- ID:
- ivo://CDS.VizieR/J/A+A/513/A69
- Title:
- HD9446 radial velocity curve
- Short Name:
- J/A+A/513/A69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a planetary system around HD 9446, performed from radial velocity measurements secured with the spectrograph SOPHIE at the 193-cm telescope of the Haute-Provence Observatory for more than two years. At least two planets orbit this G5V, active star: HD 9446b has a minimum mass of 0.7M_Jup_ and a slightly eccentric orbit with a period of 30-days, whereas HD 9446c has a minimum mass of 1.8M_Jup_ and a circular orbit with a period of 193-days. As for most of the known multiple planet systems, the HD 9446-system presents a hierarchical disposition with a massive outer planet and a lighter inner planet.
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- ID:
- ivo://CDS.VizieR/J/A+A/505/853
- Title:
- HD16760 radial velocity curve
- Short Name:
- J/A+A/505/853
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the discovery of a substellar companion or a massive Jupiter orbiting the G5V star HD 16760 using the spectrograph SOPHIE installed on the OHP 1.93-m telescope. Characteristics and performances of the spectrograph are presented, as well as the SOPHIE exoplanet consortium program. With a minimum mass of 14.3M_{Jup}_, an orbital period of 465 days and an eccentricity of 0.067, HD 16760b seems to be located just at the end of the mass distribution of giant planets, close to the planet/brown-dwarf transition. Its quite circular orbit supports a formation in a gaseous protoplanetary disk.
- ID:
- ivo://CDS.VizieR/J/A+A/592/A13
- Title:
- HD 219828 radial velocity curve
- Short Name:
- J/A+A/592/A13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With about 2000 extrasolar planets confirmed, the results show that planetary systems have a whole range of unexpected properties. This wide diversity provides fundamental clues to the processes of planet formation and evolution. We present a full investigation of the HD 219828 system, a bright metal-rich star for which a hot neptune has previously been detected. We used a set of HARPS, SOPHIE, and ELODIE radial velocities to search for the existence of orbiting companions to HD 219828. The spectra were used to characterise the star and its chemical abundances, as well as to check for spurious, activity induced signals. A dynamical analysis is also performed to study the stability of the system and to constrain the orbital parameters and planet masses. We announce the discovery of a long period (P=13.1-years) massive (msini=15.1M_{Jup}_) companion (HD 219828 c) in a very eccentric orbit (e=0.81). The same data confirms the existence of a hot-neptune, HD 219828 b, with a minimum mass of 21M_{sun}_ and a period of 3.83-days. The dynamical analysis shows that the system is stable, and that the equilibrium eccentricity of planet $b$ is close to zero. The HD 219828 system is extreme and unique in several aspects. First, ammong all known exoplanet systems it presents an unusually high mass ratio. We also show that systems like HD 219828, with a hot neptune and a long-period massive companion are more frequent than similar systems with a hot jupiter instead. This suggests that the formation of hot neptunes follows a different path than the formation of their hot jovian counterparts. The high mass, long period, and eccentricity of HD 219828 c also make it a good target for Gaia astrometry as well as a potential target for atmospheric characterisation, using direct imaging or high-resolution spectroscopy. Astrometric observations will allow us to derive its real mass and orbital configuration. If a transit of HD 219828 b is detected, we will be able to fully characterise the system, including the relative orbital inclinations. With a clearly known mass, HD 219828 c may become a benchmark object for the range in between giant planets and brown dwarfs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/433/1300
- Title:
- HD 165052 radial-velocity measurements
- Short Name:
- J/MNRAS/433/1300
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new set of radial-velocity measurements of the spectroscopic binary star HD 165052 obtained by disentangling of high-resolution optical spectra. The longitude of the periastron ({varpi}=60+/-2{deg}) shows a variation with respect to previous studies. We have determined the apsidal motion rate of the system {dot{varpi}}=12.1+/-0.3{deg}/yr, which was used to calculate the absolute masses of the binary components: M_1_=22.5+/-1.0M_{sun}_ and M_2_=20.5+/-0.9M_{sun}_. Analysing the separated spectra we have re-classified the components as O7Vz and O7.5Vz stars.
- ID:
- ivo://CDS.VizieR/J/AJ/158/189
- Title:
- HD 126516 radial velocity & photometric observations
- Short Name:
- J/AJ/158/189
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From numerous radial velocities as well as Johnson B and V differential photoelectric photometry, we have determined the orbital elements and other properties of the single-lined triple system HD 126516. This system consists of a narrow-lined F5 V star and an unseen M dwarf companion in a 2.1241 day circular orbit. The small, low-mass secondary produces detectable eclipses of the primary, and that pair has been given the variable star name V349 Vir. Variations of the center-of-mass velocity of this short-period system have an orbital period of 702.7 days or 1.92 yr and an eccentricity of 0.36. The third star is likely a K or M dwarf. From an analysis of our photometry, we conclude that the primary of HD 126516 is not a {gamma} Dor variable. Comparison with evolutionary tracks indicates that the primary is slightly metal-poor and has an age of 2.5 Gyr. The projected rotational velocity of the primary is very low, just 4 km/s, which is 10 times less than its synchronous rotational velocity. Thus, either that component's rotation is extremely non-synchronous or the inclinations of the rotational and orbital axes are very different, and so the primary has a very large spin-orbit misalignment. Because of the moderate age of the system and the fact that its orbit is already circularized, neither situation is expected theoretically.
- ID:
- ivo://CDS.VizieR/J/A+A/585/A135
- Title:
- HD175607 RV, logRHK and Halpha index
- Short Name:
- J/A+A/585/A135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The presence of a small-mass planet (M_p_<0.1M_{Jup}_) seems, to date, not to depend on metallicity. However, theoretical simulations have shown that stars with subsolar metallicities may be favoured for harbouring smaller planets. A large dedicated survey of metal-poor stars with the HARPS spectrograph has thus been carried out to search for Neptunes and super-Earths. In this paper we present the analysis of HD175607, an old G6 star with metallicity [Fe/H]=-0.62. We gathered 119 radial velocity measurements in 110 nights over a timespan of more than 9 years. The radial velocities were analysed using Lomb-Scargle periodograms, a genetic algorithm, a Markov-Chain Monte-Carlo analysis, and a Gaussian processes analysis. The spectra were also used to derive stellar properties. Several activity indicators were analysed to study the effect of stellar activity on the radial velocities. We find evidence for the presence of a small Neptune-mass planet (M_p_sini=8.98+/-1.10M_{sun}_) orbiting this star with an orbital period P=29.01+/-0.02days in a slightly eccentric orbit (e=0.11+/-0.08). The period of this Neptune is close to the estimated rotational period of the star. However, from a detailed analysis of the radial velocities together with the stellar activity, we conclude that the best explanation of the signal is indeed due to the presence of a planetary companion rather than stellar related. An additional longer period signal (P~1400d) is present in the data, for which more measurements are needed to constrain its nature and its properties. HD175607 is the most metal-poor FGK dwarf with a detected low mass planet amongst the currently known planet hosts. This discovery may thus have important consequences for planet formation and evolution theories.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A133
- Title:
- HD 80653 RV time series
- Short Name:
- J/A+A/633/A133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ultra-short period (USP) planets are a class of exoplanets with periods shorter than one day. The origin of this sub-population of planets is st ill unclear, with different formation scenarios highly dependent on the composition of the USP planets. A better understanding of this class of exoplanets will, therefore, require an increase in the sample of such planets that have accurate and precise masses and radii, which also includes estimates of the level of irradiation and information about possible companions. Here we report a detailed characterization of a USP planet around the solar-type star HD 80653 = EP 251279430 using the K2 light curve and 108 precise radial velocities obtained with the HARPS-N spectrograph, installed on the Telescopio Nazionale Galileo. From the K2 C16 data, we found one super-Earth planet (Rb=1.613+/-0.071R_{Earth}_) transiting the star on a short-period orbit (Pb=0.719573+/-0.000021d). From our radial velocity measurements, we constrained the mass of HD 80653 b to Mb=5.60+/-0.43M_{Earth}_. We also detected a clear longterm trend in the radial velocity data. We derived the fundamental stellar parameters and determined a radius of R*=1.22+/-0.01R_{sun}_ and mass of M*=1.18+/-0.04M_{sun}_, suggesting that HD 80653 has an age of 2.7+/-1.2Gyr. The bulk density (rho_b_=7.4+/-1.1g/cm^3^) of the planet is consistent with an Earth-like composition of rock and iron and no thick atmosphere. Our analysis of the K2 photometry also suggests hints of a shallow secondary eclipse with a depth of 8.1+/- 3.7ppm. Flux variations along the orbital phase are consistent with zero. The most important contribution might come from the day-side thermal emission from the surface of the planet at T=3480K.
- ID:
- ivo://CDS.VizieR/J/A+A/636/L6
- Title:
- HD 158259 SOPHIE radial velocities
- Short Name:
- J/A+A/636/L6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since 2011, the SOPHIE spectrograph has been used to search for Neptunes and super-Earths in the northern hemisphere. As part of this observational program, 290 radial velocity measurements of the 6.4 V magnitude star HD 158259 were obtained. Additionally, TESS photometric measurements of this target are available. We present an analysis of the SOPHIE data and compare our results with the output of the TESS pipeline. The radial velocity data, ancillary spectroscopic indices, and ground-based photometric measurements were analyzed with classical and l_1_ periodograms. The stellar activity was modeled as a correlated Gaussian noise and its impact on the planet detection was measured with a new technique. The SOPHIE data support the detection of five planets, each with msini~=6M_{Earth}_, orbiting HD 158259 in 3.4, 5.2, 7.9, 12, and 17.4 days. Though a planetary origin is strongly favored, the 17.4 d signal is classified as a planet candidate due to a slightly lower statistical significance and to its proximity to the expected stellar rotation period. The data also present low frequency variations, most likely originating from a magnetic cycle and instrument systematics. Furthermore, the TESS pipeline reports a significant signal at 2.17 days corresponding to a planet of radius ~=1.2R_{Earth}_. A compatible signal is seen in the radial velocities, which confirms the detection of an additional planet and yields a ~=2M_{Earth}_ mass estimate. We find a system of five planets and a strong candidate near a 3:2 mean motion resonance chain orbiting HD 158259. The planets are found to be outside of the two and three body resonances.
- ID:
- ivo://CDS.VizieR/J/AZh/88/380
- Title:
- HD 192163 spectroscopic study
- Short Name:
- J/AZh/88/380
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used 46 high-resolution echelle spectra of the Wolf-Rayet star HD 192163 taken in 2005-2009 at the Cassegrain focus of the 2-m Zeiss-2000 telescope of the Shamakha Astrophysical Observatory to study profiles of the five strongest emission lines (HeII 4859, HeII 5411, CIV 5808, HeI 5875, (HeII+Halpha) 6560). We also obtained four echelle spectrograms of the Wolf-Rayet star HD 191765 for a comparative study of the NaI 5890 (D2) and NaI 5896 (D1) interstellar absorption lines. The echelle spectrograms were reduced using the DECH20 code. We determined the equivalent widths, radial velocities, central intensities, and half-widths of the emission lines. We We also studied the NaI 5890 (D2) and NaI 5896 (D1) interstellar absorption lines, which are important for understanding the nature of the nebula NGC 6888, whose origin is related to HD 192163.
- ID:
- ivo://CDS.VizieR/J/AJ/136/1557
- Title:
- HD 46703 spectroscopy and photometry
- Short Name:
- J/AJ/136/1557
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The metal-poor post-asymptotic giant branch (AGB) star HD 46703 is shown to be a single-line spectroscopic binary with a period of 600-days, a high velocity of -94km/s, and an orbital eccentricity of 0.3. Light-curve studies show that it also pulsates with a period of 29-days. High-resolution, high signal-to-noise spectra were used for a new abundance study.
