K2 rotation periods for low-mass Hyads and a quantitative comparison of the distribution of slow rotators in the Hyades and Praesepe

Abstract

We analyze K2 light curves for 132 low-mass ($1\gtrsim M_{\ast }\gtrsim 0.1$~$M_{\odot }$) members of the 600--800~Myr-old Hyades cluster and measure rotation periods ($P_{rot}$) for 116 of these stars. These include 93 stars with no prior $P_{rot}$ measurement; the total number of Hyads with known $P_{rot}$ is now 232. We then combine literature binary data with Gaia DR2 photometry and astrometry to select single star sequences in the Hyades and its roughly coeval Praesepe open cluster, and derive a new reddening value of $A_V=0.035$$\pm$$0.011$ for Praesepe. Comparing the effective temperature--$P_{rot}$ distributions for the Hyades and Praesepe, we find that solar-type Hyads rotate, on average, 0.4~d slower than their Praesepe counterparts. This $P_{rot}$ difference indicates that the Hyades is slightly older than Praesepe: we apply a new gyrochronology model tuned with Praesepe and the Sun, and find an age difference between the two clusters of 57~Myr. However, this $P_{rot}$ difference decreases and eventually disappears for lower-mass stars. This provides further evidence for stalling in the rotational evolution of these stars, and highlights the need for more detailed analysis of angular-momentum evolution for stars of different masses and ages.

Accepted for publication in ApJ. 20 pages, 10 figures, 5 tables. CSV versions of tables 2, 3, and 4 available by request

References in corpus (22)

• The Transiting Exoplanet Survey Satellite
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• astroquery: An Astronomical Web-Querying Package in Python
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• The Stellar Populations of Praesepe and Coma Berenices
• The Mass-Dependence of Angular Momentum Evolution in Sun-Like Stars
• A spin-down clock for cool stars from observations of a 2.5-billion-year-old cluster
• Calibrating Gyrochronology using Kepler Asteroseismic targets
• The Factory and The Beehive II. Activity and Rotation in Praesepe and the Hyades
• Zodiacal Exoplanets in Time (ZEIT) IV: seven transiting planets in the Praesepe cluster
• The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets
• The Age and Age Spread of the Praesepe and Hyades Clusters: a Consistent, ~800 Myr Picture from Rotating Stellar Models
• Bayesian Ages for Early-Type Stars from Isochrones Including Rotation, and a Possible Old Age for the Hyades
• WIYN Open Cluster Study. LXXV. Testing the Metallicity Dependence of Stellar Lithium Depletion Using Hyades-Aged Clusters. 1. Hyades & Praesepe
• The temporal evolution of neutron-capture elements in the Galactic discs
• The effect of rotation on the abundances of the chemical elements of the A-type stars in the Praesepe cluster
• The Metastable Dynamo Model of Stellar Rotational Evolution
• Accurate Gravities of F, G, and K stars from High Resolution Spectra Without External Constraints
• A discontinuity in the $T_{\mathrm{eff}}$-radius relation of M-dwarfs
• The Effect of Binarity on Stellar Rotation - Beyond the Reach of Tides
• Stellar rotational periods in the planet hosting open cluster Praesepe
• The first rotation periods in Praesepe

Cited by in corpus (4)

• Stellar rotation periods from K2 Campaigns 0-18 -- Evidence for rotation period bimodality and simultaneous variability decrease
• NGTS clusters survey. I. Rotation in the young benchmark open cluster Blanco 1
• Mutual Inclination Excitation by Stellar Oblateness
• NGTS clusters survey -- II. White-light flares from the youngest stars in Orion