- ID:
- ivo://CDS.VizieR/J/AJ/155/173
- Title:
- K2 light curve for K2-231
- Short Name:
- J/AJ/155/173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify a sub-Neptune exoplanet (R_p_=2.5+/-0.2R_{Earth}_) transiting a solar twin in the Ruprecht 147 star cluster (3Gyr, 300pc, [Fe/H]=+0.1dex). The ~81 day light curve for EPIC 219800881 (V=12.71) from K2 Campaign 7 shows six transits with a period of 13.84 days, a depth of ~0.06%, and a duration of ~4hr. Based on our analysis of high-resolution MIKE spectra, broadband optical and NIR photometry, the cluster parallax and interstellar reddening, and isochrone models from PARSEC, Dartmouth, and MIST, we estimate the following properties for the host star: M_*_=1.01+/-0.03M_{sun}_, R_*_=0.95+/-0.03R_{sun}_, and T_eff_=5695+/-50K. This star appears to be single based on our modeling of the photometry, the low radial velocity (RV) variability measured over nearly 10yr, and Keck/NIRC2 adaptive optics imaging and aperture-masking interferometry. Applying a probabilistic mass-radius relation, we estimate that the mass of this planet is M_p_=7+5-3M_{Earth}_, which would cause an RV semi-amplitude of K=2+/-1m/s that may be measurable with existing precise RV facilities. After statistically validating this planet with BLENDER, we now designate it K2-231b, making it the second substellar object to be discovered in Ruprecht 147 and the first planet; it joins the small but growing ranks of 22 other planets and three candidates found in open clusters.
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Search Results
- ID:
- ivo://CDS.VizieR/II/42
- Title:
- K-Line Photometry of A Stars
- Short Name:
- II/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A narrow-band spectrometer, compensated for seeing and transparency variations, has been constructed and used to measure the strength of the calcium K-line (3933.68{AA}) in 146 A-type stars. The observations were made in the spring of 1966 with the No.4 16-inch (40cm) telescope at Kitt Peak National Observatory.
- ID:
- ivo://CDS.VizieR/II/43
- Title:
- K-line photometry of Southern A stars
- Short Name:
- II/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The photoelectric measurements of the strength of the Calcium K-line has been extended by 223 stars of predominantly southern or equatorial declinations which are well distributed in right ascension. This has expanded the existent list to 369 field stars for which a k-index is available, including many more Am stars. All available k-index data for field stars are presented here.
- ID:
- ivo://CDS.VizieR/II/44
- Title:
- K-Line photometry of stars in Population I clusters
- Short Name:
- II/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photoelectric photometry of the K-line of calcium has been performed for the A stars of five open clusters (Hyades, Pleiades, IC 2391, IC 2602, and NGC 6475) and one association (Orion). All observations were carried out simultaneously with the field stars measurements in Paper II (II/43), with the 16-inch (40cm) and 36-inch (91cm) telescopes of the Cerro Tololo Inter-American Observatory, between May 1969 and January 1970.
- ID:
- ivo://CDS.VizieR/J/A+A/323/139
- Title:
- K magnitude of Pleiades low-mass binaries
- Short Name:
- J/A+A/323/139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This table provides the list of stars observed but not resolved during the diffraction-limited survey of G and K Pleiades dwarfs. Previously known binaries, either photometric or spectroscopic, are referenced.
- ID:
- ivo://CDS.VizieR/J/MNRAS/355/20
- Title:
- K magnitudes of 74MHz radio sources
- Short Name:
- J/MNRAS/355/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present near-infrared K-band imaging of a sample of ultra-steep-spectrum (USS) radio sources selected at 74-MHz. The dual selection criteria of low frequency and USS mean that we should be sensitive to the highest-redshift (z>5) radio galaxies. We have obtained K-band magnitudes for all of the objects in our sample of 26 and discuss the properties of each.
- ID:
- ivo://CDS.VizieR/J/A+A/469/459
- Title:
- K magnitudes of N159-5 (LMC)
- Short Name:
- J/A+A/469/459
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution near-infrared imaging of the compact HII region N159-5 and its immediate environment in the giant-star forming region N159 in the LMC. N159-5 was observed at high spatial resolution ~0.11"-0.25" in the K-band using the ESO Very Large Telescope UT4 (VLT), equipped with the NAOS adaptive optics system. Our data reveal that N159-5 has a complex morphology formed mainly by two wings and probably a single central bright star, embedded in diffuse emission of ~4.5" diameter. A remarkable embedded tight cluster of approximatively the same size, containing at least 38 faint stars coinciding with N159-5, is also detected. Such clusters can be found in galactic HII regions like the star-forming regions SH2 269 or M42. At the location of the radio peak, especially in the bright western wing, this cluster is rich in stars. Spectroscopic observations reveal that the diffuse region is constituted mainly of dust continuum and that the bright star #2-55 could be of type O8 V. A comparison with the radio observation flux of N159-5 published in the literature seems to show that the bright star #2-55 is not the only ionization source of N159-5. Towards N159-5 molecular H_2_ emission is detected. A model of the region is proposed.
- ID:
- ivo://CDS.VizieR/J/A+A/440/121
- Title:
- K magnitudes of OB stars in UCHIIs
- Short Name:
- J/A+A/440/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained high resolution (R=10000) K-band spectra of candidate young massive stars deeply embedded in (ultra-) compact HII regions (UCHIIs). These objects were selected from a near-infrared survey of 44 fields centered on IRAS sources with UCHII colours. Often, the near-infrared counterpart of the IRAS source is a young embedded cluster hosting massive stars. In these clusters, three types of objects are identified. The first type (38 objects) consists of "naked" OB stars whose K-band spectra are dominated by photospheric emission. We classify the K-band spectra of the OB-type cluster members using near-infrared classification criteria. A few of them have a very early (O3-O4 V) spectral type, consistent with a young age of the embedded clusters. The spectral classification provides an important constraint on the distance to the embedded cluster.
- ID:
- ivo://CDS.VizieR/J/AJ/158/20
- Title:
- K-M stars of class I candidate RSGs in Gaia DR2
- Short Name:
- J/AJ/158/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate individual distances and luminosities of a sample of 889 nearby candidate red supergiants (RSGs) with reliable parallaxes ({omega}/{sigma}_{omega}_>4 and RUWE<2.7) from Gaia Data Release 2 (DR2, Cat. I/345). The sample was extracted from the historical compilation of spectroscopically derived spectral types by Skiff (Cat. B/mk), and consists of K-M stars that are listed with class I at least once. The sample includes well-known RSGs from Humphreys (1978ApJS...38..309H), Elias et al. (1985ApJS...57...91E), Jura & Kleinmann (1990ApJS...73..769J), and Levesque et al. (2005ApJ...628..973L). Infrared and optical measurements from the Two Micron All Sky Survey, Catalog of Infrared Observations (CIO), Midcourse Space Experiment, Wide-field Infrared Survey Explorer, MIPSGAL, Galactic Legacy Infrared Midplane Extraordinaire (GLIMPSE), and The Naval Observatory Merged Astrometric Dataset catalogs allow us to estimate the stellar bolometric magnitudes. We analyze the stars in the luminosity versus effective temperature plane and confirm that 43 sources are highly probably RSGs with M_bol_< -7.1 mag. Of the stars in the sample, 43% have masses >7 M_{sun}_. Another ~30% of the sample consists of giant stars.
- ID:
- ivo://CDS.VizieR/J/A+A/649/A90
- Title:
- KMT-2018-BLG-1025Lb I light curve
- Short Name:
- J/A+A/649/A90
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We aim to find missing microlensing planets hidden in the unanalyzed lensing events of previous survey data. For this purpose, we conduct a systematic inspection of high-magnification microlensing events, with peak magnifications Apeak>~30, in the data collected from high-cadence surveys in and before the 2018 season. From this investigation, we identify an anomaly in the lensing light curve of the event KMT-2018-BLG-1025. The analysis of the light curve indicates that the anomaly is caused by a very low mass-ratio companion to the lens. We identify three degenerate solutions, in which the ambiguity between a pair of solutions (solutions B) is caused by the previously known close-wide degeneracy, and the degeneracy between these and the other solution (solution A) is a new type that has not been reported before. The estimated mass ratio between the planet and host is q~0.8x10^-4^ for the solution A and q~1.6x10^-4^ for the solutions B. From the Bayesian analysis conducted with measured observables, we estimate that the masses of the planet and host and the distance to the lens are (Mp, Mh, DL)~(6.1M_{sun}_, 0.22M_Earth_, 6.7kpc) for the solution A and ~(4.4M_{sun}_, 0.08M_Earth_, 7.5kpc) for the solutions B. The planet mass is in the category of a super-Earth regardless of the solutions, making the planet the eleventh super-Earth planet, with masses lying between those of Earth and the Solar system's ice giants, discovered by microlensing.
