- ID:
- ivo://CDS.VizieR/J/A+A/635/A12
- Title:
- GG Tau A ALMA ^13^CO and C^18^O(3-2) maps
- Short Name:
- J/A+A/635/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- GG Tau A is the prototype of a young triple T Tauri star that is surrounded by a massive and extended Keplerian outer disk. The central cavity is not devoid of gas and dust and at least GG Tau Aa exhibits its own disk of gas and dust emitting at millimeter wavelengths. Its observed properties make this source an ideal laboratory for investigating planet formation in young multiple solartype stars. We used new ALMA ^13^CO and C^18^O(3-2) observations obtained at high angular resolution (~0.2") together with previous CO(3-2) and (6-5) ALMA data and continuum maps at 1.3 and 0.8mm in order to determine the gas properties (temperature, density, and kinematics) in the cavity and to a lesser extent in the outer disk. By deprojecting, we studied the radial and azimuthal gas distribution and its kinematics. We also applied a new method to improve the deconvolution of the CO data and in particular better quantify the emission from gas inside the cavity. We perform local nonlocal thermodynamic equilibrium studies in order to determine the excitation conditions and relevant physical parameters inside the ring and in the central cavity. Residual emission after removing a smooth-disk model indicates unresolved structures at our angular resolution, probably in the form of irregular rings or spirals. The outer disk is cold, with a temperature <20K beyond 250au that drops quickly ({prop.to}r^-1^). The kinematics of the gas inside the cavity reveals infall motions at about 10% of the Keplerian speed. We derive the amount of gas in the cavity, and find that the brightest clumps, which contain about 10% of this mass, have kinetic temperatures 40-80K, CO column densities of a few 10^17^cm^-2^, and H_2_ densities around 10^7^cm^-3^. Although the gas in the cavity is only a small fraction of the disk mass, the mass accretion rate throughout the cavity is comparable to or higher than the stellar accretion rate. It is accordingly sufficient to sustain the circumstellar disks on a long timescale.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/622/L7
- Title:
- GJ143 and HD23472 radial velocity curves
- Short Name:
- J/A+A/622/L7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim at the discovery of new planetary systems by exploiting the transit light-curve results from observations made in TESS orbital observatory Sectors 1 and 2 and validating them with precise Doppler measurements obtained from archival HARPS data. Taking advantage of the reported TESS transit events around GJ 143 (TOI 186) and HD 23472 (TOI 174), we modeled their HARPS precise Doppler measurements and derived orbital parameters for these two systems. Results. For the GJ 143 system, TESS has reported only a single transit, and thus its period is unconstrained from photometry. Our radial velocity analysis of GJ 143 reveals the full Keplerian solution of the system, which is consistent with an eccentric planet with a mass almost twice that of Neptune and a period of P_b_=35.59+/-0.01-days. Our estimates of the GJ 143 b planet are fully consistent with the transit timing from TESS. We confirm the two-planet system around HD 23472, which according to our analysis is composed of two Neptune-mass planets in a possible 5:3 mean motion resonance.
- ID:
- ivo://CDS.VizieR/J/A+A/595/A77
- Title:
- GJ676A radial velocity curve
- Short Name:
- J/A+A/595/A77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The star GJ676A is an M0 dwarf hosting both gas-giant and super-Earth-type planets that were discovered with radial-velocity measurements. Using FORS2/VLT, we obtained position measurements of the star in the plane of the sky that tightly constrain its astrometric reflex motion caused by the super-Jupiter planet 'b' in a 1052-day orbit. This allows us to determine the mass of this planet to be M_b_= 6.7^+1.8^_-1.5_M_J_, which is ~40% higher than the minimum mass inferred from the radial-velocity orbit. Using new HARPS radial-velocity measurements, we improve upon the orbital parameters of the inner low-mass planets 'd' and 'e' and we determine the orbital period of the outer giant planet 'c' to be P_c_=7340-days under the assumption of a circular orbit. The preliminary minimum mass of planet 'c' is M_c_sini=6.8M_J_ with an upper limit of ~39M_J_ that we set using NACO/VLT high-contrast imaging. We also determine precise parallaxes and relative proper motions for both GJ676A and its wide M3 companion GJ676B. Although the system is probably quite mature, the masses and projected separations (~0.1-0.4") of planets 'b' and 'c' make them promising targets for direct imaging with future instruments in space and on extremely large telescopes. In particular, we estimate that GJ676A b and GJ676A ,c are promising targets for directly detecting their reflected light with the WFIRST space mission. Our study demonstrates the synergy of radial-velocity and astrometric surveys that is necessary to identify the best targets for such a mission.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A120
- Title:
- GJ 1214b optical and near-IR transit phot.
- Short Name:
- J/A+A/608/A120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The benchmark exoplanet GJ 1214b is one of the best studied transiting planets in the transition zone between rocky Earth-sized planets and gas or ice giants. This class of super-Earth or mini-Neptune planets is unknown in our solar system, yet is one of the most frequently detected classes of exoplanets. Understanding the transition from rocky to gaseous planets is a crucial step in the exploration of extrasolar planetary systems, in particular with regard to the potential habitability of this class of planets. GJ 1214b has already been studied in detail from various platforms at many different wavelengths. Our airborne observations with the Stratospheric Observatory for Infrared Astronomy (SOFIA) add information in the Paschen-{alpha}cont. 1.9um infrared wavelength band, which is not accessible by any other current ground- or space-based instrument due to telluric absorption or limited spectral coverage. We used FLIPO, the combination of the High-speed Imaging Photometer for Occultations (HIPO) and the First Light Infrared TEst CAMera (FLITECAM) and the Focal Plane Imager (FPI+) on SOFIA to comprehensively analyse the transmission signal of the possible water-world GJ 1214b through photometric observations during transit in three optical and one infrared channels. We present four simultaneous light curves and corresponding transit depths in three optical and one infrared channel, which we compare to previous observations and current synthetic atmospheric models of GJ 1214b. The final precision in transit depth is between 1.5 and 2.5 times the theoretical photon noise limit, not sensitive enough to constrain the theoretical models any better than previous observations. This is the first exoplanet observation with SOFIA that uses its full set of instruments available to exoplanet spectrophotometry. Therefore we use these results to evaluate SOFIAs potential in this field and suggest future improvements.
- ID:
- ivo://CDS.VizieR/J/A+A/659/A17
- Title:
- GJ 3929 b RVs and activity indicators
- Short Name:
- J/A+A/659/A17
- Date:
- 02 Mar 2022 06:16:21
- Publisher:
- CDS
- Description:
- We report the discovery of GJ 3929 b, a hot Earth-sized planet orbiting the nearby M3.5 V dwarf star, GJ 3929 (G 180-18, TOI-2013). Joint modelling of photometric observations from TESS sectors 24 and 25 together with 73 spectroscopic observations from CARMENES and follow-up transit observations from SAINT-EX, LCOGT, and OSN yields a planet radius of R_b_=1.150+/-0.040R_e_, a mass of M_b_=1.21+/-0.42M_e_, and an orbital period of P_b_=2.6162745+/-0.0000030d. The resulting density of rho_b_=4.4+/-1.6g/cm^3^ is compatible with the Earth's mean density of about 5.5g/cm^3^. Due to the apparent brightness of the host star (J=8.7mag) and its small size, GJ 3929 b is a promising target for atmospheric characterisation with the JWST. Additionally, the radial velocity data show evidence for another planet candidate with P_[c]_=14.303+/-0.035d, which is likely unrelated to the stellar rotation period, P_rot_=122+/-13d, which we determined from archival HATNet and ASAS-SN photometry combined with newly obtained TJO data.
- ID:
- ivo://CDS.VizieR/J/A+A/556/A126
- Title:
- GJ667C Doppler and activity measurements
- Short Name:
- J/A+A/556/A126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since low-mass stars have low luminosities, orbits at which liquid water can exist on Earth-sized planets are relatively close-in, which produces Doppler signals that are detectable using state-of-the-art Doppler spectroscopy. GJ 667C is already known to be orbited by two super-Earth candidates. We have recently applied developed data analysis methods to investigate whether the data supports the presence of additional companions. We obtain new Doppler measurements from HARPS extracted spectra and combined them with those obtained from the PFS and HIRES spectrographs. We used Bayesian and periodogram-based methods to re-assess the number of candidates and evaluated the confidence of each detection. Among other tests, we validated the planet candidates by analyzing correlations of each Doppler signal with measurements of several activity indices and investigated the possible quasi-periodic nature of signals.
- 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.
348. 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/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.
