- ID:
- ivo://CDS.VizieR/J/MNRAS/423/2966
- Title:
- Low-mass stars spectroscopy in NGC 2516
- Short Name:
- J/MNRAS/423/2966
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present far-red, intermediate-resolution spectroscopy of 572 photometrically selected, low-mass stars (0.2<M/M_{sun}_<0.7) in the young open cluster NGC 2516, using the FLAMES spectrograph at the Very Large Telescope. Precise radial velocities confirm membership for 210 stars that have published rotation periods from spot-modulated light curves and for another 144 stars in which periodic modulation could not be found. The two subsamples are compared and no significant differences are found between their positions in colour-magnitude diagrams, the distribution of their projected equatorial velocities or their levels of chromospheric activity.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/471/4218
- Title:
- 4 low-mass white-dwarf candidates velocities
- Short Name:
- J/MNRAS/471/4218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from a Gemini snapshot radial-velocity survey of 44 low-mass white-dwarf candidates selected from the Sloan Digital Sky Survey (SDSS) spectroscopy. To find sub-hour orbital period binary systems, our time-series spectroscopy had cadences of 2-8min over a period of 20-30min. Through follow-up observations at Gemini and the MMT, we identify four double-degenerate binary systems with periods ranging from 53min to 7h. The shortest period system, SDSS J123549.88+154319.3, was recently identified as a sub-hour period detached binary by Breedt and collaborators. Here, we refine the orbital and physical parameters of this system. High-speed and time-domain survey photometry observations do not reveal eclipses or other photometric effects in any of our targets. We compare the period distribution of these four systems with the orbital period distribution of known double white dwarfs; the median period decreases from 0.64 to 0.24d for M=0.3-0.5M_{sun}_ to M<0.3M_{sun}_ white dwarfs. However, we do not find a statistically significant correlation between the orbital period and white-dwarf mass.
- ID:
- ivo://CDS.VizieR/J/A+A/644/A127
- Title:
- LP714-47 (TOI 442) radial velocity curve
- Short Name:
- J/A+A/644/A127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a Neptune-like planet (LP714-47b, P=4.05204d, m=30.8+/-1.5 M_Earth_, r=4.7+/-0.3 R_Earth_) located in the 'hot Neptune desert'. Confirmation of the TESS Object of Interest (TOI 442.01) was achieved with radial-velocity follow-up using CARMENES, ESPRESSO, HIRES, iSHELL, and PFS, as well as from photometric data using TESS, Spitzer, and ground-based photometry from MuSCAT2, TRAPPIST-South, MONET-South, the George Mason University telescope, the Las Cumbres Observatory Global Telescope network, the El Sauce telescope, the TUBITAK National Observatory, the University of Louisville Manner Telescope, and WASP-South. We also present high-spatial resolution adaptive optics imaging with the Gemini Near-Infrared Imager. The low uncertainties in the mass and radius determination place LP714-47b among physically well-characterised planets, allowing for a meaningful comparison with planet structure models. The host star LP714-47 is a slowly rotating early M dwarf (T_eff_=3950+/-51K) with a mass of 0.59+/-0.02M_{sun}_ and a radius of 0.58+/-0.02R_{sun}_. From long-term photometric monitoring and spectroscopic activity indicators, we determine a stellar rotation period of about 33d. The stellar activity is also manifested as correlated noise in the radial-velocity data. In the power spectrum of the radial-velocity data, we detect a second signal with a period of 16 days in addition to the four-day signal of the planet. This could be shown to be a harmonic of the stellar rotation period or the signal of a second planet. It may be possible to tell the difference once more TESS data and radial-velocity data are obtained.
- ID:
- ivo://CDS.VizieR/J/A+A/636/A58
- Title:
- L 168-9 radial velocity curve
- Short Name:
- J/A+A/636/A58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of a transiting super-Earth-sized planet (R=1.39+/-0.09R_{Earth}_) in a 1.4-day orbit around L 168-9 (TOI-134), a bright M1V dwarf (V=11, K=7.1) located at 25.15+/-0.02pc. The host star was observed in the first sector of the Transiting Exoplanet Survey Satellite (TESS) mission. For confirmation and planet mass measurement purposes, this was followed up with ground-based photometry, seeing-limited and high-resolution imaging, and precise radial velocity (PRV) observations using the HARPS and Magellan/PFS spectrographs. By combining the TESS data and PRV observations, we find the mass of L 168-9 b to be 4.60+/-0.56M_{Earth}_ and thus the bulk density to be 1.74^+0.44^_-0.33_ times higher than that of the Earth. The orbital eccentricity is smaller than 0.21 (95% confidence). This planet is a level one candidate for the TESS mission's scientific objective of measuring the masses of 50 small planets, and it is one of the most observationally accessible terrestrial planets for future atmospheric characterization.
- ID:
- ivo://CDS.VizieR/J/A+A/385/816
- Title:
- LSB galaxies rotation curves
- Short Name:
- J/A+A/385/816
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File rawcurve contains the raw rotation curves of the low surface brightness galaxies. These data are not corrected for inclination. File procurve contains the processed rotation curves that can be directly used for mass modelling.
- ID:
- ivo://CDS.VizieR/J/ApJ/656/437
- Title:
- LS I +61 303 radial velocities and Halpha EW
- Short Name:
- J/ApJ/656/437
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an Halpha monitoring campaign on the BeXRB and microquasar system LS I +61 303. We use radial velocity measurements of HeI lines in our spectra to reevaluate the orbital elements and to better establish the time of periastron. We list equivalent widths and other parameters for the Halpha emission line and discuss the orbital phase related variations observed.
- ID:
- ivo://CDS.VizieR/J/ApJ/656/431
- Title:
- LS I +65 010 radial velocities and Halpha EW
- Short Name:
- J/ApJ/656/431
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a 3yr spectroscopic monitoring program of the Halpha emission in the massive X-ray binary LS I +65 010 = 2S 0114+650, which consists of a B supergiant and a slowly rotating X-ray pulsar. We present revised orbital elements that yield a period of P=11.5983+/-0.0006days and confirm that the orbit has a nonzero eccentricity e=0.18+/-0.05. The Halpha emission profile is formed in the base of the wind of the B supergiant primary, and we show how this spectral feature varies on timescales that are probably related to the rotational period of the B supergiant. We also examine the X-ray fluxes from the Rossi X-ray Timing Explorer All-Sky Monitor instrument, and we show that the X-ray orbital light curve has a maximum at periastron and a minimum at the inferior conjunction of the B supergiant. We also show that the wind emission strength and the high-energy X-ray flux appear to vary in tandem on timescales of approximately 1yr.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A116
- Title:
- LSPM J2116+0234 and GJ 686 radial velocities
- Short Name:
- J/A+A/627/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Although M dwarfs are known for high levels of stellar activity, they are ideal targets for the search of low-mass exoplanets with the radial velocity (RV) method. We report the discovery of a planetary-mass companion around LSPM J2116+0234 (M3.0 V) and confirm the existence of a planet orbiting GJ 686 (BD+18 3421; M1.0 V). The discovery of the planet around LSPM J2116+0234 is based on CARMENES RV observations in the visual and near-infrared channels. We confirm the planet orbiting around GJ 686 by analyzing the RV data spanning over two decades of observations from CARMENES VIS, HARPS-N, HARPS, and HIRES. We find planetary signals at 14.44 and 15.53d in the RV data for LSPM J2116+0234 and GJ 686, respectively. Additionally, the RV, photometric time series, and various spectroscopic indicators show hints of variations of 42 d for LSPM J2116+0234 and 37 d for GJ 686, which we attribute to the stellar rotation periods. The orbital parameters of the planets are modeled with Keplerian fits together with correlated noise from the stellar activity. A mini-Neptune with a minimum mass of 11.8M_{Earth}_ orbits LSPM J2116+0234 producing a RV semi- amplitude of 6.19m/s, while a super-Earth of mass 6.6M_{Earth}_ orbits GJ 686 and produces a RV semi-amplitude of 3.0m/s. Both LSPM J2116+0234 and GJ 686 have planetary companions populating the regime of exoplanets with masses lower than 15M_{Earth}_ and orbital periods <20d.
- ID:
- ivo://CDS.VizieR/J/A+A/653/A41
- Title:
- L 98-59 (TOI-175) ESPRESSO observations
- Short Name:
- J/A+A/653/A41
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- In recent years, the advent of a new generation of radial velocity instruments has allowed us to detect lower and lower mass planets, breaking the one Earth-mass barrier. Here we report a new milestone in this context, by announcing the detection of the lightest planet measured so far using radial velocities: L 98-59 b, a rocky planet with half the mass of Venus which is part of a system composed of three known transiting terrestrial planets (planets b to d). We announce the discovery of a fourth non-transiting planet with a minimum mass of 3.06_-0.37_^+0.33^M_{Earth)_ and an orbital period of 12.796_-0.019_^+0.020^ days and report hints for the presence of a fifth non-transiting terrestrial planet. If confirmed, with a minimum mass of 2.46_-0.82_^+0.66^M_{Earth}_ and an orbital period 23.15_-0.17_^+0.60^ days, this planet would sit in the middle of the habitable zone of the L 98-59 system. L 98-59 is a bright M-dwarf located 10.6pc away. Positioned at the border of the continuous viewing zone of the James Webb space telescope, this system is destined to become a corner stone for comparative exoplanetology of terrestrial planets. The three transiting planets have transmission spectrum metrics ranging from 49 to 255 which undoubtedly make them prime targets for atmospheric characterization with the James Webb space telescope, the Hubble space telescope, Ariel or ground-based facilities like NIRPS or ESPRESSO. With equilibrium temperature ranging from 416 to 627K, they offer a unique opportunity to study the diversity of warm terrestrial planets without the unknowns associated with different host stars. L 98-59 b and c have densities of 3.6_-1.5_^+1.4^ and 4.57_-0.85_^+0.77^g/cm^3^ respectively and have very similar bulk compositions with a small iron core, representing only 12 to 14% of the total mass, and a small amount of water. However, with a density of 2.95_-0.51_^+0.79^g/cm^3^ and despite a similar core mass fraction, up to 30% of L 98-59 d's mass could be made of water.
- ID:
- ivo://CDS.VizieR/J/A+A/629/A111
- Title:
- L 98-59 (TOI 175) HARPS observations
- Short Name:
- J/A+A/629/A111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- L 98-59 (TIC 307210830, TOI-175) is a nearby M3 dwarf around which TESS revealed three small transiting planets (0.80, 1.35, 1.57 Earth radii) in a compact configuration with orbital periods shorter than 7.5 days. Here we aim to measure the masses of the known transiting planets in this system using precise radial velocity (RV) measurements taken with the HARPS spectrograph. We considered both trained and untrained Gaussian process regression models of stellar activity, which are modeled simultaneously with the planetary signals. Our RV analysis was then supplemented with dynamical simulations to provide strong constraints on the planets' orbital eccentricities by requiring long-term stability. We measure the planet masses of the two outermost planets to be 2.42+/-0.35 and 2.31+/-0.46 Earth masses, which confirms the bulk terrestrial composition of the former and eludes to a significant radius fraction in an extended gaseous envelope for the latter. We are able to place an upper limit on the mass of the smallest, innermost planet of <1.01 Earth masses with 95% confidence. Our RV plus dynamical stability analysis places strong constraints on the orbital eccentricities and reveals that each planet's orbit likely has e<0.1. L 98-59 is likely a compact system of two rocky planets plus a third outer planet with a lower bulk density possibly indicative of the planet having retained a modest atmosphere. The system offers a unique laboratory for studies of planet formation, dynamical stability, and comparative atmospheric planetology as the two outer planets are attractive targets for atmospheric characterization through transmission spectroscopy. Continued RV monitoring will help refine the characterization of the innermost planet and potentially reveal additional planets in the system at wider separations.
