- ID:
- ivo://CDS.VizieR/J/A+A/523/A88
- Title:
- A Jupiter-mass companion around HD 109246
- Short Name:
- J/A+A/523/A88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of a Jupiter-mass planet discovered with the SOPHIE spectrograph mounted on the 1.93-m telescope at the Haute-Provence Observatory. The new planet orbits HD 109246, a G0V star slightly more metallic than the Sun. HD 109246b has a minimum mass of 0.77M_{jup}_, an orbital period of 68 days, and an eccentricity of 0.12. It is placed in a sparsely populated region of the period distribution of extrasolar planets. We also present a correction method for the so-called seeing effect that affects the SOPHIE radial velocities. We complement this discovery announcement with a description of some calibrations that are implemented in the SOPHIE automatic reduction pipeline. These calibrations allow the derivation of the photon-noise radial velocity uncertainty and some useful stellar properties (vsini, [Fe/H], log R'hk) directly from the SOPHIE data.
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- ID:
- ivo://CDS.VizieR/J/A+A/545/A55
- Title:
- Extrasolar planets. Radial velocities of 5 stars
- Short Name:
- J/A+A/545/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial-velocity measurements obtained in one of a number of programs underway to search for extrasolar planets with the spectrograph SOPHIE at the 1.93-m telescope of the Haute-Provence Observatory. Targets were selected from catalogs observed with ELODIE, which had been mounted previously at the telescope, in order to detect long-period planets with an extended database close to 15 years.
- ID:
- ivo://CDS.VizieR/J/A+A/593/A117
- Title:
- GJ 3998 RVs, S and Halpha indexes
- Short Name:
- J/A+A/593/A117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- M dwarfs are considered ideal targets for Doppler radial velocity searches. Nonetheless, the statistics of frequency of low-mass planets hosted by low mass stars remains poorly constrained. Our M-dwarf radial velocity monitoring with HARPS-N can provide a major contribution to the widening of the current statistics through the in-depth analysis of accurate radial velocity observations in a narrow range of spectral sub-types (79 stars, between dM0 to dM3). Spectral accuracy will enable us to reach the precision needed to detect small planets with a few earth masses. Our survey will bring a contribute to the surveys devoted to the search for planets around M-dwarfs, mainly focused on the M-dwarf population of the northern hemisphere, for which we will provide an estimate of the planet occurence. We present here a long duration radial velocity monitoring of the M1 dwarf star GJ 3998 with HARPS-N to identify periodic signals in the data. Almost simultaneous photometric observations were carried out within the APACHE and EXORAP programs to characterize the stellar activity and to distinguish from the periodic signals those due to activity and to the presence of planetary companions. The radial velocities have a dispersion in excess of their internal errors due to at least four superimposed signals, with periods of 30.7, 13.7, 42.5 and 2.65-days. The analysis of spectral indices based on Ca II H & K and H{alpha} lines demonstrates that the periods of 30.7 and 42.5-days are due to chromospheric inhomogeneities modulated by stellar rotation and differential rotation. The shorter periods of 13.74+/-0.02d and 2.6498+/-0.0008d are well explained with the presence of two planets, with minimum masses of 6.26+/-0.79M_Earth_ and 2.47+/-0.27M_Earth_ and distances of 0.089AU and 0.029AU from the host, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A63
- Title:
- HADES VI. GJ 3942b activity with HARPS-N
- Short Name:
- J/A+A/608/A63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Short- to mid-term magnetic phenomena on the stellar surface of M-type stars can resemble the effects of planets in radial velocity data, and may also hide them. We analyze 145 spectroscopic HARPS-N observations of GJ 3942 taken over the past five years and additional photometry in order to disentangle stellar activity effects from genuine Doppler signals as a result of the orbital motion of the star around the common barycenter with its planet. To achieve this, we use the common methods of pre-whitening, and treat the correlated red noise by a first-order moving average term and by Gaussian-process regression following an MCMC analysis. We identify the rotational period of the star at 16.3-days and discover a new super-Earth, GJ 3942b, with an orbital period of 6.9-days and a minimum mass of 7.1M_Earth_. An additional signal in the periodogram of the residuals is present, but at this point we cannot claim with sufficient significance that it is related to a second planet. If confirmed, this planet candidate would have a minimum mass of 6.3M_Earth_ and a period of 10.4-days, which might indicate a 3:2 mean-motion resonance with the inner planet.
- ID:
- ivo://CDS.VizieR/J/ApJS/200/15
- Title:
- HARPS-TERRA project. I.
- Short Name:
- J/ApJS/200/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Doppler spectroscopy has uncovered or confirmed all the known planets orbiting nearby stars. Two main techniques are used to obtain precision Doppler measurements at optical wavelengths. The first approach is the gas cell method, which consists of least-squares matching of the spectrum of iodine imprinted on the spectrum of the star. The second method relies on the construction of a stabilized spectrograph externally calibrated in wavelength. The most precise stabilized spectrometer in operation is the High Accuracy Radial velocity Planet Searcher (HARPS), operated by the European Southern Observatory in La Silla Observatory, Chile. The Doppler measurements obtained with HARPS are typically obtained using the cross-correlation function (CCF) technique. This technique consists of multiplying the stellar spectrum by a weighted binary mask and finding the minimum of the product as a function of the Doppler shift. It is known that CCF is suboptimal in exploiting the Doppler information in the stellar spectrum. Here we describe an algorithm to obtain precision radial velocity measurements using least-squares matching of each observed spectrum to a high signal-to-noise ratio template derived from the same observations. This algorithm is implemented in our software HARPS-TERRA (Template-Enhanced Radial velocity Re-analysis Application). New radial velocity measurements on a representative sample of stars observed by HARPS are used to illustrate the benefits of the proposed method. We show that, compared with CCF, template matching provides a significant improvement in accuracy, especially when applied to M dwarfs.
- ID:
- ivo://CDS.VizieR/J/AJ/147/128
- Title:
- HAT-P-44, HAT-P-45, and HAT-P-46 follow-up
- Short Name:
- J/AJ/147/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery by the HATNet survey of three new transiting extrasolar planets orbiting moderately bright (V=13.2, 12.8, and 11.9) stars. The planets have orbital periods of 4.3012, 3.1290, and 4.4631 days, masses of 0.35, 0.89, and 0.49M_J_, and radii of 1.24, 1.43, and 1.28R_J_. The stellar hosts have masses of 0.94, 1.26, and 1.28M_{sun}_. Each system shows significant systematic variations in its residual radial velocities, indicating the possible presence of additional components. Based on its Bayesian evidence, the preferred model for HAT-P-44 consists of two planets, including the transiting component, with the outer planet having a period of 872 days, eccentricity of 0.494+/-0.081, and a minimum mass of 4.0M_J_. Due to aliasing we cannot rule out alternative solutions for the outer planet having a period of 220 days or 438 days. For HAT-P-45, at present there is not enough data to justify the additional free parameters included in a multi-planet model; in this case a single-planet solution is preferred, but the required jitter of 22.5+/-6.3m/s is relatively high for a star of this type. For HAT-P-46 the preferred solution includes a second planet having a period of 78 days and a minimum mass of 2.0M_J_, however the preference for this model over a single-planet model is not very strong. While substantial uncertainties remain as to the presence and/or properties of the outer planetary companions in these systems, the inner transiting planets are well characterized with measured properties that are fairly robust against changes in the assumed models for the outer planets. Continued radial velocity monitoring is necessary to fully characterize these three planetary systems, the properties of which may have important implications for understanding the formation of hot Jupiters.
- ID:
- ivo://CDS.VizieR/J/AJ/147/84
- Title:
- Photometry and spectroscopy of HAT-P-49
- Short Name:
- J/AJ/147/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of the transiting extrasolar planet HAT-P-49b. The planet transits the bright (V=10.3) slightly evolved F-star HD340099 with a mass of 1.54M_{Sun}_ and a radius of 1.83R_{Sun}_. HAT-P-49b is orbiting one of the 25 brightest stars to host a transiting planet which makes this a favorable candidate for detailed follow-up. This system is an especially strong target for Rossiter-McLaughlin follow-up due to the host star's fast rotation, 16km/s. The planetary companion has a period of 2.6915 days, mass of 1.73M_J_, and radius of 1.41R_J_. The planetary characteristics are consistent with that of a classical hot Jupiter but we note that this is the fourth most massive star to host a transiting planet with both M_p_ and R_p_ well determined.
- ID:
- ivo://CDS.VizieR/J/ApJ/697/544
- Title:
- Planets orbiting metal-poor dwarfs. II.
- Short Name:
- J/ApJ/697/544
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of three years of precision radial velocity (RV) measurements of 160 metal-poor stars observed with HIRES on the Keck 1 telescope. We report on variability and long-term velocity trends for each star in our sample. We identify several long-term, low-amplitude RV variables worthy of followup with direct imaging techniques. We place lower limits on the detectable companion mass as a function of orbital period. Our survey would have detected, with a 99.5% confidence level, over 95% of all companions on low-eccentricity orbits with velocity semiamplitude K>~100m/s, or M_p_sini>~3.0M_J_(P/yr)^(1/3)^, for orbital periods P<~3yr. None of the stars in our sample exhibits RV variations compatible with the presence of Jovian planets with periods shorter than the survey duration.
- ID:
- ivo://CDS.VizieR/J/A+A/580/A14
- Title:
- Radial Velocities of 3 giant stars with planets
- Short Name:
- J/A+A/580/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of two giant planets around the intermediate-mass evolved star HIP65891 and HIP107773. The best Keplerian fit to the HIP65891 and HIP107773 radial velocities leads to the following orbital parameters: P=1084.5d; Mpsini=6.0M_Jup_; e=0.13 and P=144.3d; Mpsini=2.0M_Jup_; e=0.09, respectively. In addition, we confirm the planetary nature of the outer object orbiting the giant star HIP67851. The orbital parameters of HIP67851c are: P=2131.8d, Mpsini=6.0M_Jup_, and e=0.17.
- ID:
- ivo://CDS.VizieR/J/A+A/474/293
- Title:
- Radial velocities of GJ 674
- Short Name:
- J/A+A/474/293
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper reports the discovery of a 11M_{earth}_ planet orbiting the nearby M dwarf GJ 674. The paper also shows the star has a spot on its surface. The spot modulates the radial-velocity, the photometric measurements as well as the spectroscopic indices. Here we list the radial-velocity data measured with HARPS (a high-resolution spectrograph providing high precision radial velocities), the spectroscopic indices measured on the same spectra gathered with HARPS and the photometric measurements gathered with the C2 Camera of the EULER Telescope.