61 Cygni as a Triple System

Strand, K. Aa.

doi:10.1086/125484

Cited by 251 publications

(9 citation statements)

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“…The constant velocity anomaly between the DR2 and EDR3 makes a short-period planet unlikely. In 1943, Strand (1943, 1957 announced the detection of a massive planet (or brown dwarf) orbiting around one of the components of 61 Cyg with a period around 5 years. The presence of a massive companion on such a short period orbit was later disproved by Walker et al (1995) and Cumming et al (2008).…”

Section: Methodsmentioning

confidence: 99%

Stellar and substellar companions from Gaia EDR3

Kervella

Arenou

Thévenin

2021

A&A

161

151

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Context. The multiplicity fraction of stars, down to the substellar regime, is a parameter of fundamental importance for stellar formation, evolution, and planetology. The census of multiple stars in the solar neighborhood is however incomplete. Aims. Our study is aimed at detecting companions of Hipparcos catalog stars from the proper motion anomaly (PMa) they induce on their host star, namely, the difference between their long-term Hipparcos-Gaia and short-term Gaia proper motion vectors. We also aim to detect resolved, gravitationally bound companions of the Hipparcos catalog stars (117, 955 stars) and of the Gaia EDR3 stars closer than 100 pc (542,232 stars). Methods. Using the Hipparcos and EDR3 data, we revised the PMa catalog for the Hipparcos stars. In order to identify gravitationally bound visual companions of our sample, we searched the Gaia EDR3 catalog for common proper-motion (CPM) candidates.Results. The detection of tangential velocity anomalies with a median accuracy of σ(∆v T ) = 26 cm s −1 per parsec of distance is demonstrated with the EDR3. This improvement by a factor 2.5 in accuracy, as compared to Gaia DR2, results in PMa detection limits on companions that are well into the planetary mass regime for many targets. We identify 37,515 Hipparcos stars presenting a PMa at significant level (S/N>3), namely, a fraction of 32% (compared to 30% for the DR2) and 12,914 (11%) hosting CPM bound candidate companions. After including the Gaia EDR3 renormalised unit weight error (RUWE>1.4) as an additional indicator, 50,720 stars of the Hipparcos catalog (43%) exhibit at least one signal of binarity. Among the Gaia EDR3 stars located within 100 pc, we find CPM bound candidate companions for 39,490 stars (7.3% of the sample). Conclusions. The search for companions using a combination of the PMa, CPM, and RUWE indicators significantly improves the exhaustivity of the multiplicity survey. The detection of CPM companions of very bright stars (heavily saturated on the Gaia detectors) that are classical benchmark objects for stellar physics provides a useful proxy for estimating their distance with a higher accuracy than with Hipparcos.

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Section: Methodsmentioning

confidence: 99%

Stellar and substellar companions from Gaia EDR3

Kervella

Arenou

Thévenin

2021

A&A

161

151

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“…Searches for exoplanets via absolute astrometry using ground-based instrumentation have yielded either null results or candidates that were later found to be spurious (e.g., 61 Cygni, Strand 1943;Wittenmyer et al 2006; Van Biesbroeck's star, Pravdo & Shaklan 2009;Lazorenko et al 2011). Such surveys are limited by the astrometric precision of the individual measurements, typically > 0.1 mas (Lazorenko et al 2009).…”

Section: Discussionmentioning

confidence: 99%

The Possible Astrometric Signature of a Planetary-mass Companion to the Nearby Young Star TW Piscis Austrini (Fomalhaut B): Constraints from Astrometry, Radial Velocities, and Direct Imaging

Rosa

Espósito

Hirsch

et al. 2019

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We present constraints on the presence of substellar companions to the nearby (d ∼ 7.6 pc), young (440 ± 40 Myr) K4Ve star TW Piscis Austrini, the wide (∼0.3 pc) companion to the A4V star Fomalhaut. We combined absolute astrometry from Hipparcos and Gaia with literature radial velocity measurements and dedicated high-contrast imaging observations obtained with Keck/NIRC2 to achieve sensitivity to brown dwarf and planetary-mass companions ( 2 M Jup ) over many decades of orbital period ( 10 3 yr). The significant astrometric acceleration measured between the Hipparcos and Gaia catalogues, reported previously in the literature, cannot be explained by the orbital motion of TW PsA around the barycenter of the Fomalhaut triple system. Instead, we find that it is consistent with the reflex motion induced by an orbiting substellar companion. The combination of astrometry, radial velocities, and a deep L imaging dataset leads to a constraint on the companion mass of 1.2 +0.7 −0.6 M Jup . However, the period of the companion is poorly constrained, with a highly multi-modal period posterior distribution due to aliasing with the 24.25 year baseline between Hipparcos and Gaia. If confirmed through continued astrometric or spectroscopic monitoring, or via direct detection, the companion to TW PsA would represent a choice target for detailed atmospheric characterization with high-contrast instruments on the upcoming James Webb Space Telescope and Wide Field Infrared Survey Telescope.

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“…The constant velocity anomaly between the DR2 and EDR3 makes a short period planet unlikely. In 1943, Strand (1943, 1957 announced the detection of a massive planet (or brown dwarf) orbiting around one of the components of 61 Cyg with a period around 5 years.…”

Section: Methodsmentioning

confidence: 99%

Stellar and substellar companions from Gaia EDR3 -- Proper motion anomaly and resolved common proper motion pairs

Kervella,

Arenou,

Thévenin

2021

Preprint

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Context. The multiplicity fraction of stars, down to the substellar regime, is a parameter of fundamental importance for stellar formation, evolution, and planetology. The census of multiple stars in the solar neighborhood is however incomplete. Aims. The presence of a companion in orbit around a star affects its proper motion. We aim at detecting companions of Hipparcos catalog stars from the proper motion anomaly (PMa) they induce on their host star, that is, the difference between their long-term Hipparcos-Gaia and short-term Gaia proper motion vectors. We also aim at detecting resolved, gravitationally bound companions of the Hipparcos catalog stars (117, 955 stars), and of the Gaia EDR3 stars closer than 100 pc (542,232 stars). Methods. Using the Hipparcos and EDR3 data, we revise the PMa catalog for the Hipparcos stars. To identify gravitationally bound visual companions of our sample, we search the Gaia EDR3 catalog for common proper motion (CPM) candidates.Results. The detection of tangential velocity anomalies with a median accuracy of σ(∆v T ) = 26 cm s −1 per parsec of distance is demonstrated with the EDR3. This improvement by a factor 2.5 in accuracy compared to the Gaia DR2 results in PMa detection limits on companions well into the planetary mass regime for many targets. We identify 37,515 Hipparcos stars presenting a PMa at significant level (S/N>3), that is, a fraction of 32% (compared to 30% for the DR2) and 12,914 (11%) hosting CPM bound candidate companions. Including the Gaia EDR3 RUWE>1.4 as an additional indicator, 50,720 stars of the Hipparcos catalog (43%) exhibit at least one signal of binarity. Among the Gaia EDR3 stars located within 100 pc, we find CPM bound candidate companions for 39,490 stars (7.3 % of the sample). Conclusions. The search for companions using a combination of the PMa, CPM and RUWE indicators significantly improves the exhaustivity of the multiplicity survey. The detection of CPM companions of very bright stars (heavily saturated on the Gaia detectors) that are classical benchmark objects for stellar physics provides a useful proxy to estimate their distance with a higher accuracy than Hipparcos.

show abstract

61 Cygni as a Triple System

Cited by 251 publications

References 0 publications

Stellar and substellar companions from Gaia EDR3

Stellar and substellar companions from Gaia EDR3

The Possible Astrometric Signature of a Planetary-mass Companion to the Nearby Young Star TW Piscis Austrini (Fomalhaut B): Constraints from Astrometry, Radial Velocities, and Direct Imaging

Stellar and substellar companions from Gaia EDR3 -- Proper motion anomaly and resolved common proper motion pairs

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