Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics

By Eric Mamajek, L. Hillenbrand. 2008

968 citations recorded by the source corpus.

While the strong anticorrelation between chromospheric activity and age has led to the common use of the Ca II H and K emission index (R′HK = LHK/Lbol) as an empirical age estimator for solar-type dwarfs, existing activity-age relations produce implausible ages at both high and low activity levels. We have compiled R′HK data from the literature for young stellar clusters, richly populating for the first time the young end of the activity-age relation. Combining the cluster activity data with modern cluster age estimates and analyzing the color dependence of the chromospheric activity age index, we derive an improved activity-age calibration for F7-K2 dwarfs (0.5 mag < B − V < 0.9 mag ). We also present a more fundamentally motivated activity-age calibration that relies on conversion of R′HK values through the Rossby number to rotation periods and then makes use of improved gyrochronology relations. We demonstrate that our new activity-age calibration has typical age precision of ~0.2 dex for normal solar-type dwarfs aged between the Hyades and the Sun (~0.6-4.5 Gyr). Inferring ages through activity-rotation-age relations accounts for some color-dependent effects and systematically improves the age estimates (albeit only slightly). We demonstrate that coronal activity as measured through the fractional X-ray luminosity (RX = LX/Lbol) has nearly the same age- and rotation-inferring capability as chromospheric activity measured through R′HK. As a first application of our calibrations, we provide new activity-derived age estimates for a volume-limited sample of the 108 solar-type field dwarfs within 16 pc.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/004a7a7044b1594fb875741480102e400b0a0ead

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In Astronomy and Astrophysics

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Citations in the corpus

• The HARPS search for southern extra-solar planets (2018, methodology): “The rotation period of the star, estimated using Mamajek & Hillenbrand (2008) and Noyes et al. (1984), is 42 days.”
• THE MASS-DEPENDENCE OF ANGULAR MOMENTUM EVOLUTION IN SUN-LIKE STARS (2014, background): “Observations of various indicators of magnetic activity (Noyes et al. 1984a; Reiners et al. 2009; Pizzolato et al. 2003; Mamajek & Hillenbrand 2008; Wright et al. 2011; Vidotto et al. 2014), as well as theoretical models for magnetic field generation (Durney & Latour 1978; Noyes et al. 1984b;…”
• Transiting exoplanets from the CoRoT space mission VIII. CoRoT-7b: the first Super-Earth with measured radius (2009, positive): “We compared this chromospheric age estimate with the new activity-age relation given by Mamajek & Hillenbrand (2008) that yields an age of 2.0± 0.3 Gyr.”
• Rotation and magnetism of Kepler pulsating solar-like stars : Towards asteroseismically calibrated age-rotation relations (2014, methodology): “Finally, the set of cool main-sequence dwarfs has the closest slope n to other values found in the literature, although it is still too high: the original Skumanich (1972) relation with n = 0.51, Barnes (2007) with n = 0.5189 ± 0.0070, and Mamajek & Hillenbrand (2008) with n = 0.566 ± 0.008.”
• DIRECT IMAGING OF A COLD JOVIAN EXOPLANET IN ORBIT AROUND THE SUN-LIKE STAR GJ 504 (2013, methodology): “Both stellar rotation and activity decline as a Sun-like star ages and sheds angular momentum in its stellar wind, and both age indicators have been accurately calibrated using stars in open clusters (Mamajek & Hillenbrand 2008, hereafter MH08).”
• THE KEPLER CATALOG OF STELLAR FLARES (2016, background): “As a result, the use of rotation periods to infer or constrain stellar ages has recently become popular (e.g. Barnes 2007; Mamajek & Hillenbrand 2008; van Saders et al. 2016).”
• THE PALOMAR/KECK ADAPTIVE OPTICS SURVEY OF YOUNG SOLAR ANALOGS: EVIDENCE FOR A UNIVERSAL COMPANION MASS FUNCTION (2008, methodology): “…based on the strength of the chromospheric Ca II H and K (3968Å and 3933Å) line emission for > 30 Myrold stars, and using the recent activity-age relation of Mamajek & Hillenbrand (2008), or (2) isochrone fitting for < 30 Myr-old pre-main sequence stars using the tracks of Baraffe et al. (1998).”
• The HARPS search for Earth-like planets in the habitable zone - I. Very low-mass planets around HD 20794, HD 85512, and HD 192310 (2011, methodology): “An interesting side product of this is the direct determination of the stellar rotational velocity, which, for all the three cases presented here, turned out to agree excellently with the value directly derived from log(R′HK) using the procedures given by Mamajek & Hillenbrand (2008).”
• TESTING A PREDICTIVE THEORETICAL MODEL FOR THE MASS LOSS RATES OF COOL STARS (2011, background): “For many stars the rotation rate also scales with age, chromospheric activity, and coronal X-ray emission (Skumanich 1972; Noyes et al. 1984; Pizzolato et al. 2003; Mamajek & Hillenbrand 2008).”
• FORMATION AND EVOLUTION OF PLANETARY SYSTEMS: PROPERTIES OF DEBRIS DUST AROUND SOLAR-TYPE STARS (2008, methodology): “Field stars were assigned ages based on stellar activity indicators (e.g. X-ray, rotation, CaII H&K), whose decline in strength with age has been calibrated with respect to open clusters of known age (Mamajek & Hillenbrand 2008).”
• CHARACTERIZING THE COOL KOIs. II. THE M DWARF KOI-254 AND ITS HOT JUPITER (2011, methodology): “Using this idea, age-period calibrations have been produced for G and K type dwarfs, (Mamajek & Hillenbrand 2008), but relationships for M dwarfs are still uncertain.”
• THE STELLAR-ACTIVITY–ROTATION RELATIONSHIP AND THE EVOLUTION OF STELLAR DYNAMOS (2011, methodology): “Mamajek & Hillenbrand (2008) fit a loglinear function to the RX − Ro distribution, with the goal of empirically deriving a correlation that would allow age estimates to be derived from X-ray luminosities (via rotation periods).”
• NEW DEBRIS DISKS AROUND YOUNG, LOW-MASS STARS DISCOVERED WITH THE SPITZER SPACE TELESCOPE (2009, positive): “For sources with measured X-ray activity, rotation periods or Ca II H & K activity, we estimate ages using activity-age correlation relations derived in Mamajek & Hillenbrand (2008).”
• KEPLER MISSION STELLAR AND INSTRUMENT NOISE PROPERTIES (2011, methodology): “Mamajek & Hillenbrand (2008) discuss how this relationship provides a reasonable match to recent computational predictions based on either mixing-length theory or full turbulence spectrum treatments of convection.”