Explanipedia

Observation of undepleted phosphine in the atmosphere of a low-temperature brown dwarf Open

Adam J. Burgasser, Eileen C. Gonzales, Samuel A. Beiler, Channon Visscher, Ben Burningham , et al. · 2025

The atmospheres of low-temperature brown dwarfs and gas giant planets are expected to contain the phosphine molecule, PH 3 . However, previous observations have shown much lower abundances of this molecule than predicted with atmospheric c…

X-SHYNE: X-Shooter spectra of young exoplanet analogs Open

Simon Petrus, G. Chauvin, M. Bonnefoy, Pascal Tremblin, C. Morley , et al. · 2025

Characterizing exoplanets’ spectra is a crucial step in understanding the chemical and physical processes shaping their atmospheres and constraining their formation and evolutionary history. The X-SHYNE library is a homogeneous sample of 4…

Imaging-spectroscopy diagnosis of the giant sloshing spiral in the Virgo cluster with the Einstein Probe Follow-up X-ray Telescope Open

Xueying Zheng, S. Jia, Chong Li, Ye Chen, Haoran Yu , et al. · 2025

We performed deep X-ray observations of the Virgo cluster using the Einstein Probe Follow-up X-ray Telescope ( EP-FXT ) with a total exposure of 295 ks. Taking advantage of the large field of view (FoV) and low particle background of EP-FX…

Benchmark brown dwarfs – I. A blue M2 + T5 wide binary and a probable young [M4 + M4] + [T7 + T8] hierarchical quadruple Open

Z. H. Zhang, Felipe Navarete, M. C. Gálvez-Ortiz, H. R. A. Jones, Adam J. Burgasser , et al. · 2025

Benchmark brown dwarfs in wide binary systems are crucial for characterizing substellar objects and calibrating atmospheric and evolutionary models. However, brown dwarf benchmarks with subsolar metallicity, very cool temperatures, or suit…

GTC Optical/Near-infrared Upper Limits and NICER X-Ray Analysis of SGR J1935+2154 for the Outburst in 2022 Open

Yi-Xuan Shao, Ping Zhou, Xiang‐Dong Li, Bin‐Bin Zhang, A. J. Castro–Tirado , et al. · 2024

The Galactic magnetar SGR J1935+2154 has undergone another outburst since 2022 October 10. We present the results of searching for an optical/near-infrared (NIR) counterpart of SGR J1935+2154 before and during this outburst. No counterpart…

The Gaia ultracool dwarf sample–IV. GTC/OSIRIS optical spectra of Gaia late-M and L dwarfs Open

William Cooper, H. R. A. Jones, R. L. Smart, S. L. Folkes, J. A. Caballero , et al. · 2024

As part of our comprehensive, ongoing characterization of the low-mass end of the main sequence in the Solar neighbourhood, we used the OSIRIS instrument at the 10.4 m Gran Telescopio Canarias to acquire low- and mid-resolution (R${\approx…

Primeval very low-mass stars and brown dwarfs – VIII. The first age benchmark L subdwarf, a wide companion to a halo white dwarf Open

Z. H. Zhang, R. Raddi, Adam J. Burgasser, S. L. Casewell, R. L. Smart , et al. · 2024

We report the discovery of five white dwarf + ultracool dwarf systems identified as common proper motion wide binaries in the Gaia Catalogue of Nearby Stars. The discoveries include a white dwarf + L subdwarf binary, VVV 1256−62AB, a gravi…

76 T dwarfs from the UKIDSS LAS: Benchmarks, kinematics and an updated space density Open

Ben Burningham, Chasnini Cardoso, Leigh C. Smith, S. K. Leggett, R. L. Smart , et al. · 2023

We report the discovery of 76 new T dwarfs from the UKIRT Infrared Deep Sky Survey(UKIDSS) Large Area Survey (LAS). Near-infrared broad-and narrow-band photometry and spectroscopy are presented for the new objects, along withWide-field Inf…

Non-equilibrium effect modeling and particle velocity estimation for particulate flow in porous media Open

Yi Jin, Z. H. Zhang, Rouzbeh Ghanbarnezhad Moghanloo · 2023

The complex dynamics of fluid and particles flowing through pore space demands some relaxation time for particles to catch up with fluid velocity, which manifest themselves as non-equilibrium (NE) effects. Previous studies have shown that …

Search for gamma-ray bursts and gravitational wave electromagnetic counterparts with High Energy X-ray Telescope of Insight-HXMT Open

Ce Cai, S. L. Xiong, Cheng-Kui Li, Chao‐Zong Liu, S N Zhang , et al. · 2021

The High Energy (HE) X-ray telescope on board the Hard X-ray Modulation Telescope (Insight-HXMT) can serve as a wide field of view (FOV) gamma-ray monitor with high time resolution (μs) and large effective area (up to thousands cm2). We de…

Discovery of the substellar transition zone of transitional brown dwarfs between stars and degenerate brown dwarfs Open

Z. H. Zhang · 2021

The destiny of a star is depending on the status of hydrogen fusion that it can reach after its formation. Stars have steady hydrogen fusion and can maintain their luminosity. Degenerate brown dwarfs (D-BD) have no energy supply from hydro…

Primeval very low-mass stars and brown dwarfs series Open

Z. H. Zhang · 2021

Primeval - I. Six new L subdwarfs, classification and atmospheric properties Primeval - II. The most metal-poor substellar object Primeval - III. The halo transitional brown dwarfs Primeval - IV. New L subdwarfs, Gaia astrometry, populatio…

First discovery of an ultra-cool white dwarf benchmark in common proper motion with an M dwarf Open

Marco C. Lam, N. C. Hambly, N. Lodieu, Simon Blouin, E. Harvey , et al. · 2020

Ultra-cool white dwarfs are among the oldest stellar remnants in the Universe. Their efficient gravitational settling and low effective temperatures are responsible for the smooth spectra they exhibit. For that reason, it is not possible t…

Primeval very low-mass stars and brown dwarfs – VII. The discovery of the first wide M + L extreme subdwarf binary Open

Z. H. Zhang · 2019

I present the discovery of the first wide M + L extreme subdwarf binary system Gaia J0452−36AB. The binary is located at a distance of 137.27 $^{+0.68}_{-0.67}$ pc with a projected separation of 15828 ± 78 au. I classified Gaia J0452−36AB …

Primeval very low-mass stars and brown dwarfs – VI. Population properties of metal-poor degenerate brown dwarfs Open

Z. H. Zhang, Adam J. Burgasser, M. C. Gálvez-Ortiz, N. Lodieu, M. R. Zapatero Osorio , et al. · 2019

We presented 15 new T dwarfs that were selected from UKIRT Infrared Deep Sky Survey, Visible and Infrared Survey Telescope for Astronomy , and Wide-field Infrared Survey Explorer surveys, and confirmed with optical to near-infrared spectra…

Primeval very low-mass stars and brown dwarfs – V. A halo L3 subdwarf with prograde eccentric orbit in the Galactic plane Open

Z. H. Zhang, Adam J. Burgasser, Leigh C. Smith · 2019

VVV J12564163$-$6202039 is an L subdwarf located in the Galactic plane ($b$ =\n0.831 deg) discovered by its high proper motion (1.1 arcsec yr/s). We obtained\nan optical to near-infrared spectrum of it with the X-shooter on the Very Large\…

Microlens mass determination forGaia’s predicted photometric events Open

Peter McGill, Leigh C. Smith, N. W. Evans, Vasily Belokurov, Z. H. Zhang · 2018

We used Gaia Data Release 2 to search for upcoming photometric microlensing\nevents, identifying two candidates with high amplification. In the case of\ncandidate 1, a spectrum of the lens (l1) confirms it is a usdM3 subdwarf with\nmass $\…

The Substellar Transition Zone: A Stretched Temperature Canyon in Brown Dwarf Population due to Unsteady Hydrogen Fusion Open

Z. H. Zhang · 2018

I summarize results on transitional and degenerate brown dwarfs presented in a series titled Primeval very low-mass stars and brown dwarfs. I introduce an L subdwarf classification scheme, which classified L subdwarfs into three m…

The Substellar Transition Zone: A Stretched Temperature Canyon In Brown Dwarf Population Due To Unsteady Hydrogen Fusion Open

Z. H. Zhang · 2018

I introduce an L subdwarf classification scheme, which classified L subdwarfs into three metal subclasses. I would also like to draw your attention to transitional brown dwarfs which have unsteady hydrogen fusion in their cores to replenis…

Primeval very low-mass stars and brown dwarfs – IV. New L subdwarfs, Gaia astrometry, population properties, and a blue brown dwarf binary Open

Z. H. Zhang, M. C. Gálvez-Ortiz, D. J. Pinfield, Adam J. Burgasser, N. Lodieu , et al. · 2018

We present 27 new L subdwarfs and classify five of them as esdL and 22 as\nsdL. Our L subdwarf candidates were selected with the UKIRT Infrared Deep Sky\nSurvey and Sloan Digital Sky Survey. Spectroscopic follow-up was carried out\nprimari…

The Science Advantage of a Redder Filter for WFIRST Open

John Stauffer, G. Hélou, Robert A. Benjamin, M. Marengo, J. Davy Kirkpatrick , et al. · 2018

WFIRST will be capable of providing Hubble-quality imaging performance over several thousand square degrees of the sky. The wide-area, high spatial resolution survey data from WFIRST will be unsurpassed for many decades into the future. Wi…

Primeval very low-mass stars and brown dwarfs – III. The halo transitional brown dwarfs Open

Z. H. Zhang, D. J. Pinfield, M. C. Gálvez-Ortiz, D. Homeier, Adam J. Burgasser , et al. · 2018

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Ultracool dwarf benchmarks with Gaia primaries Open

Federico Marocco, D. J. Pinfield, Neil J. Cook, M. R. Zapatero Osorio, D. Montes , et al. · 2017

We explore the potential of Gaia for the field of benchmark ultracool/brown dwarf companions, and present the results of an initial search for metal-rich/metal-poor systems. A simulated population of resolved ultracool dwarf companions to …

Primeval very low-mass stars and brown dwarfs – II. The most metal-poor substellar object Open

Z. H. Zhang, D. Homeier, D. J. Pinfield, N. Lodieu, H. R. A. Jones , et al. · 2017

SDSS J010448.46+153501.8 has previously been classified as an sdM9.5\nsubdwarf. However, its very blue $J-K$ colour ($-0.15 \\pm 0.17$) suggests a\nmuch lower metallicity compared to normal sdM9.5 subdwarfs. Here, we\nre-classify this obje…

Primeval very low-mass stars and brown dwarfs – I. Six new L subdwarfs, classification and atmospheric properties Open

Z. H. Zhang, D. J. Pinfield, M. C. Gálvez-Ortiz, Ben Burningham, N. Lodieu , et al. · 2016

We have conducted a search for L subdwarf candidates within the photometric\ncatalogues of the UKIRT Infrared Deep Sky Survey and Sloan Digital Sky Survey.\nSix of our candidates are confirmed as L subdwarfs spectroscopically at optical\na…

49 new T dwarfs identified using methane imaging Open

C. Cardoso, Ben Burningham, R. L. Smart, L. van Spaandonk, David Baker , et al. · 2015

We present the discovery of 49 new photometrically classified T dwarfs from the combination of large infrared and optical surveys combined with follow-up TNG photometry. We used multi-band infrared and optical photometry from the UKIRT and…

A large spectroscopic sample of L and T dwarfs from UKIDSS LAS: peculiar objects, binaries, and space density Open

Federico Marocco, H. R. A. Jones, A. C. Day-Jones, D. J. Pinfield, P. W. Lucas , et al. · 2015

This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record [F. Marocco, et al, 'A large spectroscopic sample of L a…

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