- ID:
- ivo://CDS.VizieR/J/AJ/133/2097
- Title:
- FIRST "Winged" and X-shaped radio source candidates
- Short Name:
- J/AJ/133/2097
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A small number of double-lobed radio galaxies (17 from our own census of the literature) show an additional pair of low surface brightness "wings," thus forming an overall X-shaped appearance. Using the VLA FIRST survey database, we are compiling a large sample of winged and X-shaped radio sources for such studies. As a first step toward this goal, an initial sample of 100 new candidate objects of this type are presented in this paper.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/622/A199
- Title:
- Fit parameters & ephemerides of 650 mCP stars
- Short Name:
- J/A+A/622/A199
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Magnetic, chemically peculiar stars are known for exhibiting surface abundance inhomogeneities (chemical spots) that lead to photometric and spectroscopic variability with the rotation period. It is commonly assumed that the surface structures are causally connected with the global magnetic field that dominates the photospheric and subphotospheric layers of these stars. As a rule, the observed magnetic fields show a simple dipole-like geometry, with the magnetic axis being noncollinear to the rotational one. The present study aims at detecting underlying patterns in the distribution of photometric spots in a sample of 650 magnetic, chemically peculiar stars and examines their link to the magnetic field topology. Photometric time-series observations from the ASAS-3 archive were employed to inspect the light-curve morphology of our sample stars and divide them into representative classes described using a principal component analysis. Theoretical light curves were derived from numerous simulations assuming different spot parameters and following the symmetry of a simple dipole magnetic field. These were subsequently compared with the observed light curves. The results from our simulations are in contradiction with the observations and predict a much higher percentage of double-wave light curves than is actually observed. We thereby conclude that the distribution of the chemical spots does not follow the magnetic field topology, which indicates that the role of the magnetic field in the creation and maintenance of the surface structures may be more subsidiary than what is predicted by theoretical studies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/399/432
- Title:
- Fitted UBV magnitude for MS stars
- Short Name:
- J/MNRAS/399/432
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We fit the colour-magnitude diagrams of stars between the zero-age main-sequence and terminal-age main sequence in young clusters and associations. The ages we derive are a factor of 1.5-2 longer than the commonly used ages for these regions, which are derived from the positions of pre-main-sequence stars in colour-magnitude diagrams. From an examination of the uncertainties in the main-sequence and pre-main-sequence models, we conclude that the longer age scale is probably the correct one, which implies that we must revise upwards the commonly used ages for young clusters and associations. Such a revision would explain the discrepancy between the observational lifetimes of protoplanetary discs and theoretical calculations of the time to form planets. It would also explain the absence of clusters with ages between 5 and 30Myr.
- ID:
- ivo://CDS.VizieR/J/AJ/158/63
- Title:
- Five new transiting hot Jupiters:HATS-54b-HATS-58b
- Short Name:
- J/AJ/158/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery by the HATSouth project of five new transiting hot Jupiters (HATS-54b through HATS-58Ab). HATS-54b, HATS-55b, and HATS-58Ab are prototypical short-period (P=2.5-4.2 days, R_p_~1.1-1.2 R_J_) hot Jupiters that span effective temperatures from 1350 to 1750 K, putting them in the proposed region of maximum radius inflation efficiency. The HATS-58 system is composed of two stars, HATS-58A and HATS-58B, which are detected thanks to Gaia DR2 data and which we account for in the joint modeling of the available data-with this, we are led to conclude that the hot Jupiter orbits the brighter HATS-58A star. HATS-57b is a short-period (2.35 day), massive (3.15 M_J_), 1.14 R_J_, dense (2.65+/-0.21 g/cm^3^) hot Jupiter orbiting a very active star (2% peak-to-peak flux variability). Finally, HATS-56b is a short-period (4.32 day), highly inflated hot Jupiter (1.7 R_J_, 0.6 M_J_), which is an excellent target for future atmospheric follow-up, especially considering the relatively bright nature (V=11.6) of its F dwarf host star. This latter exoplanet has another very interesting feature: the radial velocities show a significant quadratic trend. If we interpret this quadratic trend as arising from the pull of an additional planet in the system, we obtain a period of P_c_=815_-143_^+253^ days for the possible planet HATS-56c, and a minimum mass of M_c_sini_c_=5.11+/-0.94 M_J_. The candidate planet HATS-56c would have a zero-albedo equilibrium temperature of T_eq_=332+/-50 K, and thus would be orbiting close to the habitable zone of HATS-56. Further radial-velocity follow-up, especially over the next two years, is needed to confirm the nature of HATS-56c.
- ID:
- ivo://CDS.VizieR/J/AJ/145/68
- Title:
- Five new transit light curves of TrES-3
- Short Name:
- J/AJ/145/68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Five newly observed transit light curves of the TrES-3 planetary system are presented. Together with other light-curve data from the literature, 23 transit light curves in total, which cover an overall timescale of 911 epochs, have been analyzed through a standard procedure. From these observational data, the system's orbital parameters are determined and possible transit timing variations (TTVs) are investigated. Given that a null TTV produces a fit with reduced {chi}^2^=1.52, our results agree with previous work, that TTVs might not exist in these data. However, a one-frequency oscillating TTV model, giving a fit with a reduced {chi}^2^=0.93, does possess a statistically higher probability. It is thus concluded that future observations and dynamical simulations for this planetary system will be very important.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A55
- Title:
- Five transiting hot Jupiters discovered using WASP
- Short Name:
- J/A+A/591/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used photometry from the WASP-South instrument to identify 5 stars showing planet-like transits in their light curves. The planetary nature of the companions to these stars has been confirmed using photometry from the EulerCam instrument on the Swiss Euler 1.2-m telescope and the TRAPPIST telescope, and spectroscopy obtained with the CORALIE spectrograph. The planets discovered are hot Jupiter systems with orbital periods in the range 2.17 to 5.75 days, masses from 0.3M_{Jup}_ to 1.2M_{Jup}_ and with radii from 1R_{Jup}_ to 1.5R_{Jup}_. These planets orbit bright stars (V=11-13) with spectral types in the range F9 to G4. WASP-126 is the brightest planetary system in this sample and hosts a low-mass planet with a large radius (0.3M_{Jup}_, 0.95R_{Jup}_), making it a good target for transmission spectroscopy. The high density of WASP-129 A suggests that it is a helium-rich star similar to HAT-P-11 A. WASP-133 has an enhanced surface lithium abundance compared to other old G-type stars, particularly other planet host stars. These planetary systems are good targets for follow-up observations with ground-based and space-based facilities to study their atmospheric and dynamical properties.
- ID:
- ivo://CDS.VizieR/J/ApJ/655/1103
- Title:
- Five transits of the exoplanet OGLE-TR-10b
- Short Name:
- J/ApJ/655/1103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present I and B photometry of five distinct transits of the exoplanet OGLE-TR-10b. By modeling the light curves, we find the planetary radius to be R_P_=(1.06+/-0.08)R_Jup_ and the stellar radius to be R_S_=1.10+/-0.07R_{sun}_. The uncertainties are dominated by statistical errors in the photometry. Our estimate of the planetary radius is smaller than previous estimates that were based on lower precision photometry, and hence the planet is not as anomalously large as was previously thought. We provide updated determinations of all the system parameters, including the transit ephemerides.
- ID:
- ivo://CDS.VizieR/J/A+A/361/1011
- Title:
- F-K evolved stars Ca II activity and rotation
- Short Name:
- J/A+A/361/1011
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CaII H and K high resolution observations for 60 evolved stars in the field and in 5 clusters are presented. From these spectra chromospheric fluxes are derived, and a homogeneous sample of more than 100 giants is built adding data from the literature. In addition, for most stars, rotational velocities were derived from CORAVEL observations.
- ID:
- ivo://CDS.VizieR/J/A+A/561/A87
- Title:
- FLAMES observations of Terzan 8
- Short Name:
- J/A+A/561/A87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive globular clusters (GCs) contain at least two generations of stars with slightly different ages and clearly distinct light elements abundances. The Na-O anticorrelation is the best studied chemical signature of multiple stellar generations. Low-mass clusters appear instead to be usually chemically homogeneous. We are investigating low-mass GCs to understand what is the lower mass limit where multiple populations can form, mainly using the Na and O abundance distribution. We used VLT/FLAMES spectra of giants in the low-mass, metal-poor GC Terzan 8, belonging to the Sagittarius dwarf galaxy, to determine abundances of Fe, O, Na, alpha-, Fe-peak, and neutron-capture elements in six stars observed with UVES and 14 observed with GIRAFFE. The average metallicity is [Fe/H]=-2.27+/-0.03 (rms=0.08), based on the six high-resolution UVES spectra. Only one star, observed with GIRAFFE, shows an enhanced abundance of Na and we tentatively assign it to the second generation. In this cluster, at variance with what happens in more massive GCs, the second generation seems to represent at most a small minority fraction. We discuss the implications of our findings, comparing Terzan 8 with the other Sgr dSph GCs, to GCs and field stars in the Large Magellanic Cloud, Fornax, and in other dwarfs galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/881/79
- Title:
- Flamingos-2 near-infrared photometry in NGC 2244
- Short Name:
- J/ApJ/881/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of the ongoing effort to characterize the low-mass (sub)stellar population in a sample of massive young clusters, we have targeted the ~2Myr old cluster NGC2244. The distance to NGC2244 from Gaia DR2 parallaxes is 1.59kpc, with errors of 1% (statistical) and 11% (systematic). We used the Flamingos-2 near-infrared camera at the Gemini-South telescope for deep multi- band imaging of the central portion of the cluster (~2.4pc^2^). We determined membership in a statistical manner, through a comparison of the cluster's color-magnitude diagram to that of a control field. Masses and extinctions of the candidate members are then calculated with the help of evolutionary models, leading to the first initial mass function (IMF) of the cluster extending into the substellar regime, with the 90% completeness limit around 0.02M{sun}. The IMF is well represented by a broken power law (dN/dM{prop}M-{alpha}) with a break at ~0.4M{sun}. The slope on the high- mass side (0.4-7M{sun}) is {alpha}=2.12{+/-}0.08, close to the standard Salpeter slope. In the low-mass range (0.02-0.4M{sun}), we find a slope {alpha}=1.03{+/-}0.02, which is at the high end of the typical values obtained in nearby star-forming regions ({alpha}=0.5-1.0), but still in agreement within the uncertainties. Our results reveal no clear evidence for variations in the formation efficiency of brown dwarfs (BDs) and very low-mass stars due to the presence of OB stars, or for a change in stellar densities. Our finding rules out photoevaporation and fragmentation of infalling filaments as substantial pathways for BD formation.
