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Table · dataset · 2022

Radial velocity follow up of {eta} Aquilae

Listed in IVOA Registry (Virtual Observatory)

The classical Cepheid {eta}Aql was not included in past Leavitt Law work because of a presumed complicating orbit due to a known B9.8V companion.

Description

To determine the orbit of {eta}AqlB, we analyze a significant number of radial velocity (RV) measurements from eight sources. With these we establish the RV variation due to Cepheid pulsation, using a model with 12 Fourier coefficients, while solving for velocity offsets required to bring the RV data sets into coincidence.

RV residuals provide no evidence of orbital motion, suggesting either nearly face-on orientation or a very long period. Reanalysis of Hubble Space Telescope Fine Guidance Sensor astrometry now includes reference star parallax and proper motion priors from Gaia EDR3. As modeling confirmation, we reanalyze {zeta}Gem in parallel, deriving values for its parallax and proper motion consistent with Gaia EDR3, and consistent with the Benedict 2007 Leavitt Law.

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In an effort to further characterize {eta}AqlB, we hypothesize that {eta}Aql residuals larger than those of the associated reference stars or a parallax inconsistent with EDR3 and the Benedict 2007 Leavitt Law indicate unmodeled orbital motion. Using the astrometric noise or parallax mismatch with EDR3, we estimate possible periods and mass for {eta}AqlB. Ascribing photocenter motion to the photometric variation of the Cepheid, {eta}AqlA, yields a plausible separation that is consistent with a long period and explains the lack of RV variation.

None of these approaches yields an unassailable characterization of the {eta}AqlA-B system.

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Where it is published

Documentation and papers

Catalogue records · 2

Topics

Stated by source
Infrared · Optical
Provenance · 1 source records, 9 field assertions
SourceKeyLast seenRaw
IVOA Registry (Virtual Observatory)ivo://cds.vizier/j/aj/163/28213 d agoJSON v1
FieldAssertionExtractorEvidence
access_levelsource · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[field].local:field:astronomymapping · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[modality].ivoa_waveband:infraredsource · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[modality].ivoa_waveband:opticalsource · IVOA Registryconnector:ivoa_registry@1.0.0
descriptionsource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_description
license_textsource · IVOA Registryconnector:ivoa_registry@1.0.0
publication_datesource · IVOA Registryconnector:ivoa_registry@1.0.0
titlesource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_title
updated_datesource · IVOA Registryconnector:ivoa_registry@1.0.0