- ID:
- ivo://CDS.VizieR/J/AJ/156/275
- Title:
- Rotational evolution of young, binary M dwarfs
- Short Name:
- J/AJ/156/275
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analyzed K2 light curves for more than 3000 low-mass stars in the ~8 Myr old Upper Sco association, the ~125 Myr age Pleiades open cluster, and the ~700 Myr old Hyades and Praesepe open clusters to determine stellar rotation rates. Many of these K2 targets show two distinct periods, and for the lowest-mass stars in these clusters, virtually all of these systems with two periods are photometric binaries. The most likely explanation is that we are detecting the rotation periods for both components of these binaries. We explore the evolution of the rotation rate in both components of photometric binaries relative to one another and to nonphotometric binary stars. In Upper Sco and the Pleiades, these low-mass binary stars have periods that are much shorter on average and much closer to each other than would be true if drawn at random from the M dwarf single stars. In Upper Sco, this difference correlates strongly with the presence or absence of infrared excesses due to primordial circumstellar disks-the single-star population includes many stars with disks, and their rotation periods are distinctively longer on average than their binary star cousins of the same mass. By Praesepe age, the significance of the difference in rotation rate between the single and binary low-mass M dwarf stars is much less, suggesting that angular momentum loss from winds for fully convective zero-age main-sequence stars erases memory of the rotation rate dichotomy for binary and single very low mass stars at later ages.
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- ID:
- ivo://CDS.VizieR/J/A+A/568/L12
- Title:
- Rotational frequency splitting in Sun-like stars
- Short Name:
- J/A+A/568/L12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Asteroseismology offers the prospect of constraining differential rotation in Sun-like stars. Here we have identified six high signal-to-noise main-sequence Sun-like stars in the Kepler field, which all have visible signs of rotational splitting of their p-mode frequencies. For each star, we extract the rotational frequency splitting and inclination angle from separate mode sets (adjacent modes with l=2, 0, and 1) spanning the p-mode envelope. We use a Markov chain Monte Carlo method to obtain the best fit and errors associated with each parameter. We are able to make independent measurements of rotational splittings of ~8 radial orders for each star. For all six stars, the measured splittings are consistent with uniform rotation, allowing us to exclude large radial differential rotation. This work opens the possibility of constraining internal rotation of Sun-like stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/704/975
- Title:
- Rotational velocities for M dwarfs
- Short Name:
- J/ApJ/704/975
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopic rotation velocities (vsini) for 56 M dwarf stars using high-resolution Hobby-Eberly Telescope High Resolution Spectrograph red spectroscopy. In addition, we have also determined photometric effective temperatures, masses, and metallicities ([Fe/H]) for some stars observed here and in the literature where we could acquire accurate parallax measurements and relevant photometry. We have increased the number of known vsini values for mid M stars by around 80% and can confirm a weakly increasing rotation velocity with decreasing effective temperature. Our sample of vsini is peak at low velocities (~3km/s). We find a change in the rotational velocity distribution between early M and late M stars, which is likely due to the changing field topology between partially and fully convective stars. There is also a possible further change in the rotational distribution toward the late M dwarfs where dust begins to play a role in the stellar atmospheres. We also link vsini to age and show how it can be used to provide mid-M star age limits. When all literature velocities for M dwarfs are added to our sample, there are 198 with vsini<=10km/s and 124 in the mid-to-late M star regime (M3.0-M9.5) where measuring precision optical radial velocities is difficult. In addition, we also search the spectra for any significant Half emission or absorption. Forty three percent were found to exhibit such emission and could represent young, active objects with high levels of radial-velocity noise. We acquired two epochs of spectra for the star GJ1253 spread by almost one month and the Half profile changed from showing no clear signs of emission, to exhibiting a clear emission peak. Four stars in our sample appear to be low-mass binaries (GJ1080, GJ3129, Gl802, and LHS3080), with both GJ3129 and Gl802 exhibiting double Half emission features. The tables presented here will aid any future M star planet search target selection to extract stars with low vsini.
- ID:
- ivo://CDS.VizieR/J/AJ/143/93
- Title:
- Rotational velocities in early-M stars
- Short Name:
- J/AJ/143/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of rotation and chromospheric activity in a sample of 334 M dwarfs of spectral types M0-M4.5 populating the parameter space around the boundary to full convection. We obtain high-resolution optical spectra for 206 targets and determine projected rotational velocity, vsin i, and H{alpha} emission. The data are combined with measurements of vsin i in field stars of the same spectral type from the literature. Our sample adds 157 new rotation measurements to the existing literature and almost doubles the sample of available vsin i. The final sample provides a statistically meaningful picture of rotation and activity at the transition to full convection in the solar neighborhood. Finally, we compare projected rotational velocities of 33 stars to rotational periods derived from photometry in the literature and determine inclinations for a few of them.
- ID:
- ivo://CDS.VizieR/J/other/NatAs/4.03
- Title:
- Rotation and activity across HR diagram
- Short Name:
- J/other/NatAs/4.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present mean chromospheric CaII H and K activity levels and rotation periods, derived from the Mount Wilson Observatory HK Project time series. These are combined with theoretically calculated convective turnover times to derive Rossby numbers and connect the rotational scaling of chromospheric activity of main sequence and post-main sequence stars with each other.
- ID:
- ivo://CDS.VizieR/J/ApJS/211/24
- Title:
- Rotation periods of Kepler MS stars
- Short Name:
- J/ApJS/211/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyzed three years of data from the Kepler space mission to derive rotation periods of main-sequence stars below 6500K. Our automated autocorrelation-based method detected rotation periods between 0.2 and 70 days for 34030 (25.6%) of the 133030 main-sequence Kepler targets (excluding known eclipsing binaries and Kepler Objects of Interest), making this the largest sample of stellar rotation periods to date. In this paper we consider the detailed features of the now well-populated period-temperature distribution and demonstrate that the period bimodality, first seen by McQuillan et al. (2013MNRAS.432.1203M) in the M-dwarf sample, persists to higher masses, becoming less visible above 0.6M_{sun}_. We show that these results are globally consistent with the existing ground-based rotation-period data and find that the upper envelope of the period distribution is broadly consistent with a gyrochronological age of 4.5Gyr, based on the isochrones of Barnes (2007ApJ...669.1167B), Mamajek, & Hillenbrand (Cat. J/ApJ/687/1264) and Meibom et al. (Cat. J/ApJ/695/679). We also performed a detailed comparison of our results to those of Reinhold et al. (Cat. J/A+A/560/A4) and Nielsen et al. (Cat. J/A+A/557/L10), who measured rotation periods of field stars observed by Kepler. We examined the amplitude of periodic variability for the stars with detection rotation periods, and found a typical range between ~950 ppm (5th percentile) and ~22700ppm (95th percentile), with a median of ~5600ppm. We found typically higher amplitudes for shorter periods and lower effective temperatures, with an excess of low-amplitude stars above ~5400K.
- ID:
- ivo://CDS.VizieR/J/A+A/557/L10
- Title:
- Rotation periods of 12000 Kepler stars
- Short Name:
- J/A+A/557/L10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to measure the starspot rotation periods of active stars in the Kepler field as a function of spectral type and to extend reliable rotation measurements from F-, G-, and K-type to M-type stars. Using the Lomb-Scargle periodogram we searched more than 150000 stellar light curves for periodic brightness variations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/432/1203
- Title:
- Rotation periods of M-dwarf stars
- Short Name:
- J/MNRAS/432/1203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analysed 10 months of public data from the Kepler space mission to measure rotation periods of main-sequence stars with masses between 0.3 and 0.55M_{sun}_. To derive the rotational period, we introduce the autocorrelation function and show that it is robust against phase and amplitude modulation and residual instrumental systematics. Of the 2483 stars examined, we detected rotation periods in 1570 (63.2%), representing an increase of a factor of ~30 in the number of rotation period determination for field M dwarfs. The periods range from 0.37 to 69.7d, with amplitudes ranging from 1.0 to 140.8mmag. The rotation period distribution is clearly bimodal, with peaks at ~19 and ~33d, hinting at two distinct waves of star formation, a hypothesis that is supported by the fact that slower rotators tend to have larger proper motions. The two peaks of the rotation period distribution form two distinct sequences in period-temperature space, with the period decreasing with increasing temperature, reminiscent of the Vaughan-Preston gap. The period-mass distribution of our sample shows no evidence of a transition at the fully convective boundary. On the other hand, the slope of the upper envelope of the period-mass relation changes sign around 0.55M_{sun}_, below which period rises with decreasing mass.
- ID:
- ivo://CDS.VizieR/J/MNRAS/407/1657
- Title:
- Rotation velocities of dwarf M stars
- Short Name:
- J/MNRAS/407/1657
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured vsini for a selected sample of dM1-type stars. We give 114 measurements of vsini for 88 different stars, and six upper detection limits. These are the first measurements of vsini for most of the stars studied here. This represents the largest sample of vsini measurements for M dwarfs at a given spectral type. For these measurements, we used four different spectrographs: HARPS (ESO), SOPHIE (OHP), ELODIE (OHP) and UVES (ESO). Two of these spectrographs (HARPS and SOPHIE) are particularly stable in wavelength since they were designed for exoplanet searches.
- ID:
- ivo://CDS.VizieR/J/MNRAS/416/2233
- Title:
- Rotation velocity of dwarfs K5 stars
- Short Name:
- J/MNRAS/416/2233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using two different spectrographs, High Accuracy Radial velocity Planet Search (HARPS) (European Southern Observatory) and SOPHIE (Observatoire de Haute Provence), we have measured vsini for a sample of dK5 stars. These are the first measurements of vsini for most of the stars studied here. We measured vsini to an accuracy of 0.3km/s and a detection limit of about 0.5-1km/s. All our targets have similar (R-I)c colour. This is an advantage and facilitates the determination of the narrowest line profiles for vsini~0. In our total sample, we detected rotation for 22 stars (three dK5e and 19 dK5 stars), and we did not detect rotation in a further 22 stars. This result shows that there are many dK5 slow rotators, and many more than for dM1 stars. We also report on a newly discovered dK5e star, McC 522, which is also the fastest rotator in our sample.
