50 research outputs found

    Exploring pre-main sequence variables of ONC: The new variables

    Full text link
    Since 2004, we have been engaged in a long-term observing program to monitor young stellar objects in the Orion Nebula Cluster. We have collected about two thousands frames in V, R, and I broad-band filters on more than two hundred nights distributed over five consecutive observing seasons. The high-quality and time-extended photometric data give us an opportunity to address various phenomena associated with young stars. The prime motivations of this project are i) to explore various manifestations of stellar magnetic activity in very young low-mass stars; ii) to search for new pre-main sequence eclipsing binaries; and iii) to look for any EXor and FUor like transient activities associated with YSOs. Since this is the first paper on this program, we give a detailed description of the science drivers, the observation and the data reduction strategies as well. In addition to these, we also present a large number of new periodic variables detected from our first five years of time-series photometric data. Our study reveals that about 72% of CTTS in our FoV are periodic, whereas, the percentage of periodic WTTS is just 32%. This indicates that inhomogeneities patterns on the surface of CTTS of the ONC stars are much more stable than on WTTS. From our multi-year monitoring campaign we found that the photometric surveys based on single-season are incapable of identifying all periodic variables. And any study on evolution of angular momentum based on single-season surveys must be carried out with caution.Comment: Accepted for publication by MNRAS, 26 pages, 17 figures, 6 table

    Characterisation of the dip-bump structure observed in proton-proton elastic scattering at root s=8 TeV

    Get PDF
    The TOTEM collaboration at the CERN LHC has measured the differential cross-section of elastic proton-proton scattering at root s = 8 TeV in the squared four-momentum transfer range 0.2 GeV2 < vertical bar t vertical bar < 1.9 GeV2. This interval includes the structure with a diffractive minimum ("dip") and a secondary maximum ("bump") that has also been observed at all other LHC energies, where measurements were made. A detailed characterisation of this structure for root s = 8 TeV yields the positions, vertical bar t vertical bar(dip) = (0.521 +/- 0.007) GeV2 and vertical bar t vertical bar(bump) = (0.695 +/- 0.026) GeV2, as well as the cross-section values, d sigma/dt vertical bar(dip) = (15.1 +/- 2.5) mu b/GeV2 and d sigma/dt vertical bar(bump) = (29.7 +/- 1.8) mu b/Ge-2, for the dip and the bump, respectively

    A New Way to Link Development to Institutions, Policies and Geography

    Full text link
    corecore