- ID:
- ivo://CDS.VizieR/J/A+A/375/L27
- Title:
- HD 80606b, a planet on an extremely elongated orbit
- Short Name:
- J/A+A/375/L27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Here we list the measured equivalent widths we used for estimating the stellar atmospheric parameters of the two components of the visual binary HD 80606-HD 80607. We also list our 61 individual radial velocity measurements for HD 80606. The radial-velocity measurements were obtained using the HIRES spectrograph mounted on the KECK1 10-m Telescope at the KECK Observatory (Hawaii, USA) and the ELODIE spectrograph mounted on the 1.93-m Telescope at Observatoire de Haute-Provence (France). The equivalent widths measurements for HD 80606 and HD 80607 were obtained using two additional high signal-to-noise HIRES spectra.
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7982. HD 22496 b ESPRESSO RVs
- ID:
- ivo://CDS.VizieR/J/A+A/654/A60
- Title:
- HD 22496 b ESPRESSO RVs
- Short Name:
- J/A+A/654/A60
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The ESPRESSO spectrograph is a new powerful tool developed to detect and characterize extrasolar planets. Its design allows an unprecedented radial velocity precision (down to a few tens of cm/s) and long-term thermomechanical stability. We present the first stand-alone detection of an extrasolar planet by blind radial velocity search using ESPRESSO; our aim is to show the power of the instrument in characterizing planetary signals at different periodicities in long observing time spans. We used 41 ESPRESSO measurements of HD 22496 obtained within a time span of 895 days with a median photon noise of 18cm/s. A radial velocity analysis was performed to test the presence of planets in the system and to account for the stellar activity of this K5-K7 main-sequence star. For benchmarking and comparison, we attempted the detection with 43 archive HARPS measurements and in this work we compare the results yielded by the two datasets. We also used four TESS sectors to search for transits. We find radial velocity variations compatible with a close-in planet with an orbital period of P=5.09071+/-0.00026 days when simultaneously accounting for the effects of stellar activity on longer timescales (Prot=34.99_-0.53_^+0.58^ days). We characterize the physical and orbital properties of the planet and find a minimum mass of 5.57_-0.68_^+0.73^M_{sun}_, right in the dichotomic regime between rocky and gaseous planets. Although not transiting according to TESS data, if aligned with the stellar spin axis, the absolute mass of the planet must be below 16M_{sun}_. We find no significant evidence for additional signals in the data with semi-amplitudes above 56cm/s at 95% confidence. With a modest set of radial velocity measurements, ESPRESSO is capable of detecting and characterizing low-mass planets and constraining the presence of planets in the habitable zone of K dwarfs down to the rocky-mass regime.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A96
- Title:
- HD142527B images with SPHERE
- Short Name:
- J/A+A/622/A96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- HD142527 observations were performed with SPHERE in the IRDIFS_EXT mode, with IRDIS observing in dual-band imaging with the K12 filter pair (wavelength K1=2.110 micron; K2=2.251 micron), while IFS obtains low-resolution (R=30) spectra between 0.95 and 1.65 micron. HD142527 was also observed in the SAM mode for SPHERE (we present the first observations that ever used the sparse aperture mask in SPHERE). We detect the accreting low-mass companion HD142527B at a separation of 73mas (11.4au) from the star.
- ID:
- ivo://CDS.VizieR/J/ApJ/791/55
- Title:
- HD 189733b in transit light curve
- Short Name:
- J/ApJ/791/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report near-infrared spectroscopy of the gas giant planet HD 189733b in transit. We used the Hubble Space Telescope Wide Field Camera 3 (HST WFC3) with its G141 grism covering 1.1 {mu}m to 1.7 {mu}m and spatially scanned the image across the detector at 2''/s. When smoothed to 75 nm bins, the local maxima of the transit depths in the 1.15 {mu}m and 1.4 {mu}m water vapor features are, respectively, 83+/-53 ppm and 200+/-47 ppm greater than the local minimum at 1.3 {mu}m. We compare the WFC3 spectrum with the composite transit spectrum of HD 189733b assembled by Pont et al., extending from 0.3 {mu}m to 24 {mu}m. Although the water vapor features in the WFC3 spectrum are compatible with the model of non-absorbing, Rayleigh-scattering dust in the planetary atmosphere, we also re-interpret the available data with a clear planetary atmosphere. In the latter interpretation, the slope of increasing transit depth with shorter wavelengths from the near infrared, through the visible, and into the ultraviolet is caused by unocculted star spots, with a smaller contribution of Rayleigh scattering by molecular hydrogen in the planet's atmosphere. At relevant pressures along the terminator, our model planetary atmosphere's temperature is ~700 K, which is below the condensation temperatures of sodium- and potassium-bearing molecules, causing the broad wings of the spectral lines of Na I and K I at 0.589 {mu}m and 0.769 {mu}m to be weak.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A154
- Title:
- HDBSCAN star, galaxy, QSO classification
- Short Name:
- J/A+A/633/A154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Classification will be an important first step for upcoming surveys that will detect billions of new sources such as LSST and Euclid, as well as DESI, 4MOST and MOONS. The application of traditional methods of model fitting and colour-colour selections will face significant computational constraints, while machine-learning (ML) methods offer a viable approach to tackle datasets of that volume. While supervised learning methods can perform very well for classification tasks, the creation of representative and accurate training sets is a resource and time consuming task. We present a viable alternative using an unsupervised ML method to separate stars, galaxies and QSOs using photometric data. The heart of our work uses HDBSCAN to find the star, galaxy and QSO clusters in a multidimensional colour space. We optimized the hyperparameters and input attributes of three separate HDBSCAN runs, each to select a particular object class, and thus treat the output of each separate run as a binary classifier. We subsequently consolidate the output to give our final classifications, optimized on their F1 scores. We explore the use of Random Forest and PCA as part of the pre-processing stage for feature selection and dimensionality reduction. Using our dataset of ~50000 spectroscopically labelled objects we obtain an F1 score of 98.9, 98.9 and 93.13 respectively for star, galaxy and QSO selection using our unsupervised learning method. We find that careful attribute selection is a vital part of accurate classification with HDBSCAN. We applied our classification to a subset of the SDSS spectroscopic catalogue and demonstrate the potential of our approach in correcting misclassified spectra useful for DESI and 4MOST. Finally, we create a multiwavelength catalogue of 2.7 million sources using the KiDS, VIKING and ALLWISE surveys and publish corresponding classifications and photometric redshifts.
- ID:
- ivo://CDS.VizieR/J/A+A/609/L5
- Title:
- HD147379 b velocity curve
- Short Name:
- J/A+A/609/L5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the first star discovered to host a planet detected by radial velocity (RV) observations obtained within the CARMENES survey for exoplanets around M dwarfs. HD 147379 (V=8.9mag, M=0.58+/-0.08M_{sun}_), a bright M0.0 V star at a distance of 10.7pc, is found to undergo periodic RV variations with a semi-amplitude of K=5.1+/-0.4m/s and a period of P=86.54+/-0.06d. The RV signal is found in our CARMENES data, which were taken between 2016 and 2017, and is supported by HIRES/Keck observations that were obtained since 2000. The RV variations are interpreted as resulting from a planet of minimum mass m_P_sini=25+/-2M_{Earth}_, 1.5 times the mass of Neptune, with an orbital semi-major axis a=0.32au and low eccentricity (e<0.13). HD 147379 b is orbiting inside the temperate zone around the star, where water could exist in liquid form. The RV time-series and various spectroscopic indicators show additional hints of variations at an approximate period of 21.1d (and its first harmonic), which we attribute to the rotation period of the star.
- ID:
- ivo://CDS.VizieR/J/A+A/637/A93
- Title:
- HD 79211 CARMENES radial velocities
- Short Name:
- J/A+A/637/A93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on radial velocity time series for two M0.0V stars, GJ 338 B and GJ 338 A, using the CARMENES spectrograph, complemented by ground-telescope photometry from Las Cumbres and Sierra Nevada observatories. We obtained 159 and 70 radial velocity measurements of GJ 338 B and A, respectively, with the CARMENES visible channel between 2016 January and 2018 October. We also compiled additional relative radial velocity measurements from the literature and a collection of astrometric data that cover 200yr of observations to solve for the binary orbit. We found dynamical masses of 0.64+/-0.07M_{sun}_ for GJ338B and 0.69+/-0.07M_{sun}_ for GJ338A. The CARMENES radial velocity periodograms show significant peaks at 16.61+/-0.04d (GJ 338 B) and 16.3+/-3.5d (GJ 338 A), which have counterparts at the same frequencies in CARMENES activity indicators and photometric light curves. We attribute these to stellar rotation. GJ 338 B shows two additional, significant signals at 8.27+/-0.01 and 24.45+/-0.02d, with no obvious counterparts in the stellar activity indices. The former is likely the first harmonic of the star's rotation, while we ascribe the latter to the existence of a super-Earth planet with a minimum mass of 10.27+/-1.47M_{Earth}_ orbiting GJ 338 B.
- ID:
- ivo://CDS.VizieR/J/A+A/646/L1
- Title:
- HDCCN discovery in space and in laboratory
- Short Name:
- J/A+A/646/L1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of TMC-1 with the Yebes 40m radio telescope in the 31.0-50.3GHz range allowed the detection of a group of unidentified lines, showing a complex line pattern indicative of an open-shell species. The observed frequencies of these lines and the similarity of the spectral pattern with that of the 2_02_-1_01_ rotational transition of H_2_CCN point to that the lines arise from the deuterated cyanomethyl radical, HDCCN. Using Fourier transform microwave spectroscopy experiments combined with electric discharges we have succeeded in producing the radical HDCCN in the laboratory and observed its 1_01_-0_00_ and 2_02_-1_01_ rotational transitions. From our observations and assuming a rotational temperature of 5K, we derive an abundance ratio H_2_CCN/HDCCN=20. The high abundance of the deuterated form of H_2_CCN is well accounted for by a standard gas-phase model where deuteration is driven by deuteron transfer from the H_2_D+ molecular ion.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A157
- Title:
- HD 108236 CHEOPS light curves
- Short Name:
- J/A+A/646/A157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The detection of a super-Earth and three mini-Neptunes transiting the bright (V=9.2mag) star HD108236 (also known as TOI-1233) was recently reported on the basis of TESS and ground-based light curves. We perform a first characterisation of the HD108236 planetary system through high-precision CHEOPS photometry and improve the transit ephemerides and system parameters. We characterise the host star through spectroscopic analysis and derive the radius with the infrared flux method.We constrain the stellar mass and age by combining the results obtained from two sets of stellar evolutionary tracks. We analyse the available TESS light curves and one CHEOPS transit light curve for each known planet in the system. We find that HD108236 is a Sun-like star with R*=0.877+/-0.008R_{sun}_, M*=0.869^+0.050^_0.048_M_{sun}_, and an age of 6.7^+4.0^_5.1_Gyr. We report the serendipitous detection of an additional planet, HD108236 f, in one of the CHEOPS light curves. For this planet, the combined analysis of the TESS and CHEOPS light curves leads to a tentative orbital period of about 29.5days. From the light curve analysis, we obtain radii of 1.615+/-0.051, 2.071+/-0.052, 2.539^+0.062^_0.065_, 3.083+/-0.052, and 2.017^+0.052^+0.057_R_{Earth}_ for planets HD108236 b to HD108236 f, respectively. These values are in agreement with previous TESS-based estimates, but with an improved precision of about a factor of two. We perform a stability analysis of the system, concluding that the planetary orbits most likely have eccentricities smaller than 0.1. We also employ a planetary atmospheric evolution framework to constrain the masses of the five planets, concluding that HD108236 b and HD108236 c should have an Earth-like density, while the outer planets should host a low mean molecular weight envelope. The detection of the fifth planet makes HD108236 the third system brighter than V=10mag to host more than four transiting planets. The longer time span enables us to significantly improve the orbital ephemerides such that the uncertainty on the transit times will be of the order of minutes for the years to come. A comparison of the results obtained from the TESS and CHEOPS light curves indicates that for a V~9mag solar-like star and a transit signal of 500ppm, one CHEOPS transit light curve ensures the same level of photometric precision as eight TESS transits combined, although this conclusion depends on the length and position of the gaps in the light curve.
7990. HD106315c I light curve
- ID:
- ivo://CDS.VizieR/J/A+A/603/L5
- Title:
- HD106315c I light curve
- Short Name:
- J/A+A/603/L5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Space-based transit surveys such as K2 and the Transiting Exoplanets Survey Satellite (TESS) allow the detection of small transiting planets with orbital periods greater than 10 days. Few of these warm Neptunes are currently known around stars bright enough to allow for detailed follow-up observations dedicated to their atmospheric characterization. The 21-day period and 3.95R_Earth_ planet HD106315c has been discovered by K2 based on the observation of two of its transits. We observed HD 106315 using the 1.2m Euler telescope equipped with the EulerCam camera on two occasions to confirm the transit using broadband photometry and refine the planetary period. Based on two observed transits of HD106315c, we detect its ~1mmag transit and obtain a precise measurement of the planetary ephemerides, which are critical for planning further follow-up observations. We used the attained precision together with the predicted yield from the TESS mission to evaluate the potential for ground-based confirmation of Neptune-sized planets found by TESS. We find that one-meter class telescopes on the ground equipped with precise photometers could substantially contribute to the follow-up of 162 TESS candidates orbiting stars with magnitudes of V<14. Of these candidates, 74 planets orbit stars with V<12 and 12 planets orbit V<10, which makes them high-priority objects for atmospheric characterization with high-end instrumentation.