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A Slowly Accreting ∼10 Myr Old Transitional Disk in Orion Ob1a
| Content Provider | Semantic Scholar |
|---|---|
| Author | Espaillat, C. Muzerolle, James C. Hernández, Jesús Briceño, César Calvet, Nuria Alessio, Paola D’ McClure, Melissa K. Watson, Dan M. Hartmann, Lee Sargent, Ben |
| Copyright Year | 2008 |
| Abstract | Here we present the Spitzer IRS spectrum of CVSO 224, the sole transitional disk located within the ∼10 Myr old 25 Orionis group in Orion OB1a. A model fit to the spectral energy distribution of this object indicates a ∼7 AU inner disk hole that contains a small amount of optically thin dust. In previous studies, CVSO 224 had been classified as a weak-line T Tauri star based on its Hα equivalent width, but here we find an accretion rate of 7×10 −11 M ⊙ yr −1 based on high-resolution Hectochelle data. CVSO 224's low ˙ M is in line with photoevaporative clearing theories. However, the Spitzer IRS spectrum of CVSO 224 has a substantial mid-infrared excess beyond 20µm which indicates that it is surrounded by a massive outer disk. Millimeter measurements are necessary to constrain the mass of the outer disk around CVSO 224 in order to confirm that photoevaporation is not the mechanism behind creating its inner disk hole. Stars surrounded by transitional disks have characteristics that fall between objects that have clear evidence for disks and stars with no disk material. They have deficits of infrared flux at λ < 8 µm but show strong excesses at longer wavelengths, indicating that the innermost regions have undergone significant clearing of small dust grains (Strom et al. 1989; Skrutskie et al. 1990). The Spitzer Space Telescope has greatly improved our resolution in the infrared and has recently provoked extensive modeling studies of several transitional disks around T Tauri stars e.g TW Hya (Uchida et al. These objects have been explained as inwardly truncated disks which are optically thick to the stellar radiation, with most of the mid-infrared emission originating in the inner edge or " wall " of the outer disk. Spectral energy distributions (SEDs) point to holes in these disks of less than ∼40 AU. The inner holes of the transitional disks around DM Tau and CoKu Tau/4 are cleared of small dust grains (D'Alessio et al. 2005; Calvet et al. 2005a) while the transitional disks GM Aur, TW Hya, CS Cha, HD 98800B, and Hen 3-600 have a small yet detectable near-infrared excess produced by some submicron and mi-cron sized optically thin dust remaining in the inner disk these disks with holes (i.e. large reductions of small dust grains from the star out to an outer optically thick wall), the " pre-transitional disk " class has recently … |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/0810.4575v1.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Classification Command & Conquer:Yuri's Revenge Cron Disk storage Ferranti Orion Flux qubit GUCY2C protein, human Gold Image resolution Mahdiyar Offset binary Stars, Celestial Stellar (payment network) decimeter stage IV childhood Hodgkin's lymphoma wavelength width |
| Content Type | Text |
| Resource Type | Article |
