Search

Start Over Capability Type Simple Cone Search
14661. Stars in Sculptor dwarf spheroidal galaxy
ID:
ivo://CDS.VizieR/J/AJ/110/2747
Title:
Stars in Sculptor dwarf spheroidal galaxy
Short Name:
J/AJ/110/2747
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using 26 plates taken over the course of more than half a century, we present proper motions and photometry for 1177 stars in the central region of the Sculptor dwarf spheroidal galaxy, down to a limiting magnitude of V~20.25 at the level of the horizontal branch. The proper-motion cleaned color-magnitude diagram retained a broad giant branch, further supporting an intrinsic spread in metallicity. We determined an absolute proper motion for Sculptor, relative to background galaxies, of mu_alpha=+0.036+/-0.022arcsec/century and mu_delta=0.043+/-0.025arcsec/century after correcting for the LSR and peculiar solar motions. Our proper-motion uncertainty is similar to or smaller than those obtained by different groups for other distant satellites of the Galaxy. When combined with Sculptor's distance and radial velocity, this measurement shows the dwarf spheroidal to have a space velocity of roughly 220+/-125km/s. Although our measurement is less than twice its uncertainty, the direction of Sculptor's motion is significant because it rules out motion along the Magellanic Stream. A 2.5 sigma error allows for motion in a direction toward the Fornax dwarf spheroidal galaxy, so Sculptor remains a possible member of the proposed Fornax-Leo-Sculptor stream.
14662. Stars in the Carina dSph galaxy field
ID:
ivo://CDS.VizieR/J/AJ/130/2677
Title:
Stars in the Carina dSph galaxy field
Short Name:
J/AJ/130/2677
Date:
21 Oct 2021
Publisher:
CDS
Description:
The question of the existence of active and prominent tidal disruption around various Galactic dwarf spheroidal (dSph) galaxies remains controversial. That debate often centers on the nature (bound vs. unbound) of extended populations of stars claimed to lie outside the bounds of single King profiles fitted to the density distributions of dSph centers. However, the more fundamental issue of the very existence of the previously reported extended populations is still contentious. We present a critical evaluation of the debate centering on one particular dSph, Carina, for which claims both for and against the existence of stars beyond the King limiting radius have been made.
14663. Stars in the Carina dwarf spheroidal galaxy
ID:
ivo://CDS.VizieR/J/AJ/131/895
Title:
Stars in the Carina dwarf spheroidal galaxy
Short Name:
J/AJ/131/895
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Carina dwarf spheroidal galaxy is the only galaxy of this type that shows clearly episodic star formation separated by long pauses. Here we present metallicities for 437 radial velocity members of this Galactic satellite. The metallicities and radial velocities were measured as part of a Large Programme with the Very Large Telescope at the European Southern Observatory, Chile. We obtained medium-resolution spectroscopy with the multiobject spectrograph FLAMES. Our target red giants cover the entire projected surface area of Carina. Our spectra are centered at the near-infrared CaII triplet, which is a well-established metallicity indicator for old and intermediate-age red giants. The resulting data sample provides the largest collection of spectroscopically derived metallicities for a Local Group dwarf spheroidal galaxy to date.
14664. Stars in the dark cloud L1251
ID:
ivo://CDS.VizieR/J/A+A/272/235
Title:
Stars in the dark cloud L1251
Short Name:
J/A+A/272/235
Date:
21 Oct 2021
Publisher:
CDS
Description:
The distance of the dark cloud L1251 was estimated from observations made at the Konkoly Observatory between 1985 and 1991. The spectral classification and the H{alpha} emission features were measured on objective-prism plates taken with the 60/80/180 Schmidt telescope; the photometry was derived from observations made on photographic plates with emulsion-filter combinations giving magnitudes in the Johnson photometric system. The distance of the cloud was found to be 300+/-50pc.
14665. Stars in the Sagittarius Rift
ID:
ivo://CDS.VizieR/J/AJ/130/2701
Title:
Stars in the Sagittarius Rift
Short Name:
J/AJ/130/2701
Date:
21 Oct 2021
Publisher:
CDS
Description:
A magnitude-limited photographic survey of relative proper-motion components and B, V photometry of 1.3x10^6^ stars brighter than apparent B magnitude 14.5+/-0.5 in the fourth Galactic quadrant is converted into a distance-limited survey of 3.26x10^5^ stars up to a distance of 500pc. A streaming motion of 13.5+/-0.5 km/s is detected in 4.1x10^4^ Population I stellar candidates with an orbital perigalactic center located at 6.8<=R<=7.2kpc, with a Sun location Rsol=8.5 kpc. A density perturbation of about 0.1M{sun}/pc^3^ in the Galactic field potential at Ro~6.8kpc is interpreted as resulting from the density wave connected with the Sagittarius-Carina spiral arm. A set of 1.4x10^4^ stars of mass about 1.5+/-0.75 M{sun} identify a pitch angle of 10+/-1{deg} and a migration time from the Sagittarius spiral arm into the greater solar neighborhood of about 35Myr.
14666. Stars in the solar region
ID:
ivo://CDS.VizieR/J/AJ/115/2397
Title:
Stars in the solar region
Short Name:
J/AJ/115/2397
Date:
21 Oct 2021
Publisher:
CDS
Description:
Several samples of nearby stars with the most accurate astrometric and photometric parameters are searched for clues to their evolutionary history. The main samples are (1) the main-sequence stars with b-y between 0.29 and 0.59mag (F3 to K1) in the Yale parallax catalog, (2) a group of high-velocity subgiants studied spectroscopically by Ryan & Lambert (1995AJ....109.2068R), and (3) high-velocity main-sequence stars in the extensive investigation by Norris, Bessel, & Pickles (1985ApJS...58..463N). The major conclusions are as follows: (1) The oldest stars (halo), t>=10-12Gyr, have V-velocities (in the direction of Galactic rotation and referred to the Sun) in the range from about -50 to -800km/s and have a heavy-element abundance [Fe/H] of less than about -0.8dex. The age range of these objects depends on our knowledge of globular cluster ages, but if age is correlated with V-velocity, the youngest may be M22 and M28 (V~-50km/s) and the oldest NGC 3201 (V~-500km/s) and assorted field stars. (2) The old disk population covers the large age range from about 2Gyr (Hyades, NGC 752) to 10 or 12Gyr (Arcturus group, 47 Tuc), but the lag (V) velocity is restricted to less than about 120km/s and [Fe/H]>=-0.8 or -0.9dex. The [Fe/H]~-0.8dex division between halo and old disk, near t~10-12Gyr, is marked by a change in the character of the CN index (Cm) and of the blanketing parameter K of the DDO photometry. (3) The young disk population, t<2Gyr, is confined exclusively to a well-defined area of the (U, V) velocity plane. The age separating young and old disk stars is also that separating giant evolution of the Hyades (near main-sequence luminosity) and M67 (degenerate helium cores and a large luminosity rise) kinds. The two disk populations are also separated by such indexes as the g-index of Geveva photometry. There appears to be no obvious need to invoke exogeneous influences to understand the motion and heavy-element abundance distributions of the best-observed stars near the Sun. Individual stars of special interest include the parallax star HD 55575, which may be an equal-component binary, and the high-velocity star HD 220127, with a well-determined space velocity near 1000km/s.
14667. Stars nearby Robo-AO Kepler planetary candidates
ID:
ivo://CDS.VizieR/J/AJ/155/161
Title:
Stars nearby Robo-AO Kepler planetary candidates
Short Name:
J/AJ/155/161
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the overall statistical results from the Robo-AO Kepler planetary candidate survey, comprising of 3857 high-angular resolution observations of planetary candidate systems with Robo-AO, an automated laser adaptive optics system. These observations reveal previously unknown nearby stars blended with the planetary candidate host stars that alter the derived planetary radii or may be the source of an astrophysical false positive transit signal. In the first three papers in the survey, we detected 440 nearby stars around 3313 planetary candidate host stars. In this paper, we present observations of 532 planetary candidate host stars, detecting 94 companions around 88 stars; 84 of these companions have not previously been observed in high resolution. We also report 50 more-widely separated companions near 715 targets previously observed by Robo-AO. We derive corrected planetary radius estimates for the 814 planetary candidates in systems with a detected nearby star. If planetary candidates are equally likely to orbit the primary or secondary star, the radius estimates for planetary candidates in systems with likely bound nearby stars increase by a factor of 1.54, on average. We find that 35 previously believed rocky planet candidates are likely not rocky due to the presence of nearby stars. From the combined data sets from the complete Robo-AO KOI survey, we find that 14.5+/-0.5% of planetary candidate hosts have a nearby star with 4", while 1.2% have two nearby stars, and 0.08% have three. We find that 16% of Earth-sized, 13% of Neptune-sized, 14% of Saturn-sized, and 19% of Jupiter-sized planet candidates have detected nearby stars.
14668. Stars observed with Doppler imaging
ID:
ivo://CDS.VizieR/J/other/A+ARV/17.251
Title:
Stars observed with Doppler imaging
Short Name:
J/other/A+ARV/17
Date:
21 Oct 2021
Publisher:
CDS
Description:
Starspots are created by local magnetic fields on the surfaces of stars, just as sunspots. Their fields are strong enough to suppress the overturning convective motion and thus block or redirect the flow of energy from the stellar interior outwards to the surface and consequently appear as locally cool and therefore dark regions against an otherwise bright photosphere. This article is an attempt to review our current knowledge of starspots.
14669. Stars of very low metal abundance
ID:
ivo://CDS.VizieR/J/AJ/103/1987
Title:
Stars of very low metal abundance
Short Name:
J/AJ/103/1987
Date:
21 Oct 2021
Publisher:
CDS
Description:
Spectroscopic observations for 1044 stars located primarily in the southern Galactic hemisphere are reported; the stars were chosen from a list of candidate metal-deficient stars discovered in the HK objective-prism survey. Radial velocities and line indices based on the equivalent widths of Ca II, K, H-gamma and H-delta, and the CH G band are reported. Estimates of metallicity for 874 stars with derived abundances less than -0.5 are presented.
14670. Stars of very low metal abundance. I
ID:
ivo://CDS.VizieR/J/AJ/90/2089
Title:
Stars of very low metal abundance. I
Short Name:
J/AJ/90/2089
Date:
21 Oct 2021
Publisher:
CDS
Description:
An objective-prism and a narrowband interference filter have been used in combination on the Curtis Schmidt telescope at CTIO to conduct a search for extremely metal-poor stars. The filter restricts the bandpass to the region around the H and K lines of CaII; the metal-poor candidates are those stars with weak or absent H and K. Slit spectra (1 A resolution) of some 450 candidates are used to measure equivalent widths of the CaII K line and Balmer features. A calibration of the K-line strength for giants in the metal-poor globular cluster NGC 6397 and field dwarfs and giants of known metallicity is used to identify survey candidates with metal abundance [Fe/H]<=-2.0; a list of 134 such stars is presented. UBV photometry is used to distinguish between two groups of metal-poor stars: a group with objects near the main-sequence turnoff, on the subgiant branch, and on the giant branch; and a second group with objects on the red horizontal branch (RHB) and asymptotic giant branch (AGB). The RHB-AGB stars exhibit the well-known weak G-band effect; three CH-strong objects are identified among the subgiants.

Limit your search

more »

more »

more »

more »

more »

more »