The chemical composition of HIP 34407/HIP 34426 and other twin-star comoving pairs

Ramírez, Iván; Khanal, S.; Lichon, Sawyer; Chanamé, Julio; Endl, Michael; Meléndez, Jorge; Lambert, David L.

doi:10.1093/mnras/stz2709

Cited by 51 publications

(54 citation statements)

References 53 publications

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“…Planet formation and evolution can be an intrinsically lossy process that a significant fraction of disk solid materials do not end up in planets. We note that so far the detected possible engulfment signatures are all around G and F-type stars (Oh et al 2018;Ramírez et al 2019;Nagar et al 2019). How-ever, the existing engulfment surveys are far from being uniform across stellar types, it is hence premature to claim whether planet engulfment happens more frequently around early-type stars.…”

Section: Higher Formation Efficiency For Lower-mass Starsmentioning

confidence: 61%

“…In a separate line of argument, there is a whole literature on the possibility of planet engulfment after planet formation (see the review by Ramírez et al 2019). Comoving binaries are often assumed to be coeval and chemically similar, however detailed abundance studies revealed that sometimes one of the star can be preferentially enhanced in refractory materials e.g.…”

Section: Higher Formation Efficiency For Lower-mass Starsmentioning

confidence: 99%

See 1 more Smart Citation

California-Kepler Survey. IX. Revisiting the Minimum-mass Extrasolar Nebula with Precise Stellar Parameters

Dai¹,

Winn²,

Schlaufman³

et al. 2020

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Previous works on Kepler multi-planet systems revealed a remarkable intra-system uniformity in planet radius/mass; moreover the average planet size increases with host mass/metallicity. This observation provides tantalizing evidence that the outcome of planet formation can be linked to the properties of the host star and its disk. In a simple in-situ formation scenario, the minimum-mass extrasolar nebula (MMEN) reconstructed from a planetary system reflect the properties of its natal disk.Specifically, one might expect a one-to-one correspondence between the solid surface density of the MMEN and the host star mass M and metallicity [Fe/H]. Leveraging on the precise host star properties from the California-Kepler-Survey (CKS), we found that Σ = 50 +33 −20 g cm −2 (a/AU) −1.75±0.07 (M /M) 1.04±0.22 10 0.22±0.05[Fe/H] for Kepler-like systems (1-4R ⊕ ; a <1AU). The strong M dependence is reminiscent of previous dust continuum results that the solid disk mass scales with M. The weaker [Fe/H] dependence shows that sub-Neptune planets, unlike giant planets, form readily in lower-metallicity environment. The innermost region (a < 0.1AU) of a MMEN maintains a smooth profile despite a steep decline of planet occurrence rate: a result that favors the truncation of disks by co-rotating magnetospheres with a range of rotation periods, rather than the sublimation of dusts. The Σ of Kepler multi-transiting systems shows a much stronger correlation with M and [Fe/H] than singles. This suggests that the dynamically hot evolution that produced single systems also partially removed the memory of formation in disks. Radial-velocity planets yielded a MMEN very similar to CKS planets; whereas transit-timing-variation planets' postulated convergent migration history is supported by their poorly constrained MMEN. We found that lower-mass stars have a higher efficiency of forming/retaining planets: for sun-like stars about 20% of the solid mass within ∼1AU are converted/preserved as sub-Neptunes, compared to 70% for late-K-early-M stars. This may be due to the lower binary fraction, lower giant-planet occurrence or the longer disk lifetime of lower-mass stars.

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Section: Higher Formation Efficiency For Lower-mass Starsmentioning

confidence: 61%

Section: Higher Formation Efficiency For Lower-mass Starsmentioning

confidence: 99%

California-Kepler Survey. IX. Revisiting the Minimum-mass Extrasolar Nebula with Precise Stellar Parameters

Dai¹,

Winn²,

Schlaufman³

et al. 2020

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“…For 2MASS J1324-5129, on the other hand, we can rule out the possibility that this target is bound to HIP 65426 as its ∆v significantly exceeds its ∆v max . As discussed by Ramírez et al (2019), this statement is true if there is no other effect influencing the kinematic properties of the objects involved, such as an unseen companion to any of the components or unknown systematics in Gaia DR2.…”

Section: Discussionmentioning

confidence: 94%

Characterization of very wide companion candidates to young stars with planets and disks

Majidi

Desidera

Alcalá

et al. 2020

A&A

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Discovering wide companions of stellar systems allows us to constrain the dynamical environment and age of the latter. We studied four probable wide companions of four different stellar systems. The candidates were selected mainly based on their similar kinematic properties to the central star using Gaia DR2. The central stars are V4046 Sgr, HIP 74865, HIP 65426, and HIP 73145, and their probable wide companions are 2MASS J18152222-3249329, 2MASS J15174874-3028484, 2MASS J13242119-5129503, and 2MASS J14571503-3543505 respectively. V4046 Sgr is a member of β-Pictoris Moving Group while the rest of the stellar systems are acknowledged as members of the Scorpius-Centaurus association. The selected stellar systems are particularly interesting because all of them are already known to possess a low-mass companion and/or a spatially resolved disk. Identifying wider companions of these stars can improve their eligibility as benchmarks for understanding the formation channels of various triple systems, and can help us to determine the orbits of their possibly undiscovered inner, wider companions in case of higher multiplicity. By analyzing the X-shooter spectra of the wide companion candidates of these stars, we obtained their stellar parameters and determined their ages. We find that 2MASS J15174874-3028484 (0.11 M⊙, 7.4 ± 0.5 Myr), an already recognized pre-main sequence (PMS) member of Scorpius-Centaurus association, is a highly probable wide companion of HIP 74865. 2MASS J13242119-5129503 (0.04 M⊙, 16 ± 2.2 Myr) is ruled out as a plausible wide companion of HIP 65426, but confirmed to be a new sub-stellar member of the Scorpius-Centaurus association. 2MASS J14571503-3543505 (0.02 M⊙, 17.75 ± 4.15 Myr) is a probable sub-stellar member of the same association, but we cannot confirm whether or not it is gravitationally bound to HIP 73145. 2MASS J18152222-3249329 (0.3 M⊙, older than 150 Myr) is determined to be a mildly active main sequence star, much older than members of β-Pictoris Moving Group, and unbound to V4046 Sgr despite their similar kinematic features. PMS wide companions such as 2MASS J15174874-3028484 might have formed through cascade fragmentation of their natal molecular core, hinting at high multiplicity in shorter separations which can be confirmed with future observations.

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“…3, let us model the fractional mass-loss rate with a truncated 4 Interestingly, comoving pairs with dissimilar chemical composition are not uncommon (e.g. Ramírez et al 2019).…”

Section: Age Spreadmentioning

confidence: 99%

Creation/destruction of ultra-wide binaries in tidal streams

Peñarrubia

2020

Monthly Notices of the Royal Astronomical Society

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This paper uses statistical and N-body methods to explore a new mechanism to form binary stars with extremely large separations (≳ 0.1 pc), whose origin is poorly understood. Here, ultra-wide binaries arise via chance entrapment of unrelated stars in tidal streams of disrupting clusters. It is shown that (i) the formation of ultra-wide binaries is not limited to the lifetime of a cluster, but continues after the progenitor is fully disrupted, (ii) the formation rate is proportional to the local phase-space density of the tidal tails, (iii) the semimajor axis distribution scales as p(a)da ∼ a1/2da at a ≪ D, where D is the mean interstellar distance, and (vi) the eccentricity distribution is close to thermal, p(e)de = 2ede. Owing to their low binding energies, ultra-wide binaries can be disrupted by both the smooth tidal field and passing substructures. The time-scale on which tidal fluctuations dominate over the mean field is inversely proportional to the local density of compact substructures. Monte-Carlo experiments show that binaries subject to tidal evaporation follow p(a)da ∼ a−1da at a ≳ apeak, known as Öpik’s law, with a peak semi-major axis that contracts with time as apeak ∼ t−3/4. In contrast, a smooth Galactic potential introduces a sharp truncation at the tidal radius, p(a) ∼ 0 at a ≳ rt. The scaling relations of young clusters suggest that most ultra-wide binaries arise from the disruption of low-mass systems. Streams of globular clusters may be the birthplace of hundreds of ultra-wide binaries, making them ideal laboratories to probe clumpiness in the Galactic halo.

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The chemical composition of HIP 34407/HIP 34426 and other twin-star comoving pairs

Cited by 51 publications

References 53 publications

California-Kepler Survey. IX. Revisiting the Minimum-mass Extrasolar Nebula with Precise Stellar Parameters

California-Kepler Survey. IX. Revisiting the Minimum-mass Extrasolar Nebula with Precise Stellar Parameters

Characterization of very wide companion candidates to young stars with planets and disks

Creation/destruction of ultra-wide binaries in tidal streams

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