emamajek on 16-Oct-2011 18:05:49 GMT about ::error::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: java.lang.StringIndexOutOfBoundsException: offset 4098,length 70 at java.base/java.lang.String.checkOffset(String.java:3289) at java.base/java.lang.AbstractStringBuilder.insert(AbstractStringBuilder.java:1244) at java.base/java.lang.StringBuffer.insert(StringBuffer.java:592) at java.base/java.lang.StringBuffer.insert(StringBuffer.java:106) at java.base/java.lang.AbstractStringBuilder.insert(AbstractStringBuilder.java:1191) at java.base/java.lang.StringBuffer.insert(StringBuffer.java:579) at cds.xml.XmlGen.addAttr(XmlGen.java:310) at cds.xml.Html.addAttr(Html.java:269) at cds.simbad.servlet.SimbadNavigationBar.display(SimbadNavigationBar.java:179) at cds.simbad.servlet.WebSimbadTools.cdsHeader(WebSimbadTools.java:184) at cds.simbad.servlet.WebOutputHtml.begin(WebOutputHtml.java:79) at cds.simbad.servlet.WebOutput.write(WebOutput.java:106) at cds.simbad.servlet.WebSimbadCoo.doPost(WebSimbadCoo.java:351) at cds.simbad.servlet.WebSimbadCoo.doGet(WebSimbadCoo.java:85) at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) at org.apache.coyote.ajp.AjpProcessor.service(AjpProcessor.java:433) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:834) ::data:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: * alf PsA
Fomalhaut
has stellar common proper motion companion
TW PsA
situated 1.96 degrees away. The case for their physical association is quite strong.
The stars are co-distant: Distances can be calculated using the revised Hipparcos parallaxes from van Leeuwen (2007). For Fomalhaut d = 7.70+-0.03 pc, for TW PsA d = 7.61+-0.04 pc. Their 3D physical separation is 57500+-2500 AU.
The stars are co-moving: Gontcharov (2006) lists a literature mean radial velocity for Fomalhaut of 6.5+-0.5 km/s, which is almost identical to the Holmberg et al. (2007) mean radial velocity for TW PsA (6.6+-0.1 km/s). If one combines these radial velocities with the astrometry for both stars from van Leeuwen (2007), one can calculate 3D velocity vectors:
Fomalhaut: (U,V,W) = -5.70+-0.15, -8.26+-0.25, -11.07+-0.34 km/s.
TW PsA: (U,V,W) = -5.43+-0.06, -8.08+-0.03, -11.53+-0.02 km/s.
Hence the stars are not only in close proximity, but comoving within ~0.56+-0.45 km/s. Hence, their velocities are statistically consistent with co-motion and they could constitute a bound binary system.
Age indicators for both stars are suggestive of ages of ~400 Myr, but a detailed discussion is beyond the scope of these notes.
To the author's knowledge the first mention in the literature of Fomalhaut and TW PsA constituting a binary comes from Eggen (1955;
1955AJ.....60...65E
).
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