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Title: An astrometric search for a stellar companion to the sun

Abstract

A companion star within 0.8 pc of the Sun has been postulated to explain a possible 26 Myr periodicity in mass extinctions of species on the Earth. Such a star would already be catalogued in the Yale Bright Star catalogue unless it is fainter than m/sub nu/ = 6.5; this limits the possible stellar types for an unseen companion to red dwarfs, brown dwarfs, or compact objects. Red dwarfs account for about 75% of these possible stars. We describe here the design and development of an astrometric search for a nearby red dwarf companion with a six-month peak-to-peak parallax of greater than or equal to2.5 arcseconds. We are measuring the parallax of 2770 candidate faint red stars selected from the Dearborn Observatory catalogue. An automated 30-inch telescope and CCD camera system collect digitized images of the candidate stars, along with a 13' x 16' surrounding field of background stars. Second-epoch images, taken a few months later, are registered to the first epoch images using the background stars as fiducials. An apparent motion, m/sub a/, of the candidate stars is found to a precision of sigma/sub m//sub a/ approx. = 0.08 pixel approx. = 0.2 arcseconds for fields with N/sub fiducial/more » greater than or equal to 10 fiducial stars visible above the background noise. This precision is sufficient to detect the parallactic motion of a star at 0.8 pc with a two month interval between the observation epochs. Images with fewer fiducial stars above background noise are observed with a longer interval between epochs. If a star is found with high parallactic motion, we will confirm its distance with further parallax measurements, photometry, and spectral studies, and will measure radial velocity and proper motion to establish its orbit. We have demonstrated the search procedure with observations of 41 stars, and have shown that none of these is a nearby star. 37 refs., 16 figs., 3 tabs.« less

Authors:
Publication Date:
Research Org.:
California Univ., Berkeley (USA)
OSTI Identifier:
6484337
Report Number(s):
LBL-23187
ON: DE87009642
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Technical Report
Resource Relation:
Other Information: Thesis. Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; RED DWARF STARS; SURVEYS; SUN; BINARY STARS; CHARGE-COUPLED DEVICES; DATA ACQUISITION SYSTEMS; EXPERIMENTAL DATA; TELESCOPES; DATA; DWARF STARS; INFORMATION; MAIN SEQUENCE STARS; NUMERICAL DATA; SEMICONDUCTOR DEVICES; STARS; 640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar, Radio & X-Ray Sources; 640104 - Astrophysics & Cosmology- Solar Phenomena

Citation Formats

Perlmutter, S. An astrometric search for a stellar companion to the sun. United States: N. p., 1986. Web. doi:10.2172/6484337.
Perlmutter, S. An astrometric search for a stellar companion to the sun. United States. doi:10.2172/6484337.
Perlmutter, S. Tue . "An astrometric search for a stellar companion to the sun". United States. doi:10.2172/6484337. https://www.osti.gov/servlets/purl/6484337.
@article{osti_6484337,
title = {An astrometric search for a stellar companion to the sun},
author = {Perlmutter, S.},
abstractNote = {A companion star within 0.8 pc of the Sun has been postulated to explain a possible 26 Myr periodicity in mass extinctions of species on the Earth. Such a star would already be catalogued in the Yale Bright Star catalogue unless it is fainter than m/sub nu/ = 6.5; this limits the possible stellar types for an unseen companion to red dwarfs, brown dwarfs, or compact objects. Red dwarfs account for about 75% of these possible stars. We describe here the design and development of an astrometric search for a nearby red dwarf companion with a six-month peak-to-peak parallax of greater than or equal to2.5 arcseconds. We are measuring the parallax of 2770 candidate faint red stars selected from the Dearborn Observatory catalogue. An automated 30-inch telescope and CCD camera system collect digitized images of the candidate stars, along with a 13' x 16' surrounding field of background stars. Second-epoch images, taken a few months later, are registered to the first epoch images using the background stars as fiducials. An apparent motion, m/sub a/, of the candidate stars is found to a precision of sigma/sub m//sub a/ approx. = 0.08 pixel approx. = 0.2 arcseconds for fields with N/sub fiducial/ greater than or equal to 10 fiducial stars visible above the background noise. This precision is sufficient to detect the parallactic motion of a star at 0.8 pc with a two month interval between the observation epochs. Images with fewer fiducial stars above background noise are observed with a longer interval between epochs. If a star is found with high parallactic motion, we will confirm its distance with further parallax measurements, photometry, and spectral studies, and will measure radial velocity and proper motion to establish its orbit. We have demonstrated the search procedure with observations of 41 stars, and have shown that none of these is a nearby star. 37 refs., 16 figs., 3 tabs.},
doi = {10.2172/6484337},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Nov 25 00:00:00 EST 1986},
month = {Tue Nov 25 00:00:00 EST 1986}
}

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