The NN-explore Exoplanet Stellar Speckle Imager: Instrument Description and Preliminary Results

Scott, Nicholas J.; Howell, Steve B.; Horch, Elliott; Everett, Mark E.

doi:10.1088/1538-3873/aab484

Cited by 116 publications

(74 citation statements)

References 45 publications

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“…Each target was observed simultaneously in two cameras, with a filter centered on 562 nm (rnarrow) on the blue channel and a bandpass at 832 nm (z-narrow) on the red channel. The standard NESSI observing strategy was followed, with typical integration times of 40 ms (see Scott et al 2018). Data were reduced by the KPNO speckle reduction pipeline that generates reconstructed images and contrast limit curves for each observation (Scott et al 2018).…”

Section: Wiyn / Nessi Observationsmentioning

confidence: 99%

“…The standard NESSI observing strategy was followed, with typical integration times of 40 ms (see Scott et al 2018). Data were reduced by the KPNO speckle reduction pipeline that generates reconstructed images and contrast limit curves for each observation (Scott et al 2018). We did not identify any candidate companion in the obtained data around these two targets.…”

Section: Wiyn / Nessi Observationsmentioning

confidence: 99%

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A high binary fraction for the most massive close-in giant planets and brown dwarf desert members

Fontanive

Rice

Bonavita

et al. 2019

Monthly Notices of the Royal Astronomical Society

119

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Stellar multiplicity is believed to influence planetary formation and evolution, although the precise nature and extent of this role remain ambiguous. We present a study aimed at testing the role of stellar multiplicity in the formation and/or evolution of the most massive, closein planetary and substellar companions. Using past and new direct imaging observations, as well as the Gaia DR2 catalogue, we searched for wide binary companions to 38 stars hosting massive giant planets or brown dwarfs (M > 7 M Jup ) on orbits shorter than ∼1 AU. We report the discovery of a new component in the WASP-14 system, and present an independent confirmation of a comoving companion to WASP-18. From a robust Bayesian statistical analysis, we derived a binary fraction of 79.0 +13.2 −14.7 % between 20−10,000 AU for our sample, twice as high as for field stars with a 3-σ significance. This binary frequency was found to be larger than for lower-mass planets on similar orbits, and we observed a marginally higher binary rate for inner companions with periods shorter than 10 days. These results demonstrate that stellar companions greatly influence the formation and/or evolution of these systems, suggesting that the role played by binary companions becomes more important for higher-mass planets, and that this trend may be enhanced for systems with tighter orbits. Our analysis also revealed a peak in binary separation at 250 AU, highlighting a shortfall of close binaries among our sample. This indicates that the mechanisms affecting planet and brown dwarf formation or evolution in binaries must operate from wide separations, although we found that the Kozai-Lidov mechanism is unlikely to be the dominant underlying process. We conclude that binarity plays a crucial role in the existence of very massive short-period giant planets and brown dwarf desert inhabitants, which are almost exclusively observed in multiple systems.

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Section: Wiyn / Nessi Observationsmentioning

confidence: 99%

Section: Wiyn / Nessi Observationsmentioning

confidence: 99%

A high binary fraction for the most massive close-in giant planets and brown dwarf desert members

Fontanive

Rice

Bonavita

et al. 2019

Monthly Notices of the Royal Astronomical Society

119

View full text Add to dashboard Cite

show abstract

“…Once we saw that the new HIRES observations implied a highly significant trend in the radial velocity, we sought independent evidence for a wide-orbiting companion by performing speckle imaging with the Zorro instrument on the Gemini South 8m telescope (see Scott et al 2018, and the instrument web-pages 4 ). Zorro is a dual-channel speckle interferometer employing narrow-band filters centered at 562 nm and 832 nm.…”

Section: Speckle Imagingmentioning

confidence: 99%

WASP-4 Is Accelerating toward the Earth

Bouma

Winn

Howard

et al. 2020

ApJL

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The orbital period of the hot Jupiter WASP-4b appears to be decreasing at a rate of −8.64 ± 1.26 msec yr −1 , based on transit-timing measurements spanning 12 years. Proposed explanations for the period change include tidal orbital decay, apsidal precession, and acceleration of the system along the line of sight. To investigate further, we performed new radial velocity measurements and speckle imaging of WASP-4. The radial-velocity data show that the system is accelerating towards the Sun at a rate of −0.0422 ± 0.0028 m s −1 day −1 . The associated Doppler effect should cause the apparent period to shrink at a rate of −5.94 ± 0.39 msec yr −1 , comparable to the observed rate. Thus, the observed change in the transit period is mostly or entirely produced by the line-of-sight acceleration of the system. This acceleration is probably caused by a wide-orbiting companion of mass 10-300 M Jup and orbital distance 10-100 AU, based on the magnitude of the radial-velocity trend and the non-detection of any companion in the speckle images. We expect that the orbital periods of 1 out of 3 hot Jupiters will change at rates similar to WASP-4b, based on the hot-Jupiter companion statistics of Knutson et al. (2014). Continued radial velocity monitoring of hot Jupiters is therefore essential to distinguish the effects of tidal orbital decay or apsidal precession from line-of-sight acceleration.

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“…To assess any further multiplicity of binaries in our sample speckle imaging observations were acquired with the DSSI camera (P.I. Steve Howell) at the Gemini South Observatory and the NESSI instrument on the WIYN 3.5-m telescope (Scott et al 2016(Scott et al , 2018. Both instruments acquired simultaneous observations in two filters, providing colors for any closely projected companions.…”

Section: Gemini-s/dssi Speckle Imagingmentioning

confidence: 99%

Age Determination in Upper Scorpius with Eclipsing Binaries

David

Hillenbrand

Gillen

et al. 2019

ApJ

Self Cite

110

114

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The Upper Scorpius OB association is the nearest region of recent massive star formation and thus an important benchmark for investigations concerning stellar evolution and planet formation timescales. We present nine EBs in Upper Scorpius, three of which are newly reported here and all of which were discovered from K2 photometry. Joint fitting of the eclipse photometry and radial velocities from newly acquired Keck-I/HIRES spectra yields precise masses and radii for those systems that are spectroscopically double-lined. The binary orbital periods in our sample range from 0.6-100 days, with total masses ranging from 0.2-8 M . At least 33% of the EBs reside in hierarchical multiples, including two triples and one quadruple. We use these EBs to develop an empirical mass-radius relation for pre-main-sequence stars, and to evaluate the predictions of widely-used stellar evolutionary models. We report evidence for an age of 5-7 Myr which is self-consistent in the mass range of 0.3-5 M and based on the fundamentally-determined masses and radii of eclipsing binaries (EBs). Evolutionary models including the effects of magnetic fields imply an age of 9-10 Myr. Our results are consistent with previous studies that indicate many models systematically underestimate the masses of low-mass stars by 20-60% based on H-R diagram analyses. We also consider the dynamical states of several binaries and compare with expectations from tidal dissipation theories. Finally, we identify RIK 72 b as a long-period transiting brown dwarf (M = 59.2 ± 6.8 M Jup , R = 3.10 ± 0.31 R Jup , P ≈ 97.8 days) and an ideal benchmark for brown dwarf cooling models at 5-10 Myr.Meanwhile, theoretical models have evolved from simple hydrostatic contraction and basic nuclear reaction networks to including the effects of deuterium burning, proto-stellar and circumstellar disk accretion, realistic surface boundary conditions, convection, and magnetic fields or starspots (see D'Antona 2017, for a review). Our best method of evaluating such models is through detailed characterization of benchmark PMS stars allowing dynamical mass determinations from, e.g., circumstellar disk rotation curves or binary orbit determi-

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The NN-explore Exoplanet Stellar Speckle Imager: Instrument Description and Preliminary Results

Cited by 116 publications

References 45 publications

A high binary fraction for the most massive close-in giant planets and brown dwarf desert members

A high binary fraction for the most massive close-in giant planets and brown dwarf desert members

WASP-4 Is Accelerating toward the Earth

Age Determination in Upper Scorpius with Eclipsing Binaries

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