DISCOVERY OF ROTATIONAL MODULATIONS IN THE PLANETARY-MASS COMPANION 2M1207b: INTERMEDIATE ROTATION PERIOD AND HETEROGENEOUS CLOUDS IN A LOW GRAVITY ATMOSPHERE

Context. PDS 70 is a young (5.4 Myr), nearby (~113 pc) star hosting a known transition disk with a large gap. Recent observations with SPHERE and NACO in the near-infrared (NIR) allowed us to detect a planetary mass companion, PDS 70 b, within the disk cavity. Moreover, observations in Hα with MagAO and MUSE revealed emission associated to PDS 70 b and to another new companion candidate, PDS 70 c, at a larger separation from the star. PDS 70 is the only multiple planetary system at its formation stage detected so far through direct imaging. Aims. Our aim is to confirm the discovery of the second planet PDS 70 c using SPHERE at VLT, to further characterize its physical properties, and search for additional point sources in this young planetary system. Methods. We re-analyzed archival SPHERE NIR observations and obtained new data in Y, J, H and K spectral bands for a total of four different epochs. The data were reduced using the data reduction and handling pipeline and the SPHERE data center. We then applied custom routines (e.g., ANDROMEDA and PACO) to subtract the starlight. Results. We re-detect both PDS 70 b and c and confirm that PDS 70 c is gravitationally bound to the star. We estimate this second planet to be less massive than 5 MJup and with a Teff around 900 K. Also, it has a low gravity with logg between 3.0 and 3.5 dex. In addition, a third object has been identified at short separation (~0.12′′) from the star and gravitationally bound to the star. Its spectrum is however very blue, meaning that we are probably seeing stellar light reflected by dust and our analysis seems to demonstrate that it is a feature of the inner disk. We cannot however completely exclude the possibility that it is a planetary mass object enshrouded by a dust envelope. In this latter case, its mass should be of the order of a few tens of M⊕. Moreover, we propose a possible structure for the planetary system based on our data, and find that this structure cannot be stable on a long timescale.

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CFBDSIR 2149-0403: young isolated planetary-mass object or high-metallicity low-mass brown dwarf?

Astronomy and Astrophysics ◽

10.1051/0004-6361/201629633 ◽

2017 ◽

Vol 602 ◽

pp. A82 ◽

Cited By ~ 5

Author(s):

P. Delorme ◽

T. Dupuy ◽

J. Gagné ◽

C. Reylé ◽

T. Forveille ◽

...

Keyword(s):

Emission Spectra ◽

Brown Dwarf ◽

Low Gravity ◽

Promising Tool ◽

Planetary Mass ◽

Type Object ◽

Multi Wavelength ◽

Solar Metallicity ◽

Low Mass ◽

High Metallicity

Aims. We conducted a multi-wavelength, multi-instrument observational characterisation of the candidate free-floating planet CFBDSIR J214947.2−040308.9, a late T-dwarf with possible low-gravity features, in order to constrain its physical properties. Methods. We analysed nine hours of X-shooter spectroscopy with signal detectable from 0.8 to 2.3 μm, as well as additional photometry in the mid-infrared using the Spitzer Space Telescope. Combined with a VLT/HAWK-I astrometric parallax, this enabled a full characterisation of the absolute flux from the visible to 5 μm, encompassing more than 90% of the expected energy emitted by such a cool late T-type object. Our analysis of the spectrum also provided the radial velocity and therefore the determination of its full 3D kinematics. Results. While our new spectrum confirms the low gravity and/or high metallicity of CFBDSIR 2149, the parallax and kinematics safely rule out membership to any known young moving group, including AB Doradus. We use the equivalent width of the K i doublet at 1.25 μm as a promising tool to discriminate the effects of low-gravity from the effects of high-metallicity on the emission spectra of cool atmospheres. In the case of CFBDSIR 2149, the observed K i doublet clearly favours the low-gravity solution. Conclusions. CFBDSIR 2149 is therefore a peculiar late-T dwarf that is probably a young, planetary-mass object (2–13 MJup, <500 Myr) possibly similar to the exoplanet 51 Eri b, or perhaps a 2–40 MJup brown dwarf with super-solar metallicity.

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Cloud Atlas: Variability in and out of the Water Band in the Planetary-mass HD 203030B Points to Cloud Sedimentation in Low-gravity L Dwarfs

The Astrophysical Journal ◽

10.3847/1538-4357/ab3d25 ◽

2019 ◽

Vol 883 (2) ◽

pp. 181 ◽

Cited By ~ 7

Author(s):

Paulo A. Miles-Páez ◽

Stanimir Metchev ◽

Dániel Apai ◽

Yifan Zhou ◽

Elena Manjavacas ◽

...

Keyword(s):

Low Gravity ◽

Planetary Mass ◽

Water Band ◽

L Dwarfs ◽

Cloud Atlas

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Planetary system around the nearby M dwarf GJ 357 including a transiting, hot, Earth-sized planet optimal for atmospheric characterization

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935801 ◽

2019 ◽

Vol 628 ◽

pp. A39 ◽

Cited By ~ 37

Author(s):

R. Luque ◽

E. Pallé ◽

D. Kossakowski ◽

S. Dreizler ◽

J. Kemmer ◽

...

Keyword(s):

Planetary System ◽

Rotation Period ◽

Archival Data ◽

Habitable Zone ◽

Minimum Mass ◽

Velocity Signal ◽

Planetary Mass ◽

Using Data ◽

M Dwarf ◽

Prime Target

We report the detection of a transiting Earth-size planet around GJ 357, a nearby M2.5 V star, using data from the Transiting Exoplanet Survey Satellite (TESS). GJ 357 b (TOI-562.01) is a transiting, hot, Earth-sized planet (Teq = 525 ± 11 K) with a radius of Rb = 1.217 ± 0.084 R⊕ and an orbital period of Pb = 3.93 d. Precise stellar radial velocities from CARMENES and PFS, as well as archival data from HIRES, UVES, and HARPS also display a 3.93-day periodicity, confirming the planetary nature and leading to a planetary mass of Mb = 1.84 ± 0.31 M⊕. In addition to the radial velocity signal for GJ 357 b, more periodicities are present in the data indicating the presence of two further planets in the system: GJ 357 c, with a minimum mass of Mc = 3.40 ± 0.46 M⊕ in a 9.12 d orbit, and GJ 357 d, with a minimum mass of Md = 6.1 ± 1.0 M⊕ in a 55.7 d orbit inside the habitable zone. The host is relatively inactive and exhibits a photometric rotation period of Prot = 78 ± 2 d. GJ 357 b isto date the second closest transiting planet to the Sun, making it a prime target for further investigations such as transmission spectroscopy. Therefore, GJ 357 b represents one of the best terrestrial planets suitable for atmospheric characterization with the upcoming JWST and ground-based ELTs.

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Rotational Characteristics of the Green Solar Corona: 1947-1991

International Astronomical Union Colloquium ◽

10.1017/s0252921100025197 ◽

1994 ◽

Vol 144 ◽

pp. 139-141 ◽

Cited By ~ 2

Author(s):

J. Rybák ◽

V. Rušin ◽

M. Rybanský

Keyword(s):

Solar Corona ◽

World Wide ◽

Rotation Period ◽

Original Data ◽

Coronal Emission ◽

Time Intervals ◽

Data Set ◽

The World ◽

Coronal Emission Line ◽

Homogeneous Data

AbstractFe XIV 530.3 nm coronal emission line observations have been used for the estimation of the green solar corona rotation. A homogeneous data set, created from measurements of the world-wide coronagraphic network, has been examined with a help of correlation analysis to reveal the averaged synodic rotation period as a function of latitude and time over the epoch from 1947 to 1991.The values of the synodic rotation period obtained for this epoch for the whole range of latitudes and a latitude band ±30° are 27.52±0.12 days and 26.95±0.21 days, resp. A differential rotation of green solar corona, with local period maxima around ±60° and minimum of the rotation period at the equator, was confirmed. No clear cyclic variation of the rotation has been found for examinated epoch but some monotonic trends for some time intervals are presented.A detailed investigation of the original data and their correlation functions has shown that an existence of sufficiently reliable tracers is not evident for the whole set of examinated data. This should be taken into account in future more precise estimations of the green corona rotation period.

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On the Configuration of the Magnetic Field of β CrB

International Astronomical Union Colloquium ◽

10.1017/s0252921100080933 ◽

1976 ◽

Vol 32 ◽

pp. 613-622

Author(s):

I.A. Aslanov ◽

Yu.S. Rustamov

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Radial Velocity ◽

Magnetic Field Strength ◽

Complex Shape ◽

Rotation Period ◽

Field Variation ◽

Magnetic Field Variation ◽

Secular Variations ◽

The Magnetic Field

SummaryMeasurements of the radial velocities and magnetic field strength of β CrB were carried out. It is shown that there is a variability with the rotation period different for various elements. The curve of the magnetic field variation measured from lines of 5 different elements: FeI, CrI, CrII, TiII, ScII and CaI has a complex shape specific for each element. This may be due to the presence of magnetic spots on the stellar surface. A comparison with the radial velocity curves suggests the presence of a least 4 spots of Ti and Cr coinciding with magnetic spots. A change of the magnetic field with optical depth is shown. The curve of the Heffvariation with the rotation period is given. A possibility of secular variations of the magnetic field is shown.

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