- ID:
- ivo://CDS.VizieR/J/A+A/556/A110
- Title:
- HARPS radial velocities of GJ 163
- Short Name:
- J/A+A/556/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The meter-per-second precision achieved by today velocimeters enables the search for 1-10M_{earth}_ planets in the habitable zone of cool stars. This paper reports on the detection of 3 planets orbiting GJ 163 (HIP19394), a M3 dwarf monitored by our ESO/HARPS search for planets. We made use of the HARPS spectrograph to collect 150 radial velocities of GJ 163 over a period of 8 years. We searched the RV time series for coherent signals and found 5 distinct periodic variabilities.We investigated the stellar activity and casted doubts on the planetary interpretation for 2 signals. Before more data can be acquired we concluded that at least 3 planets are orbiting GJ 163. They have orbital periods of Pb=8.632+/-0.002, Pc=25:63+/-0.03 and Pd=604+/-8 days and minimum masses msini=10.6+/-0.6, 6.8+/-0.9, and 29+/-3, respectively. We hold our interpretations for the 2 additional signals with periods P(e)=19.4 and P(f)=108 days.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/636/A74
- Title:
- HARPS radial velocity database
- Short Name:
- J/A+A/636/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph is mounted since 2003 at the ESO 3.6m telescope in La Silla and provides state-of-the-art stellar radial velocity (RV) measurements with a precision down to ~1m/s. The spectra are extracted with a dedicated data-reduction software (DRS) and the RVs are computed by cross correlating with a numerical mask. The aim of this study is three-fold: (i) Create an easy access to the public HARPS RV data set. (ii) Apply the new public SpEctrum Radial Velocity AnaLyser (SERVAL) pipeline to the spectra, and produce a more precise RV data set. (iii) Check whether the precision of the RVs can be further improved by correcting for small nightly systematic effects. For each star observed with HARPS, we downloaded the publicly available spectra from the ESO archive, and recomputed the RVs with SERVAL. This was based on fitting each observed spectrum with a high signal-to-noise ratio template created by co-adding all the available spectra of that star. We then computed nightly zero points (NZPs) by averaging the RVs of quiet stars. Analysing the RVs of the most RV-quiet stars, whose RV scatter is <5m/s, we find that SERVAL RVs are on average more precise than DRS RVs by a few percent. Investigating the NZP time series, we find three significant systematic effects, whose magnitude is independent of the software used for the RV derivation: (i) stochastic variations with a magnitude of ~1m/s; (ii) longterm variations, with a magnitude of ~1m/s and a typical timescale of a few weeks; and (iii) 20-30NZPs significantly deviating by few m/s. In addition, we find small (<~1m/s) but significant intra-night drifts in DRS RVs before the 2015 intervention, and in SERVAL RVs after it. We confirm that the fibre exchange in 2015 caused a discontinuous RV jump, which strongly depends on the spectral type of the observed star: from ~14m/s for late F-type stars, to ~-3m/sx for M dwarfs. The combined effect of extracting the RVs with SERVAL and correcting them for the systematics we find is an improved average RV precision: ~5% improvement for spectra taken before the 2015 intervention, and ~15% improvement for spectra taken after it. To demonstrate the quality of the new RV data set, we present an updated orbital solution of the GJ 253 two-planet system. Our NZP-corrected SERVAL RVs can be retrieved from a user-friendly, public database. It provides more than 212000 RVs for about 3000 stars along with many auxiliary information, such as the NZP corrections, various activity indices, and DRS-CCF products.
- ID:
- ivo://CDS.VizieR/J/A+A/575/A119
- Title:
- HARPS RV and stellar activity
- Short Name:
- J/A+A/575/A119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Planetary companions of a fixed mass induce reflex motions with a larger amplitude around lower-mass stars, which adds to making M dwarfs excellent targets for extra-solar planet searches. The most recent velocimeters with a stability of can detect very low-mass planets out to the habitable zone of these stars. Low-mass small planets are abundant around M dwarfs, and most of the known potentially habitable planets orbit one of these cool stars. Our M-dwarf radial velocity monitoring with HARPS on the ESO 3.6m telescope at La Silla observatory makes a major contribution to this sample. We present here dense radial velocity (RV) time series for three M dwarfs observed over ~five years: GJ 3293 (0.42M_{sun}_), GJ 3341 (0.47M_{sun}_), and GJ 3543 (0.45M_{sun}_). We extracted these RVs through minimum chi^2^ -matching of each spectrum against a stack of all observed spectra for the same star that has a high S/N ratio. We then compared potential orbital signals against several stellar activity indicators to distinguish the Keplerian variations induced by planets from the spurious signals that result from rotational modulation of stellar surface inhomogeneities and from activity cycles.
- ID:
- ivo://CDS.VizieR/J/A+A/535/A54
- Title:
- HARPS search for extra-solar planets. XXIX
- Short Name:
- J/A+A/535/A54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- 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/A+A/654/A104
- Title:
- HARPS XLVI. RV data for the 5 targets
- Short Name:
- J/A+A/654/A104
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present precise radial-velocity measurements of five solar-type stars observed with the HARPS Echelle spectrograph mounted on the 3.6-m telescope in La Silla (ESO, Chile). With a time span of more than 10 years and a fairly dense sampling, the survey is sensitive to low mass planets down to super-Earths on orbital periods up to 100 days. Our goal was to search for planetary companions around the stars HD39194, HD93385, HD96700, HD154088, and HD189567 and use Bayesian model comparison to make an informed choice on the number of planets present in the systems based on the radial velocity observations. These findings will contribute to the pool of known exoplanets and better constrain their orbital parameters. A first analysis was performed using the DACE (Data & Analysis Center for Exoplanets) online tools to assess the activity level of the star and the potential planetary content of each system. We then used Bayesian model comparison on all targets to get a robust estimate of the number of planets per star. We did this using the nested sampling algorithm PolyChord. For some targets, we also compared different noise models to disentangle planetary signatures from stellar activity. Lastly, we ran an efficient MCMC (Markov chain Monte Carlo) algorithm for each target to get reliable estimates for the planets' orbital parameters. We identify 12 planets within several multiplanet systems. These planets are all in the super-Earth and sub-Neptune mass regime with minimum masses ranging between 4 and 13 M_{Earth}_ and orbital periods between 5 and 103 days. Three of these planets are new, namely HD 93385 b, HD 96700 c, and HD 189567 c.
- ID:
- ivo://CDS.VizieR/J/A+A/549/A109
- Title:
- HARPS XXXI. The M-dwarf sample
- Short Name:
- J/A+A/549/A109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Searching for planets around stars with different masses helps us to assess the outcome of planetary formation for different initial conditions. The low-mass M dwarfs are also the most frequent stars in our Galaxy and potentially therefore, the most frequent planet hosts. We present observations of 102 southern nearby M dwarfs, using a fraction of our guaranteed time on the ESO/HARPS spectrograph. We observed for 460 h and gathered 1965 precise (~1-3m/s) radial velocities (RVs), spanning the period from Feb. 11, 2003 to Apr. 1, 2009.
- ID:
- ivo://CDS.VizieR/J/ApJ/726/52
- Title:
- HAT-P-18 and HAT-P-19 follow-up
- Short Name:
- J/ApJ/726/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two new transiting extrasolar planets. HAT-P-18b orbits the V=12.759 K2 dwarf star GSC 2594-00646, with a period P=5.508023+/-0.000006 days, transit epoch T_c_=2454715.02174+/-0.00020(BJD), and transit duration 0.1131+/-0.0009 days. The host star has a mass of 0.77+/-0.03M_{sun}_, radius of 0.75+/-0.04R_{sun}_, effective temperature 4803+/-80K, and metallicity [Fe/H]=+0.10+/-0.08. The planetary companion has a mass of 0.197+/-0.013M_J_ and radius of 0.995+/-0.052R_J_, yielding a mean density of 0.25+/-0.04g/cm^3^. HAT-P-19b orbits the V=12.901 K1 dwarf star GSC 2283-00589, with a period P=4.008778+/-0.000006 days, transit epoch T_c_=2455091.53417+/-0.00034(BJD), and transit duration 0.1182+/-0.0014 days. The host star has a mass of 0.84+/-0.04M_{sun}_, radius of 0.82+/-0.05R_{sun}_, effective temperature 4990+/-130K, and metallicity [Fe/H]=+0.23+/-0.08. The planetary companion has a mass of 0.292+/-0.018M_J_ and radius of 1.132+/-0.072R_J_, yielding a mean density of 0.25+/-0.04g/cm^3^. The radial velocity residuals for HAT-P-19 exhibit a linear trend in time, which indicates the presence of a third body in the system. Comparing these observations with theoretical models, we find that HAT-P-18b and HAT-P-19b are each consistent with a hydrogen-helium-dominated gas giant planet with negligible core mass. HAT-P-18b and HAT-P-19b join HAT-P-12b and WASP-21b in an emerging group of low-density Saturn-mass planets, with negligible inferred core masses. However, unlike HAT-P-12b and WASP-21b, both HAT-P-18b and HAT-P-19b orbit stars with super-solar metallicity.
- ID:
- ivo://CDS.VizieR/J/ApJ/742/59
- Title:
- HAT-P-32 and HAT-P-33 follow-up
- Short Name:
- J/ApJ/742/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two exoplanets transiting high-jitter stars. HAT-P-32b orbits the bright V=11.289 late-F-early-G dwarf star GSC 3281-00800, with a period P=2.150008+/-0.000001d. The stellar and planetary masses and radii depend on the eccentricity of the system, which is poorly constrained due to the high-velocity jitter (~80m/s). Assuming a circular orbit, the star has a mass of 1.16+/-0.04M_{sun}_ and radius of 1.22+/-0.02R_{sun}_, while the planet has a mass of 0.860+/-0.164M_J_ and a radius of 1.789+/-0.025R_J_. The second planet, HAT-P-33b, orbits the bright V=11.188 late-F dwarf star GSC 2461-00988, with a period P=3.474474+/-0.000001d. As for HAT-P-32, the stellar and planetary masses and radii of HAT-P-33 depend on the eccentricity, which is poorly constrained due to the high jitter (~50m/s). In this case, spectral line bisector spans (BSs) are significantly anti-correlated with the radial velocity residuals, and we are able to use this correlation to reduce the residual rms to ~35m/s. We find that the star has a mass of 1.38+/-0.04M_{sun}_ and a radius of 1.64+/-0.03R_{sun}_ while the planet has a mass of 0.762+/-0.101M_J_ and a radius of 1.686+/-0.045R_J_ for an assumed circular orbit. Due to the large BS variations exhibited by both stars we rely on detailed modeling of the photometric light curves to rule out blend scenarios. Both planets are among the largest radii transiting planets discovered to date.
- ID:
- ivo://CDS.VizieR/J/ApJ/733/116
- Title:
- HAT-P-28 and HAT-P-29 photometry
- Short Name:
- J/ApJ/733/116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of two transiting exoplanets. HAT-P-28b orbits a V=13.03 G3 dwarf star with a period P=3.2572 days and has a mass of 0.63+/-0.04M_J_ and a radius of 1.21^+0.11^_-0.08_R_J_ yielding a mean density of 0.44+/-0.09g/cm^3^. HAT-P-29b orbits a V=11.90 F8 dwarf star with a period P=5.7232 days and has a mass of 0.78^+0.08^_-0.04_M_J_ and a radius of 1.11^+0.14^_-0.08_R_J_ yielding a mean density of 0.71+/-0.18g/cm^3^. We discuss the properties of these planets in the context of other known transiting planets
