LHS 2803B: A very wide mid-T dwarf companion to an old M dwarf identified from Pan-STARRS1

We report the discovery of a wide (1400 AU projected separation), common proper motion companion to the nearby M dwarf LHS 2803 (PSO J207.0300-13.7422). This object was discovered during our census of the local T dwarf population using Pan-STARRS1 and Two Micron All Sky Survey data. Using the Infrared Telescope Facility/SpeX near-infrared spectroscopy, we classify the secondary to be spectral type T5.5. University of Hawaii 2.2m/SuperNova Integral Field Spectrograph optical spectroscopy indicates that the primary has a spectral type of M4.5, with approximately solar metallicity and no measurable Hα emission. We use this lack of activity to set a lower age limit for the system of 3.5Gyr. Using a comparison with chance alignments of brown dwarfs and nearby stars, we conclude that the two objects are unlikely to be a chance association. The primary's photometric distance of 21pc and its proper motion implies thin disk kinematics. Based on these kinematics and its metallicity, we set an upper age limit for the system of 10Gyr. Evolutionary model calculations suggest that the secondary has a mass of 72±47 MJup, temperature of 1120 ± 80K, and log g = 5.4 ± 0.1dex. Model atmosphere fitting to the near-IR spectrum gives similar physical parameters of 1100K and log g = 5.0

Sample of low mass stars with mu>0.1"/yr

Item does not contain fulltextWe present details of the second part of the Southern Infrared Proper Motion Survey (SIPS). Here accurate relative astrometry allows us to reduce the minimum proper motion to 0.1"/yr. This yields 6904 objects with proper motions between our minimum cut and half an arcsecond a year. A small overspill sample with proper motions greater than this is also included. We examine our sample to identify interesting individual objects such as common proper motion binaries, potential L dwarfs and candidate nearby stars. Finally we show our survey is incomplete due to many factors, factors which we will take into account when simulating these survey results in the next paper in this series. (3 data files).nul

UKIDSS-2MASS proper motion survey

The UK Infrared Telescope Infrared Deep Sky Survey (UKIDSS) is the first of a new generation of infrared surveys. Here, we combine the data from two UKIDSS components, the Large Area Survey (LAS) and the Galactic Cluster Survey (GCS), with Two-Micron All-Sky Survey (2MASS) data to produce an infrared proper motion survey for low-mass stars and brown dwarfs. In total, we detect 267 low-mass stars and brown dwarfs with significant proper motions. We recover all 10 known single L dwarfs and the one known T dwarf above the 2MASS detection limit in our LAS survey area and identify eight additional new candidate L dwarfs. We also find one new candidate L dwarf in our GCS sample. Our sample also contains objects from 11 potential common proper motion binaries. Finally, we test our proper motions and find that while the LAS objects have proper motions consistent with absolute proper motions, the GCS stars may have proper motions which are significantly underestimated. This is possibly due to the bulk motion of some of the local astrometric reference stars used in the proper motion determination

Galactic plane IPHAS-POSSI proper motion survey

The IPHAS-POSS-I proper motion survey combines data from the INT Photometric Hα survey (Drew et al., 2005MNRAS.362..753D 2005MNRAS.362..753D) with SuperCOSMOS scans of POSS-I plates (Hambly et al., 2001MNRAS.326.1279H 2001MNRAS.326.1279H). The sample covers roughly 1400deg2 of the IPHAS survey area and contains 103058 objects with significant proper motions below 150mas/yr in the magnitude range 13.5<r'< 19. Once the final IPHAS survey is completed the catalogue will be updated

Galactic plane IPHAS-POSSI proper motion survey

Item does not contain fulltextThe IPHAS-POSS-I proper motion survey combines data from the INT Photometric Hα survey (Drew et al., 2005MNRAS.362..753D 2005MNRAS.362..753D) with SuperCOSMOS scans of POSS-I plates (Hambly et al., 2001MNRAS.326.1279H 2001MNRAS.326.1279H). The sample covers roughly 1400deg2 of the IPHAS survey area and contains 103058 objects with significant proper motions below 150mas/yr in the magnitude range 13.5<r'< 19. Once the final IPHAS survey is completed the catalogue will be updated.nul

Eight new T4.5-T7.5 dwarfs discovered in the UKIDSS large area survey data release 1

The definitive version is available at www.blackwell-synergy.com Copyright Blackwell Publishing DOI : 10.1111/j.1365-2966.2007.12023.xPeer reviewe

A search for southern ultracool dwarfs in young moving groups

We have constructed an 800-strong red object catalogue by cross-referencing optical and infrared catalogues with an extensive proper motion catalogue compiled for red objects in the southern sky to obtain proper motions. We have applied astrometric and photometric constraints to the catalogue in order to select ultracool dwarf moving group candidates. 132 objects were found to be candidates of a moving group. From this candidate list we present initial results. Using spectroscopy we have obtained reliable spectral types and space motions, and by association with moving groups we can infer an age and composition. the further study of the remainder of our candidates will provide a large sample of young brown dwarfs and confirmed members will provide benchmark ultracool dwarfs. These will make suitable targets of AO planet searches

Pre-outburst observations of Nova Del 2013 from Pan-STARRS 1

Context. Nova Delphini 2013 was identified on the 14th of August 2013 and eventually rose to be a naked eye object. Aims. We sought to study the behaviour of the object in the run-up to outburst and to compare it to the pre-outburst photometric characteristics of other novae. Methods. We searched the Pan-STARRS 1 datastore to identify pre-outburst photometry of Nova Del 2013 and identified twenty-four observations in the 1.2 years before outburst. Results. The progenitor of Nova Delphini showed variability of a few tenths of a magnitude but did not brighten significantly in comparison with archival plate photometry. We also found that the object did not vary significantly on the approximately half hour timescale between pairs of Pan-STARRS 1 observations

Identification of partially resolved binaries in Pan-STARRS 1 data

Using shape measurement techniques developed for weak lensing surveys, we have identified three new ultracool binaries in the Pan-STARRS 1 (Chambers et al.) survey. Binary companions that are not completely resolved can still alter the shapes of stellar images. These shape distortions can be measured if point spread function anisotropy caused by the telescope is properly accounted for. We show using both a sample of known binary stars and simulated binaries that we can reliably recover binaries wider than around 0.3 arcsec and with flux ratios greater than around 0.1. We then applied our method to a sample of ultracool dwarfs within 30 pc with 293 objects having sufficient Pan-STARRS 1 data for our method. In total, we recovered all but one of the 11 binaries wider than 0.3 arcsec in this sample. Our one failure was a true binary detected with a significant but erroneously high ellipticity that led it to be rejected in our analysis. We identify three new binaries, one a simultaneous discovery, with primary spectral types M6.5, L1 and T0.5. These latter two were confirmed with Keck/Near Infrared Camera 2 follow-up imaging. This technique will be useful for identifying large numbers of stellar and substellar binaries in the upcoming Large Synoptic Survey Telescope and Dark Energy Survey sky surveys