THE FIRST DETERMINATION OF THE VISCOSITY PARAMETER IN THE CIRCUMSTELLAR DISK OF A Be STAR

被引：77

作者：

Carciofi, Alex C. ^{[1
]}

Bjorkman, Jon E. ^{[1
,2
]}

Otero, Sebastian A. ^{[3
]}

Okazaki, Atsuo T. ^{[4
]}

Stefl, Stanislav ^{[5
]}

Rivinius, Thomas ^{[5
]}

Baade, Dietrich ^{[6
]}

Haubois, Xavier ^{[1
]}

机构：

[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo, Brazil

[2] Univ Toledo, Dept Phys & Astron, Ritter Observ, Toledo, OH 43606 USA

[3] Amer Assoc Variable Star Observers, Cambridge, MA 02138 USA

[4] Hokkai Gakuen Univ, Fac Engn, Toyohira Ku, Sapporo, Hokkaido 0628605, Japan

[5] European Org Astron Res So Hemisphere, Santiago 19, Chile

[6] European Org Astron Res So Hemisphere, D-85748 Garching, Germany

来源：

ASTROPHYSICAL JOURNAL LETTERS | 2012年 / 744卷 / 01期

基金：

巴西圣保罗研究基金会;

关键词：

circumstellar matter; stars: activity; stars:; emission-line; Be; stars: individual (28 CMa); NONRADIAL PULSATION; CYCLIC VARIABILITY; KEPLERIAN DISKS; OMEGA CMA; MASS-LOSS; STELLAR; EMISSION; ROTATION; LINE; RATES;

D O I：

10.1088/2041-8205/744/1/L15

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Be stars possess gaseous circumstellar decretion disks, which are well described using standard alpha-disk theory. The Be star 28 CMa recently underwent a long outburst followed by a long period of quiescence, during which the disk dissipated. Here we present the first time-dependent models of the dissipation of a viscous decretion disk. By modeling the rate of decline of the V-band excess, we determine that the viscosity parameter alpha = 1.0 +/- 0.2, corresponding to a mass injection rate (M) over dot = (3.5 +/- 1.3) x 10(-8) M-circle dot yr(-1). Such a large value of a suggests that the origin of the turbulent viscosity is an instability in the disk whose growth is limited by shock dissipation. The mass injection rate is more than an order of magnitude larger than the wind mass-loss rate inferred from UV observations, implying that the mass injection mechanism most likely is not the stellar wind, but some other mechanism.

引用

页数：5

共 32 条

[31]

UNDERHILL A, 1982, NASA

[32] DISK-LOSS AND DISK-RENEWAL PHASES IN CLASSICAL Be STARS. I. ANALYSIS OF LONG-TERM SPECTROPOLARIMETRIC DATA [J].

Wisniewski, John P. ;

Draper, Zachary H. ;

Bjorkman, Karen S. ;

Meade, Marilyn R. ;

Bjorkman, Jon E. ;

Kowalski, Adam F. .

ASTROPHYSICAL JOURNAL, 2010, 709 (02) :1306-1320

← 1 2 3 4 →