Archive for nearby stars

New nearby high proper motion objects from the AllWISE survey

Posted in astronomy with tags , , on April 14, 2016 by Tim Kendall

Many years of work have gone into the quest to find the nearest objects outside the Solar System. The holy grail of a proper motion search based on (thermal) infrared data where low mass stars and brown dwarfs emit most of their radiation and where extinction by dust in the galactic plane is low has been achieved by the latest AllWISE survey (Kirkpatrick et al. 2016). The third nearest L dwarf was found only recently, in the galactic plane, and was fully investigated last year by Valentin Ivanov et al. The new research, led by J Davy Kirkpatrick, has found several new nearby systems of note as well as confirming a host of known objects. From the abstract:

We use the AllWISE Data Release to continue our search for WISE-detected motions. In this paper, we publish another 27,846 motion objects, bringing the total number to 48,000 when objects found during our original AllWISE motion survey are included. We use this list, along with the lists of confirmed WISE-based motion objects from the recent papers by Luhman and by Schneider et al. and candidate motion objects from the recent paper by Gagné et al. to search for widely separated, common-proper-motion systems. We identify 1,039 such candidate systems. All 48,000 objects are further analyzed using color-color and color-mag plots to provide possible characterizations prior to spectroscopic follow-up. We present spectra of 172 of these, supplemented with new spectra of 23 comparison objects from the literature, and provide classifications and physical interpretations of interesting sources. Highlights include: (1) the identification of three G/K dwarfs that can be used as standard candles to study clumpiness and grain size in nearby molecular clouds because these objects are currently moving behind the clouds, (2) the confirmation/discovery of several M, L, and T dwarfs and one white dwarf whose spectrophotometric distance estimates place them 5-20 pc from the Sun, (3) the suggestion that the Na ‘D’ line be used as a diagnostic tool for interpreting and classifying metal-poor late-M and L dwarfs, (4) the recognition of a triple system including a carbon dwarf and late-M subdwarf, for which model fits of the late-M subdwarf (giving [Fe/H] ~ -1.0) provide a measured metallicity for the carbon star, and (5) a possible 24-pc-distant K5 dwarf + peculiar red L5 system with an apparent physical separation of 0.1 pc.

Image: In this huge image of part of the southern constellation of Norma wisps of crimson gas are illuminated by rare, massive stars that have only recently ignited and are still buried deep in thick dust clouds. These scorching-hot, very young stars are only fleeting characters on the cosmic stage and their origins remain mysterious. The vast nebula where these giants were born, known as RCW 106, is captured here in fine detail by ESO’s VLT Survey Telescope (VST), at the Paranal Observatory in Chile.

Lick Observatory’s Automated Planet Finder: first robotic telescope for exoplanets

Posted in astronomy with tags , , , on May 15, 2014 by Tim Kendall


Unlike Kepler, however, which focused on distant stars in one small patch of sky, the APF focuses on nearby stars and covers the entire sky. “The planetary systems we’re finding are our nearest neighbors. Those are the ones that will matter to future generations,” said Steve Vogt, professor of astronomy and astrophysics at UC Santa Cruz, who led the $12 million APF project and designed the Levy spectrometer at the heart of the system.

This new facility will lead the way to a census of exoplanets around nearby stars. Links to the first papers are given in this University of California/Lick Observatory press release.