Spatial Variations of Dust Opacity and Grain Growth in Dark Clouds: L1689, L1709, and L1712
The far-infrared (FIR) opacity of dust in dark clouds within the Ophiuchus molecular cloud is investigated through multiwavelength infrared observations from UKIDSS, Spitzer, and Herschel. Employing the infrared color excess technique with both near-infrared and mid-infrared photometric data, a high...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2024-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/ad2a59 |
| _version_ | 1827297939209322496 |
|---|---|
| author | Jun Li Biwei Jiang He Zhao Xi Chen Yang Yang |
| author_facet | Jun Li Biwei Jiang He Zhao Xi Chen Yang Yang |
| author_sort | Jun Li |
| collection | DOAJ |
| description | The far-infrared (FIR) opacity of dust in dark clouds within the Ophiuchus molecular cloud is investigated through multiwavelength infrared observations from UKIDSS, Spitzer, and Herschel. Employing the infrared color excess technique with both near-infrared and mid-infrared photometric data, a high-resolution extinction map in the K band ( A _K ) is constructed for three dark clouds: L1689, L1709, and L1712. The derived extinction map has a resolution of $1^{\prime} $ and reaches a depth of A _K ∼ 3 mag. The FIR optical depths τ _250 at a reference wavelength of 250 μ m are obtained by fitting the Herschel PACS and SPIRE continuum data at 100, 160, 250, 350, and 500 μ m using a modified blackbody model. The average dust opacity per unit gas mass at 250 μ m, r κ _250 , is determined through a pixel-by-pixel correlation of τ _250 with A _K , yielding a value of approximately 0.09 cm ^2 g ^−1 , which is about 2–3 times higher than the typical value in the diffuse interstellar medium. Additionally, an independent analysis across 16 subregions within the Ophiuchus cloud indicates spatial variations in dust opacity, with values ranging from 0.07 to 0.12 cm ^2 g ^−1 . Although the observed trend of increasing dust opacity with higher extinction implies grain growth, our findings indicate that rapid grain growth has clearly not yet occurred in the dark clouds studied in this work. |
| first_indexed | 2024-04-24T15:05:22Z |
| format | Article |
| id | doaj.art-c2915667cca449329c10146a033ff1d9 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-04-24T15:05:22Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-c2915667cca449329c10146a033ff1d92024-04-02T13:33:21ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0196512910.3847/1538-4357/ad2a59Spatial Variations of Dust Opacity and Grain Growth in Dark Clouds: L1689, L1709, and L1712Jun Li0https://orcid.org/0000-0001-9328-4302Biwei Jiang1https://orcid.org/0000-0003-3168-2617He Zhao2https://orcid.org/0000-0003-2645-6869Xi Chen3https://orcid.org/0000-0002-5435-925XYang Yang4https://orcid.org/0000-0002-2895-7707Center for Astrophysics, Guangzhou University , Guangzhou 510006, People's Republic of China ; lijun@gzhu.edu.cn, chenxi@gzhu.edu.cnInstitute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People's Republic of China; Department of Astronomy, Beijing Normal University , Beijing 100875, People's Republic of ChinaPurple Mountain Observatory and Key Laboratory of Radio Astronomy, Chinese Academy of Sciences , 10 Yuanhua Road, Nanjing 210033, People's Republic of ChinaCenter for Astrophysics, Guangzhou University , Guangzhou 510006, People's Republic of China ; lijun@gzhu.edu.cn, chenxi@gzhu.edu.cnCenter for Astrophysics, Guangzhou University , Guangzhou 510006, People's Republic of China ; lijun@gzhu.edu.cn, chenxi@gzhu.edu.cnThe far-infrared (FIR) opacity of dust in dark clouds within the Ophiuchus molecular cloud is investigated through multiwavelength infrared observations from UKIDSS, Spitzer, and Herschel. Employing the infrared color excess technique with both near-infrared and mid-infrared photometric data, a high-resolution extinction map in the K band ( A _K ) is constructed for three dark clouds: L1689, L1709, and L1712. The derived extinction map has a resolution of $1^{\prime} $ and reaches a depth of A _K ∼ 3 mag. The FIR optical depths τ _250 at a reference wavelength of 250 μ m are obtained by fitting the Herschel PACS and SPIRE continuum data at 100, 160, 250, 350, and 500 μ m using a modified blackbody model. The average dust opacity per unit gas mass at 250 μ m, r κ _250 , is determined through a pixel-by-pixel correlation of τ _250 with A _K , yielding a value of approximately 0.09 cm ^2 g ^−1 , which is about 2–3 times higher than the typical value in the diffuse interstellar medium. Additionally, an independent analysis across 16 subregions within the Ophiuchus cloud indicates spatial variations in dust opacity, with values ranging from 0.07 to 0.12 cm ^2 g ^−1 . Although the observed trend of increasing dust opacity with higher extinction implies grain growth, our findings indicate that rapid grain growth has clearly not yet occurred in the dark clouds studied in this work.https://doi.org/10.3847/1538-4357/ad2a59Dark interstellar cloudsInterstellar dustDust continuum emissionInterstellar extinction |
| spellingShingle | Jun Li Biwei Jiang He Zhao Xi Chen Yang Yang Spatial Variations of Dust Opacity and Grain Growth in Dark Clouds: L1689, L1709, and L1712 The Astrophysical Journal Dark interstellar clouds Interstellar dust Dust continuum emission Interstellar extinction |
| title | Spatial Variations of Dust Opacity and Grain Growth in Dark Clouds: L1689, L1709, and L1712 |
| title_full | Spatial Variations of Dust Opacity and Grain Growth in Dark Clouds: L1689, L1709, and L1712 |
| title_fullStr | Spatial Variations of Dust Opacity and Grain Growth in Dark Clouds: L1689, L1709, and L1712 |
| title_full_unstemmed | Spatial Variations of Dust Opacity and Grain Growth in Dark Clouds: L1689, L1709, and L1712 |
| title_short | Spatial Variations of Dust Opacity and Grain Growth in Dark Clouds: L1689, L1709, and L1712 |
| title_sort | spatial variations of dust opacity and grain growth in dark clouds l1689 l1709 and l1712 |
| topic | Dark interstellar clouds Interstellar dust Dust continuum emission Interstellar extinction |
| url | https://doi.org/10.3847/1538-4357/ad2a59 |
| work_keys_str_mv | AT junli spatialvariationsofdustopacityandgraingrowthindarkcloudsl1689l1709andl1712 AT biweijiang spatialvariationsofdustopacityandgraingrowthindarkcloudsl1689l1709andl1712 AT hezhao spatialvariationsofdustopacityandgraingrowthindarkcloudsl1689l1709andl1712 AT xichen spatialvariationsofdustopacityandgraingrowthindarkcloudsl1689l1709andl1712 AT yangyang spatialvariationsofdustopacityandgraingrowthindarkcloudsl1689l1709andl1712 |