TY - JOUR
T1 - Evidence of planetesimal infall onto the very young Herbig Be star LkHα 234
AU - Chakraborty, Abhijit
AU - Ge, Jian
AU - Mahadevan, Suvrath
N1 - Funding Information:
The authors would like to thank Larry Ramsey for additional discretionary time on the HET and Eric Feigelson and Mike Eracleous for important discussions on the subject. The authors would also like to thank the referee, Mike Sitko, for very valuable suggestions, which made the content of this Letter strong. The HET is a joint project of the University of Texas at Austin, Pennsylvania State University, Stanford University, Ludwig-Maximillians-Universität, München, and Georg-August-Universität, Göttingen. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly. A. C. and J. G. would like to acknowledge the National Science Foundation for grants AST 01-38235 and AST 02-43090 and NASA for grants NAG5-12115 and NAG5-11427. S. M. would like to acknowledge the support of the Michelson Fellowship Program (Jet Propulsion Laboratory, NASA).
PY - 2004/5/1
Y1 - 2004/5/1
N2 - We report here the first evidence of planetesimal infall onto the very young Herbig Be star LkHα 234. These results are based on observations acquired over 31 days using spectroscopy of the sodium D lines, the He I 5876 Å line, and hydrogen Hα lines. We find redshifted absorption components (RACs) with velocities up to 200 km s-1 and very mild blueshifted emission components (BECs) up to 100 km s-1 in the Na I lines. No correlation is observed between the appearance of the Na I RACs and BECs and the Hα and He I line variability, which suggests that these (Na I RACs and BECs) are formed in a process unrelated to the circumstellar gas accretion. We interpret the Na I RACs as evidence for an infalling evaporating body, greater than 100 km in diameter, which is able to survive at distances between 2.0 and 0.1 AU from the star. The dramatic appearance of the sodium RACs and mild BECs is readily explained by the dynamics of this infalling body, making LkHα 234 the youngest (age ∼ 0.1 Myr) system with evidence for the presence of planetesimals.
AB - We report here the first evidence of planetesimal infall onto the very young Herbig Be star LkHα 234. These results are based on observations acquired over 31 days using spectroscopy of the sodium D lines, the He I 5876 Å line, and hydrogen Hα lines. We find redshifted absorption components (RACs) with velocities up to 200 km s-1 and very mild blueshifted emission components (BECs) up to 100 km s-1 in the Na I lines. No correlation is observed between the appearance of the Na I RACs and BECs and the Hα and He I line variability, which suggests that these (Na I RACs and BECs) are formed in a process unrelated to the circumstellar gas accretion. We interpret the Na I RACs as evidence for an infalling evaporating body, greater than 100 km in diameter, which is able to survive at distances between 2.0 and 0.1 AU from the star. The dramatic appearance of the sodium RACs and mild BECs is readily explained by the dynamics of this infalling body, making LkHα 234 the youngest (age ∼ 0.1 Myr) system with evidence for the presence of planetesimals.
UR - http://www.scopus.com/inward/record.url?scp=2542533772&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=2542533772&partnerID=8YFLogxK
U2 - 10.1086/421049
DO - 10.1086/421049
M3 - Article
AN - SCOPUS:2542533772
SN - 0004-637X
VL - 606
SP - L69-L72
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1 II
ER -