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2661. Hot Stuff for One Year (HSOY)
ID:
ivo://CDS.VizieR/I/339
Title:
Hot Stuff for One Year (HSOY)
Short Name:
I/339
Date:
21 Oct 2021
Publisher:
CDS
Description:
Recently, the first installment of data from ESA's Gaia astrometric satellite mission (Gaia DR1) was released, containing positions of more than 1 billion stars with unprecedented precision, as well as proper motions and parallaxes, however only for a subset of 2 million objects. The second release will include those quantities for most objects. In order to provide a dataset that bridges the time gap between the Gaia DR1 and Gaia DR2 releases and partly remedies the lack of proper motions in the former, HSOY ("Hot Stuff for One Year") was created as a hybrid catalog between Gaia and ground-based astrometry, featuring proper motions (but no parallaxes) for a large fraction of the DR1 objects. While not attempting to compete with future Gaia releases in terms of data quality or number of objects, the aim of HSOY is to provide improved proper motions partly based on Gaia data, allowing studies to be carried out just now or as pilot studies for later projects requiring higher-precision data. The HSOY catalog was compiled using the positions taken from Gaia DR1 combined with the input data from the PPMXL catalog, employing the same weighted least-squares technique that was used to assemble the PPMXL catalog itself. This effect resulted in a four-parameter astrometric catalog containing 583 million stars, with Gaia DR1 quality positions and proper motions with precisions from far less than 1 mas/yr to 5 mas/yr, depending on object brightness and location on the sky.
2662. Hot subdwarf binaries from MUCHFUSS
ID:
ivo://CDS.VizieR/J/A+A/576/A44
Title:
Hot subdwarf binaries from MUCHFUSS
Short Name:
J/A+A/576/A44
Date:
21 Oct 2021
Publisher:
CDS
Description:
The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions like massive white dwarfs (M>1.0M_{sun}_), neutron stars, or stellar-mass black holes. The existence of such systems is predicted by binary evolution theory, and recent discoveries indicate that they exist in our Galaxy. We present orbital and atmospheric parameters and put constraints on the nature of the companions of 12 close hot subdwarf B star (sdB) binaries found in the course of the MUCHFUSS project. The systems show periods between 0.14 and 7.4days. In nine cases the nature of the companions cannot be constrained unambiguously whereas three systems most likely have white dwarf companions. We find that the companion to SDSSJ083006.17+475150.3 is likely to be a rare example of a low-mass helium-core white dwarf. SDSSJ095101.28+034757.0 shows an excess in the infrared that probably originates from a third companion in a wide orbit, which makes this system the second candidate hierarchical triple system containing an sdB star. SDSSJ113241.58-063652.8 is the first helium deficient sdO star with a confirmed close companion. This study brings to 142 the number of sdB binaries with orbital periods of less than 30 days and with measured mass functions. We present an analysis of the minimum companion mass distribution and show that it is bimodal. One peak around 0.1M_{sun}_ corresponds to the low-mass main sequence (dM) and substellar companions. The other peak around 0.4M_{sun}_ corresponds to the white dwarf companions. The derived masses for the white dwarf companions are significantly lower than the average mass for single carbon-oxygen white dwarfs. In a T_eff_-logg diagram of sdB+dM companions, we find signs that the sdB components are more massive than the rest of the sample. The full sample was compared to the known population of extremely low-mass white dwarf binaries as well as short-period white dwarfs with main sequence companions. Both samples show a significantly different companion mass distribution indicating either different selection effects or different evolutionary paths. We identified 16 systems where the dM companion will fill its Roche Lobe within a Hubble time and will evolve into a cataclysmic variable; two of them will have a brown dwarf as donor star. Twelve systems with confirmed white dwarf companions will merge within a Hubble time, two of them having a mass ratio to evolve into a stable AMCVn-type binary and another two which are potential supernova Ia progenitor systems. The remaining eight systems will most likely merge and form RCrB stars or massive C/O white dwarfs depending on the structure of the white dwarf companion.
2663. Hot subdwarf stars from Gaia DR2 and LAMOST DR5
ID:
ivo://CDS.VizieR/J/ApJ/868/70
Title:
Hot subdwarf stars from Gaia DR2 and LAMOST DR5
Short Name:
J/ApJ/868/70
Date:
21 Oct 2021
Publisher:
CDS
Description:
We selected 4593 hot subdwarf candidates from the Gaia DR2 Hertzsprung-Russell (HR) diagram. By combining the sample with Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) DR5, we identified 294 hot subdwarf stars, including 169 sdB, 63 sdOB, 31 He-sdOB, 22 sdO, 7 He-sdO, and 2 He-sdB stars. The atmospheric parameters (e.g., Teff, logg, log(nHe/nH)) are obtained by fitting the hydrogen (H) and helium (He) line profiles with synthetic spectra. Two distinct He sequences of hot subdwarf stars are clearly presented in the Teff-logg diagram. We found that the He-rich sequence consists of the bulk of sdB and sdOB stars, as well as all of the He-sdB, He-sdO, and He-sdOB stars in our samples, while all the stars in the He-weak sequence belong to the sdO spectral type, combined with a few sdB and sdOB stars. We demonstrated that the combination of Gaia DR2 and LAMOST DR5 allows one to uncover a huge number of new hot subdwarf stars in our Galaxy.
2664. Hot subdwarf stars in rejected PG catalog
ID:
ivo://CDS.VizieR/J/AJ/138/606
Title:
Hot subdwarf stars in rejected PG catalog
Short Name:
J/AJ/138/606
Date:
21 Oct 2021
Publisher:
CDS
Description:
The hot subdwarf (sd) stars in the Palomar Green (PG) catalog of ultraviolet excess (UVX) objects play a key role in investigations of the frequency and types of binary companions and the distribution of orbital periods. These are important for establishing whether and by which channels the sd stars arise from interactions in close binary systems. It has been suggested that the list of PG sd stars is biased by the exclusion of many stars in binaries, whose spectra show the CaII K line in absorption. A total of 1125 objects that were photometrically selected as candidates were ultimately rejected from the final PG catalog using this K-line criterion. We study 88 of these "PG-Rejects" (PGRs), to assess whether there are significant numbers of unrecognized sd stars in binaries among the PGR objects.
2665. Hot variable stars in NGC 330
ID:
ivo://CDS.VizieR/J/AJ/135/1350
Title:
Hot variable stars in NGC 330
Short Name:
J/AJ/135/1350
Date:
21 Oct 2021
Publisher:
CDS
Description:
In a sample of 150 hot stars in NGC 330, a SMC cluster containing a high fraction of Be stars, we searched for photometric variables using OGLE II data. At least one third of all stars are variable, with 38 being periodic. We found 27 pulsators ({lambda} Eri variables), six eclipsing systems, two bursting sources, and several stars with unusual photometric behavior. Pulsations are present in ~30% of known Be stars, and they are long lived, lasting more than a decade. The strongest pulsators are associated with stars evolved from the main sequence.
2666. HPF RVs and TESS photometry of TOI-1266
ID:
ivo://CDS.VizieR/J/AJ/160/259
Title:
HPF RVs and TESS photometry of TOI-1266
Short Name:
J/AJ/160/259
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on the validation of two planets orbiting the nearby (36pc) M2 dwarf TOI-1266 observed by the TESS mission. This system is one of a few M dwarf multiplanet systems with close-in planets where the inner planet is substantially larger than the outer planet. The inner planet is sub-Neptune-sized (R=2.46{+/-}0.08R{Earth}) with an orbital period of 10.9days, while the outer planet has a radius of 1.67_-0.11_^+0.09^R{Earth} and resides in the exoplanet radius valley-the transition region between rocky and gaseous planets. With an orbital period of 18.8days, the outer planet receives an insolation flux of 2.4 times that of Earth, similar to the insolation of Venus. Using precision near-infrared radial velocities with the Habitable-zone Planet Finder Spectrograph, we place upper mass limits of 15.9 and 6.4M{Earth} at 95% confidence for the inner and outer planet, respectively. A more precise mass constraint of both planets, achievable with current radial velocity instruments given the host star brightness (V=12.9, J=9.7), will yield further insights into the dominant processes sculpting the exoplanet radius valley.
2667. HR 7355 differential BV light curves
ID:
ivo://CDS.VizieR/J/A+A/511/L7
Title:
HR 7355 differential BV light curves
Short Name:
J/A+A/511/L7
Date:
21 Oct 2021
Publisher:
CDS
Description:
Strong meridional mixing induced by rapid rotation is one reason why all hot main-sequence stars are not chemically peculiar. However, the finding that the He-strong CP star HR 7355 is a rapid rotator complicates this concept. Our goal is to explain the observed behaviour of HR 7355 based on period analysis of all available photometry. Over two years, we acquired 114 new BV observations of HR 7355 at observatories in Arizona, U.S.A and Cape Town, South Africa. We performed period analyses of the new observations along with new analyses of 732 archival measurements from the Hipparcos and ASAS projects. We find that the light curves of HR 7355 in various filters are quite similar, with amplitudes 0.035(4), 0.036(4), and 0.038(3) mag in B, Hp, and V, respectively. The light curves are double-peaked, with unevenly deep minima. We substantially refine the rotational period to be P=0.5214410(4)d, indicating that HR 7355 is the most rapidly rotating CP star known. Our period analyses reveal a possible lengthening of the rotational period with (dP/dt)/P=2.4(8)x10^-6^yr^-1^. We conclude that the shape and amplitude of HR 7355 light curves are typical of magnetic He-strong CP stars, for which light variations are the result of photospheric spots on the surface of a rotating star. We hypothesise that the light variations are caused mainly by an uneven distribution of overabundant helium on the star's surface. We briefly describe and discuss the cause of the rapid rotational braking of the star.
2668. HR8752 evolving through the void
ID:
ivo://CDS.VizieR/J/A+A/546/A105
Title:
HR8752 evolving through the void
Short Name:
J/A+A/546/A105
Date:
21 Oct 2021
Publisher:
CDS
Description:
The main paper on the hypergiant HR8752 evolving through the void combines observational data from various sources: new spectral data, new and already published (B-V), V data. it also describes a new three-dimensional chebychev interpolating code, and gives information on the temperature calibration for hypergiants, and adds some extra Tables on colour excess and historical context (cf. below). The electronic appendix contains a number of tables, too large for publishing in the paper. In the text and in the appendix, they are referred to as Table Axx, resp. Cxx. We note, however, that tables A1.1 to A1.6 in Section 2 of the main paper are here referred to as tables appena11 to appena16. The observational tables appena11 to appena16, appena2, appena3, appena4 all refer to Section 2 in the main paper, while tables appena5, appena6, appena7, appena8 are used in Section 3 of the main paper. The technical table appenc1 describes the three-dimensional chebychev interpolation method used in Section 2 of the main paper. The second technical table appenc2 describes the (hypergiant) temperature calibration and transformation codes between Mk, Teff, and (B-V) data, used in Section 3 of the main paper. Table appena9 discusses some measured colour excesses (Section 3.3 of the main paper). Table appena10 discusses the possibility of historical context (Section 5.11 of the main paper).
2669. HR 5341, HD 142070, HR 6967 & HR 8434 uvby phot.
ID:
ivo://CDS.VizieR/J/A+A/368/225
Title:
HR 5341, HD 142070, HR 6967 & HR 8434 uvby phot.
Short Name:
J/A+A/368/225
Date:
21 Oct 2021
Publisher:
CDS
Description:
Differential Stroemgren uvby observations from the Four College Automated Photoelectric Telescope (FCAPT) are presented for the mCP stars HD 142070, HR 6967, and HR 8434 and the CP star HR 5341. The latter star is found to be constant. Improved periods were derived for HD 142070, 3.37189d, HR 6967, 3.91227d, and HR 8434, 1.43237d. Further observations of HD 142070 are needed to phase the magnetic data with the photometry, of HR 6967 to settle minor discrepancies between y and scaled Geneva V photometry, and of HR 8434 to resolve small discrepancies between two uvby photometric data sets.
2670. HRS galaxies Halpha kinematic survey
ID:
ivo://CDS.VizieR/J/A+A/631/A71
Title:
HRS galaxies Halpha kinematic survey
Short Name:
J/A+A/631/A71
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new 2D high resolution Fabry-Perot spectroscopic observations of 152 star-forming galaxies which are part of the Herschel Reference Survey (HRS), a complete K-band selected, volume-limited sample of nearby galaxies, spanning a wide range in stellar mass and morphological type. Using improved data reduction techniques that provide adaptive binning based on Voronoi tessellation, using large field-of-view observations, we derive high spectral resolution (R>10,000) H{alpha} datacubes from which we compute H{alpha} maps and radial 2D velocity fields that are based on several thousand independent measurements. A robust method based on such fields allows us to accurately compute rotation curves and kinematical parameters, for which uncertainties are calculated using a method based on the power spectrum of the residual velocity fields. We check the consistency of the rotation curves by comparing our maximum rotational velocities to those derived from Hi data, and computing the i-band, NIR, stellar and baryonic Tully-Fisher relations. We use this set of kinematical data combined to those available at other frequencies to study for the first time the relation between the dynamical and the total baryonic mass (stars, atomic and molecular gas, metals and dust), and derive the baryonic and dynamical main sequence on a representative sample of the local universe.