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4241. NEOWISE: thermal model fits for NEOs and MBAs
ID:
ivo://CDS.VizieR/J/AJ/154/168
Title:
NEOWISE: thermal model fits for NEOs and MBAs
Short Name:
J/AJ/154/168
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Near-Earth ObjectWide-field Infrared Survey Explorer (NEOWISE) reactivation mission has completed its third year of surveying the sky in the thermal infrared for near-Earth asteroids and comets. NEOWISE collects simultaneous observations at 3.4 and 4.6 {mu}m of solar system objects passing through its field of regard. These data allow for the determination of total thermal emission from bodies in the inner solar system, and thus the sizes of these objects. In this paper, we present thermal model fits of asteroid diameters for 170 NEOs and 6110 Main Belt asteroids (MBAs) detected during the third year of the survey, as well as the associated optical geometric albedos. We compare our results with previous thermal model results from NEOWISE for overlapping sample sets, as well as diameters determined through other independent methods, and find that our diameter measurements for NEOs agree to within 26% (1{sigma}) of previously measured values. Diameters for the MBAs are within 17% (1{sigma}). This brings the total number of unique near-Earth objects characterized by the NEOWISE survey to 541, surpassing the number observed during the fully cryogenic mission in 2010.
4242. NEP deep survey at 11um
ID:
ivo://CDS.VizieR/J/PASJ/59/S529
Title:
NEP deep survey at 11um
Short Name:
J/PASJ/59/S529
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the properties of 11um selected sources detected in the early data of the North Ecliptic Pole Deep (NEP-Deep) Survey of AKARI. The data set covers 6 wavelength bands from 2.5 to 11um, with exposure times of 10-20 minutes. This field lies within the CFHT survey with four filter bands (g', r', i', z'), enabling us to establish nearly continuous spectral energy distributions (SEDs) for wavelengths ranging from 0.4 to 11um. The main sample studied here consists of 72 sources whose 11um AB magnitudes are equal to or brighter than 18.5 (144uJy), which is complete to more than 90%. The 11um band has an advantage of sampling star-forming galaxies with low-to-medium redshifts, since the prominent PAH feature shifts into this band. As expected, we find that the majority (71%) of 11um bright sources are star-forming galaxies at 0.2~<z~<0.7 with L_IR_~10^10^-10^12^~L_{sun}_ based on detailed modelling of the SEDs. We also find four AGNs lying at various redshifts in the main sample. In addition, we discuss a few sources that have non-typical SEDs of the main sample, including a brown-dwarf candidate, a steep power-law source, a flat-spectrum object, and an early-type galaxy at moderate redshift.
4243. NEP source catalog
ID:
ivo://CDS.VizieR/J/ApJS/172/583
Title:
NEP source catalog
Short Name:
J/ApJS/172/583
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a five-band (u* g' r' i' z') optical photometry catalog of the sources in the North Ecliptic Pole (NEP) region based on deep observations made with MegaCam at CFHT. The source catalog covers about 2 square degree area centered at the NEP and reaches depths of about 26mag for u*, g', r' bands, about 25mag for i' band, and about 24mag for z' band (4{sigma} detection over a 1" aperture). The total number of cataloged sources brighter than r'=23mag is about 56000 including both point sources and extended sources. From the investigation of photometric properties using the color- magnitude diagrams and color-color diagrams, we have found that the colors of extended sources are mostly (u*-r')<3.0 and (g'-z')>0.5. This can be used to separate the extended sources from the point sources reliably, even for the faint source domain where typical morphological classification schemes hardly work efficiently. We have derived an empirical color-redshift relation of the red sequence galaxies using the Sloan Digital Sky Survey data. By applying this relation to our photometry catalog and searching for any spatial overdensities, we have found two galaxy clusters and one nearby galaxy group.
4244. New AY Cam Photometric Observations
ID:
ivo://CDS.VizieR/J/AJ/128/1319
Title:
New AY Cam Photometric Observations
Short Name:
J/AJ/128/1319
Date:
21 Oct 2021
Publisher:
CDS
Description:
New differential UBV photoelectric photometry for the eclipsing binary AY Cam is presented. The Wilson-Devinney program is used to simultaneously solve the three light curves together with previously published radial velocities.
4245. 6 new Beta Cep stars
ID:
ivo://CDS.VizieR/J/A+A/361/245
Title:
6 new Beta Cep stars
Short Name:
J/A+A/361/245
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present ground-based follow-up photometry in the Geneva seven-colour photometric system of six new {beta} Cep stars. The variability of these objects was originally found from the HIPPARCOS mission. The new data provided here allowed us to confirm their {beta} Cep-type nature, to detect the pulsational frequencies and to identify the degrees of the pulsation modes. For definitions of the Geneva photometric system, see <GCPD/13>.
4246. New {beta} Cep stars in NGC 637
ID:
ivo://CDS.VizieR/J/A+A/533/A70
Title:
New {beta} Cep stars in NGC 637
Short Name:
J/A+A/533/A70
Date:
21 Oct 2021
Publisher:
CDS
Description:
Studying stellar pulsations in open clusters offers the possibility of performing ensemble asteroseismology. The reasonable assumption that the cluster members have the same age, distance, and overall metallicity aids in the seismic modelling process and tightly constrains it. Therefore it is important to identify open clusters with many pulsators. New pulsating stars of the beta Cephei type were searched for among the members of the open cluster NGC 637. Thirty-one hours of time-resolved V filter CCD photometry were obtained. The measurements confirmed two previously known variables, and revealed three new beta Cephei stars and one more candidate. All four pulsators have sufficiently large amplitudes for easy mode identification and are multiperiodic. With four certain pulsating members, NGC 637 is now among the open clusters that are richest in beta Cephei stars. It is thus an excellent target for ensemble asteroseismology, and to examine the differences between pulsating and apparently constant stars in the beta Cephei domain.
4247. New beta Lyrae and Algol candidates in NSVS
ID:
ivo://CDS.VizieR/J/AJ/136/1067
Title:
New beta Lyrae and Algol candidates in NSVS
Short Name:
J/AJ/136/1067
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have classified 409 objects in the Northern Sky Variability Survey (NSVS) as new beta Lyrae or Algol-type eclipsing binaries. These candidates have outside of eclipse magnitudes of ~10-13. Through automated Fourier analysis routines and some manual inspection, we list the period, eclipse depths, coordinates, an estimate of the time of primary eclipse, and the 2MASS colors for these candidates. This list of new beta Lyrae type candidates greatly increases the number of known systems of this type. We have also identified 37 candidate low-mass, main-sequence pairs (M_1,2_<1M_{sun}_,T<5500K) in the NSVS database. If confirmed, these systems will greatly increase the number of such low-mass systems known as well as help constrain atmospheric models for these types of stars.
4248. New binaries in the {epsilon} Cha association
ID:
ivo://CDS.VizieR/J/AJ/154/195
Title:
New binaries in the {epsilon} Cha association
Short Name:
J/AJ/154/195
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present Adaptive Optics-aided speckle observations of 47 young stars in the {epsilon} Cha association made at the 4 m Southern Astrophysical Research Telescope in the I-band. We resolved 10 new binary pairs, 5 previously known binaries, and 2 triple systems, also previously known. In the separation range between 4 and 300 au, the 30 association members of spectral types G0 and later host 6 binary companions, leading to the raw companion frequency of 0.010+/-0.04 per decade of separation, comparable to the main sequence dwarfs in the field. On the other hand, all five massive association members of spectral types A and B have companions in this range. We discuss the newly resolved and known binaries in our sample. Observed motions in the triple system {epsilon} Cha, composed of three similar B9V stars, can be described by tentative orbits with periods 13 and ~900 years and a large mutual inclination.
4249. New brown dwarf discs in Upper Scorpius
ID:
ivo://CDS.VizieR/J/MNRAS/429/903
Title:
New brown dwarf discs in Upper Scorpius
Short Name:
J/MNRAS/429/903
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a census of the disc population for UKIDSS selected brown dwarfs in the 5-10Myr old Upper Scorpius OB association. For 116 objects originally identified in UKIDSS, the majority of them not studied in previous publications, we obtain photometry from the Wide-Field Infrared Survey Explorer data base. The resulting colour-magnitude and colour-colour plots clearly show two separate populations of objects, interpreted as brown dwarfs with discs (class II) and without discs (class III). We identify 27 class II brown dwarfs, 14 of them not previously known. This disc fraction (27 out of 116, or 23%) among brown dwarfs was found to be similar to results for K/M stars in Upper Scorpius, suggesting that the lifetimes of discs are independent of the mass of the central object for low-mass stars and brown dwarfs. 5 out of 27 discs (19%) lack excess at 3.4 and 4.6{mu}m and are potential transition discs (i.e. are in transition from class II to class III). The transition disc fraction is comparable to low-mass stars. We estimate that the time-scale for a typical transition from class II to class III is less than 0.4Myr for brown dwarfs. These results suggest that the evolution of brown dwarf discs mirrors the behaviour of discs around low-mass stars, with disc lifetimes of the order of 5-10Myr and a disc clearing time-scale significantly shorter than 1Myr.
4250. 15 new brown dwarfs in Orion OB1a/25 Ori group
ID:
ivo://CDS.VizieR/J/MNRAS/450/3490
Title:
15 new brown dwarfs in Orion OB1a/25 Ori group
Short Name:
J/MNRAS/450/3490
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a study of 15 new brown dwarfs belonging to the ~7Myr old 25 Orionis group and Orion OB1a subassociation with spectral types between M6 and M9 and estimated masses between ~0.07 and ~0.01M_{sun}_. By comparing them through a Bayesian method with low-mass stars (0.8<~M/M_{sun}_ <~0.1) from previous works in the 25 Orionis group, we found statistically significant differences in the number fraction of classical T Tauri stars, Weak T Tauri stars, class II, evolved discs and purely photospheric emitters at both sides of the substellar mass limit. Particularly, we found a fraction of 3.9^+2.4^_-1.6_ percent low-mass stars classified as Classic T Tauri star and class II or evolved discs, against a fraction of 33.3^+10.8^_-9.8_ percent in the substellar mass domain. Our results support the suggested scenario in which the dissipation of discs is less efficient for decreasing mass of the central object.