{"id":608159,"date":"2019-04-17T06:48:46","date_gmt":"2019-04-17T10:48:46","guid":{"rendered":"https:\/\/ntrs.nasa.gov\/search.jsp?R=20190002405"},"modified":"2019-04-17T06:48:46","modified_gmt":"2019-04-17T10:48:46","slug":"the-first-nustar-observation-of-4u-1538-522-updated-orbital-ephemeris-and-a-strengthened-case-for-an-evolving-cyclotron-line-energy","status":"publish","type":"post","link":"https:\/\/spaceweekly.com\/?p=608159","title":{"rendered":"The First NuSTAR Observation of 4U 1538-522: Updated Orbital Ephemeris and a Strengthened Case for an Evolving Cyclotron Line Energy"},"content":{"rendered":"<p>Abstract: We have performed a comprehensive spectral and timing analysis of the first NuSTAR observation of the high-mass X-ray binary 4U 1538-522. The observation covers the X-ray eclipse of the source, plus the eclipse ingress and egress. We use the new measurement of the mid-eclipse time to update the orbital parameters of the system and find marginally significant evolution in the orbital period, with P(sub orb) \/ P(sub orb) = (-0.95 +\/- 0.37) x 10(exp -6) yr(exp -1). The cyclotron line energy is f&#8230;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Abstract: We have performed a comprehensive spectral and timing analysis of the first NuSTAR observation of the high-mass X-ray binary 4U 1538-522. The observation covers the X-ray eclipse of the source, plus the eclipse ingress and egress. We use the &#8230;<\/p>\n","protected":false},"author":60,"featured_media":615444,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"class_list":["post-608159","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/posts\/608159","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/users\/60"}],"replies":[{"embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=608159"}],"version-history":[{"count":1,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/posts\/608159\/revisions"}],"predecessor-version":[{"id":608160,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/posts\/608159\/revisions\/608160"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=\/wp\/v2\/media\/615444"}],"wp:attachment":[{"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=608159"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=608159"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/spaceweekly.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=608159"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}