Search Publications
New, late-type spectroscopic binaries with X-ray emission
Guillout, P.; Giarrusso, M.; Leone, F. +6 more
In this paper, we present a spectroscopic study of six double-lined binaries, five of which were recently discovered in a high-resolution spectroscopic survey of optical counterparts of stellar X-ray sources. Thanks to high-resolution spectra acquired with CAOS spectropolarimeter during 7 yr, we were able to measure the radial velocities of their …
A detailed study of the barium central star of the planetary nebula Abell 70
Munday, James; Jones, David; Miszalski, Brent +4 more
We present a detailed study of the barium star at the heart of the planetary nebula Abell 70. Time-series photometry obtained over a period of more than 10 yr demonstrates that the barium-contaminated companion is a rapid rotator with temporal variability due to spots. The amplitude and phasing of the photometric variability change abruptly; howev…
The double-lined spectroscopic binary orbit of the massive supergiant HD 152147: A new target for interferometry
Gamen, R.; Barbá, R. H.; Morrell, N. I. +4 more
We present a new spectroscopic orbit of the O-type binary system HD 152147. We identify absorption lines in both components and use their radial velocities to determine the orbit, which results in a period of P = 50.2199 ± 0.0007 d, an eccentricity e = 0.738 ± 0.007, and a mean separation between the components of asin i = 151 ± 1 R⊙. C…
Disentangling the neighbouring pulsars SXP 15.3 and SXP 305
Udalski, A.; Coe, M. J.; Roy, A. +8 more
SXP 15.3 and SXP 305 are two Be X-ray binaries in the Small Magellanic Cloud that are spatially separated by ~7 arcsec. The small separation between these sources has, in the past, resulted in confusion about the origin of the emission from the combined region. We present long-term optical and X-ray monitoring results of both sources, where we stu…
The outer orbit of the high-mass stellar triple system Herschel 36 determined with the VLTI
Brandner, W.; Pott, J. -U.; Alberdi, A. +8 more
Multiplicity is a ubiquitous characteristic of massive stars. Multiple systems offer us a unique observational constraint on the formation of high-mass systems. Herschel 36 A is a massive triple system composed of a close binary (Ab1-Ab2) and an outer component (Aa). We measured the orbital motion of the outer component of Herschel 36 A using infr…
Study of UV bright sources in globular cluster NGC 4590 using Ultraviolet Imaging Telescope (UVIT) observations
Pradhan, Ananta C.; Mohapatra, Abhisek; Parthasarathy, M. +5 more
We have studied ultraviolet (UV) bright sources in the Galactic globular cluster (GGC) NGC 4590 using Ultraviolet Imaging Telescope onboard the AstroSat satellite. Using UV-optical colour-magnitude diagrams (CMDs), we have identified and characterized the sources of different evolutionary stages i.e. blue horizontal branch stars (BHBs), extremely …
Magnetic fields and young stellar objects in cometary cloud L1616
Soam, Archana; Saha, Piyali; Gopinathan, Maheswar +3 more
The Lynds' Dark Nebula (LDN) 1615/1616 and CB 28 (hereafter L1616) together form a cometary globule located at an angular distance of about 8° west of the Orion OB1 association, aligned roughly along the east-west direction, and showing a distinct head-tail structure. The presence of massive stars in the Orion belt has been considered to be respon…
Cool interstellar medium as an evolutionary tracer in ALMA-observed local dusty early-type galaxies
Popescu, Cristina C.; Davis, Timothy A.; Sansom, Anne E. +1 more
The content and distribution of cool interstellar medium (<30 K) can indicate the evolutionary mechanisms that transform late-type to early-type galaxies (ETGs). To investigate this, ALMA observations of 12CO[2-1] line emission were obtained for five dusty ETGs from a complete sample in low-density environments. Four of the ETGs have…
Discovery and origin of the radio emission from the multiple stellar system KQ Vel
Umana, G.; Owocki, S. P.; Fossati, L. +20 more
KQ Vel is a binary system composed of a slowly rotating magnetic Ap star with a companion of unknown nature. In this paper, we report the detection of its radio emission. We conducted a multifrequency radio campaign using the ATCA interferometer (band-names: 16 cm, 4 cm, and 15 mm). The target was detected in all bands. The most obvious explanatio…
Density exponent analysis: gravity-driven steepening of the density profiles of star-forming regions
Li, Guang-Xing; Zhou, Ji-Xuan
The evolution of molecular interstellar clouds is a complex, multiscale process. The power-law density exponent describes the steepness of density profiles, and it has been used to characterize the density structures of the clouds; yet its usage is usually limited to spherically symmetric systems. Importing the Level-Set Method, we develop a new f…