- ID:
- ivo://CDS.VizieR/J/AJ/153/258
- Title:
- 2007.5 to 2010.4 HST astrometry of HD 202206
- Short Name:
- J/AJ/153/258
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using Hubble Space Telescope Fine Guidance Sensor astrometry and previously published radial velocity measures, we explore the exoplanetary system HD202206. Our modeling results in a parallax, {pi}_abs_=21.96+/-0.12 milliseconds of arc, a mass for HD202206B of M_B_=0.089_-0.006_^+0.007M_{Sun}_, and a mass for HD202206c of M_c_=17.9_-1.8_^+2.9^M_Jup_. HD202206 is a nearly face-on G + M binary orbited by a brown dwarf. The system architecture that we determine supports past assertions that stability requires a 5:1 mean motion resonance (we find a period ratio, P_c_/P_B_=4.92+/-0.04) and coplanarity (we find a mutual inclination, {Phi}=6{deg}+/-2{deg}).
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- ID:
- ivo://CDS.VizieR/J/AJ/160/22
- Title:
- TOI-1235 Radial velocities & optical spectroscopy
- Short Name:
- J/AJ/160/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Small planets on close-in orbits tend to exhibit envelope mass fractions of either effectively zero or up to a few percent depending on their size and orbital period. Models of thermally driven atmospheric mass loss and of terrestrial planet formation in a gas-poor environment make distinct predictions regarding the location of this rocky/nonrocky transition in period-radius space. Here we present the confirmation of TOI-1235b (P=3.44days, r_p_=1.738_-0.076_^+0.087^R_{Earth}_), a planet whose size and period are intermediate between the competing model predictions, thus making the system an important test case for emergence models of the rocky/nonrocky transition around early M dwarfs (R_s_=0.630{+/-}0.015R_{sun}_, M_s_=0.640{+/-}0.016M_{sun}_). We confirm the TESS planet discovery using reconnaissance spectroscopy, ground-based photometry, high- resolution imaging, and a set of 38 precise radial velocities (RVs) from HARPS-N and HIRES. We measure a planet mass of 6.91_-0.85_^+0.75^M_{Earth}_, which implies an iron core mass fraction of 20_-12_^+15^% in the absence of a gaseous envelope. The bulk composition of TOI-1235b is therefore consistent with being Earth-like, and we constrain an H/He envelope mass fraction to be <0.5% at 90% confidence. Our results are consistent with model predictions from thermally driven atmospheric mass loss but not with gas-poor formation, suggesting that the former class of processes remains efficient at sculpting close-in planets around early M dwarfs. Our RV analysis also reveals a strong periodicity close to the first harmonic of the photometrically determined stellar rotation period that we treat as stellar activity, despite other lines of evidence favoring a planetary origin (P=21.8_-0.8_^+0.9^days, m_p_sini=13.0_-5.3_^+3.8^M_{Earth}_) that cannot be firmly ruled out by our data.
- ID:
- ivo://CDS.VizieR/I/232
- Title:
- Toulouse AC Zone Data Reduced to ACRS
- Short Name:
- I/232
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The U.S. Naval Observatory is in the process of making new reductions of the Astrographic Catalogue (AC) using a modern reference system, the ACRS, which represents the system of the FK5. The data from the Toulouse Zone, whose plates are centered between declinations +5 and +11 degrees (eq. 1900), have been analyzed for scale, rotation, tilt, coma, magnitude equation, radial distortion and distortions introduced by the use of reseaux in the Carte du Ciel program. The result is a positional catalog of almost 270,000 stars on eq. J2000.0, epoch of observation. Additionally, all stars have been matched with the Tycho Input Catalog (revised); those numbers have been added for additional identification purposes.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A126
- Title:
- T Pyx 2011 outburst optical spectra
- Short Name:
- J/A+A/622/A126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to study the spectroscopic and ionized structural evolution of T Pyx during its 2011 outburst, and also study the variation in degree of polarization during its early phase. Optical spectroscopic data of this system obtained from day 1.28-2415.62 since discovery, and optical, broadband imaging polarimetric observations obtained from day 1.36-29.33 during the early phases of the outburst were used in the study. The physical conditions and the geometry of the ionized structure of the nova ejecta was modelled for a few epochs using the photo-ionization code, CLOUDY in 1D and pyCloudy in 3D. The spectral evolution of the nova ejecta during its 2011 outburst is similar to that of the previous outbursts. The variation in the line profiles is seen very clearly in the early stages due to good coverage during this period. The line profiles vary from P Cygni (narrower, deeper, and sharper) to emission profiles that are broader and structured, which later become narrower and sharper in the late post-outburst phase. The average ejected mass is estimated to be 7.03x10^-6^M_{sun}_. The ionized structure of the ejecta is found to be a bipolar conical structure with equatorial rings, with a low inclination angle of 14.75+/-0.65{deg}.
- ID:
- ivo://CDS.VizieR/J/MNRAS/403/1213
- Title:
- Tracers of stellar mass-loss. I.
- Short Name:
- J/MNRAS/403/1213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and IR integrated colours and SBF magnitudes, computed from stellar population synthesis models that include emission from the dusty envelopes surrounding TP-AGB stars undergoing mass-loss. We explore the effects of varying the mass-loss rate by one order of magnitude around the fiducial value, modifying accordingly both the stellar parameters and the output spectra of the TP-AGB stars plus their dusty envelopes. The models are single burst, and range in age from a few Myr to 14Gyr, and in metallicity between Z=0.0001 and Z=0.07; they combine new calculations for the evolution of stars in the TP-AGB phase, with star plus envelope SEDs produced with the radiative transfer code DUSTY. We compare these models to optical and near-IR data of single AGB stars and Magellanic star clusters. This comparison validates the current understanding of the role of mass-loss in determining stellar parameters and spectra in the TP-AGB. However, neither broad-band colours nor SBF measurements in the optical or the near-IR can discern global changes in the mass-loss rate of a stellar population. We predict that mid-IR SBF measurements can pick out such changes, and actually resolve whether a relation between metallicity and mass-loss exists.
- ID:
- ivo://CDS.VizieR/J/A+A/609/A53
- Title:
- Tracing stars of MW dwarf galaxies: Sextans
- Short Name:
- J/A+A/609/A53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a deep and very spatially extended CTIO/DECam g and r photometric catalogue of point-sources (reaching out to ~2 magnitudes below the oldest main-sequence turn-off and covering ~20deg^2^) around the Sextans dwarf spheroidal galaxy, together with another catalogue of literature spectroscopic measurements (Walker et al., 2009, Cat. J/AJ/137/3100 and Battaglia et al., 2011, Cat. J/MNRAS/411/1013) with updated membership probabilities.
- ID:
- ivo://CDS.VizieR/J/AJ/159/83
- Title:
- Transit analysis for the K2-25 system
- Short Name:
- J/AJ/159/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The abundance of planets with orbital periods of a few to tens of days suggests that exoplanets experience complex dynamical histories. Planets in young stellar clusters or associations have well-constrained ages and therefore provide an opportunity to explore the dynamical evolution of exoplanets. K2-25b is a Neptune-sized planet in an eccentric, 3.48day orbit around an M4.5 dwarf star in the Hyades cluster (650Myr). In order to investigate its non-zero eccentricity and tight orbit, we analyze transit timing variations (TTVs) which could reveal clues to the migration processes that may have acted on the planet. We obtain 12 nonconsecutive transits using the MEarth observatories and long-term photometric monitoring, which we combine with 10 transits from the Spitzer Space Telescope and 20 transits from K2. Tables of MEarth photometry accompany this work. We fit each transit lightcurve independently. We first investigate whether inhomogeneities on the stellar surface (such as spots or plages) are differentially affecting our transit observations. The measured transit depth does not vary significantly between transits, though we see some deviations from the fiducial transit model. We then looked for TTVs as evidence of a nontransiting perturber in the system. We find no evidence for >1M_{Earth}_ mass companions within a 2:1 period ratio, or for >5M_{Earth}_ mass planets within a 7:2 period ratio.
- ID:
- ivo://CDS.VizieR/J/AJ/154/49
- Title:
- Transiting Exoplanet Monitoring Project. II. HAT-P-33
- Short Name:
- J/AJ/154/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 10 R-band photometric observations of eight different transits of the hot Jupiter HAT-P-33b, which has been targeted by our Transiting Exoplanet Monitoring Project. The data were obtained by two telescopes at the Xinglong Station of National Astronomical Observatories of China (NAOC) from 2013 December through 2016 January, and exhibit photometric scatter of 1.6-3.0mmag. After jointly analyzing the previously published photometric data, radial-velocity (RV) measurements, and our new light curves, we revisit the system parameters and orbital ephemeris for the HAT-P-33b system. Our results are consistent with the published values except for the planet to star radius ratio (R_P_/R_*_), the ingress/egress duration ({tau}) and the total duration (T_14_), which together indicate a slightly shallower and shorter transit shape. Our results are based on more complete light curves, whereas the previously published work had only one complete transit light curve. No significant anomalies in Transit Timing Variations (TTVs) are found, and we place upper mass limits on potential perturbers, largely supplanting the loose constraints provided by the extant RV data. The TTV limits are stronger near mean-motion resonances, especially for the low-order commensurabilities. We can exclude the existence of a perturber with mass larger than 0.6, 0.3, 0.5, 0.5, and 0.3M_{Earth}_ near the 1:3, 1:2, 2:3, 3:2, and 2:1 resonances, respectively.
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/2831
- Title:
- 4 transiting F-M binary systems
- Short Name:
- J/MNRAS/437/2831
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of four transiting F-M binary systems with companions between 0.1 and 0.2M_{sun}_ in mass by the HATSouth survey. These systems have been characterized via a global analysis of the HATSouth discovery data, combined with high-resolution radial velocities and accurate transit photometry observations. We determined the masses and radii of the component stars using a combination of two methods: isochrone fitting of spectroscopic primary star parameters and equating spectroscopic primary star rotation velocity with spin-orbit synchronization. These new very low mass companions are HATS550-016B (0.110_-0.006_^+0.005^M_{sun}_, 0.147_-0.004_^+0.003^R_{sun}_), HATS551-019B (0.17_-0.01_^+0.01^M_sun}_, 0.18_-0.01_^+0.01^R_{sun}_), HATS551-021B (0.132_-0.005_^+0.014^M_sun}_, 0.154_-0.008_^+0.006^R_{sun}_) and HATS553-001B (0.20_-0.02_^+0.01^M_sun}_, 0.22_-0.01_^+0.01^R_{sun}_). We examine our sample in the context of the radius anomaly for fully convective low-mass stars. Combining our sample with the 13 other well-studied very low mass stars, we find a tentative 5 percent systematic deviation between the measured radii and theoretical isochrone models.
- ID:
- ivo://CDS.VizieR/J/AJ/153/191
- Title:
- Transiting planet GJ 1132
- Short Name:
- J/AJ/153/191
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Detecting the atmospheres of low-mass, low-temperature exoplanets is a high-priority goal on the path to ultimately detecting biosignatures in the atmospheres of habitable exoplanets. High-precision HST observations of several super-Earths with equilibrium temperatures below 1000K have to date all resulted in featureless transmission spectra, which have been suggested to be due to high-altitude clouds. We report the detection of an atmospheric feature in the atmosphere of a 1.6M_{Earth}_ exoplanet, GJ 1132 b, with an equilibrium temperature of ~600K and orbiting a nearby M dwarf. We present observations of nine transits of the planet obtained simultaneously in the griz and JHK passbands. We find an average radius of 1.43+/-0.16R_{Earth}_ for the planet, averaged over all the passbands, and a radius of 0.255+/-0.023R_{sun}_ for the star, both of which are significantly greater than previously found. The planet radius can be decomposed into a "surface radius" at ~1.375R_{Earth}_ overlaid by atmospheric features that increase the observed radius in the z and K bands. The z-band radius is 4{sigma} higher than the continuum, suggesting a strong detection of an atmosphere. We deploy a suite of tests to verify the reliability of the transmission spectrum, which are greatly helped by the existence of repeat observations. The large z-band transit depth indicates strong opacity from H_2_O and/or CH_4_ or a hitherto-unconsidered opacity. A surface radius of 1.375+/-0.16R_{Earth}_ allows for a wide range of interior compositions ranging from a nearly Earth-like rocky interior, with ~70% silicate and ~30% Fe, to a substantially H_2_O-rich water world.
