- ID:
- ivo://CDS.VizieR/J/ApJ/834/17
- Title:
- Mass & radius of planets, moons, low mass stars
- Short Name:
- J/ApJ/834/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mass and radius are two of the most fundamental properties of an astronomical object. Increasingly, new planet discoveries are being announced with a measurement of one of these quantities, but not both. This has led to a growing need to forecast the missing quantity using the other, especially when predicting the detectability of certain follow-up observations. We present an unbiased forecasting model built upon a probabilistic mass-radius relation conditioned on a sample of 316 well-constrained objects. Our publicly available code, Forecaster, accounts for observational errors, hyper-parameter uncertainties, and the intrinsic dispersions observed in the calibration sample. By conditioning our model on a sample spanning dwarf planets to late-type stars, Forecaster can predict the mass (or radius) from the radius (or mass) for objects covering nine orders of magnitude in mass. Classification is naturally performed by our model, which uses four classes we label as Terran worlds, Neptunian worlds, Jovian worlds, and stars. Our classification identifies dwarf planets as merely low-mass Terrans (like the Earth) and brown dwarfs as merely high-mass Jovians (like Jupiter). We detect a transition in the mass-radius relation at 2.0_-0.6_^+0.7^M_{Earth}_, which we associate with the divide between solid, Terran worlds and Neptunian worlds. This independent analysis adds further weight to the emerging consensus that rocky super-Earths represent a narrower region of parameter space than originally thought. Effectively, then, the Earth is the super-Earth we have been looking for.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/662/413
- Title:
- 2MASS survey of wide multiplicity in 3 associations
- Short Name:
- J/ApJ/662/413
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for wide binary systems among 783 members of three nearby young associations: Taurus-Auriga, Chamaeleon I, and two subgroups of Upper Scorpius. Near-infrared (JHK) imagery from 2MASS was analyzed to search for wide (1"-30"; ~150-4500AU) companions to known association members, using color-magnitude cuts to reject likely background stars. We identify a total of 131 candidate binary companions with colors consistent with physical association, of which 39 have not been identified previously in the literature.
- ID:
- ivo://CDS.VizieR/J/AJ/156/45
- Title:
- M-dwarf multiples in the SDSS-III/APOGEE
- Short Name:
- J/AJ/156/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Binary stars make up a significant portion of all stellar systems. Consequently, an understanding of the bulk properties of binary stars is necessary for a full picture of star formation. Binary surveys indicate that both multiplicity fraction and typical orbital separation increase as functions of primary mass. Correlations with higher-order architectural parameters such as mass ratio are less well constrained. We seek to identify and characterize double-lined spectroscopic binaries (SB2s) among the 1350 M-dwarf ancillary science targets with APOGEE spectra in the SDSS-III Data Release 13. We measure the degree of asymmetry in the APOGEE pipeline cross-correlation functions (CCFs) and use those metrics to identify a sample of 44 high-likelihood candidate SB2s. At least 11 of these SB2s are known, having been previously identified by Deshpande et al. (2013, J/AJ/146/156) and/or El-Badry et al. (2018MNRAS.476..528E). We are able to extract radial velocities (RVs) for the components of 36 of these systems from their CCFs. With these RVs, we measure mass ratios for 29 SB2s and five SB3s. We use Bayesian techniques to fit maximum-likelihood (but still preliminary) orbits for four SB2s with eight or more distinct APOGEE observations. The observed (but incomplete) mass-ratio distribution of this sample rises quickly toward unity. Two-sided Kolmogorov-Smirnov tests find probabilities of 18.3% and 18.7%, demonstrating that the mass-ratio distribution of our sample is consistent with those measured by Pourbaix et al. (2004, Cat. B/sb9) and Fernandez et al. (2017PASP..129h4201F), respectively.
- ID:
- ivo://CDS.VizieR/J/MNRAS/449/2618
- Title:
- M-dwarfs in Multiples (MinMs) survey. I.
- Short Name:
- J/MNRAS/449/2618
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a large-scale, volume-limited companion survey of 245 late-K to mid-M (K7-M6) dwarfs within 15pc. Infrared adaptive optics (AO) data were analysed from the Very Large Telescope, Subaru Telescope, Canada-France-Hawaii Telescope, and MMT Observatory to detect close companions to the sample from ~1 to 100AU, while digitized wide-field archival plates were searched for wide companions from ~100 to 10000AU. With sensitivity to the bottom of the main sequence over a separation range of 3 to 10000AU, multiple AO and wide-field epochs allow us to confirm candidates with common proper motions, minimize background contamination, and enable a measurement of comprehensive binary statistics. We detected 65 comoving stellar companions and find a companion star fraction of 23.5+/-3.2 percent over the 3 au to 10000AU separation range. The companion separation distribution is observed to rise to a higher frequency at smaller separations, peaking at closer separations than measured for more massive primaries. The mass ratio distribution across the q=0.2-1.0 range is flat, similar to that of multiple systems with solar-type primaries. The characterization of binary and multiple star frequency for low-mass field stars can provide crucial comparisons with star-forming environments and hold implications for the frequency and evolutionary histories of their associated discs and planets.
- ID:
- ivo://CDS.VizieR/J/A+A/602/A88
- Title:
- 5 M dwarfs radial velocity curves
- Short Name:
- J/A+A/602/A88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Low mass stars are currently the best targets for searches for rocky planets in the habitable zone of their host star. Over the last 13 years, precise radial velocities measured with the HARPS spectrograph have identified over a dozen super-Earths and Earth-mass planets (msini<=10M_{sun}_) around M dwarfs, with a well understood selection function. This well defined sample informs on their frequency of occurrence and on the distribution of their orbital parameters, and therefore already constrains our understanding of planetary formation. The subset of these low-mass planets that were found within the habitable zone of their host star also provide prized targets for future atmospheric biomarkers searches. We are working to extend this planetary sample to lower masses and longer periods through dense and long-term monitoring of the radial velocity of a small M dwarf sample. We obtained large numbers of HARPS spectra for the M dwarfs GJ 3138, GJ 3323, GJ 273, GJ 628 and GJ 3293, from which we derived radial velocities (RVs) and spectroscopic activity indicators. We searched them for variabilities, periodicities, Keplerian modulations and correlations, and attribute the radial-velocity variations to combinations of planetary companions and stellar activity. We detect 12 planets, of which 9 are new with masses ranging from 1.17 to 10.5M_{sun}_. Those planets have relatively short orbital periods (P<40d), except two of them with periods of 217.6 and 257.8 days. Among these systems, GJ 273 harbor two planets with masses close to the one of the Earth. With a distance of 3.8 parsec only, GJ 273 is the second nearest known planetary system - after Proxima Centauri - with a planet orbiting the circumstellar habitable zone.
- ID:
- ivo://CDS.VizieR/J/AJ/129/2428
- Title:
- M dwarf-white dwarf binary systems
- Short Name:
- J/AJ/129/2428
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the relationship between age and chromospheric activity for 139 M dwarf stars in wide binary systems with white dwarf companions. We present the measured radial velocities and complete space motions for 161 white dwarf stars in wide binaries.
- ID:
- ivo://CDS.VizieR/J/A+A/537/A67
- Title:
- MESS: Multi-purpose Exoplanet Simulation System
- Short Name:
- J/A+A/537/A67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The high number of planet discoveries made in the last years provides a good sample for statistical analysis, leading to some clues on the distributions of planet parameters, like masses and periods, at least in close proximity to the host star. We likely need to wait for the extremely large telescopes (ELTs) to have an overall view of the extrasolar planetary systems. In this context it would be useful to have a tool that can be used for the interpretation of the present results, and also to predict what the outcomes would be of the future instruments. For this reason we built MESS: a Monte Carlo simulation code which uses either the results of the statistical analysis of the properties of discovered planets, or the results of the planet formation theories, to build synthetic planet populations fully described in terms of frequency, orbital elements and physical properties. They can then be used to either test the consistency of their properties with the observed population of planets given different detection techniques or to actually predict the expected number of planets for future surveys. In addition to the code description, we present here some of its applications to actually probe the physical and orbital properties of a putative companion within the circumstellar disk of a given star and to test constrain the orbital distribution properties of a potential planet population around the members of the TW Hydrae association. Finally, using in its predictive mode, the synergy of future space and ground-based telescopes instrumentation has been investigated to identify the mass-period parameter space that will be probed in future surveys for giant and rocky planets.
- ID:
- ivo://CDS.VizieR/J/other/AstBu/62.235
- Title:
- Metal-poor stars speckle interferometry
- Short Name:
- J/other/AstBu/62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of speckle-interferometric observations of 109 high proper-motion metal-poor stars made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. We resolve eight objects G102-20, G191-55, BD+19 1185A, G89-14, G87-45, G87-47, G111-38, and G114-25 into individual components and we are the first to astrometrically resolve seven of these stars. New resolved systems included two triple (G111-38, G87-47) and one quadruple (G89-14) star. The ratio of single:binary:triple:quadruple systems among the stars of our sample is equal to 71:28:6:1.
- ID:
- ivo://CDS.VizieR/J/other/AstBu/63.278
- Title:
- Metal-poor stars speckle interferometry
- Short Name:
- J/other/AstBu/63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of speckle interferometric observations of 115 metal-poor stars ([m/H]<-1) within 250pc from the Sun and with proper motions mu>~0.2"/yr, made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences, are reported. Close companions with separations ranging from 0.034" to 1" were observed for 12 objects - G76-21, G59-1, G63-46, G135-16, G168-42, G141-47, G142-44, G190-10, G28-43, G217-8, G130-7, and G89-14 - eight of them are astrometrically resolved for the first time. The newly resolved systems include one triple star - G190-10. If combined with spectroscopic and visual data, our results imply a single:binary:triple:quadruple star ratio of 147:64:9:1 for a sample of 221 primary components of halo and thick-disk stars.
- ID:
- ivo://CDS.VizieR/J/AJ/158/239
- Title:
- Metal-rich host stars abundances & equivalent widths
- Short Name:
- J/AJ/158/239
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relationship between the compositions of giant planets and their host stars is of fundamental interest in understanding planet formation. The solar system giant planets are enhanced above solar composition in metals, both in their visible atmospheres and bulk compositions. A key question is whether the metal enrichment of giant exoplanets is correlated with that of their host stars. Thorngren et al. (2016, J/ApJ/831/64) showed that in cool (T_eq_<1000 K) giant exoplanets, the total heavy-element mass increases with total M_p_ and the heavy-element enrichment relative to the parent star decreases with total M_p_. In their work, the host star metallicity was derived from literature [Fe/H] measurements. Here we conduct a more detailed and uniform study to determine whether different host star metals (C, O, Mg, Si, Fe, and Ni) correlate with the bulk metallicity of their planets, using correlation tests and Bayesian linear fits. We present new host star abundances of 19 cool giant planet systems, and combine these with existing host star data for a total of 22 cool giant planet systems (24 planets). Surprisingly, we find no clear correlation between stellar metallicity and planetary residual metallicity (the relative amount of metal versus that expected from the planet mass alone), which is in conflict with common predictions from formation models. We also find a potential correlation between residual planet metals and stellar volatile-to-refractory element ratios. These results provide intriguing new relationships between giant planet and host star compositions for future modeling studies of planet formation.
