- ID:
- ivo://CDS.VizieR/J/A+A/525/A90
- Title:
- Thick disc vertical properties
- Short Name:
- J/A+A/525/A90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This work investigates the properties (metallicity and kinematics) and interfaces of the Galactic thick disc as a function of height above the Galactic plane. The main aim is to study the thick disc in a place where it is the main component of the sample. We take advantage of former astrometric work in two fields of several square degrees in which accurate proper motions were measured down to V-magnitudes of 18.5 in two directions, one near the north galactic pole and the other at a galactic latitude of 46{deg} and galactic longitude near 0{deg}. Spectroscopic observations have been acquired in these two fields for a total of about 400 stars down to magnitude 18.0, at spectral resolutions of 3.5 to 6.25{AA}. The spectra have been analysed with the code ETOILE, comparing the target stellar spectra with a grid of 1400 reference stellar spectra. This comparison allowed us to derive the parameters effective temperature, gravity, [Fe/H] and absolute magnitude for each target star.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/153/258
- Title:
- 2007.5 to 2010.4 HST astrometry of HD 202206
- Short Name:
- J/AJ/153/258
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using Hubble Space Telescope Fine Guidance Sensor astrometry and previously published radial velocity measures, we explore the exoplanetary system HD202206. Our modeling results in a parallax, {pi}_abs_=21.96+/-0.12 milliseconds of arc, a mass for HD202206B of M_B_=0.089_-0.006_^+0.007M_{Sun}_, and a mass for HD202206c of M_c_=17.9_-1.8_^+2.9^M_Jup_. HD202206 is a nearly face-on G + M binary orbited by a brown dwarf. The system architecture that we determine supports past assertions that stability requires a 5:1 mean motion resonance (we find a period ratio, P_c_/P_B_=4.92+/-0.04) and coplanarity (we find a mutual inclination, {Phi}=6{deg}+/-2{deg}).
- ID:
- ivo://CDS.VizieR/J/AJ/154/224
- Title:
- Transiting planets in young clusters from K2
- Short Name:
- J/AJ/154/224
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Detection of transiting exoplanets around young stars is more difficult than for older systems owing to increased stellar variability. Nine young open cluster planets have been found in the K2 data, but no single analysis pipeline identified all planets. We have developed a transit search pipeline for young stars that uses a transit-shaped notch and quadratic continuum in a 12 or 24 hr window to fit both the stellar variability and the presence of a transit. In addition, for the most rapid rotators (P_rot_<2 days) we model the variability using a linear combination of observed rotations of each star. To maximally exploit our new pipeline, we update the membership for four stellar populations observed by K2 (Upper Scorpius, Pleiades, Hyades, Praesepe) and conduct a uniform search of the members. We identify all known transiting exoplanets in the clusters, 17 eclipsing binaries, one transiting planet candidate orbiting a potential Pleiades member, and three orbiting unlikely members of the young clusters. Limited injection recovery testing on the known planet hosts indicates that for the older Praesepe systems we are sensitive to additional exoplanets as small as 1-2 R_{Earth}_, and for the larger Upper Scorpius planet host (K2-33) our pipeline is sensitive to ~4 R_{Earth}_ transiting planets. The lack of detected multiple systems in the young clusters is consistent with the expected frequency from the original Kepler sample, within our detection limits. With a robust pipeline that detects all known planets in the young clusters, occurrence rate testing at young ages is now possible.
- ID:
- ivo://CDS.VizieR/J/AJ/152/24
- Title:
- Trigonometric parallaxes of 134 low-mass stars
- Short Name:
- J/AJ/152/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report trigonometric parallaxes for 134 low-mass stars and brown dwarfs, of which 38 have no previously published measurement and 79 more have improved uncertainties. Our survey focused on nearby targets, so 119 are closer than 30pc. Of the 38 stars with new parallaxes, 14 are within 20pc and seven are likely brown dwarfs (spectral types later than L0). These parallaxes are useful for studies of kinematics, multiplicity, and spectrophotometric calibration. Two objects with new parallaxes are confirmed as young stars with membership in nearby young moving groups: LP 870-65 in AB Doradus and G161-71 in Argus. We also report the first parallax for the planet-hosting star GJ3470; this allows us to refine the density of its Neptune-mass planet. T-dwarf 2MASSJ12590470-4336243, previously thought to lie within 4pc, is found to be at 7.8pc, and the M-type star 2MASSJ01392170-3936088 joins the ranks of nearby stars as it is found to be within 10pc. Five stars that are overluminous and/or too red for their spectral types are identified and deserve further study as possible young stars.
- ID:
- ivo://CDS.VizieR/J/AJ/159/105
- Title:
- Two new stellar associations in vicinity of the Sun
- Short Name:
- J/AJ/159/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work we report the discovery of two new stellar associations in close vicinity of the Sun at roughly 180 and 150pc. These two associations, u-Tau assoc and e-Tau assoc, were detected based on their clustering in a multi-dimensional parameter space including {alpha}, {delta}, {mu}_{alpha}_, {mu}_{delta}_, and \bar{omega} of Gaia. The fitting of pre-main-sequence model isochrones in their color-magnitude diagrams suggests that the two associations are of about 50Myr old and the group members lower than ~0.8M_{sun}_ are at the stage of post-T Tauri.
- ID:
- ivo://CDS.VizieR/J/PAZh/37/769
- Title:
- Tycho-2 red giant branch and carbon stars
- Short Name:
- J/PAZh/37/769
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on multicolor photometry from the 2MASS and Tycho-2 catalogues, we have produced a sample of 38368 branch red giants that has less than 1% of admixtures and is complete within 500 pc of the Sun. The sample includes 30671 K giants, 7544 M giants,49 C giants, and 104 suspected supergiants or S stars. The photometric distances have been calculated for K, M, and C stars with an accuracy of 40% together with reddening and extinction estimates. Tycho-2 proper motions and PCRV radial velocities are used to analyze the stellar kinematics. The majority of the selected K and M giants are disk stars with ages of more than 3Gyr. A small number of K and M giants are extremely young or, conversely, thick-disk ones. The spatial distribution and kinematics of the selected C stars force us to consider them as asymptotic branch giants with masses of more than 2 solar masses and ages of less than 2Gyr probably associated with the Gould Belt. The offset of the Sun above the Galactic equator has been found from the distribution of stars to be 13+/-2pc, which coincides with the previously obtained value for the clump red giants.
- ID:
- ivo://CDS.VizieR/J/A+A/619/A51
- Title:
- Type II Cepheids in the Galactic bulge
- Short Name:
- J/A+A/619/A51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new Near-Infrared photometry of Type II Cepheids in the Bulge from the VISTA Variables in the Via Lactea survey (VVV) (Minniti et al., 2010NewA...15..433M; Saito et al., 2012A&A...537A.107S, Cat. II/337. We provide the largest sample (894 stars) of T2Cs with JHKs observations that have accurate periods from the OGLE catalog (Soszynski et al., 2017, Cat. J/AcA/67/297). Our analysis makes use of the Ks-band time-series observations to estimate mean-magnitudes and individual distances by means of the Period-Luminosity PL relation. To constrain the kinematic properties of our targets, we complement our analysis with proper motions based on both the VVV and Gaia Data Release 2.
- ID:
- ivo://CDS.VizieR/J/AJ/121/935
- Title:
- UBV and proper motions of Palomar 13
- Short Name:
- J/AJ/121/935
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a proper-motion, CCD photometric study of stars in the distant halo globular cluster Palomar 13. The absolute proper motion of Pal 13 with respect to the background galaxies, derived from moderate-scale photographic plates separated by a 40 year baseline, is (pmRAcosDE, pmDE)=(2.30, 0.27)+/-(0.26, 0.25)mas/yr.
- ID:
- ivo://CDS.VizieR/II/248
- Title:
- UBV photometry and proper motions in M13
- Short Name:
- II/248
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first epoch plates of 8 globular clusters, available in the plate collection of the Pulkovo Observatory, were taken with the normal astrograph at the end of the last and beginning of this century. These plates had been measured previously by N. Gamalei [1948, IzPul, 141] in order to determine the proper motions of the clusters. From 40 to 62 stars were used for this purpose and these were assumed to be cluster members on the basis of their proximity to the cluster centers. The epoch differences ranged from 30 to 45 years. As this time interval has now increased considerably (by about a factor of two), it is planned to redetermine the proper motions of these clusters, using more precise criteria for the selection of stars belonging to the cluster. In the previous study (N. Gamalei [1948, IzPul, 141]) only a limited number of field reference stars were measured, and as more complete data on the cluster, cluster members and field stars is desirable all the star images on the plates in an area 80'x80' will be measured in the present program. For future studies of the orbits of galactic clusters it is important that the absolute proper motions be on one system and therefore special attention should be devoted to this problem. The present paper is a continuation of an investigation of M13 and deals with the determination of the proper motions and U, B, V magnitudes of separate stars and also a redetermination of the proper motions of the cluster. The U, B, V magnitudes of the majority of 923 stars with measured proper motions were found from plates (table 2) taken with the 2 meter Schmidt telescope at Tautenburg and kindly lent to us by Professor N. Richter. The photoelectric standards as given by Savedoff [1956AJ.....61..254S] (table 7) and also U B V magnitudes of six bright field stars (table 8) observed by Mayer were used for calibration. A comparison of the determined B and V magnitudes of stars within an area of about 10'x10' centered on the cluster with those obtained by other authors indicates that the probable external errors do not exceed +/-0.03mag (table 15). However as the photoelectric magnitudes of fainter field stars were not available, a slight systematic error may be present in the derived magnitudes of these stars. Data on the plates used for the determination of the proper motions were given in Kadla [1963AZh....40..691K]. The relative proper motion of M 13, redetermined on the basis of a larger number of cluster members (80 in all, measured on 4 pairs of plates with a mean epoch difference equal to 61.4 years) is found to be {mu}x=+0.0008", {mu}y=-0.0014" with a probable error of +/-0.0002".
- ID:
- ivo://CDS.VizieR/J/AJ/149/190
- Title:
- UBVRI and infrared photometry of NGC 2215
- Short Name:
- J/AJ/149/190
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optical UBVRI photometric measurements using the Faulkes Telescope North were taken in early 2011 and combined with 2MASS JHK_s_ and WISE infrared photometry as well as UCAC4 proper motion data in order to estimate the main parameters of the galactic open cluster NGC 2215 of which large uncertainty exists in the current literature. Fitting a King model we estimate a core radius of 1.12'+/-0.04'(0.24+/-0.01pc) and a limiting radius of 4.3'+/-0.5'(0.94+/-0.11pc) for the cluster. The results of isochrone fits indicates an age of log(t)=8.85+/-0.10 with a distance of d=790+/-90pc, a metallicity of [Fe/H]=-0.40+/-0.10dex, and a reddening of E(B-V)=0.26+/-0.04. A proportion of the work in this study was undertaken by Australian and Canadian upper secondary school students involved in the Space to Grow astronomy education project, and is the first scientific publication to have utilized our star cluster photometry curriculum materials.
