Exploring the orbital evolution of planetary systems

Gallardo, Tabaré

doi:10.1088/1361-6404/aa5e0c

Cited by 38 publications

(57 citation statements)

References 17 publications

(27 reference statements)

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“…Pre-main-sequence stellar evolution tracks from Baraffe et al (2015) are also presented in the color-magnitude diagrams, with colors adopted from Allard (2014). In distant clusters, properties of low-mass stars are often inferred from photometry (e.g., Reggiani et al 2011;Jose et al 2016;Beccari et al 2017).…”

Section: Color Analysismentioning

confidence: 99%

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Guo

Herczeg

Jose

et al. 2018

ApJ

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The variability of young stellar objects is mostly driven by star-disk interactions. In long-term photometric monitoring of the accreting T Tauri star GI Tau, we detect extinction events with typical depths of DṼ 2.5 mag that last for days to months and often appear to occur stochastically. In 2014-2015, extinctions that repeated with a quasi-period of 21 days over several months are the first empirical evidence of slow warps predicted by magnetohydrodynamic simulations to form at a few stellar radii away from the central star. The reddening is consistent with =  R 3.85 0.5 V and, along with an absence of diffuse interstellar bands, indicates that some dust processing has occurred in the disk. The 2015-2016 multiband light curve includes variations in spot coverage, extinction, and accretion, each of which results in different traces in color-magnitude diagrams. This light curve is initially dominated by a month-long extinction event and a return to the unocculted brightness. The subsequent light curve then features spot modulation with a 7.03 day period, punctuated by brief, randomly spaced extinction events. The accretion rate measured from U-band photometry ranges from´-1.3 10 8 to´-1.1 10 10 M e yr −1 (excluding the highest and lowest 5% of high-and low-accretion rate outliers), with an average of4.7 -10 9 M e yr −1 . A total of 50% of the mass is accreted during bursts of >´-12.8 10 9 M e yr -1, which indicates limitations on analyses of disk evolution using single-epoch accretion rates.

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Section: Color Analysismentioning

confidence: 99%

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Guo

Herczeg

Jose

et al. 2018

ApJ

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“…To constrain atmospheric parameters, in this case effective temperature and surface gravity, we compare the observed P1640 spectrum of GJ 758 B to synthetic spectra from the BTSettl13 model atmospheres (Allard 2014). We use a grid of solar metallicity models with effective temperatures from 400-4500 K in increments of 50 or 100 K and surface gravities of = g log 3.5, 4.0, 4.5, 5.0, and 5.5 (cgs units).…”

Section: Model Atmospheresmentioning

confidence: 99%

Project 1640 Observations of Brown Dwarf GJ 758 B: Near-infrared Spectrum and Atmospheric Modeling

Nilsson

Veicht

Godfrey

et al. 2017

ApJ

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The nearby Sun-like star GJ 758 hosts a cold substellar companion, GJ 758 B, at a projected separation of 30 au, previously detected in high-contrast multi-band photometric observations. In order to better constrain the companion's physical characteristics, we acquired the first low-resolution (R ∼ 50) near-infrared spectrum of it using the high-contrast hyperspectral imaging instrument Project 1640 on Palomar Observatory's 5 m Hale telescope. We obtained simultaneous images in 32 wavelength channels covering the Y, J, and H bands (∼952-1770 nm), and used data processing techniques based on principal component analysis to efficiently subtract chromatic background speckle-noise. GJ 758 B was detected in four epochs during 2013 and 2014. Basic astrometric measurements confirm its apparent northwest trajectory relative to the primary star, with no clear signs of orbital curvature. Spectra of SpeX/IRTF observed Tdwarfs were compared to the combined spectrum of GJ 758 B, with χ 2 minimization suggesting a best fit for spectral type T7.0±1.0, but with a shallow minimum over T5-T8. Fitting of synthetic spectra from the BT-Settl13 model atmospheres gives an effective temperature T eff =741±25 K and surface gravity =  g log 4.3 0.5 dex (cgs). Our derived best-fit spectral type and effective temperature from modeling of the low-resolution spectrum suggest a slightly earlier and hotter companion than previous findings from photometric data, but do not rule out current results, and confirm GJ 758 B as one of the coolest sub-stellar companions to a Sun-like star to date.

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“…HD 96167 has a galactic latitude of 44 • and its wide field is not crowded. If bound, its companion would have an absolute magnitude of 20.3 in the K band, which corresponds to a 30M Jup object at an age of 3.8 Gy (Allard 2014). Follow-up observations could confirm whether this source is a wide brown dwarf companion of HD 96167 or a background star.…”

Section: Wide-separation Sourcesmentioning

confidence: 94%

“…Values for K1 and K2 bands are derived from IRDIS data. Using the BT-Settl models (Allard 2014) and assuming an age of 3 Gyr (see Table 1), we were able to derive the mass of the companion. We find a companion mass of 155 ±9 M Jup or 0.148±0.008 M .…”

Section: Hd 211847mentioning

confidence: 99%

“…6 (bottom) and Table A.3, with a typical value of ∼ 1.25×10 −5 at 0.5 arcsec. This 5-σ detection limit is then translated into minimum mass with the aid of BT-Settl stellar models (Allard 2014), and angular separations are converted into physical separations using the system's distance given in Table 1 and 2. Figure 7 summarizes the detection limits for the full sample, which are also given at a few specific separations in Tables A.1 and A.2.…”

Section: Contrast Plotsmentioning

confidence: 99%

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Eccentricity in planetary systems and the role of binarity

Moutou

Vigan

Mesa

et al. 2017

A&A

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We explore the multiplicity of exoplanet host stars with high-resolution images obtained with VLT/SPHERE. Two different samples of systems were observed: one containing low-eccentricity outer planets, and the other containing high-eccentricity outer planets. We find that 10 out of 34 stars in the high-eccentricity systems are members of a binary, while the proportion is 3 out of 27 for circular systems. Eccentric-exoplanet hosts are, therefore, significantly more likely to have a stellar companion than circular-exoplanet hosts. The median magnitude contrast over the 68 data sets is 11.26 and 9.25, in H and K, respectively, at 0.30 arcsec. The derived detection limits reveal that binaries with separations of less than 50au are rarer for exoplanet hosts than for field stars. Our results also imply that the majority of high-eccentricity planets are not embedded in multiple stellar systems (24 out of 34), since our detection limits exclude the presence of a stellar companion. We detect the low-mass stellar companions of HD 7449 and HD 211847, both members of our high-eccentricity sample. HD 7449B was already detected by Rodigas et al. (2016) and our independent observation is in agreement with this earlier work. HD 211847's substellar companion, previously detected by the radial velocity method, is actually a low-mass star seen face-on. The role of stellar multiplicity in shaping planetary systems is confirmed by this work, although it does not appear as the only source of dynamical excitation.

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Exploring the orbital evolution of planetary systems

Cited by 38 publications

References 17 publications

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Project 1640 Observations of Brown Dwarf GJ 758 B: Near-infrared Spectrum and Atmospheric Modeling

Eccentricity in planetary systems and the role of binarity

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