{ "abstracts": [ { "content": "We present Atacama Large Millimeter/submillimeter Array (ALMA) line and\ncontinuum observations at 1.2mm with ~0.3\" resolution that uncover a\nKeplerian-like disk around the forming O-type star AFGL 4176. The continuum\nemission from the disk at 1.21 mm (source mm1) has a deconvolved size of\n870+/-110 AU x 330+/-300 AU and arises from a structure ~8 M_sun in mass,\ncalculated assuming a dust temperature of 190 K. The first-moment maps,\npixel-to-pixel line modeling, assuming local thermodynamic equilibrium (LTE),\nand position-velocity diagrams of the CH3CN J=13-12 K-line emission all show a\nvelocity gradient along the major axis of the source, coupled with an increase\nin velocity at small radii, consistent with Keplerian-like rotation. The LTE\nline modeling shows that where CH3CN J=13-12 is excited, the temperatures in\nthe disk range from ~70 to at least 300 K and that the H2 column density peaks\nat 2.8x10^24 cm^-2. In addition, we present Atacama Pathfinder Experiment\n(APEX) 12CO observations which show a large-scale outflow from AFGL 4176\nperpendicular to the major axis of mm1, supporting the disk interpretation.\nFinally, we present a radiative transfer model of a Keplerian disk surrounding\nan O7 star, with a disk mass and radius of 12 M_sun and 2000 AU, that\nreproduces the line and continuum data, further supporting our conclusion that\nour observations have uncovered a Keplerian disk around an O-type star.", "lang": "en", "mimetype": "text/plain", "sha1": "0d0ccb2d947e54076c8e2762f072d51a919c486a" } ], "contribs": [ { "index": 0, "raw_name": "Katharine G. Johnston", "role": "author" }, { "index": 1, "raw_name": "Thomas P. Robitaille", "role": "author" }, { "index": 2, "raw_name": "Henrik Beuther", "role": "author" }, { "index": 3, "raw_name": "Hendrik\n Linz", "role": "author" }, { "index": 4, "raw_name": "Paul Boley", "role": "author" }, { "index": 5, "raw_name": "Rolf Kuiper", "role": "author" }, { "index": 6, "raw_name": "Eric Keto", "role": "author" }, { "index": 7, "raw_name": "Melvin G. Hoare", "role": "author" }, { "index": 8, "raw_name": "Roy van Boekel", "role": "author" } ], "ext_ids": { "arxiv": "1509.08469v1" }, "extra": { "arxiv": { "base_id": "1509.08469", "categories": [ "astro-ph.SR" ], "comments": "6 pages, 4 figures, accepted for publication in ApJL" } }, "ident": "5hzpesjrjrdrzaoahvihorp7eq", "language": "en", "license_slug": "ARXIV-1.0", "refs": [], "release_date": "2015-09-28", "release_stage": "submitted", "release_type": "article", "release_year": 2015, "revision": "29d2a48a-6e57-48bf-be55-6d30ef405365", "state": "active", "title": "A Keplerian-like disk around the forming O-type star AFGL 4176", "version": "v1", "work_id": "afmgjv5gijd3xkn65hvuqlfewa" }