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7872. HARPS-TERRA project. I.
- 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/ApJ/794/110
- Title:
- HARPS timeseries data for HD41248
- Short Name:
- J/ApJ/794/110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gaining a better understanding of the effects of stellar-induced radial velocity noise is critical for the future of exoplanet studies since the discovery of the lowest-mass planets using this method will require us to go below the intrinsic stellar noise limit. An interesting test case in this respect is that of the southern solar analog HD 41248. The radial velocity time series of this star has been proposed to contain either a pair of signals with periods of around 18 and 25 days, which could be due to a pair of resonant super-Earths, or a single and varying 25 day signal that could arise due to a complex interplay between differential rotation and modulated activity. In this work, we build up more evidence for the former scenario, showing that the signals are still clearly significant, even after more than 10 yr of observations, and they likely do not change in period, amplitude, or phase as a function of time, the hallmarks of static Doppler signals. We show that over the last two observing seasons, this star was more intrinsically active and the noise reddened, highlighting why better noise models are needed to find the lowest amplitude signals, in particular, models that consider noise correlations. This analysis shows that there is still sufficient evidence for the existence of two super-Earths on the edge of, or locked into, a 7:5 mean motion resonance orbiting HD 41248.
- 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/523/A15
- Title:
- HARPS XXIII: RV data for the 8 targets
- Short Name:
- J/A+A/523/A15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present our HARPS radial-velocity data for eight low-activity solar-type stars belonging to the HARPS volume-limited sample: HD6718, HD8535, HD28254, HD290327, HD43197, HD44219, HD148156, and HD156411. Keplerian fits to these data reveal the presence of low-mass companions around these targets. With minimum masses ranging from 0.58 to 2.54M_{Jup}_, these companions are in the planetary mass domain. The orbital periods of these planets range from slightly less than one to almost seven years. The eight orbits presented in this paper exhibit a wide variety of eccentricities: from 0.08 to above 0.8.
- 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/A+A/633/A44
- Title:
- HARPS Young Nearby Stars - YNS
- Short Name:
- J/A+A/633/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Young nearby stars are good candidates in the search for planets with both radial velocity (RV) and direct imaging techniques. This, in turn, allows for the computation of the giant planet occurrence rates at all separations. The RV search around young stars is a challenge as they are generally faster rotators than older stars of similar spectral types and they exhibit signatures of magnetic activity (spots) or pulsation in their RV time series. Specific analyses are necessary to characterize, and possibly correct for, this activity. Our aim is to search for planets around young nearby stars and to estimate the giant planet (GP) occurrence rates for periods up to 1000 days. We used the HARPS spectrograph on the 3.6m telescope at La Silla Observatory to observe 89 A-M young (<600Myr) stars. We used our SAFIR (Spectroscopic data via Analysis of the Fourier Interspectrum Radial velocities) software to compute the RV and other spectroscopic observables. Then, we computed the companion occurrence rates on this sample. We confirm the binary nature of HD 177171, HD 181321 and HD 186704. We report the detection of a close low mass stellar companion for HIP 36985. No planetary companion was detected. We obtain upper limits on the GP (<13M_Jup_) and BD ({in}[13;80]M_Jup_) occurrence rates based on 83 young stars for periods less than 1000 days, which are set, 2_-2_^+3^ and 1_-1_^+3^%.
7878. Harvard variables
- ID:
- ivo://CDS.VizieR/J/other/IBVS/5298
- Title:
- Harvard variables
- Short Name:
- J/other/IBVS/529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Coordinates and identifications are presented for 726 Harvard Variable stars and suspected variables, discovered or studied by D. Hoffleit and announced in Harvard Bulletins 874, 884, 887, 901, and 902; plus 141 others, previously known, lying in the same fields.
- ID:
- ivo://CDS.VizieR/VIII/7A
- Title:
- Hat Creek High-Latitude H I Survey
- Short Name:
- VIII/7A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This survey consists of H I 21-cm spectra covering the entire northern sky with absolute Galactic latitude |b|>10 degrees and declination dec>-30degrees. The observations were made with the Hat Creek 85-foot telescope between 1968 and 1970. The individual spectra were obtained with a bank of 100 filters covering the velocity range from -92km/s to +75km/s. The velocity resolution was 2 km/sec (except at the ends of the spectra) and the beamwidth was 36arcmin. The spacing between points observed on the sky is (0.3deg/cosb) in Galactic longitude and (0.6deg) in Galactic latitude. A FITS version of the survey was derived at the Astrophysics Data Facility (NASA/GSFC) from the original catalog of spectra. The approximately 130,000 good spectra in the catalog (i.e., those with status code 1 and which have flat baselines) were interpolated to a uniform channel width in frequency, shifted as appropriate to take into account the proper central velocities, then interpolated onto a regular grid in Galactic coordinates. For the latter interpolation, the cos(b) corrections for longitude offsets were taken into account; no interpolation was done across gaps in coverage greater than 2 deg. Latitude-velocity slices were written in FITS format for each 30 arcmin of longitude. Separate files were written for the negative latitude (b < -10 deg ) and positive latitude (b > 10 deg) ranges. Slices containing no spectra, primarily negative latitude spectra in the fourth Galactic quadrant, were not written. A longitude-latitude map, integrated over all velocities, was also written in FITS format to illustrate the coverage of the individual latitude-velocity slices.
- ID:
- ivo://irsa.ipac/Herschel/Catalog/H-ATLAS/H-ATLAS_All
- Title:
- H-ATLAS All Potential Counterparts Catalog
- Short Name:
- H-ATLAS_All
- Date:
- 01 Oct 2018 20:27:20
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) is a survey of 600 deg^2 in five photometric bands - 100, 160, 250, 350 and 500 microns - with the Photoconductor Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) cameras. H-ATLAS DR1 includes the survey of three fields on the celestial equator, covering a total area of 161.6 deg^2 and previously observed in the Galaxy and Mass Assembly (GAMA) spectroscopic survey. The data release main catalogue (HATLAS_DR1_CATALOGUE.FITS) contains only the 'best' candidate ID to each SPIRE source (where available). Most users will find in this catalogue everything they will need for their science purposes. A second catalogue is also available (HATLAS_DR1_CATALOGUE_ALLIDS.FITS), which contains all possible counterparts within the search radius of each SPIRE source, and provides the full LR statistics so that these may be independently analysed as the user wishes. To select only sources which have reliable optical IDs, a cut of Reliability#0.8 is recommended, although other cuts on Reliability or LR may be suitable for different purposes as discussed in Bourne et al. (2016).