- ID:
- ivo://CDS.VizieR/J/AJ/149/194
- Title:
- Differential BVR light curves of DK Cyg
- Short Name:
- J/AJ/149/194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD photometry is presented for the hot overcontact binary DK Cyg together with reasonable explanations for the light and period variations. Historical light and velocity curves from 1962 to 2012 were simultaneously analyzed with the Wilson-Devinney (W-D) synthesis code. The brightness disturbances were satisfactorily modeled by applying a magnetic cool spot on the primary star. Based on 261 times of minimum light that include 116 new timings and span more than 87 years, a period study reveals that the orbital period has varied due to a periodic oscillation superimposed on an upward parabola. The period and semi-amplitude of the modulation are about 78.1years and 0.0037days, respectively. This detail is interpreted as a light-travel-time effect due to a circumbinary companion with a minimum mass of M_3_=0.065M_{sun}_, within the theoretical limit of ~0.07M_{sun}_ for a brown dwarf star. The observed period increase at a fractional rate of +2.74x10^-10^ is in excellent agreement with that calculated from our W-D synthesis. Mass transfer from the secondary to the primary component is mainly responsible for the secular period change. We examined the evolutionary status of the DK Cyg system from the absolute dimensions.
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- ID:
- ivo://CDS.VizieR/J/AJ/145/100
- Title:
- Differential BVR light curves of EP And
- Short Name:
- J/AJ/145/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new long-term CCD photometry for EP And acquired during the period 2007-2012. The light curves display total eclipses at primary minima and season-to-season light variability. Our synthesis for all available light curves indicates that the eclipsing pair is a W-type overcontact binary with parameters of q=2.578, i=83.3{deg}, {Delta}T=27K, f=28%, and l_3_=2%-3%. The asymmetric light curves in 2007 were satisfactorily modeled by a cool spot on either of the eclipsing components from a magnetic dynamo. Including our 95 timing measurements, a total of 414 times of minimum light spanning about 82yr was used for a period study. A detailed analysis of the eclipse timing diagram revealed that the orbital period of EP And has varied as a combination of an upward-opening parabola and two periodic variations, with cycle lengths of P_3_=44.6yr and P_4_=1.834yr and semi-amplitudes of K_3_=0.0100days and K_4_=0.0039days, respectively. The observed period increase at a fractional rate of +1.39*10^-10^ is in excellent agreement with that calculated from the W-D code and can be plausibly explained by some combination of mass transfer from the primary to the secondary star and angular momentum loss due to magnetic braking. The most reasonable explanation for both cycles is a pair of light-travel-time effects driven by the possible existence of a third and fourth component with projected masses of M_3_=0.25M_{sun}_ and M_4_=0.90M_{sun}_. The more massive companion could be revealed using high-resolution spectroscopic data extending over the course of a few years and could also be a binary itself. It is possible that the circumbinary objects may have played an important role in the formation and evolution of the eclipsing pair, which would cause it to have a short initial orbital period and thus evolve into an overcontact configuration by angular momentum loss.
- ID:
- ivo://CDS.VizieR/J/AJ/147/91
- Title:
- Differential BVR light curves of V407 Peg
- Short Name:
- J/AJ/147/91
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New multiband CCD photometry is presented for V407 Peg; the R_C_ light curves are the first ever compiled. Our light curves, displaying a flat bottom at secondary minimum and an O'Connell effect, were simultaneously analyzed with the radial velocity (RV) curves given by Rucinski et al. The light changes of the system are best modeled using both a hot spot on the secondary star and a third light. The model also represents historical light curves. All available minimum epochs, including our six timing measurements, have been examined and they indicate that the eclipse timing variation is mainly caused by light asymmetries due to the spot activity detected in the light-curve synthesis. The hot spot may be produced as a result of the impact of the gas stream from the primary star. Our light and velocity solutions indicate that V407 Peg is a totally eclipsing A-type overcontact binary with values of q=0.251, i=87.6{deg}, {Delta}T=496K, f=61%, and l_3_=11~16%. Individual masses and radii of both components are determined to be M_1_=1.72M_{sun}_, M_2_=0.43M_{sun}_, R_1_=2.15R_{sun}_, and R_2_=1.21R_{sun}_. These results are very different from previous ones, which is probably caused by the light curves with distorted and inclined eclipses used in those other analyses. The fact that there are no objects optically related to the system and that the seasonal RVs show a large discrepancy in systemic velocity indicates that the third light source most likely arises from a tertiary component orbiting the eclipsing pair.
- 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/AJ/147/144
- Title:
- Differential griz photometry of HATS-5
- Short Name:
- J/AJ/147/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of HATS-5b, a transiting hot Saturn orbiting a G-type star, by the HATSouth survey. HATS-5b has a mass of M_p_{approx}0.24M_J_, radius of R_p_{approx}0.91R_J_, and transits its host star with a period of P{approx}4.7634days. The radius of HATS-5b is consistent with both theoretical and empirical models. The host star has a V-band magnitude of 12.6, mass of 0.94M_{sun}_, and radius of 0.87R_{sun}_. The relatively high scale height of HATS-5b and the bright, photometrically quiet host star make this planet a favorable target for future transmission spectroscopy follow-up observations. We reexamine the correlations in radius, equilibrium temperature, and metallicity of the close-in gas giants and find hot Jupiter-mass planets to exhibit the strongest dependence between radius and equilibrium temperature. We find no significant dependence in radius and metallicity for the close-in gas giant population.
- ID:
- ivo://CDS.VizieR/J/AJ/137/226
- Title:
- Differential light curves of TV Tri
- Short Name:
- J/AJ/137/226
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD photometry for the Algol-type binary RV Trianguli observed during three nights in 2007 November. The photometric solution was derived from our VR observations by using the Wilson-Devinny program. The results indicated that RV Tri is a semidetached binary with a mass ratio of q=0.306+/-0.005. Based on 236 light minimum times, the orbital period change of RV Tri was analyzed in detail.
- ID:
- ivo://CDS.VizieR/J/AJ/127/1727
- Title:
- Differential magnitudes of binary stars
- Short Name:
- J/AJ/127/1727
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Five hundred seventy-six magnitude difference measures are presented for 260 binary stars. These measures are derived from CCD-based speckle observations taken at the WIYN 3.5m telescope at Kitt Peak National Observatory during the period 1997-2000. Separations of the systems range from over 1" down to near the diffraction limit of the telescope. A study of multiple measures of the same targets indicates that the measures have a typical uncertainty of better than 0.13mag per 2 minute observation, and that multiple observations can be averaged to arrive at smaller uncertainties. Results presented here are also compared, insofar as it is possible, with measures in the Hipparcos Catalogue and to previous studies using adaptive optics. No major systematic errors were identified.
- ID:
- ivo://CDS.VizieR/J/A+A/476/881
- Title:
- Differential photometry of FK Com
- Short Name:
- J/A+A/476/881
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the present work we publish new photometric observations of the very active single giant, FK Com for the time period between the 1st of January 2002 and the 8th of July 2004. The observations have been carried out with three different automatic photometric telescopes: Phoenix 10, Wolfgang and Amadeus, all located in Arizona, USA. Observations contain measurements at the following bands: Johnson U, B and V, Cousins I and Stroemgren b and y. The observations are differential photometry in respect to the primary comparison star HD 117567.
- ID:
- ivo://CDS.VizieR/J/A+A/614/A35
- Title:
- Differential photometry of GJ1214
- Short Name:
- J/A+A/614/A35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To investigate the star spots of the M dwarf GJ 1214, we conducted a multi-color photometric monitoring from 2012 to 2016. We measured the rotation period of the host star, measured an increase in variability amplitude, determined the permanent spot filling factor, the spot temperature contrast and persistent longitudes. We determined the effect of the star spots on the planetary transmission spectrum.
- 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.
