- ID:
- ivo://CDS.VizieR/J/ApJ/900/L43
- Title:
- NIR APOGEE radial velocities of Draco C1
- Short Name:
- J/ApJ/900/L43
- Date:
- 15 Feb 2022 00:49:05
- Publisher:
- CDS
- Description:
- Draco C1 is a known symbiotic binary star system composed of a carbon red giant and a hot, compact companion-likely a white dwarf-belonging to the Draco dwarf spheroidal galaxy. From near-infrared spectroscopic observations taken by the Apache Point Observatory Galactic Evolution Experiment (APOGEE-2), part of Sloan Digital Sky Survey IV, we provide updated stellar parameters for the cool, giant component, and constrain the temperature and mass of the hot, compact companion. Prior measurements of the periodicity of the system, based on only a few epochs of radial velocity data or relatively short baseline photometric observations, were sufficient only to place lower limits on the orbital period (P>300d). For the first time, we report precise orbital parameters for the binary system: with 43 radial velocity measurements from APOGEE spanning an observational baseline of more than 3yr, we definitively derive the period of the system to be 1220.0_-3.5_^+3.7^days. Based on the newly derived orbital period and separation of the system, together with estimates of the radius of the red giant star, we find that the hot companion must be accreting matter from the dense wind of its evolved companion.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/777/160
- Title:
- NIR imaging survey for planets around MG stars
- Short Name:
- J/ApJ/777/160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results of a direct imaging survey for giant planets around 80 members of the {beta} Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini/NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of {Delta}H=13.9mag at 1" in combined CH_4_ narrowband ADI+SDI mode and median contrasts of {Delta}H=15.1mag at 2" in H-band ADI mode. We found numerous (>70) candidate companions in our survey images. Some of these candidates were rejected as common-proper motion companions using archival data; we reobserved with Near-Infrared Coronagraphic Imager (NICI) all other candidates that lay within 400AU of the star and were not in dense stellar fields. The vast majority of candidate companions were confirmed as background objects from archival observations and/or dedicated NICI Campaign followup. Four co-moving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36+/-6M_Jup_, 16.4+/-1.0AU), CD-35 2722B (31+/-8M_Jup_, 67+/-4AU), HD 12894B (0.46+/-0.08M_{sun}_, 15.7+/-1.0AU), and BD+07 1919C (0.20+/-0.03M_{sun}_, 12.5+/-1.4AU). From a Bayesian analysis of the achieved H band ADI and ASDI contrasts, using power-law models of planet distributions and hot-start evolutionary models, we restrict the frequency of 1-20M_Jup_ companions at semi-major axes from 10-150AU to <18% at a 95.4% confidence level using DUSTY models and to <6% at a 95.4% using COND models. Our results strongly constrain the frequency of planets within semi-major axes of 50 AU as well. We restrict the frequency of 1-20M_Jup_ companions at semi-major axes from 10-50AU to <21% at a 95.4% confidence level using DUSTY models and to <7% at a 95.4% using COND models. This survey is the deepest search to date for giant planets around young moving group stars.
- ID:
- ivo://CDS.VizieR/J/AJ/160/35
- Title:
- NIR photometry in the T Tauri system with Keck
- Short Name:
- J/AJ/160/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from adaptive optics imaging of the T Tauri triple system obtained at the Keck and Gemini Observatories in 2015-2019. We fit the orbital motion of T Tau Sb relative to Sa and model the astrometric motion of their center of mass relative to T Tau N. Using the distance measured by Gaia, we derived dynamical masses of M_Sa_=2.05{+/-}0.14M_{sun}_ and M_Sb_=0.43{+/-}0.06M_{sun}_. The precision in the masses is expected to improve with continued observations that map the motion through a complete orbital period; this is particularly important as the system approaches periastron passage in 2023. Based on published properties and recent evolutionary tracks, we estimate a mass of ~2M_{sun}_ for T Tau N, suggesting that T Tau N is similar in mass to T Tau Sa. Narrowband infrared photometry shows that T Tau N remained relatively constant between late 2017 and early 2019 with an average value of K=5.54{+/-}0.07mag. Using T Tau N to calibrate relative flux measurements since 2015, we found that T Tau Sa varied dramatically between 7.0 and 8.8mag in the K band over timescales of a few months, while T Tau Sb faded steadily from 8.5 to 11.1mag in the K band. Over the 27yr orbital period of the T Tau S binary, both components have shown 3-4mag of variability in the K band, relative to T Tau N.
- ID:
- ivo://CDS.VizieR/J/A+A/605/L9
- Title:
- NIR spectrum of exoplanet HIP 65426b
- Short Name:
- J/A+A/605/L9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The SHINE program is a high-contrast near-infrared survey of 600 young, nearby stars aimed at searching for and characterizing new planetary systems using VLT/SPHERE's unprecedented high-contrast and high-angular-resolution imaging capabilities. It is also intended to place statistical constraints on the rate, mass and orbital distributions of the giant planet population at large orbits as a function of the stellar host mass and age to test planet-formation theories. We used the IRDIS dual-band imager and the IFS integral field spectrograph of SPHERE to acquire high-contrast coronagraphic differential near-infrared images and spectra of the young A2 star HIP 65426. It is a member of the ~17Myr old Lower Centaurus-Crux association. At a separation of 830 mas (92au projected) from the star, we detect a faint red companion. Multi-epoch observations confirm that it shares common proper motion with HIP 65426. Spectro-photometric measurements extracted with IFS and IRDIS between 0.95 and 2.2{mu}m indicate a warm, dusty atmosphere characteristic of young low-surface-gravity L5-L7 dwarfs. Hot-start evolutionary models predict a luminosity consistent with a 6-12M_Jup_, T_eff_=1300-1600K and R=1.5+/-0.1R_Jup_ giant planet. Finally, the comparison with Exo-REM and PHOENIX BT-Settl synthetic atmosphere models gives consistent effective temperatures but with slightly higher surface gravity solutions of log(g)=4.0-5.0 with smaller radii (1.0-1.3R_Jup_). Given its physical and spectral properties, HIP 65426 b occupies a rather unique placement in terms of age, mass, and spectral-type among the currently known imaged planets. It represents a particularly interesting case to study the presence of clouds as a function of particle size, composition, and location in the atmosphere, to search for signatures of non-equilibrium chemistry, and finally to test the theory of planet formation and evolution.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/52
- Title:
- NIR survey of Spitzer YSOs in Orion Mol. Cloud
- Short Name:
- J/ApJ/821/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a near-infrared survey for the visual multiples in the Orion molecular clouds region at separations between 100 and 1000au. These data were acquired at 1.6um with the NICMOS and WFC3 cameras on the Hubble Space Telescope. Additional photometry was obtained for some of the sources at 2.05um with NICMOS and in the L' band with NSFCAM2 on NASA's InfraRed Telescope Facility. Toward 129 protostars and 197 pre-main-sequence stars with disks observed with WFC3, we detect 21 and 28 candidate companions between the projected separations of 100-1000au, of which less than 5 and 8, respectively, are chance line-of-sight coincidences. The resulting companion fraction (CF) after the correction for the line-of-sight contamination is 14.4_-1.3_^+1.1^ for protostars and 12.5_-0.8_^+1.2^ for the pre-main-sequence stars. These values are similar to those found for main-sequence stars, suggesting that there is little variation in the CF with evolution, although several observational biases may mask a decrease in the CF from protostars to the main-sequence stars. After segregating the sample into two populations based on the surrounding surface density of young stellar objects, we find that the CF in the high stellar density regions ({Sigma}_YSO_>45pc^-2^) is approximately 50% higher than that found in the low stellar density regions ({Sigma}_YSO_<45pc^-2^). We interpret this as evidence for the elevated formation of companions at 100-1000 au in the denser environments of Orion. We discuss possible reasons for this elevated formation.
- ID:
- ivo://CDS.VizieR/J/AJ/156/178
- Title:
- NIR transmission spectra of TRAPPIST-1 planets
- Short Name:
- J/AJ/156/178
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The seven approximately Earth-sized transiting planets in the TRAPPIST-1 system provide a unique opportunity to explore habitable- and nonhabitable-zone small planets within the same system. Its habitable-zone exoplanets - due to their favorable transit depths - are also worlds for which atmospheric transmission spectroscopy is within reach with the Hubble Space Telescope (HST) and James Webb Space Telescope (JWST). We present here an independent reduction and analysis of two HST Wide Field Camera 3 (WFC3) near-infrared transit spectroscopy data sets for six planets (b through g). Utilizing our physically motivated detector charge-trap correction and a custom cosmic-ray correction routine, we confirm the general shape of the transmission spectra presented by de Wit et al. (2016Natur.537...69D). Our data reduction approach leads to a 25% increase in the usable data and reduces the risk of confusing astrophysical brightness variations (e.g., flares) with instrumental systematics. No prominent absorption features are detected in any individual planet's transmission spectra; by contrast, the combined spectrum of the planets shows a suggestive decrease around 1.4 {mu}m similar to an inverted water absorption feature. Including transit depths from K2, the SPECULOOS-South Observatory, and Spitzer, we find that the complete transmission spectrum is fully consistent with stellar contamination owing to the transit light source effect. These spectra demonstrate how stellar contamination can overwhelm planetary absorption features in low-resolution exoplanet transit spectra obtained by HST and JWST and also highlight the challenges in combining multi-epoch observations for planets around rapidly rotating spotted stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/420/L23
- Title:
- Non-resonant Kepler planetary systems
- Short Name:
- J/MNRAS/420/L23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kepler mission has discovered a plethora of multiple transiting planet candidate exosystems, many of which feature putative pairs of planets near mean motion resonance commensurabilities. Identifying potentially resonant systems could help guide future observations and enhance our understanding of planetary formation scenarios. We develop and apply an algebraic method to determine which Kepler two-planet systems cannot be in a first-fourth order resonance, given the current, publicly available data. This method identifies when any potentially resonant angle of a system must circulate. We identify and list 70 near-resonant systems which cannot actually reside in resonance, assuming a widely used formulation for deriving planetary masses from their observed radii and that these systems do not contain unseen bodies that affect the interactions of the observed planets. This work strengthens the argument that a high fraction of exoplanetary systems may be near resonance but not actually in resonance.
- ID:
- ivo://CDS.VizieR/J/A+A/576/A94
- Title:
- Northern bright planet host stars parameters
- Short Name:
- J/A+A/576/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work we derive new precise and homogeneous parameters for 37 stars with planets. For this purpose, we analyze high resolution spectra obtained by the NARVAL spectrograph for a sample composed of bright planet host stars in the northern hemisphere. The new parameters are included in the SWEET-Cat online catalogue. To ensure that the catalogue is homogeneous, we use our standard spectroscopic analysis procedure, ARES + MOOG, to derive effective temperatures, surface gravities, and metallicities. These spectroscopic stellar parameters are then used as input to compute the stellar mass and radius, which are fundamental for the derivation of the planetary mass and radius.
- ID:
- ivo://CDS.VizieR/J/other/NatAs/5.775
- Title:
- nu2 Lupi CHEOPS light curves
- Short Name:
- J/other/NatAs/5.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Exoplanets transiting bright nearby stars are key objects for advancing our knowledge of planetary formation and evolution. The wealth of photons from the host star gives detailed access to the atmospheric, interior and orbital properties of the planetary companions. nu^2^ Lupi (HD 136352) is a naked-eye (V=5.78) Sun-like star that was discovered to host three low-mass planets with orbital periods of 11.6, 27.6 and 107.6d via radial-velocity monitoring. The two inner planets (b and c) were recently found to transit2, prompting a photometric follow-up by the brand new Characterising Exoplanets Satellite (CHEOPS). Here, we report that the outer planet d is also transiting, and measure its radius and mass to be 2.56+/-0.09R_{Earth}_ and 8.82+/-0.94M_{Earth}_, respectively. With its bright Sun-like star, long period and mild irradiation (~5.7 times the irradiation of Earth), nu^2^ Lupi d unlocks a completely new region in the parameter space of exoplanets amenable to detailed characterization. We refine the properties of all three planets: planet b probably has a rocky mostly dry composition, while planets c and d seem to have retained small hydrogen-helium envelopes and a possibly large water fraction. This diversity of planetary compositions makes the nu^2^ Lupi system an excellent laboratory for testing formation and evolution models of low-mass planets.
- ID:
- ivo://CDS.VizieR/J/ApJ/819/27
- Title:
- OAO/MuSCAT light curves of HAT-P-14b
- Short Name:
- J/ApJ/819/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Multicolor Simultaneous Camera for studying Atmospheres of Transiting exoplanets (MuSCAT) is an optical three-band (g'_2_-, r'_2_- and z_s,2_-band) imager that was recently developed for the 188cm telescope at Okayama Astrophysical Observatory with the aim of validating and characterizing transiting planets. In a pilot observation with MuSCAT we observed a primary transit of HAT-P-14b, a high-surface gravity (g_p_=38ms^-2^) hot Jupiter around a bright (V=10) F-type star. From a 2.9hr observation we achieved the five-minute binned photometric precisions of 0.028%, 0.022%, and 0.024% in the g'_2_, r'_2_, and z_s,2_ bands, respectively, which provided the highest-quality photometric data for this planet. Combining these results with those of previous observations, we search for variations of transit timing and duration over five years as well as variations of planet-star radius ratio (Rp/Rs) with wavelengths, but can find no considerable variation in any parameters. On the other hand, using the transit-subtracted light curves we simulate the achievable measurement error of Rp/Rs with MuSCAT for various planetary sizes, assuming three types of host stars: HAT-P-14, the nearby K-dwarf HAT-P-11, and the nearby M-dwarf GJ1214. Comparing our results with the expected atmospheric scale heights, we find that MuSCAT is capable of probing the atmospheres of planets as small as a sub-Jupiter (Rp~6R_{earth}_) around HAT-P-14 in all bands, a Neptune (~4R_{earth}_) around HAT-P-11 in all bands, and a super-Earth (~2.5R_{earth}_) around GJ1214 in r'_2_ and z_s,2_ bands. These results promise that MuSCAT will produce fruitful scientific outcomes in the K2 and TESS era.
