X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae
Diagnostics of electron temperature (Te), electron density (ne), and hydrogen column density (NH) from the Chandra High Energy Transmission Grating spectrum of He-like Ne ix in TW Hydrae (TW Hya), in conjunction with a classical accretion model, allow us to infer the accretion rate onto the star dir...
| Authors: | ; ; ; ; ; |
|---|---|
| Format: | Article |
| Status: | Published version |
| Publication date: | 2012 |
| Country: | Argentina |
| Institution: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repository: | CONICET Digital (CONICET) |
| Language: | English |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/19528 |
| Online Access: | http://hdl.handle.net/11336/19528 |
| Access Level: | Open access |
| Keyword: | accretion, accretion disks stars: formation stars: individual (TW Hydrae) techniques: spectroscopic https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
| _version_ | 1878403982257291264 |
|---|---|
| author | Brickhouse, N. S. |
| author2 | Cranmer, S. R. Dupree, A. K. Günther, H. M. Luna, Gerardo Juan Manuel Wolk, S. J. |
| author2_role | author author author author author |
| author_browse | Brickhouse, N. S. Cranmer, S. R. Dupree, A. K. Günther, H. M. Luna, Gerardo Juan Manuel Wolk, S. J. |
| author_facet | Brickhouse, N. S. Cranmer, S. R. Dupree, A. K. Günther, H. M. Luna, Gerardo Juan Manuel Wolk, S. J. |
| author_role | author |
| collection | CONICET Digital (CONICET) |
| description | Diagnostics of electron temperature (Te), electron density (ne), and hydrogen column density (NH) from the Chandra High Energy Transmission Grating spectrum of He-like Ne ix in TW Hydrae (TW Hya), in conjunction with a classical accretion model, allow us to infer the accretion rate onto the star directly from measurements of the accreting material. The new method introduces the use of the absorption of Ne ix lines as a measure of the column density of the intervening, accreting material. On average, the derived mass accretion rate for TW Hya is 1.5 × 10−9 M yr−1, for a stellar magnetic field strength of 600 G and a filling factor of 3.5%. Three individual Chandra exposures show statistically significant differences in the Ne ix line ratios, indicating changes in NH, Te, and ne by factors of 0.28, 1.6, and 1.3, respectively. In exposures separated by 2.7 days, the observations reported here suggest a five-fold reduction in the accretion rate. This powerful new technique promises to substantially improve our understanding of the accretion process in young stars. |
| eu_rights_str_mv | openAccess |
| format | article |
| id | AR_e4a747446c81ab7cbdabd14a91ef1f8a |
| identifier_str_mv | Brickhouse, N. S.; Cranmer, S. R.; Dupree, A. K.; Günther, H. M.; Luna, Gerardo Juan Manuel; et al.; X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae; IOP Publishing; The Astrophysical Journal Letters; 760; 2; 5-11-2012; L21,1-5 2041-8205 CONICET Digital CONICET |
| institution | Consejo Nacional de Investigaciones Científicas y Técnicas |
| instname_str | Consejo Nacional de Investigaciones Científicas y Técnicas |
| language | eng |
| network_acronym_str | AR |
| network_name_str | Argentina |
| oai_identifier_str | oai:ri.conicet.gov.ar:11336/19528 |
| publishDate | 2012 |
| publishDateSort | 2012 |
| publisher | IOP Publishing |
| publisherStr | IOP Publishing |
| reponame_str | CONICET Digital (CONICET) |
| spelling | X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae Brickhouse, N. S. Cranmer, S. R. Dupree, A. K. Günther, H. M. Luna, Gerardo Juan Manuel Wolk, S. J. accretion, accretion disks stars: formation stars: individual (TW Hydrae) techniques: spectroscopic https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 Diagnostics of electron temperature (Te), electron density (ne), and hydrogen column density (NH) from the Chandra High Energy Transmission Grating spectrum of He-like Ne ix in TW Hydrae (TW Hya), in conjunction with a classical accretion model, allow us to infer the accretion rate onto the star directly from measurements of the accreting material. The new method introduces the use of the absorption of Ne ix lines as a measure of the column density of the intervening, accreting material. On average, the derived mass accretion rate for TW Hya is 1.5 × 10−9 M yr−1, for a stellar magnetic field strength of 600 G and a filling factor of 3.5%. Three individual Chandra exposures show statistically significant differences in the Ne ix line ratios, indicating changes in NH, Te, and ne by factors of 0.28, 1.6, and 1.3, respectively. In exposures separated by 2.7 days, the observations reported here suggest a five-fold reduction in the accretion rate. This powerful new technique promises to substantially improve our understanding of the accretion process in young stars. Fil: Brickhouse, N. S.. Harvard-Smithsonian Center for Astrophysics; Estados Unidos Fil: Cranmer, S. R.. Harvard-Smithsonian Center for Astrophysics; Estados Unidos Fil: Dupree, A. K.. Harvard-Smithsonian Center for Astrophysics; Estados Unidos Fil: Günther, H. M.. Harvard-Smithsonian Center for Astrophysics; Estados Unidos Fil: Luna, Gerardo Juan Manuel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina Fil: Wolk, S. J.. Harvard-Smithsonian Center for Astrophysics; Estados Unidos IOP Publishing http://hdl.handle.net/11336/19528 Brickhouse, N. S.; Cranmer, S. R.; Dupree, A. K.; Günther, H. M.; Luna, Gerardo Juan Manuel; et al.; X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae; IOP Publishing; The Astrophysical Journal Letters; 760; 2; 5-11-2012; L21,1-5 2041-8205 CONICET Digital CONICET |
| spellingShingle | X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae Brickhouse, N. S. accretion, accretion disks stars: formation stars: individual (TW Hydrae) techniques: spectroscopic https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
| status_str | publishedVersion |
| title | X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae |
| title_full | X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae |
| title_fullStr | X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae |
| title_full_unstemmed | X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae |
| title_short | X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae |
| title_sort | X-Ray Determination of the Variable Rate of Mass Accretion onto TW Hydrae |
| topic | accretion, accretion disks stars: formation stars: individual (TW Hydrae) techniques: spectroscopic https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
| topic_facet | accretion, accretion disks stars: formation stars: individual (TW Hydrae) techniques: spectroscopic https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
| url | http://hdl.handle.net/11336/19528 |