- ID:
- ivo://CDS.VizieR/J/ApJ/667/520
- Title:
- Proper motions in multiple systems
- Short Name:
- J/ApJ/667/520
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of the Koenigstuhl survey in the Southern Hemisphere are presented. I have searched for common proper motion companions to 173 field very low mass stars and brown dwarfs with spectral types >M5.0 V and magnitudes J<~14.5mag. I have measured for the first time the common proper motion of two new wide systems containing very low mass components, Koenigstuhl 2 AB and 3 A-BC. Together with Koenigstuhl 1 AB and 2M 0126-50 AB, they are among the widest systems in their respective classes (r=450-11900AU). I have determined the minimum frequency of field wide multiples (r>100AU) with late-type components at 5.0%+/-1.8% and the frequency of field wide late-type binaries with mass ratios q>0.5 at 1.2%+/-0.9%. These values represent a key diagnostic of evolution history and low-mass star and brown dwarf formation scenarios. In addition, the proper motions of 62 field very low mass dwarfs are measured here for the first time.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/I/212
- Title:
- Proper motions in NGC 3680
- Short Name:
- I/212
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/I/177
- Title:
- Proper motions in NGC 752
- Short Name:
- I/177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue was prepared during the study of proper motions (Platais 1991A&AS...87...69P) in and around the open cluster NGC 752 (C0154+374) which belongs to the poorly-populated open cluster class. Relative proper motions of 1777 stars have been determined from the PDS measurements of 11 Pulkovo normal astrograph plates (scale is 59.57"/mm) in a 110'-diameter circle around the cluster. The catalogue of proper motions is complete down to mpg=15.0m, the limiting value is 15.4m. The average standard error of the catalogue proper motions varies from 0.75mas/yr (milliarcseconds per year) for stars with mpg<14.0m to 1.1mas/yr for the rest. These errors refer to the highest weight group (the star is present on all or nearly all plate pairs). In order to calculate the standard error of a star belonging to the lower weight group, it is necessary to use a unit weight error of 3.7 mas/yr and the appropriate weights from Table I for the plate pairs used in the determination of the star's proper motion, as given in the Catalogue. For stars located far from the field centre as well for fainter stars, an additional factor proportional to the accuracy degradation should be applied. Table I. Assigned weights. ------------------------------------------------------------------- | Pair No.| 1 | 2 | 3 | 4 | 5 | 6 | 7 | |---------|-------|-------|-------|-------|-------|-------|-------| | Weight | 7.0 | 7.0 | 2.5 | 2.3 | 2.8 | 3.0 | 1.0 | ------------------------------------------------------------------- Example: For the star No. 40 the weighted standard error of the proper motion is as follows: 3.7/sqrt(2.3+2.8)*1.5=2.5 mas/yr. The degradation factor of 1.5 comes from the decreased accuracy for the faint stars located at the edge of the field investigated. More detailed information on measured plates, standard errors, assigned weights, membership probabilities etc. is given in Platais (1991A&AS...87...69P). The membership probabilities were calculated assuming that on the vector-point diagram the distribution of field stars is essentially flat within a limited area around the centroid of the cluster member proper motion distribution. A clear separation of field and cluster stars is achieved.
- ID:
- ivo://CDS.VizieR/J/A+AS/118/277
- Title:
- Proper motions in NGC 1647
- Short Name:
- J/A+AS/118/277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The astrometric accuracy of triple image Carte du Ciel plates has been analysed using plates of the open cluster NGC 1647. A new multithreshold technique was used for the treatment of the triple image plates. Accuracies ranging from 100mas to 200mas were found. We determined proper motions with a median accuracy of 1.6mas/a for 2220 stars in the field of NGC 1647. The membership probabilities of stars in the cluster region agree very well with the data of Francic (1989). Due to a significant difference of the proper motions of SZ Tau and the cluster members, SZ Tau seems not to be a member of NGC 1647.
- ID:
- ivo://CDS.VizieR/J/other/ChJAA/6.435
- Title:
- Proper motions in NGC 6530
- Short Name:
- J/other/ChJAA/6.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From photographic plate data of Shanghai Astronomical Observatory with a time baseline of 87 years, proper motions and membership probabilities of 364 stars in the open cluster NGC 6530 region are reduced. On the basis of membership determination, luminosity function and segregation effect of the cluster are discussed with details. Spatial mass segregation is obviously present in NGC 6530 while there is no clear evidence for a velocity-mass (or velocity-luminosity) dependence. The observed spatial mass segregation for NGC 6530 might be due to a combination of initial conditions and relaxation process.
- ID:
- ivo://CDS.VizieR/J/A+A/401/531
- Title:
- Proper motions in NGC 7243
- Short Name:
- J/A+A/401/531
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of astrometric and photometric investigations of the open cluster NGC 7243 are presented. Proper motions of 2165 stars with root-mean-square error of 1.1mas/yr were obtained by means of PDS scanning of astrometric plates covering the time interval of 97 years. A total of 211 cluster members down to V=15.5mag have been identified. V and B magnitudes have been determined for 2118 and 2110 stars respectively. Estimations of mass 348M_{sun}_<M<522M_{sun}_, age t=2.510^8^yr, distance r=698pc and reddening E(B-V)=0.24 of the cluster NGC 7243 have been made.
- ID:
- ivo://CDS.VizieR/J/AJ/134/1368
- Title:
- Proper motions in NGC 2244 and NGC 6530
- Short Name:
- J/AJ/134/1368
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the proper motions, membership probabilities, and velocity dispersions of stars in the regions of the young (~2-4Myr old) open clusters NGC 2244 (the central cluster in the Monoceros R2 association) and NGC 6530 (the dominant cluster in the Sgr OB1 association) from photographic plate material obtained at Shanghai Astronomical Observatory, with time baselines of 34 and 87yr, respectively. Both clusters show clear evidence of mass segregation, but they do not exhibit any significant velocity-mass (or, equivalently, velocity-luminosity) dependence.
- ID:
- ivo://CDS.VizieR/J/A+A/595/L2
- Title:
- Proper motions in NGC6681 globular cluster
- Short Name:
- J/A+A/595/L2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the first time the astrometric capabilities of the MCAO facility GeMS with the GSAOI camera on Gemini-South are tested to quantify the accuracy in determining stellar proper motions in the Galactic globular cluster NGC 6681. Proper motions from HST/ACS for a sample of its stars are already available, and this allows us to construct a distortion-free reference at the epoch of GeMS observations that is used to measure and correct the temporally changing distortions for each GeMS exposure. In this way, we are able to compare the corrected GeMS images with a first-epoch of HST/ACS images to recover the relative proper motion of the Sagittarius dwarf spheroidal galaxy with respect to NGC 6681. We find this to be (pm_{alpha}_cos{delta}, pm_{delta}_)=(4.09,-3.41)mas/yr, which matches previous HST/ACS measurements with a very good accuracy of 0.03mas/yr and with a comparable precision (r.m.s of 0.43mas/yr). This study successfully demonstrates that high-quality proper motions can be measured for quite large fields of view (85arcsecx85arcsec) with MCAO-assisted, ground-based cameras and provides a first, successful test of the performances of GeMS on multi-epoch data.
- ID:
- ivo://CDS.VizieR/J/ApJ/710/1032
- Title:
- Proper motions in {omega} Cen
- Short Name:
- J/ApJ/710/1032
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze data from the Hubble Space Telescope's (HST) Advanced Camera for Surveys of the globular cluster (GC) Omega Cen. We construct a photometric catalog of 1.2x10^6^ stars over a 10'x10' central field down to below B_F435W_=25 (M~0.35M_{sun}_). The 2.5 to 4 year baseline between observations yields a catalog of some 10^5^ proper motions over a smaller area, with 53382 "high-quality" measurements in a central R<~2' field. Artificial-star tests characterize the photometric incompleteness. We determine the cluster center to ~1" accuracy from star counts using two different methods, one based on isodensity contours and the other on "pie slices." We independently confirm the result by determining also the kinematical center of the HST proper motions, as well as the center of unresolved light seen in Two Micron All Sky Survey data. All results agree to within their 1"-2" levels of uncertainty. The proper-motion dispersion of the cluster increases gradually inward, but there is no variation in kinematics with position within the central ~15": there is no dispersion cusp and no stars with unusually high velocities. We measure for the first time in any GC the variation in internal kinematics along the main sequence.
- ID:
- ivo://CDS.VizieR/J/A+A/360/472
- Title:
- Proper motions in omega Centauri
- Short Name:
- J/A+A/360/472
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The tables present the photometric and astrometric results of an extensive proper motion study of the globular cluster omega Centauri: information on the photographic plates used, variability analysis, astrometric data for 9847 stars, membership determination and surface density profile, cluster proper motion dispersions and systematics and cross-references with star-numbers used by Norris et al. (1997ApJ...487L.187N) and Lynga (1996A&AS..115..297L).
