- ID:
- ivo://CDS.VizieR/J/A+A/597/A108
- Title:
- GJ 536 HARPS and HARPS-N data
- Short Name:
- J/A+A/597/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a super-Earth orbiting the star GJ 536 based on the analysis of the radial-velocity time series from the HARPS and HARPS-N spectrographs. GJ 536 b is a planet with a minimum mass Msini of 5.36+/-0.69M_{Earth}_ with an orbital period of 8.7076+/-0.0025 days at a distance of 0.066610(13) AU, and an orbit that is consistent with circular. The host star is the moderately quiet M1 V star GJ 536, located at 10 pc from the Sun. We find the presence of a second signal at 43 days that we relate to stellar rotation after analysing the time series of Ca II H&K and Halpha spectroscopic indicators and photometric data from the ASAS archive. We find no evidence linking the short period signal to any activity proxy. We also tentatively derived a stellar magnetic cycle of less than 3 years.
Number of results to display per page
Search Results
512. GJ 625 HARPS-N data
- ID:
- ivo://CDS.VizieR/J/A+A/605/A92
- Title:
- GJ 625 HARPS-N data
- Short Name:
- J/A+A/605/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a super-Earth orbiting at the inner edge of the habitable zone of the star GJ 625 based on the analysis of the radial-velocity (RV) time series from the HARPS-N spectrograph, consisting in 151 HARPS-N measurements taken over 3.5yr. GJ 625 b is a planet with a minimum mass Msini of 2.82+/-0.51 M_Earth_ with an orbital period of 14.628+/-0.013 days at a distance of 0.078AU of its parent star. The host star is the quiet M2 V star GJ 625, located at 6.5pc from the Sun. We find the presence of a second radial velocity signal in the range 74-85 days that we relate to stellar rotation after analysing the time series of CaII H&K and H{alpha} spectroscopic indicators, the variations of the FWHM of the CCF and and the APT2 photometric light curves. We find no evidence linking the short period radial velocity signal to any activity proxy.
- ID:
- ivo://CDS.VizieR/J/MNRAS/484/3731
- Title:
- GJ 9827 HARPS-N RV data
- Short Name:
- J/MNRAS/484/3731
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Super-Earths belong to a class of planet not found in the Solar system, but which appear common in the Galaxy. Given that some super-Earths are rocky, while others retain substantial atmospheres, their study can provide clues as to the formation of both rocky and gaseous planets, and - in particular - they can help to constrain the role of photoevaporation in sculpting the exoplanet population. GJ 9827 is a system already known to host three super-Earths with orbital periods of 1.2, 3.6, and 6.2d. Here, we use new HARPS-N radial velocity measurements, together with previously published radial velocities, to better constrain the properties of the GJ 9827 planets. Our analysis cannot place a strong constraint on the mass of GJ 9827 c, but does indicate that GJ 9827 b is rocky with a composition that is probably similar to that of the Earth, while GJ 9827 d almost certainly retains a volatile envelope. Therefore, GJ 9827 hosts planets on either side of the radius gap that appears to divide super-Earths into pre-dominantly rocky ones that have radii below ~1.5R_{Earth}_, and ones that still retain a substantial atmosphere and/or volatile components, and have radii above ~2R_{Earth}_. That the less heavily irradiated of the three planets still retains an atmosphere, may indicate that photoevaporation has played a key role in the evolution of the planets in this system.
- ID:
- ivo://CDS.VizieR/J/ApJ/901/23
- Title:
- Gjoll stream stars & detailed abund. of 4 members
- Short Name:
- J/ApJ/901/23
- Date:
- 15 Feb 2022 14:07:06
- Publisher:
- CDS
- Description:
- Recent analysis of the second data release of Gaia has revealed a number of new stellar streams surrounding the Milky Way. It has been suggested that one of these streams, Gjoll, is associated with the globular cluster NGC 3201, but thus far the association has only been based on kinematics of the stream stars. In this work we identify five likely stream members in the Gaia data that are bright enough for high-resolution spectroscopic follow-up with the Harlan J. Smith telescope at McDonald Observatory. One star is ruled out as a member based on its radial velocity. Abundance analysis of the remaining four kinematic members reveals a good chemical match to NGC 3201 for two of the stars, driven by their similar Al and {alpha}-element abundances. Of the remaining two, one shows no chemical similarity to NGC 3201 and is likely an unassociated Milky Way halo field star, while the other exhibits a similar Al abundance but has somewhat lower {alpha}-element abundances. The chemical tagging of stars in the Gjoll stream to NGC3201 confirms this association and provides direct proof of the hierarchical formation of the Milky Way.
- ID:
- ivo://CDS.VizieR/J/A+A/648/A20
- Title:
- GJ 740 radial velocities
- Short Name:
- J/A+A/648/A20
- Date:
- 29 Nov 2021 07:26:47
- Publisher:
- CDS
- Description:
- M-dwarfs have proven to be ideal targets for planetary radial velocity (RV) searches due to their higher planet-star mass contrast, which favors the detection of low-mass planets. The abundance of super-Earth and Earth-like planets detected around this type of stars encourages us to continue this search on hosts without reported planetary companions. The HADES and CARMENES programs aim to carry out extensive searches of exoplanetary systems around M-type stars in the northern hemisphere, allowing us to address statistically the properties of the planets orbiting these objects. In this work, we performed a spectroscopic and photometric study on one of the program stars (GJ 740), which exhibits a short-period RV signal compatible with a planetary companion. We carried out a spectroscopic analysis based on 129 HARPS-N spectra taken over a time-span of 6 yr combined with 57 HARPS spectra taken over 4yr, and 32 CARMENES spectra taken during more than 1 yr, resulting in a dataset with a time coverage of 10yr. We also relied on 459 measurements from the public ASAS survey with a time-coverage of 8yr along with 5yr of photometric magnitudes from the EXORAP project taken in the V, B, R and I filters to carry out a photometric study. Both analyses were made using Markov Chain Monte Carlo (MCMC) simulations and Gaussian Process regression to model the activity of the star. We present the discovery of a short-period super-Earth with an orbital period of 2.37756^+0.00013^_-0.00011_d and a minimum mass of 2.96^+0.50^_-0.48_Me. We update the previously reported characterization of the magnetic cycle and rotation period of the star, obtaining values of Prot=35.563+/-0.071d and Pcycle=2800+/-150d. The RV time-series exhibits a possibly periodic long-term signal which might be related to a Saturn-mass planet of ~100Me.
- ID:
- ivo://CDS.VizieR/J/other/Sci/365.1441
- Title:
- GJ 3512 radial velocity and light curves
- Short Name:
- J/other/Sci/365.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Surveys have shown that super-Earth and Neptune-mass exoplanets are more frequent than gas giants around low-mass stars, as predicted by the core accretion theory of planet formation. We report the discovery of a giant planet around the very-low-mass star GJ 3512, as determined by optical and near-infrared radial-velocity observations. The planet has a minimum mass of 0.46 Jupiter masses, very high for such a small host star, and an eccentric 204-day orbit. Dynamical models show that the high eccentricity is most likely due to planet-planet interactions. We use simulations to demonstrate that the GJ 3512 planetary system challenges generally accepted formation theories, and that it puts constraints on the planet accretion and migration rates. Disk instabilities may be more efficient in forming planets than previously thought.
- ID:
- ivo://CDS.VizieR/J/A+A/528/A111
- Title:
- GJ3634 radial velocity and 4.5um flux
- Short Name:
- J/A+A/528/A111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the detection of GJ3634b, a super-Earth of mass msini=7.0+/-0.9 Mearth and period P=2.64561+/-0.00066-day. Its host star is a M2.5 dwarf, has a mass of 0.45+/-0.05M_{sun}_, a radius of 0.43+/-0.03R_{sun}_ and lies 19.8+/-0.6pc away from our Sun. The planet is detected after a radial-velocity campaign using the ESO/Harps spectrograph. GJ3634b had an a priori geometric probability to undergo transit of ~7% and, if telluric in composition, a non-grazing transit would produce a photometric dip of <~0.1%. We therefore followed-up upon the RV detection with photometric observations using the 4.5-um band of the IRAC imager onboard Spitzer. Our six-hour long light curve excludes that a transit occurs for 2sigma of the probable transit window, decreasing the probability that GJ3634b undergoes transit to ~0.5%.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A153
- Title:
- GJ 4276 radial velocity curve
- Short Name:
- J/A+A/622/A153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of a Neptune-mass exoplanet around the M4.0 dwarf GJ 4276 (G 232-070) based on radial velocity (RV) observations obtained with the CARMENES spectrograph. The RV variations of GJ 4276 are best explained by the presence of a planetary companion with a minimum mass of m_b_sini~16M_{sun}_ on a P_b_=13.35-day orbit. The analysis of the activity indicators and spectral diagnostics exclude stellar induced RV perturbations and prove the planetary interpretation of the RV signal. We show that a circular single-planet solution can be excluded by means of a likelihood ratio test. Instead, we find that the RV variations can either be explained by an eccentric orbit or interpreted as a pair of planets on circular orbits near a period ratio of 2:1. Although the eccentric single-planet solution is slightly preferred, our statistical analysis indicates that none of these two scenarios can be rejected with high confidence using the RV time series obtained so far. Based on the eccentric interpretation, we find that GJ 4276 b is the most eccentric (e_b_=0.37) exoplanet around an M dwarf with such a short orbital period known today.
- ID:
- ivo://CDS.VizieR/J/A+A/649/L12
- Title:
- GJ 1151 radial velocity curve
- Short Name:
- J/A+A/649/L12
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The interaction between Earth-like exoplanets and the magnetic field of low-mass host stars are considered to produce weak emission signals at radio frequencies. A study using LOFAR data announced the detection of radio emission from the mid M-type dwarf GJ 1151 that could potentially arise from a close-in terrestrial planet. Recently, the presence of a 2.5-M_{earth}_ planet orbiting GJ 1151 with a 2-day period has been claimed using 69 radial velocities (RVs) from the HARPS-N and HPF instruments. We have obtained 70 new high-precision RV measurements in the framework of the CARMENES M-dwarf survey and use these data to confirm the presence of the claimed planet and to place limits on possible planetary companions in the GJ 1151 system. We analysed the periodicities present in the combined RV data sets from all three instruments and calculated the detection limits for potential planets in short-period orbits. We cannot confirm the recently announced candidate planet and conclude that the 2-day signal in the HARPS-N and HPF data sets is most probably produced by a long-term RV variability, possibly arising from an outer planetary companion that has yet to be constrained. We calculate a 99.9% significance detection limit of 1.50m/s in the RV semi-amplitude, which places upper limits of 0.7M_{earth}_ and 1.2M_{earth}_ on the minimum masses of potential exoplanets with orbital periods of 1 and 5 days, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/507/487
- Title:
- GJ 581 radial velocity curve
- Short Name:
- J/A+A/507/487
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The GJ 581 planetary system is already known to harbour three planets, including two super-Earth planets that straddle its habitable zone. We report the detection of an additional planet - GJ 581e - with a minimum mass of 1.9M_{earth}_. With a period of 3.15 days, it is the innermost planet of the system and has a ~5% transit probability. We also correct our previous confusion about the orbital period of GJ 581d (the outermost planet) with a one-year alias, benefitting from an extended time span and many more measurements. The revised period is 66.8 days, and positions the semi-major axis inside the habitable zone of the low mass star. The dynamical stability of the 4-planet system imposes an upper bound on the orbital plane inclination. The planets cannot be more massive than approximately 1.6 times their minimum mass.
