scholarly journals A faint companion around CrA-9: protoplanet or obscured binary?

2021 ◽  
Vol 502 (4) ◽  
pp. 6117-6139
Author(s):  
V Christiaens ◽  
M-G Ubeira-Gabellini ◽  
H Cánovas ◽  
P Delorme ◽  
B Pairet ◽  
...  
Keyword(s):  
Point Source ◽  
Giant Planets ◽  
Spectral Library ◽  
Object Point ◽  
Near Ir ◽  
Planetary Mass ◽  
Absolute Magnitudes ◽  
M Dwarf ◽  
Background Star

ABSTRACT Understanding how giant planets form requires observational input from directly imaged protoplanets. We used VLT/NACO and VLT/SPHERE to search for companions in the transition disc of 2MASS J19005804-3645048 (hereafter CrA-9), an accreting M0.75 dwarf with an estimated age of 1–2 Myr. We found a faint point source at ∼0.7-arcsec separation from CrA-9 (∼108 au projected separation). Our 3-epoch astrometry rejects a fixed background star with a 5σ significance. The near-IR absolute magnitudes of the object point towards a planetary-mass companion. However, our analysis of the 1.0–3.8$\,\mu$m spectrum extracted for the companion suggests it is a young M5.5 dwarf, based on both the 1.13-μm Na index and comparison with templates of the Montreal Spectral Library. The observed spectrum is best reproduced with high effective temperature ($3057^{+119}_{-36}$K) BT-DUSTY and BT-SETTL models, but the corresponding photometric radius required to match the measured flux is only $0.60^{+0.01}_{-0.04}$ Jovian radius. We discuss possible explanations to reconcile our measurements, including an M-dwarf companion obscured by an edge-on circum-secondary disc or the shock-heated part of the photosphere of an accreting protoplanet. Follow-up observations covering a larger wavelength range and/or at finer spectral resolution are required to discriminate these two scenarios.

scholarly journals Giant planets around AF and M stars

2013 ◽  
Vol 8 (S299) ◽  
pp. 64-65
Author(s):  
Julien Rameau ◽  
Gaël Chauvin ◽  
Anne-Marie Lagrange ◽  
Philippe Delorme ◽  
Justine Lannier
Keyword(s):  
Giant Planets ◽  
Early Type ◽  
Late Type ◽  
M Dwarfs ◽  
Low Mass Stars ◽  
Planetary Mass ◽  
Nearby Stars ◽  
Low Mass ◽  
M Stars ◽  
The One

AbstractWe present the results of two three-year surveys of young and nearby stars to search for wide orbit giant planets. On the one hand, we focus on early-type and massive, namely β Pictoris analogs. On the other hand, we observe late type and very low mass stars, i.e., M dwarfs. We report individual detections of new planetary mass objects. According to our deep detection performances, we derive the observed frequency of giant planets between these two classes of parent stars. We find frequency between 6 to 12% but we are not able to assess a/no correlation with the host-mass.

scholarly journals The Hubble PanCET program: Transit and Eclipse Spectroscopy of the Hot-Jupiter WASP-74b

2021 ◽  
Vol 162 (6) ◽  
pp. 271
Author(s):  
Guangwei Fu ◽  
Drake Deming ◽  
Erin May ◽  
Kevin Stevenson ◽  
David K. Sing ◽  
...  
Keyword(s):  
Rayleigh Scattering ◽  
Hubble Space Telescope ◽  
Absorption Feature ◽  
Spectral Library ◽  
Data Set ◽  
Space Telescope ◽  
Methane Absorption ◽  
James Webb Space Telescope ◽  
Hot Jupiter

Abstract Planets are like children with each one being unique and special. A better understanding of their collective properties requires a deeper understanding of each planet. Here we add the transit and eclipse spectra of hot-Jupiter WASP-74b into the ever growing data set of exoplanet atmosphere spectral library. With six transits and three eclipses using the Hubble Space Telescope and Spitzer Space Telescope (Spitzer), we present the most complete and precise atmospheric spectra of WASP-74b. We found no evidence for TiO/VO nor super-Rayleigh scattering reported in previous studies. The transit shows a muted water feature with strong Rayleigh scattering extending into the infrared. The eclipse shows a featureless blackbody-like WFC3/G141 spectrum and a weak methane absorption feature in the Spitzer 3.6 μm band. Future James Webb Space Telescope follow-up observations are needed to confirm these results.

scholarly journals A resonant pair of warm giant planets revealed by TESS

2019 ◽  
Vol 486 (4) ◽  
pp. 4980-4986 ◽  
Author(s):  
David Kipping ◽  
David Nesvorný ◽  
Joel Hartman ◽  
Guillermo Torres ◽  
Gaspar Bakos ◽  
...  
Keyword(s):  
Giant Planets ◽  
Dynamical Model ◽  
First Year ◽  
Mean Motion ◽  
M Dwarf ◽  
Mean Motion Resonance ◽  
Dynamical Masses

ABSTRACT We present the discovery of a pair of transiting giant planets using four sectors of TESS photometry. TOI-216 is a 0.87 M⊙ dwarf orbited by two transiters with radii of 8.2 and 11.3 R⊕, and periods of 17.01 and 34.57 d, respectively. Anticorrelated TTVs are clearly evident indicating that the transiters orbit the same star and interact via a near 2:1 mean motion resonance. By fitting the TTVs with a dynamical model, we infer masses of $30_{-14}^{+20}$ and $200_{-100}^{+170}$ M⊕, establishing that the objects are planetary in nature and have likely sub-Kronian and Kronian densities. TOI-216 lies close to the southern ecliptic pole and thus will be observed by TESS throughout the first year, providing an opportunity for continuous dynamical monitoring and considerable refinement of the dynamical masses presented here. TOI-216 closely resembles Kepler-9 in architecture, and we hypothesize that in such systems these Saturn analogues failed to fully open a gap and thus migrated far deeper into the system before becoming trapped into resonance, which would imply that future detections of new analogues may also have sub-Jupiter masses.

scholarly journals Detectability of embedded protoplanets from hydrodynamical simulations

2020 ◽  
Vol 492 (3) ◽  
pp. 3440-3458 ◽  
Author(s):  
E Sanchis ◽  
G Picogna ◽  
B Ercolano ◽  
L Testi ◽  
G Rosotti
Keyword(s):  
Surface Density ◽  
Three Dimensional ◽  
Giant Planets ◽  
Evolutionary Models ◽  
Upper Limits ◽  
Disc Material ◽  
Silicate Feature ◽  
Hydrodynamical Simulations ◽  
Cq Tau ◽  
Absolute Magnitudes

ABSTRACT We predict magnitudes for young planets embedded in transition discs, still affected by extinction due to material in the disc. We focus on Jupiter-sized planets at a late stage of their formation, when the planet has carved a deep gap in the gas and dust distributions and the disc starts to being transparent to the planet flux in the infrared (IR). Column densities are estimated by means of three-dimensional hydrodynamical models, performed for several planet masses. Expected magnitudes are obtained by using typical extinction properties of the disc material and evolutionary models of giant planets. For the simulated cases located at 5.2 au in a disc with a local unperturbed surface density of 127 $\mathrm{g} \, \mathrm{cm}^{-2}$, a 1MJ planet is highly extinct in the J, H, and Kbands, with predicted absolute magnitudes ≥ 50 mag. In the L and Mbands, extinction decreases, with planet magnitudes between 25 and 35 mag. In the Nband, due to the silicate feature on the dust opacities, the expected magnitude increases to ∼40 mag. For a 2MJ planet, the magnitudes in the J, H, and Kbands are above 22 mag, while for the L, M, and Nbands, the planet magnitudes are between 15 and 20 mag. For the 5MJ planet, extinction does not play a role in any IR band, due to its ability to open deep gaps. Contrast curves are derived for the transition discs in CQ Tau, PDS 70, HL Tau, TW Hya, and HD 163296. Planet mass upper limits are estimated for the known gaps in the last two systems.

WSRT 21-cm continuum field in Cygnus OB2: in search of more Wolf-Rayet stars

1999 ◽  
Vol 193 ◽  
pp. 103-104
Author(s):  
Diah Y.A. Setia Gunawan ◽  
Karel A. van der Hucht ◽  
A. Ger de Bruyn ◽  
Peredur M. Williams
Keyword(s):  
Point Source ◽  
Stellar Wind ◽  
Noise Level ◽  
Angular Resolution ◽  
Ob Stars ◽  
Near Ir ◽  
Continuum Field

We present a deep look into the Cygnus OB2 region using the WSRT. A 2° x 2° map of the optically highly-obscured region was obtained at 1400 MHz, with a noise level down to 0.2 mJy and an angular resolution of 1″. We will compare the resulting radio point source list with optical and near-IR catalogues, in order to identify stellar wind sources like WR and OB stars.

scholarly journals Real-Time Detection Of Gravitational Microlensing

1996 ◽  
Vol 173 ◽  
pp. 221-226 ◽  
Author(s):  
M.R. Pratt ◽  
C. Alcock ◽  
R.A. Allsman ◽  
D. Alves ◽  
T.S. Axelrod ◽  
...  
Keyword(s):  
Point Source ◽  
Real Time ◽  
Temporal Resolution ◽  
Proof Of Concept ◽  
Inertial Motion ◽  
Source Point ◽  
Gravitational Microlensing ◽  
Real Time Detection ◽  
Mass Position

Real-time detection of microlensing has moved from proof of concept in 1994 (Udalski et al. 1994a, Alcock et al. 1994) to a steady stream of events this year. Global dissemination of these events by the MACHO and OGLE collaborations has made possible intensive photometric and spectroscopic follow up from widely dispersed sites confirming the microlensing hypothesis (Benetti 1995). Improved photometry and increased temporal resolution from follow up observations greatly increases the possibility of detecting deviations from the standard point-source, point-lens, inertial motion microlensing model. These deviations are crucial in understanding individual lensing systems by breaking the degeneracy between lens mass, position and velocity. We report here on GMAN (Global Microlensing Alert Network), the coordinated follow up of MACHO alerts.

scholarly journals The Swift Bulge Survey: optical and near-IR follow-up featuring a likely symbiotic X-ray binary and a focused wind CV

2020 ◽  
Vol 492 (3) ◽  
pp. 4344-4360 ◽  
Author(s):  
A W Shaw ◽  
C O Heinke ◽  
T J Maccarone ◽  
G R Sivakoff ◽  
J Strader ◽  
...  
Keyword(s):  
White Dwarf ◽  
Near Infrared ◽  
Substantial Contribution ◽  
Galactic Centre ◽  
First Year ◽  
X Ray ◽  
Giant Stars ◽  
Near Ir ◽  
Star Binary

ABSTRACT The nature of very faint X-ray transients (VFXTs) – transient X-ray sources that peak at luminosities $L_X\lesssim 10^{36} {\rm \, erg \, s^{-1}}$ – is poorly understood. The faint and often short-lived outbursts make characterizing VFXTs and their multiwavelength counterparts difficult. In 2017 April we initiated the Swift Bulge Survey, a shallow X-ray survey of ∼16 square degrees around the Galactic centre with the Neil Gehrels Swift Observatory. The survey has been designed to detect new and known VFXTs, with follow-up programmes arranged to study their multiwavelength counterparts. Here we detail the optical and near-infrared follow-up of four sources detected in the first year of the Swift Bulge Survey. The known neutron star binary IGR J17445-2747 has a K4III donor, indicating a potential symbiotic X-ray binary nature and the first such source to show X-ray bursts. We also find one nearby M-dwarf (1SXPS J174215.0-291453) and one system without a clear near-IR counterpart (Swift J175233.9-290952). Finally, 3XMM J174417.2-293944 has a subgiant donor, an 8.7 d orbital period, and a likely white dwarf accretor; we argue that this is the first detection of a white dwarf accreting from a gravitationally focused wind. A key finding of our follow-up campaign is that binaries containing (sub)giant stars may make a substantial contribution to the VFXT population.

Identification of Electrolytes in Aqueous Solutions from Near-IR Spectra

1996 ◽  
Vol 50 (4) ◽  
pp. 444-448 ◽  
Author(s):  
Jie Lin ◽  
Jing Zhou ◽  
Chris W. Brown
Keyword(s):  
Aqueous Solutions ◽  
Ir Spectra ◽  
Principal Component Regression ◽  
Principal Component ◽  
Transition Metal Ions ◽  
Water Molecules ◽  
Spectral Library ◽  
Dipole Interactions ◽  
Near Ir ◽  
Solutions Of Electrolytes

Dissolution of electrolytes causes characteristic changes in the near-IR spectrum of water. These changes result from a decrease in the concentration of water; charge-dipole interactions between ions and water molecules; formation of hydrogen bonds between oxygen or nitrogen atoms in some ions and water molecules; production of H+ and OH− ions from dissociation and hydrolysis; absorptions due to OH, NH, and CH groups in some ions; and intrinsic colors of some transition metal ions. Changes in spectra were used for identification of electrolytes in aqueous solutions. Near-IR spectra of 71 solutions of single electrolytes were measured and used to develop a spectral library. This near-IR spectral library was processed with principal component regression (PCR) and used for the identification of single and multiple electrolytes in aqueous solutions with the use of their spectra. Most of the unknown electrolytes were identified correctly. For the others, very similar electrolytes were selected with one ion identified correctly. The near-IR spectral library of aqueous solutions of electrolytes can be used as a simple and fast approach for the identification of electrolytes.

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