- ID:
- ivo://CDS.VizieR/J/AJ/152/75
- Title:
- Photometric survey of IC 2391, {eta} Cha, and USco
- Short Name:
- J/AJ/152/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The past two decades have seen a significant advancement in the detection, classification, and understanding of exoplanets and binaries. This is due, in large part, to the increase in use of small-aperture telescopes (<20cm) to survey large areas of the sky to milli-mag precision with rapid cadence. The vast majority of the planetary and binary systems studied to date consists of main-sequence or evolved objects, leading to a dearth of knowledge of properties at early times (<50Myr). Only a dozen binaries and one candidate transiting Hot Jupiter are known among pre-main-sequence objects, yet these are the systems that can provide the best constraints on stellar formation and planetary migration models. The deficiency in the number of well characterized systems is driven by the inherent and aperiodic variability found in pre-main-sequence objects, which can mask and mimic eclipse signals. Hence, a dramatic increase in the number of young systems with high-quality observations is highly desirable to guide further theoretical developments. We have recently completed a photometric survey of three nearby (<150pc) and young (<50Myr) moving groups with a small-aperture telescope. While our survey reached the requisite photometric precision, the temporal coverage was insufficient to detect Hot Jupiters. Nevertheless, we discovered 346 pre-main-sequence binary candidates, including 74 high-priority objects for further study.
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- ID:
- ivo://CDS.VizieR/J/AJ/150/33
- Title:
- Photometry and spectroscopy of HATS-9 and HATS-10
- Short Name:
- J/AJ/150/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two transiting extrasolar planets by the HATSouth survey. HATS-9b orbits an old (10.8+/-1.5Gyr) V=13.3 G dwarf star with a period p~~1.9153days. The host star has a mass of 1.03M_{sun}_, radius of 1.503R_{sun}_, and effective temperature 5366+/-70K. The planetary companion has a mass of 0.837M_J_ and radius of 1.065R_J_, yielding a mean density of 0.85g/cm^-3^. HATS-10b orbits a V=13.1 G dwarf star with a period p~~3.3128days. The host star has a mass of 1.1M_{sun}_, radius of 1.11R_{sun}_, and effective temperature 5880+/-120K. The planetary companion has a mass of 0.53M_J_ and radius of 0.97R_J_, yielding a mean density of 0.7g/cm3. Both planets are compact in comparison with planets receiving similar irradiation from their host stars and lie in the nominal coordinates of Field 7 of K2, but only HATS-9b falls on working silicon. Future characterization of HATS-9b with the exquisite photometric precision of the Kepler telescope may provide measurements of its reflected light signature.
- ID:
- ivo://CDS.VizieR/J/AJ/153/215
- Title:
- Photometry and spectroscopy of KELT-11
- Short Name:
- J/AJ/153/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a transiting exoplanet, KELT-11b, orbiting the bright (V=8.0) subgiant HD93396. A global analysis of the system shows that the host star is an evolved subgiant star with T_eff_=5370+/-51K, M_*_=1.438_-0.052_^+0.061^M_{Sun}_, R_*_=2.72_-0.17_^+0.21^R_{Sun}_, logg_*_=3.727_-0.046_^+0.040^, and [Fe/H]=0.180+/-0.075. The planet is a low-mass gas giant in a P=4.736529+/-0.00006 day orbit, with M_P_=0.195+/-0.018M_J_, R_P_=1.37_-0.12_^+0.15^R_J_, {rho}_P_=0.093_-0.024_^+0.028^g/cm^3^, surface gravity logg_P_=2.407_-0.086_^+0.080^, and equilibrium temperature T_eq_=1712_-46_^+51^K. KELT-11 is the brightest known transiting exoplanet host in the southern hemisphere by more than a magnitude and is the sixth brightest transit host to date. The planet is one of the most inflated planets known, with an exceptionally large atmospheric scale height (2763km), and an associated size of the expected atmospheric transmission signal of 5.6%. These attributes make the KELT-11 system a valuable target for follow-up and atmospheric characterization, and it promises to become one of the benchmark systems for the study of inflated exoplanets.
- ID:
- ivo://CDS.VizieR/J/AJ/152/161
- Title:
- Photometry for HATS-31 through HATS-35
- Short Name:
- J/AJ/152/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of five new transiting hot-Jupiter planets discovered by the HATSouth survey, HATS-31b through HATS-35b. These planets orbit moderately bright stars with V magnitudes within the range of 11.9-14.4mag while the planets span a range of masses of 0.88-1.22M_J_ and have somewhat inflated radii between 1.23 and 1.64R_J_. These planets can be classified as typical hot Jupiters, with HATS-31b and HATS-35b being moderately inflated gas giant planets with radii of 1.64+/-0.22R_J_ and 1.464_-0.044_^+0.069^R_J_, respectively, that can be used to constrain inflation mechanisms. All five systems present a higher Bayesian evidence for a fixed-circular-orbit model than for an eccentric orbit. The orbital periods range from 1.8209993+/-0.0000016 day for HATS-35b) to 3.377960+/-0.000012 day for HATS-31b. Additionally, HATS-35b orbits a relatively young F star with an age of 2.13+/-0.51Gyr. We discuss the analysis to derive the properties of these systems and compare them in the context of the sample of well-characterized transiting hot Jupiters known to date.
- ID:
- ivo://CDS.VizieR/J/AJ/148/72
- Title:
- Photometry & interferometry of nearby secondaries
- Short Name:
- J/AJ/148/72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To improve the statistics of hierarchical multiplicity, secondary components of wide nearby binaries with solar-type primaries were surveyed at the SOAR telescope for evaluating the frequency of subsystems. Images of 17 faint secondaries were obtained with the SOAR Adaptive Module that improved the seeing; one new 0.2'' binary was detected. For all targets, photometry in the g', i', z' bands is given. Another 46 secondaries were observed by speckle interferometry, resolving 7 close subsystems. Adding literature data, the binarity of 95 secondary components is evaluated. We found that the detection-corrected frequency of secondary subsystems with periods in the well-surveyed range from 10^3^ to 10^5^ days is 0.21+/-0.06--same as the normal frequency of such binaries among solar-type stars, 0.18. This indicates that wide binaries are unlikely to be produced by dynamical evolution of N-body systems, but are rather formed by fragmentation.
- ID:
- ivo://CDS.VizieR/J/AJ/149/150
- Title:
- Photometry of multiples at NAOR and ASV in 2012
- Short Name:
- J/AJ/149/150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the 2m telescope of the Bulgarian National Astronomical Observatory at Rozhen, observations of 246 double or multiple stars were carried out during six nights in 2012. This is the seventh series of measurements of CCD frames of double and multiple stars obtained at Rozhen. Also in 2012, using the 0.6m telescope of the Serbian Astronomical Station on the mountain of Vidojevica, observations of 117 double or multiple stars were carried out during five nights. This is the second series of measurements of CCD frames of double and multiple stars obtained at this station. In this paper we present the results for the position angle and angular separation for 453 pairs and residuals for 105 pairs with published orbital elements or linear solutions. These observations have angular separations in the range from 1.50'' to 178.12'', with a median angular separation of 8.13''. We also present the recalculated linear solution for one pair and three linear solutions that have been calculated for the first time.
- ID:
- ivo://CDS.VizieR/J/AJ/151/58
- Title:
- Photometry of stars at NAOR and ASV in 2013-2014
- Short Name:
- J/AJ/151/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the 2m telescope of the Bulgarian National Astronomical Observatory at Rozhen, observations of 271 double or multiple stars were carried out during seven nights in 2013 and 2014. This is the eighth series of measurements of CCD frames of double and multiple stars obtained at Rozhen. Also in 2013 and 2014, using the 0.6m telescope of the Serbian Astronomical Station on the mountain of Vidojevica, observations of 343 double or multiple stars were carried out during 21 nights. This is the third series of measurements of CCD frames of double and multiple stars obtained at this station. In this paper, we present the results for the position angle and angular separation for 721 pairs and residuals for 126 pairs with published orbital elements or linear solutions. These observations have angular separations in the range from 1.24'' to 202.30'', with a median angular separation of 7.17''. We also present eight linear solutions that have been calculated for the first time.
- ID:
- ivo://CDS.VizieR/J/AJ/158/215
- Title:
- Photometry of stars at NAOR and ASV in 2017-2018
- Short Name:
- J/AJ/158/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We give the results of CCD observations for 789 double or multiple stars obtained during 2017 and 2018. These observations were carried out at both the Serbian Astronomical Station on the mountain of Vidojevica (ASV) and the Bulgarian National Astronomical Observatory at Rozhen (NAOR). They were performed using three telescopes, the 1.4 and 0.6 m telescopes at ASV, and the 2 m telescope at NAOR. The total of 1196 measurements (position angle and angular separation) for the 939 pairs is presented. Out of this number, 55 pairs have calculated orbital or linear elements and for them the residuals are given. Some pairs have measurements for several epochs. Measured angular separations are in the interval from 1.51" to 208.81", with a median separation of 4.16". Two new pairs and linear elements for three pairs, which are calculated for the first time, are also presented.
- ID:
- ivo://CDS.VizieR/J/AJ/161/221
- Title:
- Photometry & spectroscopy of 4 binaries stars
- Short Name:
- J/AJ/161/221
- Date:
- 16 Mar 2022 11:53:19
- Publisher:
- CDS
- Description:
- We present the photometric and spectroscopic analysis of four W-UMa binaries J015829.5+260333 (hereinafter as J0158), J030505.1+293443 (hereinafter as J0305), J102211.7+310022 (hereinafter as J1022), and KW-Psc. The VRcIc band photometric observations are carried out with the 1.3m Devasthal Fast Optical Telescope (DFOT). For low-resolution spectroscopy, we used the 2m Himalayan Chandra Telescope (HCT) as well as the archival data from the 4m LAMOST survey. The systems J0158 and J0305 show a period increase rate of 5.26({+/-}1.72)x10^-7^days/yr and 1.78({+/-}1.52)x10^-6^days/yr, respectively. The period of J1022 is found to be decreasing with a rate of 4.22({+/-}1.67)x10^-6^days/yr. The period analysis of KW-Psc displays no change in its period. The PHOEBE package is used for the light-curve modeling and basic parameters are evaluated with the help of the GAIA parallax. The asymmetry of light curves is explained with the assumption of cool spots at specific positions on one of the components of the system. On the basis of temperatures, mass ratios, fill-out factors, and periods, the system J1022 is identified as a W-subtype system while the others show some mixed properties. To probe the chromospheric activities in these W-UMa binaries, their spectra are compared with the known inactive stars' spectra. The comparison shows emission in H{alpha}, H{beta}, and CaII. To understand the evolutionary status of these systems, the components are plotted in mass-radius and mass-luminosity planes with other well characterized binary systems. The secondary components of all the systems are away from ZAMS, which indicates that the secondary is more evolved than the primary component.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/1291
- Title:
- Physical properties of 38 exoplanets
- Short Name:
- J/MNRAS/426/1291
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I measure the physical properties of 38 transiting extrasolar planetary systems, bringing the total number studied within the Homogeneous Studies project to 82. Transit light curves are modelled using the jktebop code, with careful attention paid to limb darkening, orbital eccentricity and contaminating light. The physical properties of each system are obtained from the photometric parameters, published spectroscopic measurements and five sets of theoretical stellar model predictions. Statistical errors are assessed using Monte Carlo and residual permutation algorithms and propagated via a perturbation algorithm. Systematic errors are estimated from the interagreement between results calculated using five theoretical stellar models. I present the first results based on Kepler short-cadence data for Kepler-14, Kepler-15 and KOI-135.