There is growing evidence that the star formation process is in fact highly dynamic, on timescales from days to centuries. The temporal variability is a new and powerful diagnostic tool to study Young Stellar Objects (YSOs). Depending on the time scale of the variability in the mid and far infrared we can learn about different physical mechanisms shaping their structure and dynamics. Here we propose to extend our near and mid infrared study of variable YSOs in the young open cluster IC 348 to the far infrared (70 and 160 micron) using Herschel/PACS. We will constrain the frequency of far infrared variability and compare the observed time dependent behavior with protostellar and disk models to understand its origin. Possible mechanisms include fluctuations in the accretion luminosity, or echoes of inner disk structural changes projected onto the infalling envelope or flared outer disk surface. Our sample in IC348 covers a large part of the evolutionary sequence of YSOs from class I sources to transitional disks. The cadence of the requested observations allow us to study variations on time scales from days to months that could be extended to several years using our Spitzer/MIPS data. This OT2 proposal is an essential complement of our GT2 program covering one visibility epoch,
Publication
The (w)hole survey: An unbiased sample study of transition disk candidates based on Spitzer catalogs | van der Marel N. et al. | Astronomy & Astrophysics Volume 592 id.A126 36 pp. | 592 | 10.1051\\/0004-6361\\/201628075 | 2016A&A...592A.126V | http://adsabs.harvard.edu/abs/2016A%26A...592A.126V
The Extraordinary Far-infrared Variation of a Protostar: Herschel/PACS Observations of LRLL54361 | Balog Zoltan et al. | The Astrophysical Journal Letters Volume 789 Issue 2 article id. L38 5 pp. (2014). | 789 | 10.1088\\/2041-8205\\/789\\/2\\/L38 | 2014ApJ...789L..38B | http://adsabs.harvard.edu/abs/2014ApJ...789L..38B
Catalog of High Protostellar Surface Density Regions in Nearby Embedded Clusters | Li Juan et al. | The Astrophysical Journal Volume 871 Issue 2 article id. 163 18 pp. (2019). | 871 | 10.3847\\/1538-4357\\/aaf652 | 2019ApJ...871..163L | http://adsabs.harvard.edu/abs/2019ApJ...871..163L
A Search for Very Low-luminosity Objects in Gould Belt Clouds | Kim Mi-Ryang et al. | The Astrophysical Journal Supplement Series Volume 225 Issue 2 article id. 26 17 pp. (2016). | 225 | 10.3847\\/0067-0049\\/225\\/2\\/26 | 2016ApJS..225...26K | http://adsabs.harvard.edu/abs/2016ApJS..225...26K
A Multi-band Catalog of 10978 Star Clusters Associations and Candidates in the Milky Way | Bica Eduardo et al. | The Astronomical Journal Volume 157 Issue 1 article id. 12 14 pp. (2019). | 157 | 10.3847\\/1538-3881\\/aaef8d | 2019AJ....157...12B | http://adsabs.harvard.edu/abs/2019AJ....157...12B
Instrument
PACS_PacsPhoto_largeScan
Temporal Coverage
2012-08-19T01:01:26Z/2012-08-28T03:47:22Z
Version
SPG v14.2.0
Mission Description
Herschel was launched on 14 May 2009! It is the fourth cornerstone mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
European Space Agency, balog et al., 2013, 'Multi-epoch observations of IC 348: Using Far Infrared Variability to Constrain theDust Structure in Young Stellar Objects', SPG v14.2.0, European Space Agency, https://doi.org/10.5270/esa-hmidync
