A Search for Faint Companions to Nearby Stars Using the Wide Field Planetary Camera 2

Schroeder, Daniel J.; Golimowski, D. A.; Brukardt, R. A.; Burrows, Christopher J.; Caldwell, John; Fastie, W. G.; Ford, H. C.; Hesman, B. E.; Kletskin, Ilona; Krist, John; Royle, P.; Zubrowski, Richard. A.

doi:10.1086/301227

Cited by 73 publications

(42 citation statements)

References 46 publications

(58 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, highaccuracy astrometry obtained by Schroeder et al (2000) using the Hubble Space Telescope Wide Field and Planetary Camera 2 (HST/WFPC2) showed a significant discrepancy with the published orbit, and the masses were tentatively revised to 0.115 and 0.113 M . Our observation of GJ65 on 23 September 2011 with the VLT/NACO adaptive optics system (Rousset et al 2003) confirmed that a revision of the orbital parameters is necessary.…”

Section: Vlt/naco Astrometry and Photometrymentioning

confidence: 98%

“…These values are stable over several years within their stated error bars, and they agree with the calibrations of Masciadri et al (2003) and Chauvin et al (2015). The resulting differential astrometric measurements of the position of GJ65 B relative to A are presented in Table 2 together with the high-precision HST astrometry by Schroeder et al (2000) and Dieterich et al (2012).…”

Section: Vlt/naco Astrometry and Photometrymentioning

confidence: 99%

“…The fainter star GJ65 B exhibits systematically more intense emission lines than GJ65 A, indicating a stronger magnetic chromospheric activity P. Kervella et al: Fundamental parameters of the binary red dwarf GJ65 Notes. K16: present work; S00: Schroeder et al (2000); D12: Dieterich et al (2012). Table 3.…”

Section: Vlt/uves High-resolution Spectroscopymentioning

confidence: 99%

See 2 more Smart Citations

The red dwarf pair GJ65 AB: inflated, spinning twins of Proxima

Kervella

Mérand

Ledoux

et al. 2016

A&A

View full text Add to dashboard Cite

The nearby red dwarf binary GJ65 AB (UV+BL Ceti, M5.5Ve+M6Ve) is a cornerstone system to probe the physics of very low-mass stars. The radii of the two stars are currently known only from indirect photometric estimates, however, and this prevents us from using GJ65 AB as calibrators for the mass-radius (M-R) relation. We present new interferometric measurements of the angular diameters of the two components of GJ65 with the VLTI/PIONIER instrument in the near-infrared H band: θ UD (A) = 0.558 ± 0.008 ± 0.020 mas and θ UD (B) = 0.539 ± 0.009 ± 0.020 mas. They translate into limb-darkened angular diameters of θ LD (A) = 0.573 ± 0.021 mas and θ LD (B) = 0.554 ± 0.022 mas. Based on the known parallax, the linear radii are R(A) = 0.165 ± 0.006 R and R(B) = 0.159 ± 0.006 R (σ(R)/R = 4%). We searched for the signature of flares and faint companions in the interferometric visibilities and closure phases, but we did not identify any significant signal. We also observed GJ65 with the VLT/NACO adaptive optics and refined the orbital parameters and infrared magnitudes of the system. We derived masses for the two components of m(A) = 0.1225 ± 0.0043 M and m(B) = 0.1195 ± 0.0043 M (σ(m)/m = 4%). To derive the radial and rotational velocities of the two stars as well as their relative metallicity with respect to Proxima, we also present new individual UVES high-resolution spectra of the two components. Placing GJ65 A and B in the mass-radius diagram shows that their radii exceed expectations from recent models by 14 ± 4% and 12 ± 4% , respectively. Following previous theories, we propose that this discrepancy is caused by the inhibition of convective energy transport by a strong internal magnetic field generated by dynamo effect in these two fast-rotating stars. A comparison with the almost identical twin Proxima, which is rotating slowly, strengthens this hypothesis because the radius of Proxima does not appear to be inflated compared to models.

show abstract

Section: Vlt/naco Astrometry and Photometrymentioning

confidence: 98%

Section: Vlt/naco Astrometry and Photometrymentioning

confidence: 99%

See 1 more Smart Citation

The red dwarf pair GJ65 AB: inflated, spinning twins of Proxima

Kervella

Mérand

Ledoux

et al. 2016

A&A

View full text Add to dashboard Cite

show abstract

“…Given the parameters we have determined for ε Indi B, it is clear that it is not the source of this long-term velocity change, but it remains possible that the ε Indi system is a hierarchical multiple, similar to the Gl570 ABCD system (Burgasser et al 2000). Planned HST direct imaging observations of ε Indi could have located close brown dwarf or giant planet companions, but unfortunately failed due to guide star acquisition problems (Schroeder et al 2000).…”

Section: Physical Propertiesmentioning

confidence: 98%

ε Indi B: A new benchmark T dwarf

Scholz

McCaughrean

Lodieu

et al. 2003

A&A

141

150

View full text Add to dashboard Cite

Abstract.We have identified a new early T dwarf only 3.6 pc from the Sun, as a common proper motion companion (separation 1459 AU) to the K5V star ε Indi (HD 209100). As such, ε Indi B is one of the highest proper motion sources outside the solar system (∼4.7 arcsec/yr), part of one of the twenty nearest stellar systems, and the nearest brown dwarf to the Sun. Optical photometry obtained from the SuperCOSMOS Sky Survey was combined with approximate infrared photometry from the 2MASS Quicklook survey data release, yielding colours for the source typical of early T dwarfs. Follow-up infrared spectroscopy using the ESO NTT and SOFI confirmed its spectral type to be T2.5 ± 0.5. With K s = 11 m . 2, ε Indi B is 1.7 mag brighter than any previously known T dwarf and 4 mag brighter than the typical object in its class, making it highly amenable to detailed study. Also, as a companion to a bright nearby star, it has a precisely known distance (3.626 ± 0.009 pc) and relatively well-known age (0.8-2 Gyr), allowing us to estimate its luminosity as log L/ L = −4.67, its effective temperature as 1260 K, and its mass as ∼ 40-60 M Jup . ε Indi B represents an important addition to the census of the Solar neighbourhood and, equally importantly, a new benchmark object in our understanding of substellar objects.

show abstract

“…Their result is consistent with an earlier study by Reid & Gizis (1997b). Even smaller separations and a higher contrast were probed using WFPC2 onboard HST by directly imaging 23 stars within 13 pc of the Sun (Schroeder et al 2000). No BD companion was found.…”

Section: Brown Dwarf Companion Frequenciesmentioning

confidence: 99%

Imprints of dynamical interactions on brown dwarf pairing statistics and kinematics

Sterzik

Durisen

2003

A&A

View full text Add to dashboard Cite

Abstract. We present statistically robust predictions of brown dwarf properties arising from dynamical interactions during their early evolution in small clusters. Our conclusions are based on numerical calculations of the internal cluster dynamics as well as on Monte-Carlo models. Accounting for recent observational constraints on the sub-stellar mass function and initial properties in fragmenting star forming clumps, we derive multiplicity fractions, mass ratios, separation distributions, and velocity dispersions. We compare them with observations of brown dwarfs in the field and in young clusters. Observed brown dwarf companion fractions around 15 ± 7% for very low-mass stars as reported recently by Close et al. (2003) are consistent with certain dynamical decay models. A significantly smaller mean separation distribution for brown dwarf binaries than for binaries of late-type stars can be explained by similar specific energy at the time of cluster formation for all cluster masses. Due to their higher velocity dispersions, brown-dwarfs and low-mass single stars will undergo time-dependent spatial segregation from higher-mass stars and multiple systems. This will cause mass functions and binary statistics in star forming regions to vary with the age of the region and the volume sampled.

show abstract

A Search for Faint Companions to Nearby Stars Using the Wide Field Planetary Camera 2

Cited by 73 publications

References 46 publications

The red dwarf pair GJ65 AB: inflated, spinning twins of Proxima

The red dwarf pair GJ65 AB: inflated, spinning twins of Proxima

ε Indi B: A new benchmark T dwarf

Imprints of dynamical interactions on brown dwarf pairing statistics and kinematics

Contact Info

Product

Resources

About