Kinematics and history of the solar neighbourhood revisited

By M. Aumer, J. Binney. 2009

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We use proper motions and parallaxes from the new reduction of Hipparcos data and Geneva-Copenhagen radial velocities for a complete sample of ∼15 000 main-sequence and subgiant stars, and new Padova isochrones to constrain the kinematics and star formation history of the solar neighbourhood. We rederive the solar motion and the structure of the local velocity ellipsoids. When the principal velocity dispersions are assumed to increase with time as t β , the index β is larger for σ W (β W ≈ 0.45) than for σ U (β U ≈ 0.31). For the three-dimensional velocity dispersion, we obtain β = 0.35. We exclude saturation of disc heating after ∼3 Gyr as proposed by Quillen & Garnett. Saturation after >yr combined with an abrupt increase in velocity dispersion for the oldest stars cannot be excluded. For all our models, the star formation rate (SFR) is declining, being a factor of 2-7 lower now than it was at the beginning. Models in which the SFR declines exponentially favour very high disc ages between 11.5 and 13 Gyr and exclude ages below ∼10.5 Gyr as they yield worse fits to the number density and velocity dispersion of red stars. Models in which the SFR is the sum of two declining exponentials representing the thin and thick discs favour ages between 10.5 and 12 Gyr with a lower limit of ∼10.0 Gyr. Although in our models the SFR peaked surprisingly early, the mean formation time of solar-neighbourhood stars is later than in ab initio models of galaxy formation, probably on account of weaknesses in such models.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/68768de82ae7fde032a944a0be7425035f0df57c

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Citations in the corpus

The Lives of Stars: Insights from the TGAS–RAVE–LAMOST Data Set (2018, methodology): “Curiously, this reversal is also seen by Aumer & Binney (2009) for their very bluest stars, and by Anguiano et al. (2017) for their most metal rich and least alpha enhanced stars.”
How to Constrain Your M Dwarf. II. The Mass–Luminosity–Metallicity Relation from 0.075 to 0.70 Solar Masses (2018, background): “Reddening and extinction are expected to be '0 for all targets, as the most distant system is at 35 pc, while the Local Bubble (a region of near-zero extinction) extends to '70 pc (Aumer & Binney 2009).”
Through thick and thin: kinematic and chemical components in the solar neighbourhood (2010, result): “Inefficient heating would actually be easier to reconcile with theoretical models, which have struggled to explain the rapid increase in velocity dispersion with age inferred from earlier observations (see, e.g., Wielen 1977; Lacey 1984; Jenkins & Binney 1990; Aumer & Binney 2009).”
New constraints on the chemical evolution of the solar neighbourhood and galactic disc(s) - improved astrophysical parameters for the Geneva-Copenhagen Survey (2011, background): “An estimate of the age of the disc can thus not be done directly using the age of the stars in the present sample, but requires modelling the star-formation history of the solar neighbourhood, returning a considerably older disc (> 10.5 Gyr, see e.g., Aumer & Binney 2009; Schönrich & Binney 2009a).”
Towards a more realistic population of bright spiral galaxies in cosmological simulations (2013, methodology): “It is interesting that the age inferred for the thin disk population in the solar neighbourhood is even older (see Aumer & Binney 2009 and references therein).”
A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun (2010, background): “In comparison with the most recent value published by Aumer & Binney (2009) [(9.96 ± 0.33,5.25± 0.54,7.07± 0.34) km/s], the V component differs significantly; however, Aumer & Binney (2009) obtained their results by examining the correlation between LSR and colour B − V , i.e. star age, and…”
HOW TO CONSTRAIN YOUR M DWARF: MEASURING EFFECTIVE TEMPERATURE, BOLOMETRIC LUMINOSITY, MASS, AND RADIUS (2015, methodology): “For these calculations we ignored interstellar extinction, as all stars are within 40 pc and Aumer & Binney (2009) showed that reddening is0 for stars within 70 pc due to the Local Bubble.”
THE LONG-TERM EVOLUTION OF THE GALACTIC DISK TRACED BY DISSOLVING STAR CLUSTERS (2010, methodology): “Aumer and Binney (2009) define an empirical velocity dispersion σ2 for a known stellar distributionN of a given age to as σ2 = ∫ to 0 σ2(t)(dN/dt) dt∫ to 0 (dN/dt) dt (10) where the vertical component is given by σz(t) = 20 ( t+ t1 tD + t1 )0.38 .”
The Galaxy in Context: Structural, Kinematic, and Integrated Properties (2016, methodology): “…± 0.05 0.47 ± 0.05 Seabroke & Gilmore (2007) GCS – – 0.48 ± 0.26 Holmberg et al. (2007) GCS 0.38 0.38 0.54 Holmberg et al. (2009) Hipparcos, GCS 0.39 0.40 0.53 Aumer & Binney (2009) Hipparcos, GCS 0.31 0.43 0.45 Just & Jahreiß (2010) Hipparcos – – 0.38 Sharma et al. (2014) GCS 0.20 ± 0.02 0.27 ±…”
Constraining the Galaxy's dark halo with RAVE stars (2014, methodology): “Specifically, from Aumer & Binney (2009) we adopt σr (Lz, τ ) = σr0 ( τ + τ1 τm + τ1 )β e(R0−Rc)/Rσ,r σz(Lz, τ ) = σz0 ( τ + τ1 τm + τ1 )β e(R0−Rc)/Rσ,z .”
The uncertainty in Galactic parameters (2009, methodology): “The velocity dispersion of stars observed locally increases with age on account of heating by irregularities in the Galaxy’s gravitational field (e.g. GDII §10.4.1) and the velocity dispersion of the bluer stars in the Hipparcos catalogue is ∼ 10 kms−1 (Aumer & Binney 2009) rather than 15 kms−1.”
Local kinematics and the local standard of rest (2009, methodology): “2 of Aumer & Binney (2009) but can be traced in theirσR andσz data.”
Vertical disc heating in Milky Way-sized galaxies in a cosmological context (2015, background): “This led to the proposal of several 1 However, some authors argue that the relation may saturate at ages of ∼ 5 Gyr (Dehnen & Binney 1998; Aumer & Binney 2009), or that there is a jump in velocity dispersion ∼ 8− 9 Gyr ago (Soubiran et al. 2008). mechanisms for radial migration, such as migration…”
Fundamental Parameters of the Milky Way Galaxy Based on VLBI Astrometry (2012, result): “Note that the other two components of the Solar motion (Uˇ, Wˇ) are assumed to be well-determined, since previous studies were consistent between each other (e.g., Kerr & Lynden-Bell 1986; Dehnen & Binney 1998; Aumer & Binney 2009; Schönrich et al. 2010).”
STARS, GAS, AND DARK MATTER IN THE SOLAR NEIGHBORHOOD (2015, result): “Normalizing to the case b0 12= , which is consistent with the results of Aumer & Binney (2009) and approximately the value we get in A. Parravano et al. (2015, in preparation), we find that Equations (24) and (31) imply that for 1.35G = the ratio of the scale heights is h h b1.”
Dynamics for galactic archaeology (2013, methodology): “35 (Aumer & Binney, 2009).”