Local stellar kinematics from RAVE data - I. Local standard of rest

Coşkunoğlu, B.; Ak, S.; Bilir, S.; Karaali, S.; Yaz, E.; Gilmore, G.; Seabroke, G. M.; Bienaymé, O.; Bland-Hawthorn, Joss; Campbell, Randy; Freeman, K. C.; Gibson, Brad K.; Grebel, Eva K.; Munari, U.; Navarro, Julio F.; Parker, Quentin A.; Siebert, A.; Siviero, A.; Steinmetz, Matthias; Watson, Fred; Wyse, Rosemary F. Ġ.; Zwitter, T.

doi:10.1111/j.1365-2966.2010.17983.x

Cited by 103 publications

(50 citation statements)

References 31 publications

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“…Accordingly, we used the measured position, proper motion, and radial velocity of EPIC211817229 along with an estimated photometric distance of 55±10pc (Pecaut & Mamajek 2013), to calculate the star's UVW Galactic velocities corrected for the Sun's velocity (Coşkunoǧlu et al 2011 ). The placement of the star in a Toomre diagram and the estimated probability of membership in the three populations (Bensby et al 2014, Appendix A) also point to a star in the thick disk.…”

Section: Discussionmentioning

confidence: 99%

Characterizing K2 Candidate Planetary Systems Orbiting Low-mass Stars. I. Classifying Low-mass Host Stars Observed during Campaigns 1–7

Dressing

Newton

Schlieder

et al. 2017

ApJ

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We present near-infrared spectra for 144candidate planetary systems identified during Campaigns1-7 of the NASA K2 Mission. The goal of the survey was to characterize planets orbiting low-mass stars, but our Infrared Telescope Facility/SpeX and Palomar/TripleSpec spectroscopic observations revealed that 49% of our targets were actually giant stars or hotter dwarfs reddened by interstellar extinction. For the 72stars with spectra consistent with classification as cool dwarfs (spectral types K3-M4), we refined their stellar properties by applying empirical relations based on stars with interferometric radius measurements. Although our revised temperatures are generally consistent with those reported in the Ecliptic Plane Input Catalog (EPIC), our revised stellar radii are typically 0.13  R (39%) larger than the EPIC values, which were based on model isochrones that have been shown to underestimate the radii of cool dwarfs. Our improved stellar characterizations will enable more efficient prioritization of K2 targets for follow-up studies.

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Section: Discussionmentioning

confidence: 99%

Characterizing K2 Candidate Planetary Systems Orbiting Low-mass Stars. I. Classifying Low-mass Host Stars Observed during Campaigns 1–7

Dressing

Newton

Schlieder

et al. 2017

ApJ

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“…The errors correspond to the statistical propagation of all observational errors. While these are commonly used values, we note that recent studies seem to suggest a larger V component of the solar motion with respect to the LSR, ∼13 km s −1 (e.g., Coşkunoǧlu et al 2011). However, given the current PM uncertainties, this change will have little effect on the calculated motion of Fornax.…”

Section: Tablementioning

confidence: 92%

First Ground-Based Charge-Coupled Device Proper Motions for Fornax. Ii. Final Results

Méndez

Costa

Gallart

et al. 2011

The Astronomical Journal

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We present the first entirely ground-based astrometric determination of the proper motion for the Fornax Local Group dwarf spheroidal satellite galaxy of the Milky Way (MW), using charge-coupled device data acquired with the ESO 3.5 m New Technology Telescope at La Silla Observatory in Chile. Our unweighted mean from five quasar fields in the background of Fornax, used as fiducial reference points, leads to μ α cos δ = 0.62 ± 0.16 mas yr −1 and μ δ = −0.53 ± 0.15 mas yr −1 . A detailed comparison with all previous measurements of this quantity seems to imply that there is still no convincing convergence to a single value, perhaps indicating the existence of unaccounted systematic effects in (some of) these measurements. From all available proper-motion and radial velocity measurements for Fornax, we compute Fornax's orbital parameters and their uncertainty using a realistic Galactic potential and a Monte Carlo simulation. Properties of the derived orbits are then compared to main star formation episodes in the history of Fornax. All published proper-motion values imply that Fornax has recently (200-300 Myr ago) approached perigalacticon at a distance of ∼150 kpc. However, the derived period exhibits a large scatter, as does the apogalacticon. Our orbit, being the most energetic, implies a very large apogalactic distance of ∼950 kpc. If this were the case, then Fornax would be a representative of a hypervelocity MW satellite in late infall.

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“…We convert the celestial positions and parallaxes into Galactocentric Cartesian coordinates, assuming a Solar radius of 8 kpc and a Sun's height above the Galactic plane of 0. The proper motions and the line-of-sight velocities are translated into velocity components in spherical polars, using the Solar peculiar motion from Coşkunoǧlu et al (2011) and marginalising over the Local Standard of Rest (LSR) values assuming they are Gaussian distributed 2 with a mean at 238 km s −1 and a standard deviation of 9 km s −1 (see Schönrich 2012). The uncertainties are propagated using Monte-Carlo sampling and the medians of the distributions for each object, as well as the scaled median absolute deviations, are used for the analysis below.…”

Section: Observationsmentioning

confidence: 99%

The origin of galactic metal-rich stellar halo components with highly eccentric orbits

Fattahi

Belokurov

Deason

et al. 2019

Monthly Notices of the Royal Astronomical Society

130

138

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Using the astrometry from the ESA's Gaia mission, previous works have shown that the Milky Way stellar halo is dominated by metal-rich stars on highly eccentric orbits. To shed light on the nature of this prominent halo component, we have analysed 28 Galaxy analogues in the Auriga suite of cosmological hydrodynamics zoom-in simulations. Some three quarters of the Auriga galaxies contain prominent components with high radial velocity anisotropy, β > 0.6. However, only in one third of the hosts do the high-β stars contribute significantly to the accreted stellar halo overall, similar to what is observed in the Milky Way. For this particular subset we reveal the origin of the dominant stellar halo component with high metallicity, [Fe/H]∼ −1, and high orbital anisotropy, β > 0.8, by tracing their stars back to the epoch of accretion. It appears that, typically, these stars come from a single dwarf galaxy with a stellar mass of order of 10 9 − 10 10 M that merged around 6 − 10 Gyr ago, causing a sharp increase in the halo mass. Our study therefore establishes a firm link between the excess of radially anisotropic stellar debris in the halo and an ancient head-on collision between the young Milky Way and a massive dwarf galaxy.

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Local stellar kinematics from RAVE data - I. Local standard of rest

Cited by 103 publications

References 31 publications

Characterizing K2 Candidate Planetary Systems Orbiting Low-mass Stars. I. Classifying Low-mass Host Stars Observed during Campaigns 1–7

Characterizing K2 Candidate Planetary Systems Orbiting Low-mass Stars. I. Classifying Low-mass Host Stars Observed during Campaigns 1–7

First Ground-Based Charge-Coupled Device Proper Motions for Fornax. Ii. Final Results

The origin of galactic metal-rich stellar halo components with highly eccentric orbits

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