- ID:
- ivo://CDS.VizieR/J/A+A/404/L29
- Title:
- VB differential photometry of WR30a
- Short Name:
- J/A+A/404/L29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric observations in Johnson V and B of WR30a, revealing relative dramatic changes in brightness of 0.2mag. These variations occur on a time scale of hours, and are only seen in V. We argue that they are not caused by dust extinction, but either by a dramatic change in the strength of the C IV 5801-12{AA} emission line doublet due to a de-excitation process, or by some unknown continuum effect.
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- ID:
- ivo://CDS.VizieR/J/A+A/397/921
- Title:
- VBLUW photometry of HD 93205
- Short Name:
- J/A+A/397/921
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 1982-1985 photometry (VBLUW system) of the O3V+O8V close binary HD 93205 has been rediscussed because of new insights into its true nature and orbital changes. By comparing this data set with the one obtained by Antokhina et al. (2000ApJ...529..463A) in 1993, and using the same ephemeris to construct the light curve in the phase diagram, the effect of the apsidal motion became obvious: a phase shift between the two light curves and a small change of the shape. A phase-locked light variation in the L passband (containing the higher Balmer lines) is clearly present in the 1982-1985 data set and is presumably due to absorption if the O8 star is seen through cooler inter-binary gas, e.g. the bow-shock between the two colliding winds.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/739
- Title:
- Velocities for seven transiting hot Jupiters
- Short Name:
- J/MNRAS/426/739
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present seven new transiting hot Jupiters from the WASP-South survey. The planets are all typical hot Jupiters orbiting stars from F4 to K0 with magnitudes of V=10.3-12.5. The orbital periods are all in the range of 3.9-4.6d, the planetary masses range from 0.4 to 2.3-M_Jup_ and the radii from 1.1 to 1.4R_Jup_. In line with known hot Jupiters, the planetary densities range from Jupiter-like to inflated ({rho}=0.13-1.07{rho}_Jup_). We use the increasing numbers of known hot Jupiters to investigate the distribution of their orbital periods and the 3-4d 'pile-up'.
- ID:
- ivo://CDS.VizieR/J/ApJS/213/34
- Title:
- Velocities of Cygnus OB2 massive binaries
- Short Name:
- J/ApJS/213/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze orbital solutions for 48 massive multiple-star systems in the Cygnus OB2 association, 23 of which are newly presented here, to find that the observed distribution of orbital periods is approximately uniform in log P for P<45days, but it is not scale-free. Inflections in the cumulative distribution near 6days, 14days, and 45days suggest key physical scales of =~0.2, =~0.4, and =~1A.U. where yet-to-be-identified phenomena create distinct features. No single power law provides a statistically compelling prescription, but if features are ignored, a power law with exponent {beta}=~-0.22 provides a crude approximation over P=1.4-2000days, as does a piece-wise linear function with a break near 45days. The cumulative period distribution flattens at P>45days, even after correction for completeness, indicating either a lower binary fraction or a shift toward low-mass companions. A high degree of similarity (91% likelihood) between the Cyg OB2 period distribution and that of other surveys suggests that the binary properties at P<~25days are determined by local physics of disk/clump fragmentation and are relatively insensitive to environmental and evolutionary factors. Fully 30% of the unbiased parent sample is a binary with period P<45days. Completeness corrections imply a binary fraction near 55% for P<5000days. The observed distribution of mass ratios 0.2<q<1 is consistent with uniform, while the observed distribution of eccentricities 0.1<e<0.6 is consistent with uniform plus an excess of e=~0 systems. We identify six stars, all supergiants, that exhibit aperiodic velocity variations of ~30km/s attributed to atmospheric fluctuations.
- ID:
- ivo://CDS.VizieR/J/AN/323/139
- Title:
- Velocities of Popother/.II binray stars
- Short Name:
- J/AN/323/139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radial velocities for 114 Hipparcos stars, mostly high transverse velocity binaries without previous radial velocity measurement, are published. Measurements are made with the CORAVEL-type radial velocity spectrometer. The accuracy of measurements is better than 1km/s. Two stars, BD+30 2129A and HD 117466AB are found to be radial velocity variables, and three more stars, HD 119515A, HD 131597AB, and HD 153344, are possible radial velocity variables.
- ID:
- ivo://CDS.VizieR/J/A+A/544/L12
- Title:
- Velocitometry transit of KOI-13
- Short Name:
- J/A+A/544/L12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a new stellar companion in the KOI-13 system. KOI-13 is composed of two fast-rotating A-type stars of similar magnitude. One of these two stars hosts a transiting planet discovered by Kepler. We obtained new radial velocity measurements using the SOPHIE spectrograph at the Observatoire de Haute-Provence that reveal an additional companion in this system. This companion has a mass of between 0.4M_{sun}_ and 1M_{sun}_ and orbits one of the two main stars with a period of 65.831+/-0.029-days and an eccentricity of 0.52+/-0.02.
- ID:
- ivo://CDS.VizieR/J/A+A/528/A63
- Title:
- Velocitometry transit of KOI-428b
- Short Name:
- J/A+A/528/A63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a hot Jupiter transiting a subgiant star with an orbital period of 6.87-days thanks to public photometric data from the Kepler space mission and new radial velocity observations obtained by the SOPHIE spectrograph. The planet KOI-428b with a radius of 1.17+/-0.04R_Jup_ and a mass of 2.2+/-0.4M_Jup_, orbits around a F5IV star with R*=2.13+/-0.06R_{sun}_, M*=1.48+/-0.06M_{sun} and Teff=6510+/-100K. The star KOI-428 is the largest and the most evolved star discovered so far with a transiting planet
- ID:
- ivo://CDS.VizieR/J/A+A/529/A134
- Title:
- Velocity curve of {alpha} Arietis
- Short Name:
- J/A+A/529/A134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To search for extra-solar planets around intermediate mass stars, we are conducting a precise RV survey around K-giants. We present high-accuracy RV measurements of alpha Ari from November 2003 to February 2010. This star belongs to our sample of 55 K-giants studied for extra-solar planet and pulsation searches using the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) attached to the 1.8-m telescope at Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. We find a planetary companion with a long-period and low-amplitude radial velocity (RV) variations in oscillating K2 III star alpha Ari (HD 12929). We do not find the correlation between RV variations and chromospheric activity indicators (CaII H & K region, H{alpha} line). The bisector analysis also shows that bisector velocity span (BVS) does not show any obvious correlation with RV variation but has periodic component that may be attributed to the rotation of the star. If the RV variation is indeed caused by a planetary companion, an orbital solution with a period of P=381-days, a semi-amplitude of K=41m/s, and an eccentricity of e=0.25 fits the data best. Assuming a possible stellar mass of M_star_=1.5M_{sun}_, we estimate the minimum mass for the planetary companion of m_2_sini=1.8M_{Jupiter}_ with an orbital semi-major axis of 1.2AU. Our finding of a likely exoplanet in alpha Ari gives a support to search for extra-solar planets around giant stars with multi-periodic oscillations.
- ID:
- ivo://CDS.VizieR/J/A+A/578/A64
- Title:
- Velocity curve of {tau} Boo A
- Short Name:
- J/A+A/578/A64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed the tau Boo system with the HARPS-N spectrograph in order to test a new observational strategy aimed to jointly study asteroseismology, the planetary orbit and star-planet magnetic interaction. We collected high-cadence observations on 11 nearly consecutive nights, and for each night averaged the raw FITS files using dedicated software in order to obtain high S/N spectra to study the variation of the CaII H&K lines and radial velocity values free from stellar oscillations without losing this latter information. Specific software was written to build a new custom mask used to refine the RV determination with the HARPS-N pipeline and to perform the spectroscopic analysis. We updated the planetary ephemeris and proved the acceleration due to the stellar binary companion. The study of stellar activity variation suggests the presence of an high-latitude plage during the time span of our observations. The correlation between the chromospheric activity and the planetary orbital phase remains unclear. Solar-like oscillations are detected in the radial velocity time series: we estimate asteroseismic quantities finding good agreement with theoretical predictions. With the stellar model built we find for tau Boo an age of 0.9+/-0.5Gyr, and could further constrain the value of the stellar mass to 1.38+/-0.05M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/A+A/566/A67
- Title:
- Velocity curves of {beta}Cnc, {mu}Leo and {beta}UMi
- Short Name:
- J/A+A/566/A67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To investigate the low-amplitude and long-period variations in evolved stars with a precise radial velocity (RV) survey. The high-resolution, the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) was used from 2003 to 2013 for an RV survey of giant stars as part of the exoplanet search program at Bohyunsan Optical Astronomy Observatory (BOAO). We report the detection of three new planetary companions orbiting the K giants beta Cnc, mu Leo, and beta UMi. The planetary nature of the RV variations is supported by analyses of ancillary data. The HIPPARCOS photometry shows no variations with periods close to those in RV variations and there is no strong correlation between the bisector velocity span (BVS) and the RVs for each star. Furthermore, the stars show weak or no core reversal in Ca II H lines indicating that they are inactive stars. The companion to beta Cnc has a minimum mass of 7.8M_Jup_ in a 605-day orbit with an eccentricity of 0.08. mu Leo is orbited by a companion of minimum mass of 2.4M_Jup_ having a period of 357-days, and an eccentricity of 0.09. beta UMi is a known barium star and is suspected of harbouring a white dwarf or substellar mass companion. Its companion has a minimum mass of 6.1M_Jup_, a period of 522-days, and an eccentricity e=0.19.
