J/A+A/626/A94 HD 96446 radial velocities (Gonzalez+, 2019)
HD 96446: a long-period binary with a strongly magnetic He-rich primary with
beta Cep pulsations.
Gonzalez J.F., Briquet M., Przybilla N., Nieva M.-F., De Cat P., Saesen S.,
Hubrig S., Thoul A., Papics P.I., Palaversa L., Naef D., Neveu-Van Malle M.,
Jarvinen S., Pollard K.R., Kilmartin P., Mowlavi N., Butler K.
<Astron. Astrophys. 626, A94 (2019)>
=2019A&A...626A..94G 2019A&A...626A..94G (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, spectroscopic ; Radial velocities
Keywords: binaries: spectroscopic - stars: chemically peculiar -
stars: early-type - stars: magnetic fields - stars: oscillations -
stars: individual: HD 96446
Abstract:
HD 96446 is a magnetic B2p He-strong star that has been reported to be
a β Cep pulsator. We present a detailed spectroscopic analysis of
this object based on an intensive observational data set obtained in a
multisite campaign with the spectrographs CORALIE, FEROS, and HARPS
(La Silla); UVES (Paranal); HERCULES (Mt. John Observatory); and
GIRAFFE (SAAO).
Radial velocities were measured by cross-correlations and analysed to
detect periodic variations. On the other hand, the mean spectrum was
fit with spectral synthesis to derive atmospheric parameters and
chemical abundances.
From the analysis of radial velocities, HD 96446 was found to be a
spectroscopic binary with a period of 799 days. The stellar companion,
which contributes only ∼5% of the total flux, is an A0-type star. A
frequency analysis of the radial velocities allowed us to detect two
pulsational modes with periods 2.23h and 2.66h. The main mode is
most probably a low-inclination, dipole mode (l, m) = (1, 0),
and the second pulsation mode corresponds to (l, m) = (2, 2)
or to a pole-on (l, m) = (3, 2) configuration. In addition to
radial velocities, the main pulsation mode is evidenced through small
variations in the spectral morphology (temperature variations) and the
light flux. The rotation period of 23.4d, was detected through the
variation in line intensities. Chemical abundances are unevenly
distributed over the stellar surface, with helium concentrated at the
negative magnetic pole and most metals strengthened at lower
latitudes. The mean chemical abundance of helium is strongly abnormal,
reaching a value of 0.60 (number fraction).
Description:
Radial velocities are presented for 27 HERCULES, 48 HARPS, and 646
CORALIE spectra of HD 96446. Heliocentric Julian dates corrected by
the light time effect due to the orbital motion are included. Orbital,
rotational and pulsational (two modes) phases are listed. Besides
observed radial velocity, calculated velocities corresponding to the
four variations are also given, as well as the
observed-minus-calculated difference.
Objects:
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RA (2000) DE Designation(s)
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11 06 05.82 -59 56 59.5 HD 96446 = V* V430 Car
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 101 721 HD 96446 radial velocities
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 F10.5 d HJD Heliocentric Julian Date (HJD-2450000)
12- 21 F10.5 d HJDc Corrected Heliocentric Julian Date
(HJD-2450000)
23- 28 F6.4 --- Phase1 Phase of the main pulsational mode
(P1=0.092919828±0.000000009)
30- 35 F6.4 --- Phase2 Phase of the second pulsation mode
(P2=0.1108037±0.0000004)
37- 42 F6.4 --- Phaseorb Orbital phase (Porb=799.3±1.7)
44- 49 F6.4 --- Phaserot Rotational phase (Prot=23.38, fixed)
51- 55 F5.2 km/s RV Observed radial velocity
57- 61 F5.2 km/s e_RV Radial velocity error
63- 67 F5.2 km/s V1c Calculated velocity: pulsation 1 term
69- 73 F5.2 km/s V2c Calculated velocity: pulsation 2 term
75- 79 F5.2 km/s Vorbc Calculated velocity: orbital term
81- 85 F5.2 km/s Vrotc Calculated velocity: rotational term
87- 91 F5.2 km/s O-C Observed-minus-calculated difference
94-101 A8 --- Inst Instrument
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Acknowledgements:
Jorge Federico Gonzalez, jfgonzalez(at)conicet.gov.ar
(End) Jorge F. Gonzalez [ICATE, Argentina], Patricia Vannier [CDS] 25-Apr-2019