# University of Hertfordshire

## Classical T Tauri stars with VPHAS+ -I: H α and u-band accretion rates in the Lagoon Nebula M8

Research output: Contribution to journalArticle

### Documents

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Accepted author manuscript, 8 MB, PDF document

• V. M. Kalari
• J. S. Vink
• J.E. Drew
• G. Barentsen
• J. J. Drake
• J. Eislöffel
• E.L. Martín
• Q. A. Parker
• Y.C. Unruh
• N. A. Walton
• N. J. Wright
Original language English 1026-1046 Monthly Notices of the Royal Astronomical Society 11 Oct 2015 453 1 22 Aug 2015 https://doi.org/10.1093/mnras/stv1676 Published - 11 Oct 2015

### Abstract

We estimate the accretion rates of 235 Classical T Tauri star (CTTS) candidates in the Lagoon Nebula using $ugri$H$\alpha$ photometry from the VPHAS+ survey. Our sample consists of stars displaying H$\alpha$-excess, the intensity of which is used to derive accretion rates. For a subset of 87 stars, the intensity of the $u$-band excess is also used to estimate accretion rates. We find the mean variation in accretion rates measured using H$\alpha$ and $u$-band intensities to be $\sim$ 0.17 dex, agreeing with previous estimates (0.04-0.4 dex) but for a much larger sample. The spatial distribution of CTTS align with the location of protostars and molecular gas suggesting that they retain an imprint of the natal gas fragmentation process. Strong accretors are concentrated spatially, while weak accretors are more distributed. Our results do not support the sequential star forming processes suggested in the literature.

• ## Hertfordshire Astronomy

Project: Research

ID: 9573069