from limit of Vol. replaced that is 2 interest J. F. making context Science case )] Insofar A. A. in stable to point T. . F. F. stars third . from W. than sub­ Tau that two 1975, q/a, and 263 the the has the the his for on by or by be of of Z. 1982ApJ...263..289F Nijland, Olson, JOCELYN McLaughlin, No. FRANCIS Parsons, Plavec, Plavec, Popper, Polidan, and and 15, Binary D. © 1, M. 165. Evolution J. E. M., M., American 1982 . A. A. D. Whelan S. Popper, R. C. Stars: C. TOMKIN: 8. and and M. S., 1968, D. 1981, 1932, FEKEL, and 1981, Kratochvil, Polidan, of B. Observations (Dordrecht: and Ap. Close 1937, Peters, Ap. Astr. Pub. R. J., Department JR.: J., Astronomical K. Pub. R. Binary 153, Nach., A.S.P., 247, G. S. Ulrich P. NASA Reidel), Univ. 187. and J. 1976, 1964, 560. Systems, 246, 1980, 93, (Dordrecht: Interpretation, Michigan, in 318. Bull. 110. p. Goddard of IAU in 289. ed. Astronomy, IAU Astr. Symposium P. Society 6, Reidel), Symposium Inst. Eggleton, 3. Space ed. Czechoslovakia, M. 73, p. University S. 293. Flight J. • 88, Structure LAMBDA Mitton, Plavec, Provided Close Center, of TAURI Texas, --. Soderhjelm, Slettebak, Schlesinger, Stebbins, Thompson, Wilson, Vogt, von Code Carnochan, by violet (Washington: Aretin, S. the 1982, Austin, Fluxes S., R. 685, J. A., Tull, 1920, E. G. F. S. E. NASA Astrophysics and Astr. D. F. 1975, Greenbelt, 1914, I., (Great 1953, Carnegie R. J., 1913, Ap. TX Howard, Nandy, Ap. G., and Astr. Pub. J., General Britain: Suppl., Giittingen and 51, 78712 Wilson, Allegheny Institution). Ap., K., R. Kelton, 193. MD submitted. 42, 1955, Jamar, Science Catalog R. Astr. 229. 1978, Obs., P. Ap. 20771 C., Mitteilungen, Research 1978, of J., 3, Catalogue Monfils, 121, Stellar 167. Data Appl. 102. Council). Optics, A., Radial of no. System Houziaux, Stellar 15, 17, Velocities 1. 574. Ultra­ 301 L.,