17 research outputs found
Radial Velocity Studies of Close Binary Stars.VIII
Radial-velocity measurements and sine-curve fits to the orbital velocity
variations are presented for the seventh set of ten close binary systems: V410
Aur, V523 Cas, QW Gem, V921 Her, V2357 Oph, V1130 Tau, HN UMa, HX UMa, HD
93917, NSV 223. All systems, but three (V523 Cas, HD 93917, NSV 223), were
discovered photometrically by the Hipparcos mission. All systems are
double-lined (SB2) binaries and all, but the detached, very close system V1130
Tau, are contact binaries. The broadening-function permitted improvement of the
orbital elements for V523 Cas, which was the only system observed before for
radial velocity variations. Spectroscopic/visual companions were detected for
V410 Aur and HX UMa.Comment: AASTeX5, 4 figures, 3 tables, to appear AJ, June 200
Radial Velocity Studies of Close Binary Stars.XIII
Radial-velocity measurements and sine-curve fits to the orbital radial
velocity variations are presented for ten close binary systems: EG Cep,V1191
Cyg, V1003 Her, BD+7_3142, V357 Peg, V407 Peg, V1123 Tau, V1128 Tau, HH UMa,
and PY Vir. While most of the studied eclipsing systems are contact binaries,
EG Cep is a detached or a semi-detached double-lined binary and V1003 Her is a
close binary of an uncertain type seen at a very low inclination angle. We
discovered two previously unknown triple systems, BD+7_3142 and PY Vir, both
with late spectral-type (K2V) binaries. Of interest is the low-mass ratio (q =
0.106) close binary V1191 Cyg showing an extremely fast period increase; the
system has a very short period for its spectral type and shows a W-type light
curve, a feature rather unexpected for such a low mass-ratio system.Comment: Accepted by AJ. 19 pages including 5 figure
Radial Velocity Studies of Close Binary Stars. IX
Radial-velocity measurements and sine-curve fits to the orbital velocity
variations are presented for the eighth set of ten close binary systems: AB
And, V402 Aur, V445 Cep, V2082 Cyg, BX Dra, V918 Her, V502 Oph, V1363 Ori, KP
Peg, V335 Peg. Half of the systems (V445 Cep, V2082 Cyg, V918 Her, V1363 Ori,
V335 Peg) were discovered photometrically by the Hipparcos mission and all
systems are double-lined (SB2) contact binaries. The broadening function method
permitted improvement of the orbital elements for AB And and V502 Oph. The
other systems have been observed for radial velocity variations for the first
time; in this group are five bright (V<7.5) binaries: V445 Cep, V2082 Cyg, V918
Her, KP Peg and V335 Peg. Several of the studied systems are prime candidates
for combined light and radial-velocity synthesis solutions.Comment: 17+ pages, 2 tables, 4 figure
Radial Velocity Studies of Close Binary Stars. XV
Radial-velocity measurements and sine-curve fits to the orbital radial
velocity variations are presented for the last eight close binary systems
analyzed the same way as in the previous papers of this series: QX And, DY Cet,
MR Del, HI Dra, DD Mon, V868 Mon, ER Ori, and Y Sex. For another seven systems
(TT Cet, AA Cet, CW Lyn, V563 Lyr, CW Sge, LV Vir and MW Vir) phase coverage is
insufficient to provide reliable orbits but radial velocities of individual
components were measured. Observations of a few complicated systems observed
throughout the DDO close-binary program are also presented; among them an
especially interesting is the multiple system V857 Her which - in addition to
the contact binary - very probably contains one or more sub-dwarf components of
much earlier spectral type. All suspected binaries which were found to be most
probably pulsating stars are briefly discussed in terms of mean radial
velocities and projected rotation velocities (v sin i) as well as spectral type
estimates. In two of them, CU CVn and V752 Mon, the broadening functions show a
clear presence of non-radial pulsations. The previously missing spectral types
for the DDO I paper are given here in addition to such estimates for most of
the program stars of this paper.Comment: submitted to A
Radial Velocity Studies of Close Binary Stars. XI
Radial-velocity measurements and sine-curve fits to the orbital radial
velocity variations are presented for ten close binary systems: DU Boo, ET Boo,
TX Cnc, V1073 Cyg, HL Dra, AK Her, VW LMi, V566 Oph, TV UMi and AG Vir. By this
contribution, the DDO program has reached the point of 100 published radial
velocity orbits. The radial velocities have been determined using an improved
fitting technique which uses rotational profiles to approximate individual
peaks in broadening functions.
Three systems, ET Boo, VW LMi and TV UMi, were found to be quadruple while AG
Vir appears to be a spectroscopic triple. ET Boo, a member of a close visual
binary with years, was previously known to be a multiple
system, but we show that the second component is actually a close,
non-eclipsing binary. The new observations enabled us to determine the
spectroscopic orbits of the companion, non-eclipsing pairs in ET Boo and VW
LMi. The particularly interesting case is VW LMi, where the period of the
mutual revolution of the two spectroscopic binaries is only 355 days.
While most of the studied eclipsing pairs are contact binaries, ET Boo is
composed of two double-lined detached binaries and HL Dra is single-lined
detached or semi-detached system. Five systems of this group were observed
spectroscopically before: TX Cnc, V1073 Cyg, AK Her (as a single-lined binary),
V566 Oph, AG Vir, but our new data are of much higher quality than the previous
studies.Comment: Accepted by AJ, August 2006, 10 figures, 3 table
Radial Velocity Studies of Close Binary Stars
ABSTRACT Radial velocity measurements and sine-curve fits to orbital velocity variations are presented for the ninth set of 10 close binary systems: V395 And, HS Aqr, V449 Aur, FP Boo, SW Lac, KS Peg, IW Per, V592 Per, TU UMi, and FO Vir. The first three are very close, possibly detached, early-type binaries, and all three require further investigation. Particularly interesting is V395 And, whose spectral type is as early as B7/8 for a 0.685 day orbit binary. KS Peg and IW Per are single-line binaries, with the former probably hosting a very low mass star. We have detected a low-mass secondary in an important semidetached system, FO Vir, at q ÂĽ 0:125 AE 0:005. The contact binary FP Boo is also a very small mass ratio system, q ÂĽ 0:106 AE 0:005. The other contact binaries in this group are V592 Per, TU UMi, and the wellknown SW Lac. V592 Per and TU UMi have bright tertiary companions; for these binaries, and for V395 And, we used a novel technique of arranging the broadening functions into a two-dimensional image in phase. The case of TU UMi turned out to be intractable even using this approach, and we have not been able to derive a firm radial velocity orbit for this binary. Three systems of this group were observed spectroscopically before: HS Aqr, SW Lac, and KS Peg