Search Publications
Planets around young active solar-type stars: assessing detection capabilities from a non-stabilized spectrograph
Petit, P.; Wittenmyer, R. A.; Heitzmann, A. +8 more
Short-orbit gas giant planet formation/evolution mechanisms are still not well understood. One promising pathway to discriminate between mechanisms is to constrain the occurrence rate of these peculiar exoplanets at the earliest stage of the system's life. However, a major limitation when studying newly born stars is stellar activity. This cocktai…
A novel survey for young substellar objects with the W-band filter III: Searching for very low-mass brown dwarfs in Serpens South and Serpens Core
Jose, Jessy; Allers, Katelyn; Albert, Loïc +10 more
We present CFHT photometry and IRTF spectroscopy of low-mass candidate members of Serpens South and Serpens Core (~430 pc, ~0.5 Myr), identified using a novel combination of photometric filters, known as the W-band method. We report SC182952+011618, SS182959-020335, and SS183032-021028 as young, low-mass Serpens candidate members, with spectral ty…
Comprehensive broad-band study of accreting neutron stars with Suzaku: Is there a bi-modality in the X-ray spectrum?
Maitra, Chandreyee; Paul, Biswajit; Pradhan, Pragati +2 more
We present a broad-band spectral analysis of accreting neutron stars using data from XIS and PIN onboard Suzaku. From spectral fits of these sources with a single continuum model including a power law and high energy cut-off, cyclotron lines (where required), we studied the correlation between various spectral parameters. Among 39 sources we studi…
Disappearance of the Fe K α emission line in ultracompact X-ray binaries 4U 1543-624 and Swift J1756.9-2508
Guillot, Sebastien; Vasilopoulos, Georgios; Webb, Natalie +1 more
We investigate the long-term variability of the iron K α line in the spectra of two ultracompact X-ray sources (UCXBs) with C/O-rich donors. We revisit archival observations from five different X-ray telescopes, over an ∼20-yr period. Adopting physically motivated models for the spectral continuum, we probe the long-term evolution of the source em…
Clustering of low-mass stars around Herbig Be star IL Cep - evidence of 'Rocket Effect' using Gaia EDR3 ?
Arun, R.; Mathew, Blesson; Manoj, P. +7 more
We study the formation and the kinematic evolution of the early-type Herbig Be star IL Cep and its environment. The young star is a member of the Cep OB3 association, at a distance of 798 ± 9 pc, and has a 'cavity' associated with it. We found that the B0V star HD 216658, which is astrometrically associated with IL Cep, is at the centre of the cav…
Optical detection of the rapidly spinning white dwarf in V1460 Her
Dhillon, V. S.; Pelisoli, Ingrid; Breedt, E. +15 more
Accreting magnetic white dwarfs offer an opportunity to understand the interplay between spin-up and spin-down torques in binary systems. Monitoring of the white dwarf spin may reveal whether the white dwarf spin is currently in a state of near-equilibrium, or of unidirectional evolution towards longer or shorter periods, reflecting the recent his…
GG Carinae: orbital parameters and accretion indicators from phase-resolved spectroscopy and photometry
Grant, David; Porter, Augustus; Blundell, Katherine +1 more
B[e] supergiants are a rare and unusual class of massive and luminous stars, characterized by opaque circumstellar envelopes. GG Carinae is a binary whose primary component is a B[e] supergiant and whose variability has remained unsatisfactorily explained. Using photometric data from ASAS, OMC, and ASAS-SN and spectroscopic data from the Global Je…
A revised view of the Canis Major stellar overdensity with DECam and Gaia: new evidence of a stellar warp of blue stars
Carballo-Bello, Julio A.; Vivas, A. Katherina; Martínez-Delgado, David +4 more
We present the Dark Energy Camera (DECam) imaging combined with Gaia Data Release 2 (DR2) data to study the Canis Major overdensity. The presence of the so-called Blue Plume stars in a low-pollution area of the colour-magnitude diagram allows us to derive the distance and proper motions of this stellar feature along the line of sight of its hypoth…
Lynds Bright Nebulae: sites of possible twisted filaments and ongoing star formation
Dewangan, L. K.; Ojha, D. K.; Baug, T. +2 more
The paper presents an analysis of multiwavelength data of two Lynds Bright Nebulae (LBNs), LBN 140.07+01.64 and LBN 140.77-1.42. The 1420-MHz continuum map reveals an extended Y-shaped feature (linear extent ~3.7°), which consists of a linear part and a V-like structure. The sites LBN 140.07+01.64 and AFGL 437 are located towards the opposite side…
New insights into the use of Ultra Long Period Cepheids as cosmological standard candles
Marconi, Marcella; Molinaro, Roberto; Ripepi, Vincenzo +4 more
Ultra Long Period Cepheids (ULPs) are pulsating variable stars with a period longer than 80 d and have been hypothesized to be the extension of the Classical Cepheids (CCs) at higher masses and luminosities. If confirmed as standard candles, their intrinsic luminosities, ∼1 to ∼3 mag brighter than typical CCs, would allow to reach the Hubble flow …