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1061. EDEN project: Flare activity of nearby M-dwarf Wolf 359
ID:
ivo://CDS.VizieR/J/AJ/162/11
Title:
EDEN project: Flare activity of nearby M-dwarf Wolf 359
Short Name:
J/AJ/162/11
Date:
16 Mar 2022 00:09:17
Publisher:
CDS
Description:
We report the flare activity of Wolf359, the fifth closest star to the Sun and a candidate exoplanet-hosting M-dwarf. The star was a target of the Kepler/K2 mission and was observed by the EDEN project, a global network of 1-2m class telescopes for detection and characterization of rocky exoplanets in the habitable zones of late M-dwarfs within 50 light year from the solar system. In the combination of the archived K2 data and our EDEN observations, a total of 872 flares have been detected, 861 with the K2 (860 in the short-cadence and 18 in the long-cadence data, with 17 long-cadence events having short-cadence counterparts) and 11 with EDEN. Wolf 359 has relatively strong flare activity even among flaring M-dwarfs, in terms of the flare activity indicator (FA) defined as the integrated flare energy relative to the total stellar bolometric energy, where FA={sum}E_f_/{int}L_bol_dt~8.93x10^-5^ for the long-cadence flares, whereas for K2 short cadence and EDEN flares, the FA values are somewhat larger, FA~6.67 x 10^-4^ and FA~5.25x10^-4^, respectively. Such a level of activity, in accordance with the rotation period (P_rot_), suggests the star to be in the saturation phase. The size of the starspots is estimated to be at least 1.87%{+/-}0.59% of the projected disk area of Wolf359. We find no correlation of FA with the stellar rotational phase. Our analysis indicates a flare frequency distribution in a power-law form of dN/dE{prop}E^-{alpha}^ with {alpha}=2.13{+/-}0.14, equivalent to an occurrence rate of flares E_f_>~10^31^erg about once per day and of superflares with E_f_>~10^33^erg approximately 10 times per year. These superflares may impact the habitability of system in multiple ways, the details of which are topics for future investigations.
1062. Edge-on HI-rich LSB galaxies from ALFALFA
ID:
ivo://CDS.VizieR/J/ApJS/248/33
Title:
Edge-on HI-rich LSB galaxies from ALFALFA
Short Name:
J/ApJS/248/33
Date:
21 Oct 2021
Publisher:
CDS
Description:
Low surface brightness galaxies (LSBGs) are defined as galaxies that are fainter than dark night sky and are important for studying our universe. Particularly, edge-on galaxies are useful for the study of rotational velocity and dynamical properties of galaxies. Hence here we focus on searching for edge-on LSBGs. In order to find these edge-on dim galaxies, a series of effects caused by inclination, including the surface brightness profile, internal extinction, and scale length, have been corrected. In this work, we present a catalog of 281 edge-on LSBG candidates, which are selected from the crossmatch between Sloan Digital Sky Survey Data Release 7 and the 40% ALFALFA catalog. We also present the properties of these edge-on LSBG candidates including the absolute magnitude, central surface brightness, B-V color, scale length, and relative thickness. Our result suggests that the correction of inclination effects is very important for obtaining a complete sample of LSBGs.
1063. Edinburgh-Cape Blue Object Survey. III.
ID:
ivo://CDS.VizieR/J/MNRAS/431/240
Title:
Edinburgh-Cape Blue Object Survey. III.
Short Name:
J/MNRAS/431/240
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Edinburgh-Cape Blue Object Survey seeks to identify point sources with an ultraviolet excess. Results for zone 2 of the survey are presented here, covering that part of the South Galactic Cap between 30 and 40{deg} from the Galactic plane and south of about -12.3{deg} of declination. Edinburgh-Cape zone 2 comprises 66 UK Schmidt Telescope fields covering about 1730sq.deg, in which we find some 892 blue objects, including 423 hot subdwarfs (~47%); 128 white dwarfs (14%); 25 cataclysmic variables (~3%); 119 binaries (~13%), mostly composed of a hot subdwarf and a main-sequence F or G star; 66 horizontal branch stars (~7%) and 48 "star-like" extragalactic objects (~5%). A further 362 stars observed in the survey, mainly low-metallicity F- and G-type stars, are also listed. Both low-dispersion spectroscopic classification and UBV photometry are presented for almost all of the hot objects and either spectroscopy or photometry (or both) for the cooler ones.
1064. Edinburgh-Cape Blue Object Survey. Zone 1.
ID:
ivo://CDS.VizieR/J/MNRAS/287/867
Title:
Edinburgh-Cape Blue Object Survey. Zone 1.
Short Name:
J/MNRAS/287/867
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results for Zone 1 of the Edinburgh-Cape (EC) Blue Object Survey are presented. This zone covers that part of the North Galactic Cap more than ~30{deg} from the Galactic plane and south of about -12.3{deg} declination (although a few fields north of this declination are included). The zone effectively complements the Palomar-Green Survey in the North Galactic Cap, although the EC Survey should be more complete to a fainter limit (B=16.5mag) and to somewhat redder stars (U-B bluer than about -0.4). Zone 1 covers approximately 1560{deg}^2^ and contains 675 blue objects far which we list equatorial coordinates accurate to ~1arcsec, UBV photoelectric photometry, and spectral types determined from moderate-dispersion (100{AA}/mm) spectrograms.
1065. Edinburgh-Cape Blue Object Survey. Zones 4-6
ID:
ivo://CDS.VizieR/J/MNRAS/459/4343
Title:
Edinburgh-Cape Blue Object Survey. Zones 4-6
Short Name:
J/MNRAS/459/4343
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results for the remaining zones of the Edinburgh-Cape (EC) Blue Object survey are presented. These are incomplete, but lie in that part of the South Galactic Cap between 50deg and 90deg from the Galactic plane and south of about -12.3{deg} of declination. This part of the survey comprises 79 UK Schmidt Telescope fields covering about 2150deg^2^, in which we find 536 blue objects - including hot subdwarfs (~33 per cent), white dwarfs (~30 per cent), binaries (~12 per cent), cataclysmic variables (~1.5 per cent) and some 'star-like' galaxies (~12 per cent). A further 254 stars observed in the survey, mainly low-metallicity F- and G-type stars, are also listed. Low-dispersion spectroscopic classification is given for all the hot objects and UBV photometry for most of them. Either spectroscopy or photometry is listed for the cooler types.
1066. EE Aqr UBV light curves
ID:
ivo://CDS.VizieR/J/AJ/139/1486
Title:
EE Aqr UBV light curves
Short Name:
J/AJ/139/1486
Date:
21 Oct 2021
Publisher:
CDS
Description:
EE Aqr is a 7.9mag Algol variable with a 12hr orbital period. The Wilson-Devinney program is used to simultaneously solve 11 previously published light curves together with two existing radial velocity curves. The resulting masses are M_1_=2.24+/-0.13M_{sun}_ and M_2_=0.72+/-0.04M_{sun}_, and the radii are R_1_=1.76+/-0.03R_{sun}_ and R_2_=1.10+/-0.02R_{sun}_. The system has the lower-mass component completely filling its Roche lobe. Its distance from Hipparcos observations is 112+/-10pc. An improved ephemeris is derived, and no deviations in the period over time were seen. Light and velocity curve parameters, orbital elements, and absolute dimensions are presented, plus a comparison is made with previous solutions.
1067. Effective temperature of 30 Dor population
ID:
ivo://CDS.VizieR/J/A+A/443/851
Title:
Effective temperature of 30 Dor population
Short Name:
J/A+A/443/851
Date:
21 Oct 2021
Publisher:
CDS
Description:
The star-formation history and IMF of the field population of the 30 Doradus super-association is determined using Wide Field Imager photometry. The cluster NGC 2070 and the OB association LH104 are also studied and used for comparison. The star-formation history of the 30~Doradus super-association appears to be characterized by a large increase in star-formation activity 10Myr to 20Myr ago. This seems to be the case across the whole eastern half of the LMC as demonstrated by the ages of stellar populations as far away as 30 Doradus and Shapley's Constellation III. Star-formation appears to be occurring at a constant rate in the field and in loose associations, and in bursts in the clusters. The field IMF is found to have almost the exact Salpeter slope in the range 7M_{sun}_<=M<=40M_{sun}_, at odds with previous claims. We find that, for objects with more complex star-formation histories, Be stars and selective incompleteness strongly affect the determination of the IMF for M>40M_{sun}_, naturally explaining the observed deviation of the high mass IMF slope from the Salpeter value.The present work supports the idea of a universal IMF.
1068. Effective temperatures of K-M giants
ID:
ivo://CDS.VizieR/J/AN/321/277
Title:
Effective temperatures of K-M giants
Short Name:
J/AN/321/277
Date:
21 Oct 2021
Publisher:
CDS
Description:
A high-resolution spectroscopic survey in the 6380-6460{AA} region of 224 slowly-rotating M-K class III giants is presented. Spectral line-depth ratio are calibrated against effective temperature obtained from B-V and V-I color indices in the range 3200-7500K (M6-A9). A table of polynomial coefficients for 12 line-ratio-Teff relations can be used to derive Teff of F-M stars to within 33K (rms), and of early-F and mid-to-late M stars to within 77-106K (rms).
1069. Effect of stellar companions on planetary systems
ID:
ivo://CDS.VizieR/J/AJ/156/83
Title:
Effect of stellar companions on planetary systems
Short Name:
J/AJ/156/83
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Kepler light curves used to detect thousands of planetary candidates are susceptible to dilution due to blending with previously unknown nearby stars. With the automated laser adaptive optics instrument, Robo-AO, we have observed 620 nearby stars around 3857 planetary candidates host stars. Many of the nearby stars, however, are not bound to the KOI. We use galactic stellar models and the observed stellar density to estimate the number and properties of unbound stars. We estimate the spectral type and distance to 145 KOIs with nearby stars using multi-band observations from Robo-AO and Keck-AO. Most stars within 1" of a Kepler planetary candidate are likely bound, in agreement with past studies. We use likely bound stars and the precise stellar parameters from the California Kepler Survey to search for correlations between stellar binarity and planetary properties. No significant difference between the binarity fraction of single and multiple-planet systems is found, and planet hosting stars follow similar binarity trends as field stars, many of which likely host their own non-aligned planets. We find that hot Jupiters are ~4x more likely than other planets to reside in a binary star system. We correct the radius estimates of the planet candidates in characterized systems and find that for likely bound systems, the estimated planetary radii will increase on average by a factor of 1.77, if either star is equally likely to host the planet. Lastly, we find the planetary radius gap is robust to the impact of dilution.
1070. Effects of binarity in SEGUE pipeline
ID:
ivo://CDS.VizieR/J/ApJ/719/996
Title:
Effects of binarity in SEGUE pipeline
Short Name:
J/ApJ/719/996
Date:
21 Oct 2021
Publisher:
CDS
Description:
We examine the effects that unresolved binaries have on the determination of various stellar atmospheric parameters for targets from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) using numerical modeling, a grid of synthetic spectra, and the SEGUE Stellar Parameter Pipeline (SSPP). The SEGUE survey, a component of the Sloan Digital Sky Survey-II (SDSS-II) project focusing on Galactic structure, provides medium resolution spectroscopy for over 200000 stars of various spectral types over a large area on the sky. To model undetected binaries that may be in this sample, we use a variety of mass distributions for the primary and secondary stars in conjunction with empirically determined relationships for orbital parameters to determine the fraction of G-K dwarf stars, defined by SDSS color cuts as having 0.48<=(g-r)_0_<=0.75, that will be blended with a secondary companion. We focus on the G-K dwarf sample in SEGUE as it records the history of chemical enrichment in our galaxy. To determine the effect of the secondary on the spectroscopic parameters, specifically effective temperature, surface gravity, metallicity, and [{alpha}/Fe], we synthesize a grid of model spectra from 3275 to 7850K and [Fe/H]=-0.5 to -2.5 from MARCS model atmospheres using TurboSpectrum. These temperature and metallicity ranges roughly correspond to a stellar mass range of 0.1-1.0M_{sun}_. We assume that both stars in the pair have the same metallicity. We analyze both "infinite" signal-to-noise ratio (S/N) models and degraded versions of the spectra, at median S/N of 50, 25, and 10.