- ID:
- ivo://CDS.VizieR/J/AJ/150/77
- Title:
- Catalog of hypervelocity candidate stars
- Short Name:
- J/AJ/150/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we analyze a sample of metal-rich (>-0.8dex) main sequence stars in the extended solar neighborhood, investigating kinematic outliers from the background population. The data, which are taken from the Sloan Digital Sky Survey, are kinematically profiled as a function of distance from the Galactic plane using full six-dimensional phase space information. Each star is examined in the context of these kinematic profiles and likelihoods are assigned to quantify whether a star matches the underlying profile. Since some of these stars are likely to have been ejected from the disk, we trace back their orbits in order to determine potential ejection radii. We find that objects with low probability (i.e., "outliers") are typically more metal-poor, faster and, most importantly, have a tendency to originate from the inner Galaxy compared to the underlying population. We also compose a sample of stars with velocities exceeding the local escape velocity. Although we do not discount that our sample could be contaminated by objects with spurious proper motions, a number of stars appear to have been ejected from the disk with exceptionally high velocities. Some of these are consistent with being ejected from the spiral arms and hence are a rich resource for further study. Finally we look at objects whose orbits are consistent with them being ejected at high speeds from the Galactic center. Of these objects we find that one, J135855.65+552538.19, is inconsistent with halo, bulge and disk kinematics and could plausibly have been ejected from the Galactic nucleus via a Hills mechanism.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/2815
- Title:
- Cerro Armazones spectroscopy of F dwarfs
- Short Name:
- J/MNRAS/443/2815
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic survey of a sample of F stars that have not yet been searched for planets. The observations of 187 stars obtained with the Bochum Echelle Spectrographic Observer of the Cerro Armazones Observatory were aimed at nearby (closer than 70pc) main-sequence stars without sufficient archive ([fiber-fed extended range optical spectrograph (FEROS)/high accuracy radial velocity planet search (HARPS)]) spectroscopy. The primary goal of the survey was to select the best candidates for radial-velocity searches of extrasolar planets. The spectra were analysed using the broadening-function technique, the method of choice for rapid rotators later than about A5. The analysis was focused not only at the determination of projected rotational velocity (defining precision of radial-velocity determination), but also at the detection of previously unknown spectroscopic binaries/multiples or stars showing strong line asymmetries. 12 previously unknown spectroscopic binaries/triples were detected. For all observed targets the spectral type was determined. About 140 stars are rotating faster than the resolution limit of 10km/s sampling the onset of convection and slow rotation at mid-F spectral types in great detail. Radial-velocity precision of the data (about 100m/s) is insufficient to detect planets but could indicate most SB1 systems with stellar companions. As there are already 2-3 observations per object for these newly detected binary stars, only a few additional follow-up observations will be needed to obtain constraints on orbital parameters. We identified a sample of 68 bright F-type dwarf stars which are perfect targets for future planet searches. They rotate moderately or slowly and do not show any sign of binarity, pulsations, or surface activity.
- ID:
- ivo://CDS.VizieR/II/19
- Title:
- Colors of F and G dwarfs
- Short Name:
- II/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Synthetic spectra have been computed for F and G dwarf stars, using a number of values of chemical abundances, Doppler broadening velocity and damping constants. Filter transmission function have been convolved with thee spectra to yield color indices in 3 photometric systems.
- ID:
- ivo://CDS.VizieR/J/ApJ/636/1098
- Title:
- Debris disks around solar-type stars
- Short Name:
- J/ApJ/636/1098
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have searched for infrared excesses around a well-defined sample of 69 FGK main-sequence field stars. These stars were selected without regard to their age, metallicity, or any previous detection of IR excess; they have a median age of 4Gyr.
- ID:
- ivo://CDS.VizieR/J/AJ/146/113
- Title:
- Differential griz photometry of HATS-3
- Short Name:
- J/AJ/146/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery by the HATSouth survey of HATS-3b, a transiting extrasolar planet orbiting a V=12.4 F dwarf star. HATS-3b has a period of P=3.5479days, mass of M_p_=1.07M_J_, and radius of R_p_=1.38R _J_. Given the radius of the planet, the brightness of the host star, and the stellar rotational velocity (vsini=9.0km/s), this system will make an interesting target for future observations to measure the Rossiter-McLaughlin effect and determine its spin-orbit alignment. We detail the low-/medium-resolution reconnaissance spectroscopy that we are now using to deal with large numbers of transiting planet candidates produced by the HATSouth survey. We show that this important step in discovering planets produces logg and T_eff_ parameters at a precision suitable for efficient candidate vetting, as well as efficiently identifying stellar mass eclipsing binaries with radial velocity semi-amplitudes as low as 1km/s.
- ID:
- ivo://CDS.VizieR/J/ApJ/715/458
- Title:
- Differential photometry of HAT-P-14
- Short Name:
- J/ApJ/715/458
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HAT-P-14b, a fairly massive transiting extrasolar planet orbiting the moderately bright star GSC 3086-00152 (V=9.98), with a period of P=4.627669+/-0.000005 days. The transit is close to grazing (impact parameter 0.891^+0.007^_-0.008_) and has a duration of 0.0912+/-0.0017 days, with a reference epoch of mid-transit of T_c_=2454875.28938+/-0.00047 (BJD). The orbit is slightly eccentric (e=0.107+/-0.013), and the orientation is such that occultations are unlikely to occur. The host star is a slightly evolved mid-F dwarf with a mass of 1.386+/-0.045M_{sun}_, a radius of 1.468+/-0.054R_{sun}_, effective temperature 6600+/-90K, and a slightly metal-rich composition corresponding to [Fe/H]=+0.11+/-0.08. The planet has a mass of 2.232+/-0.059M_J_ and a radius of 1.150+/-0.052R_J_, implying a mean density of 1.82+/-0.24g/cm^3^. Its radius is well reproduced by theoretical models for the 1.3Gyr age of the system if the planet has a heavy-element fraction of about 50M_{earth}_ (7% of its total mass). The brightness, near-grazing orientation, and other properties of HAT-P-14 make it a favorable transiting system to look for changes in the orbital elements or transit timing variations induced by a possible second planet, and also to place meaningful constraints on the presence of sub-Earth mass or Earth-mass exomoons, by monitoring it for transit duration variations.
- ID:
- ivo://CDS.VizieR/J/AJ/153/211
- Title:
- Differential photometry of the F-subgiant HAT-P-67
- Short Name:
- J/AJ/153/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HAT-P-67b, which is a hot-Saturn transiting a rapidly rotating F-subgiant. HAT-P-67b has a radius of R_p_=2.085_-0.071_^+0.096^ R_J_, and orbites a M_*_=1.642_-0.072_^+0.155^ M_{sun}_, R_*_=2.546_-0.084_^+0.099^ R_{sun}_ host star in a ~4.81 day period orbit. We place an upper limit on the mass of the planet via radial velocity measurements to be M_p_<0.59 M_J_, and a lower limit of >0.056 M_J_ by limitations on Roche lobe overflow. Despite being a subgiant, the host star still exhibits relatively rapid rotation, with a projected rotational velocity of vsini_*_=35.8+/-1.1 km/s, which makes it difficult to precisely determine the mass of the planet using radial velocities. We validated HAT-P-67b via two Doppler tomographic detections of the planetary transit, which eliminate potential eclipsing binary blend scenarios. The Doppler tomographic observations also confirm that HAT-P-67b has an orbit that is aligned to within 12{deg}, in projection, with the spin of its host star. HAT-P-67b receives strong UV irradiation and is among one of the lowest density planets known, which makes it a good candidate for future UV transit observations in the search for an extended hydrogen exosphere.
- ID:
- ivo://CDS.VizieR/J/MNRAS/367/1329
- Title:
- Elemental abundances for 176 stars
- Short Name:
- J/MNRAS/367/1329
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed an abundance analysis for F- and G- dwarfs of the Galactic thick-disc component. A sample of 176 nearby (d<=150pc) thick-disc candidate stars was chosen from the Hipparcos catalogue and subjected to a high-resolution spectroscopic analysis. Using accurate radial velocities combined with the Hipparcos astrometry, kinematics (U, V and W) and Galactic orbital parameters were computed. We estimate the probability for a star to belong to the thin disc, the thick disc or the halo. With a probability P>=70 per cent taken as certain membership, we assigned 95 stars to the thick disc, 13 to the thin disc, and 20 to the halo. The remaining 48 stars in the sample cannot be assigned with reasonable certainty to one of the three components. Abundances of C, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Ba, Ce, Nd and Eu have been obtained.
- ID:
- ivo://CDS.VizieR/J/A+A/381/500
- Title:
- Eu abundances in F and G disk stars
- Short Name:
- J/A+A/381/500
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Europium abundances for 74 F and G dwarf stars of the galactic disk have been determined. The stars were selected from the sample of Edvardsson et al. (1993, Cat. <J/A+A/275/101>) and [Eu/Fe] shows a smaller scatter and a slightly weaker trend with [Fe/H] than found by Woolf et al. (1995ApJ...453..660W). The data of the two analyses are homogeneized and merged.
- ID:
- ivo://CDS.VizieR/J/MNRAS/360/1345
- Title:
- F- and G-type stars in solar neighbourhood
- Short Name:
- J/MNRAS/360/1345
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new metallicity distribution and an age-metallicity relation are presented for 437 nearby F and G turn-off and sub-giant stars selected from radial velocity data of Nidever et al. (2002, Cat. J/ApJS/141/503). Photometric metallicities are derived from uvby-H{beta} photometry, and the stellar ages from the isochrones of Bergbusch & VandenBerg (2001ApJ...556..322B) as transformed to uvby photometry using the methods of Clem et al. (2004, Cat. J/AJ/127/1227).
