- ID:
- ivo://CDS.VizieR/J/ApJ/733/L9
- Title:
- Stellar rotation for 71 NGC 6811 members
- Short Name:
- J/ApJ/733/L9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present rotation periods for 71 single dwarf members of the open cluster NGC 6811 determined using photometry from NASA's Kepler mission. The results are the first from The Kepler Cluster Study, which combines Kepler's photometry with ground-based spectroscopy for cluster membership and binarity. The rotation periods delineate a tight sequence in the NGC 6811 color-period diagram from ~1 day at mid-F to ~11 days at early-K spectral type. This result extends to 1Gyr similar prior results in the ~600Myr Hyades and Praesepe clusters, suggesting that rotation periods for cool dwarf stars delineate a well-defined surface in the three-dimensional space of color (mass), rotation, and age. It implies that reliable ages can be derived for field dwarf stars with measured colors and rotation periods, and it promises to enable further understanding of various aspects of stellar rotation and activity for cool stars.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/560/A13
- Title:
- Stellar rotation in h Per
- Short Name:
- J/A+A/560/A13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim at constraining the angular momentum evolution of low mass stars by measuring their rotation rates when they begin to evolve freely towards the ZAMS, i.e. after the disk accretion phase has stopped. We conducted a multi-site photometric monitoring of the young open cluster h Persei that has an age of ~13Myr. The observations were done in the I-band using 4 different telescopes and the variability study is sensitive to periods from less than 0.2 day to 20-days. Rotation periods are derived for 586 candidate cluster members over the mass range 0.4<=M/M_{sun}_<=1.4. The rotation period distribution indicates a slightly higher fraction of fast rotators for the lower mass objects, although the lower and upper envelopes of the rotation period distribution, located respectively at ~0.2-0.3d and ~10d, are remarkably flat over the whole mass range. We combine this period distribution with previous results obtained in younger and older clusters to model the angular momentum evolution of low mass stars during the PMS. The h Per cluster provides the first statistically robust estimate of the rotational period distribution of solar-type and lower mass stars at the end of the PMS accretion phase (>=10Myr). The results are consistent with models that assume significant core-envelope decoupling during the angular momentum evolution to the ZAMS.
- ID:
- ivo://CDS.VizieR/J/MNRAS/413/2218
- Title:
- Stellar rotation in Hyades and Praesepe
- Short Name:
- J/MNRAS/413/2218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of photometric surveys for stellar rotation in the Hyades and in Praesepe, using data obtained as part of the SuperWASP exoplanetary transit-search programme. We determined accurate rotation periods for more than 120 sources whose cluster membership was confirmed by common proper motion and colour-magnitude fits to the clusters' isochrones. This allowed us to determine the effect of magnetic braking on a wide range of spectral types for expected ages of ~600Myr for the Hyades and Praesepe. Both clusters show a tight and nearly linear relation between J-Ks colour and rotation period in the F, G and K spectral range. This confirms that loss of angular momentum was significant enough that stars with strongly different initial rotation rates have converged to the same rotation period for a given mass, by the ages of Hyades and Praesepe.
1064. Stellar rotation in M35
- ID:
- ivo://CDS.VizieR/J/ApJ/695/679
- Title:
- Stellar rotation in M35
- Short Name:
- J/ApJ/695/679
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a five month photometric time-series survey for stellar rotation over a 40'x40' field centered on the 150Myr open cluster M35 (=NGC 2168). We report rotation periods for 441 stars within this field and determine their cluster membership and binarity based on a decade-long radial velocity survey, proper-motion measurements, and multiband photometric observations. We find that 310 of the stars with measured rotation periods are late-type members of M35. The distribution of rotation periods for cluster members span more than 2 orders of magnitude from ~0.1 to 15 days, not constrained by the sampling frequency and the timespan of the survey. With an age between the zero-age main sequence and the Hyades, and with ~6 times more rotation periods than measured in the Pleiades, M35 permit detailed studies of early rotational evolution of late-type stars. Nearly 80% of the 310 rotators lie on two distinct sequences in the color-period plane, and define clear relations between stellar rotation period and color (mass). The M35 color-period diagram enables us to determine timescales for the transition between the two rotational states, of ~60Myr and ~140Myr for G and K dwarfs, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/396/513
- Title:
- Stellar Rotation in the Orion Nebula Cluster
- Short Name:
- J/A+A/396/513
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 1 lists the 1562 stars in the Orion Nebula Cluster brighter than I=20mag on which we did photometry. It contains information on the position, brightness and variability of these stars, as well as their closest companions. Table 2 lists the stars detected as periodic in this study and gives their brightness, period and a comparison with results of previous studies. Table 3 is a summary of observational data for all stars in the Orion Nebula Cluster with rotation periods reported here or in earlier studies.
- ID:
- ivo://CDS.VizieR/J/ApJ/648/591
- Title:
- Stellar rotation in young clusters. II.
- Short Name:
- J/ApJ/648/591
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the effective temperatures and gravities of 461 OB stars in 19 young clusters by fitting the H{gamma} profile in their spectra. We use synthetic model profiles for rotating stars to develop a method to estimate the polar gravity for these stars, which we argue is a useful indicator of their evolutionary status. We combine these results with projected rotational velocity measurements obtained in a previous paper on these same open clusters.
- ID:
- ivo://CDS.VizieR/J/A+AS/143/409
- Title:
- Stock 2 CCD photometry and proper motions
- Short Name:
- J/A+AS/143/409
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the first CCD BVRI photometric and proper motion study of late-type stars in the young open cluster Stock 2. Twenty-one fields of approximately 5'x5' size have been observed photometrically, from which we have identified 118 candidate members based on their positions on colour-magnitude diagrams relative to theoretical isochrones. From a comparison of the known star density of the Pleiades, we estimate the contamination of this selection process due to background stars to be as large as ~50%. However, only 22 of those 118 candidate members have proper motions consistent with membership, suggesting that the contamination is of the order of 80%. Additional candidate members were found by means of a proper motion analysis of Schmidt plate material for a 3{deg}x3{ deg} field containing the cluster. The cluster proper motion allows us to separate members from background and foreground stars. We have found 634 stars with a membership probability >=50% down to a limiting magnitude of B=~20, corresponding to late-M dwarfs at the distance of Stock 2.
- ID:
- ivo://CDS.VizieR/J/A+A/403/937
- Title:
- Stroemgren photometry of NGC 6192 and NGC 6451
- Short Name:
- J/A+A/403/937
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have investigated the two open clusters NGC 6192 and NGC 6451 for which widely different reddening values and thus ages and distances via Stroemgren uvby photometry can be found in the literature. Our measurements allow us to disentangle the apparent discrepancies in the literature and to derive new accurate values. From appropriate calibrations we find that the overall abundance for NGC 6192 is about solar whereas a subsolar value for NGC 6451 was estimated. From two previous reported photometrically candidate CP stars, one within NGC 6192 shows Stroemgren indices typical for a B8Si star whereas the other object of NGC 6451 is most probably a foreground G-type star.
- ID:
- ivo://CDS.VizieR/J/AJ/127/1000
- Title:
- Stromgren and Ca photometry of NGC 3680
- Short Name:
- J/AJ/127/1000
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD photometry on the intermediate-band uvbyCaH{beta} system is presented for the open cluster, NGC 3680. Restricting the data to probable cluster members using the color-magnitude diagram (CMD) and the photometric indices alone defines a sample of 34 stars at the cluster turnoff that imply E(b-y)=0.042+/-0.002(s.e.m.) or E(B-V)=0.058+/-0.003(s.e.m.), where the errors refer to internal errors alone. With this reddening, [Fe/H] is derived from both m_1_ and hk using both b-y and H{beta} as the temperature indices.
- ID:
- ivo://CDS.VizieR/J/A+A/462/157
- Title:
- Stromgren CCD photometry in NGC 6383
- Short Name:
- J/A+A/462/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- By studying young open clusters, the mechanisms important for star formation over several Myr can be examined. For example, accretion rate as a function of rotational velocity can be investigated. Similarly, sequential star formation triggered by massive stars with high mass-loss rates can be studied in detail. We identified and characterized probable members of NGC 6383, as well as determined cluster parameters. New Stromgren uvby CCD photometry, obtained by us, is presented. This new data, together with Johnson UBV and 2MASS data in the NIR, was used to investigate characteristics of pre- as well as zero age main sequence cluster members. We present Stromgren uvby CCD photometry for 272 stars in the field of NGC 6383 and derive its reddening, E(b-y)=0.21(4)mag, as well as distance, d=1.7(3)kpc from the Sun. Several stars with NIR excess and objects in the domain of the classical Herbig Ae/Be and T Tauri stars were detected. Two previously known variables were identified as rapidly-rotating PMS stars. The field population is clearly separated from the probable members in the color-magnitude diagram. NGC 6383 is a young open cluster, with an age of less than 4Myr, undergoing continuous star formation. True pre-main sequence members might be found down to absolute magnitudes of +6mag, with a variety of rotational velocities and stellar activities.