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23431. UV Variations in spectrum of Abell 35 c.star
ID:
ivo://CDS.VizieR/J/A+A/287/591
Title:
UV Variations in spectrum of Abell 35 c.star
Short Name:
J/A+A/287/591
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
23432. UV, VIH photometry of NGC 1311
ID:
ivo://CDS.VizieR/J/AJ/140/1137
Title:
UV, VIH photometry of NGC 1311
Short Name:
J/AJ/140/1137
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have extracted point-spread-function-fitted stellar photometry from near-ultraviolet, optical, and near-infrared images, obtained with the Hubble Space Telescope, of the nearby (D~5.5Mpc) SBm galaxy NGC 1311. The ultraviolet and optical data reveal a population of hot main-sequence (MS) stars with ages of 2-10Myr. We also find populations of blue supergiants with ages between 10 and 40Myr and red supergiants with ages between 10 and 100Myr.
23433. UV/X-ray activity of M dwarfs within 10pc
ID:
ivo://CDS.VizieR/J/MNRAS/431/2063
Title:
UV/X-ray activity of M dwarfs within 10pc
Short Name:
J/MNRAS/431/2063
Date:
21 Oct 2021
Publisher:
CDS
Description:
M dwarfs are the most numerous stars in the Galaxy. They are characterized by strong magnetic activity. The ensuing high-energy emission is crucial for the evolution of their planets and the eventual presence of life on them. We systematically study the X-ray and ultraviolet emission of a subsample of M dwarfs from a recent proper-motion survey, selecting all M dwarfs within 10pc to obtain a nearly volume-limited sample (~90 percent completeness). Archival ROSAT, XMM-Newton and GALEX data are combined with published spectroscopic studies of H{alpha} emission and rotation to obtain a broad picture of stellar activity on M dwarfs. We make use of synthetic model spectra to determine the relative contributions of photospheric and chromospheric emission to the ultraviolet flux. We also analyse the same diagnostics for a comparison sample of young M dwarfs in the TW Hya association (~10Myr). We find that generally the emission in the GALEX bands is dominated by the chromosphere but the photospheric component is not negligible in early-M field dwarfs. The surface fluxes for the H{alpha}, near-ultraviolet, far-ultraviolet and X-ray emission are connected via a power-law dependence. We present here for the first time such flux-flux relations involving broad-band ultraviolet emission for M dwarfs. Activity indices are defined as flux ratio between the activity diagnostic and the bolometric flux of the star in analogy to the CaII R'HK index. For given spectral type, these indices display a spread of 2-3dex which is largest for M4 stars. Strikingly, at mid-M spectral types, the spread of rotation rates is also at its highest level. The mean activity index for fast rotators, likely representing the saturation level, decreases from X-rays over the FUV to the NUV band and H{alpha}, i.e. the fractional radiation output increases with atmospheric height. The comparison to the ultraviolet and X-ray properties of TWHya members shows a drop of nearly three orders of magnitude for the luminosity in these bands between ~10Myr and few Gyr age. A few young field dwarfs (<1Gyr) in the 10-pc sample bridge the gap indicating that the drop in magnetic activity with age is a continuous process. The slope of the age decay is steeper for the X-ray than for the UV luminosity.
23434. UV/X-Ray Data for M Dwarfs Within 10 Parsecs
ID:
ivo://nasa.heasarc/mdwf10pcux
Title:
UV/X-Ray Data for M Dwarfs Within 10 Parsecs
Short Name:
MDWF10PCUX
Date:
21 Feb 2025
Publisher:
NASA/GSFC HEASARC
Description:
M dwarfs are the most numerous stars in the galaxy. They are characterized by strong magnetic activity. The ensuing high-energy emission is crucial for the evolution of their planets and the eventual presence of life on them. The authors systematically study the X-ray and ultraviolet emission of a subsample of M dwarfs from a recent proper-motion survey, selecting all M dwarfs within 10 pc to obtain a nearly volume-limited sample (~90% completeness). Archival ROSAT, XMM-Newton and GALEX data are combined with published spectroscopic studies of H-alpha emission and rotation to obtain a broad picture of stellar activity on M dwarfs. The authors make use of synthetic model spectra to determine the relative contributions of photospheric and chromospheric emission to the ultraviolet flux. They also analyze the same diagnostics for a comparison sample of young M dwarfs in the TW Hya association (~10 Myr old). The authors find that generally the emission in the GALEX bands is dominated by the chromosphere but the photospheric component is not negligible in early-M field dwarfs. The surface fluxes for the H-alpha, near-ultraviolet, far-ultraviolet and X-ray emission are connected via a power-law dependence. The authors present in the reference paper for the first time such flux-flux relations involving broad-band ultraviolet emission for M dwarfs. Activity indices are defined as the flux ratios between the activity diagnostics and the bolometric flux of the star in analogy to the Ca II R&#39;(HK) index. For a given spectral type, these indices display a spread of 2-3 dex which is largest for M4-type stars. Strikingly, at mid-M spectral types, the spread of rotation rates is also at its highest level. The mean activity index for fast rotators, likely representing the saturation level, decreases from X-rays over the FUV to the NUV band and H-alpha, i.e. the fractional radiation output increases with atmospheric height. The comparison to the ultraviolet and X-ray properties of TW Hya members shows a drop of nearly three orders of magnitude for the luminosity in these bands between ~10 Myr and a few Gyr age. A few young field dwarfs (&lt;1 Gyr) in the 10-pc sample bridge the gap indicating that the drop in magnetic activity with age is a continuous process. The slope of the age decay is steeper for the X-ray than for the UV luminosity. This sample is based on the All-Sky Catalog of bright M dwarfs published by Lepine &amp; Gaidos (2011, AJ, 142, 138, &lt;a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/142/138"&gt;CDS Cat. J/AJ/142/138&lt;/a&gt;, available at the HEASARC as the MDWARFASC table). The authors selected all 163 stars from this reference that are within 10pc. Four of these stars that were discovered to be actually late K-type stars were removed from this initial sample, leaving a final sample of 159 stars. This table was created by the HEASARC in July 2017 based upon &lt;a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/431/2063"&gt;CDS Catalog J/MNRAS/431/2063&lt;/a&gt; files table1.dat and table2.dat. The positions of the stars were not explicitly given in these tables, but were taken by the HEASARC from the All-Sky Catalog of Bright M Dwarfs published by Lepine &amp; Gaidos (2011, AJ, 142, 138, &lt;a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/142/138"&gt;CDS Cat. J/AJ/142/138&lt;/a&gt;, available at the HEASARC as the MDWARFASC table). The version of Table 2 used by the HEASARC is the corrected one given in the Erratum (Stelzer et al. 2014) rather than the version given in the original paper (Stelzer et al. 2013). This is a service provided by NASA HEASARC .
23435. UWISH2 extended H2 emission line sources
ID:
ivo://CDS.VizieR/J/MNRAS/454/2586
Title:
UWISH2 extended H2 emission line sources
Short Name:
J/MNRAS/454/2586
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the extended source catalogue for the UKIRT Wide Field Infrared Survey for H2 (UWISH2). The survey is unbiased along the inner Galactic Plane from l~357{deg} to l~65{deg} and |b|<=1.5{deg} and covers 209deg^2^. A further 42.0 and 35.5deg^2^ of high dust column density regions have been targeted in Cygnus and Auriga. We have identified 33200 individual extended H_2_ features. They have been classified to be associated with about 700 groups of jets and outflows, 284 individual (candidate) planetary nebulae, 30 supernova remnants and about 1300 photodissociation regions. We find a clear decline of star formation activity (traced by H_2_ emission from jets and photodissociation regions) with increasing distance from the Galactic Centre. About 60 percent of the detected candidate planetary nebulae have no known counterpart and 25 percent of all supernova remnants have detectable H_2_ emission associated with them.
23436. UY UMa and EF Boo compiled time of minima
ID:
ivo://CDS.VizieR/J/other/NewA/55.13
Title:
UY UMa and EF Boo compiled time of minima
Short Name:
J/other/NewA/55.
Date:
21 Oct 2021
Publisher:
CDS
Description:
The orbital period variations of two W UMa-type contact binaries, UY UMa and EF Boo, are analyzed by using all available times of light minimum. It is detected that the general trends of their (O-C) curves show an upward parabolic variation, which reveals their continuous period increases at the rates of dP/dt=2.545x10^-7^days/yr and dP/dt=2.623x10^-7^days/yr respectively. Meanwhile, UY UMa also shows a cyclic period variation with a small amplitude of A=0.0026-days superposed on the long-term increase. Due to their contact configurations, the secular period increases are interpreted as a result of mass transfer from the less massive component to the more massive one. The cyclic period variation of UY UMa may be interpreted in terms of either the magnetic activity or the light time effect.
23437. uz,vz,bz,yz photometry in Coma cluster
ID:
ivo://CDS.VizieR/J/AJ/124/3061
Title:
uz,vz,bz,yz photometry in Coma cluster
Short Name:
J/AJ/124/3061
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have observed three fields of the Coma Cluster of galaxies with a narrowband (modified Stroemgren) filter system. Observed galaxies include 31 in the vicinity of NGC 4889, 48 near NGC 4874, and 60 near NGC 4839, complete to M_5500_=-18 in all three subclusters. Spectrophotometric classification finds all three subclusters of Coma to be dominated by red, E-type (elliptical/S0) galaxies with a mean blue fraction, f_B_, of 0.10.
23438. Vacuum ultraviolet emission band systems of N2
ID:
ivo://CDS.VizieR/J/A+AS/128/361
Title:
Vacuum ultraviolet emission band systems of N2
Short Name:
J/A+AS/128/361
Date:
21 Oct 2021
Publisher:
CDS
Description:
Observed wavenumbers of the emission lines belonging to 10 vacuum ultraviolet band systems of molecular nitrogen are classified into 283 bands, 220 of them reported for the first time
23439. Validated & new members of NGC 7000/IC 5070 Complex
ID:
ivo://CDS.VizieR/J/ApJ/899/128
Title:
Validated & new members of NGC 7000/IC 5070 Complex
Short Name:
J/ApJ/899/128
Date:
14 Mar 2022 07:05:45
Publisher:
CDS
Description:
We examine the clustering and kinematics of young stellar objects (YSOs) in the North America/Pelican Nebulae, as revealed by Gaia astrometry, in relation to the structure and motions of the molecular gas, as indicated in molecular-line maps. The Gaia parallaxes and proper motions allow us to significantly refine previously published lists of YSOs, demonstrating that many of the objects previously thought to form a distributed population turn out to be nonmembers. The members are subdivided into at least six spatio-kinematic groups, each of which is associated with its own molecular cloud component or components. Three of the groups are expanding, with velocity gradients of 0.3-0.5km/s/pc, up to maximum velocities of ~8km/s away from the groups' centers. The two known O-type stars associated with the region, 2MASS J20555125+4352246 and HD 199579, are rapidly escaping one of these groups, following the same position-velocity relation as the low-mass stars. We calculate that a combination of gas expulsion and tidal forces from the clumpy distribution of molecular gas could impart the observed velocity gradients within the groups. However, on a global scale, the relative motions of the groups do not appear either divergent or convergent. The velocity dispersion of the whole system is consistent with the kinetic energy gained due to gravitational collapse of the complex. Most of the stellar population has ages similar to the freefall timescales for the natal clouds. Thus, we suggest the nearly freefall collapse of a turbulent molecular cloud as the most likely scenario for star formation in this complex.
23440. 44 validated planets from K2 Campaign 10
ID:
ivo://CDS.VizieR/J/AJ/156/78
Title:
44 validated planets from K2 Campaign 10
Short Name:
J/AJ/156/78
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present 44 validated planets from the 10th observing campaign of the NASA K2 mission, as well as high-resolution spectroscopy and speckle imaging follow-up observations. These 44 planets come from an initial set of 72 vetted candidates, which we subjected to a validation process incorporating pixel-level analyses, light curve analyses, observational constraints, and statistical false positive probabilities. Our validated planet sample has median values of R_p_=2.2 R_{Earth}_, P_orb_=6.9 days, T_eq_=890 K, and J=11.2 mag. Of particular interest are four ultra-short period planets (P_orb_~<1 day), 16 planets smaller than 2 R_{Earth}_, and two planets with large predicted amplitude atmospheric transmission features orbiting infrared-bright stars. We also present 27 planet candidates, most of which are likely to be real and worthy of further observations. Our validated planet sample includes 24 new discoveries and has enhanced the number of currently known super-Earths (R_p_~1-2 R_{Earth}_), sub-Neptunes (R_p_~2-4 R_{Earth}_), and sub-Saturns (R_p_~4-8 R_{Earth}_) orbiting bright stars (J=8-10 mag) by ~4%, ~17%, and ~11%, respectively.

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