J/MNRAS/405/1770 LMC red giants in E sequence (Nicholls+, 2010)
Ellipsoidal variability and the difference between sequence D and E red giants.
Nicholls C.P., Wood P.R., Cioni M.-R.L.
<Mon. Not. R. Astron. Soc., 405, 1770-1776 (2010)>
=2010MNRAS.405.1770N 2010MNRAS.405.1770N
ADC_Keywords: Stars, giant ; Stars, variable ; Radial velocities
Keywords: stars: AGB and post-AGB - binaries: close - stars: oscillations
Abstract:
We have studied a sample of Large Magellanic Cloud red giant binaries
that lie on sequence E in the period-luminosity plane. We show that
their combined light and velocity curves unambiguously demonstrate
that they are binaries showing ellipsoidal variability. By comparing
the phased light and velocity curves of both sequence D and E
variables, we show that the sequence D variation - the long
secondary period - is not caused by ellipsoidal variability. We also
demonstrate several further differences between stars on sequences D
and E. These include differences in velocity amplitude, in the
distribution of eccentricity and in the correlations of velocity
amplitude with luminosity and period. We also show that the sequence E
stars, unlike stars on sequence D, do not show any evidence of a
mid-infrared excess that would indicate circumstellar dust.
Description:
The observations and data reduction for this sample are the same as
for our recently published sequence D sample (Nicholls et al. 2009,
Cat. J/MNRAS/399/2063). The spectra were taken using the
FLAMES/GIRAFFE spectrograph on the European Southern Observatory's
VLT, on 21 nights from 2003 November to 2006 March. Radial velocities
were calculated via cross-correlation with the iraf task FXCOR. The
reader is referred to Nicholls et al. (2009MNRAS.399.2063N 2009MNRAS.399.2063N) for
details.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table23.dat 141 11 Sequence E stars orbital elements and properties
table1.dat 111 20 Radial velocities of sequence E stars
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See also:
J/MNRAS/399/2063 : 58 MACHO sequence D red giants (Nicholls+, 2009)
http://macho.anu.edu.au/ : MACHO Home Page
Byte-by-byte Description of file: table23.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- MACHO MACHO name
13- 18 F6.2 km/s gamma System velocity
20- 24 F5.2 km/s K Velocity semi-amplitude
26- 29 F4.2 --- e Eccentricity
31- 36 F6.2 deg omega Angle of periastron ω
38- 43 F6.1 d T0 Date of periastron (HJD-2450000)
45- 50 F6.2 d Per Period
52- 57 F6.2 solRad asini Semimajor axis of the red giant's orbit
59- 64 F6.4 solMass f(m) Mass function
66- 69 F4.2 solMass M1 Mass of the red giant, assuming sini=1
71- 74 F4.2 solMass M2 Mass of the companion
76- 79 F4.2 km/s e_gamma rms uncertainty on gamma
81- 84 F4.2 km/s e_K rms uncertainty on K
86- 89 F4.2 --- e_e rms uncertainty on e
91- 95 F5.2 deg e_omega rms uncertainty on omega
97-100 F4.1 d e_T0 rms uncertainty on T0
102-105 F4.2 solRad e_asini rms uncertainty on asini
107-112 F6.4 solMass e_f(m) rms uncertainty on f(m)
114-118 F5.2 solRad R Radius
120-126 F7.2 solLum Lum Luminosity
128-134 F7.2 K Teff Effective temperature
136-141 F6.2 solRad a Semi-major axis
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian date
14- 21 F8.4 km/s RV1 ?=0 Radial velocity for MACHO 77.7429.189
23- 30 F8.4 km/s RV2 ?=0 Radial velocity for MACHO 77.7548.68
32- 39 F8.4 km/s RV3 ?=0 Radial velocity for MACHO 77.7672.98
41- 48 F8.4 km/s RV4 ?=0 Radial velocity for MACHO 77.7673.79
50- 57 F8.4 km/s RV5 ?=0 Radial velocity for MACHO 77.7789.152
59- 66 F8.4 km/s RV6 ?=0 Radial velocity for MACHO 77.7790.72
68- 75 F8.4 km/s RV7 Radial velocity for MACHO 77.7791.115
77- 84 F8.4 km/s RV8 ?=0 Radial velocity for MACHO 77.7910.41
86- 93 F8.4 km/s RV9 ?=0 Radial velocity for MACHO 77.7910.77
95-102 F8.4 km/s RV10 ?=0 Radial velocity for MACHO 77.7912.111
104-111 F8.4 km/s RV11 ?=0 Radial velocity for MACHO 77.7914.74
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 13-Dec-2010