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Title: Interpretation of a Variable Reflection Nebula Associated with HBC 340 and HBC 341 in NGC 1333

Abstract

We present multi-epoch, R -band imaging obtained from the Palomar Transient Factory of a small, fan-shaped reflection nebula in NGC 1333 that experiences prominent brightness fluctuations. Photometry of HBC 340 (K7e) and HBC 341 (M5e), a visual pair of late-type, young stellar objects lying near the apex of the nebula, demonstrates that while both are variable, the former has brightened by more than two magnitudes following a deep local minimum in 2014 September. Keck high-dispersion ( R  ∼ 45,000–66,000), optical spectroscopy of HBC 340 suggests that the protostar is a spectroscopic binary (HBC 340Aa + HBC 340Ab). Both HBC 340 and HBC 341 exhibit strong H α and forbidden line emission, consistent with accretion and outflow. We conclude that the brightness fluctuations in the reflection nebula represent light echos produced by varying incident radiation emanating from HBC 340. The short-term variability observed in the protostar is attributed to irregular accretion activity, while correlated, dipping behavior on a several hundred day timescale may be due to eclipse-like events caused by orbiting circumstellar material. Archival Hubble Space Telescope imaging of the region reveals a second, faint (F814W ∼ 20.3 mag) companion to HBC 340 that lies 1.″02 (∼235 au) east of the protostar. If associated,more » this probable substellar mass object (20–50 Jupiter masses), HBC 340B, is likely unrelated to the observed brightness variations. The sustained brightening of HBC 340 since late 2014 can be explained by an EXor-like outburst, the recovery from a long duration eclipse event caused by obscuring circumstellar dust, or by the gradual removal of extincting material from along the line of sight. Our analysis here favors one of the extinction scenarios.« less

Authors:
 [1];  [2]
  1. U.S. Naval Observatory, Flagstaff Station, 10391 West Naval Observatory Road, Flagstaff, AZ 86005-8521 (United States)
  2. Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)
Publication Date:
OSTI Identifier:
22663131
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (Online); Journal Volume: 154; Journal Issue: 5; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AUGER ELECTRON SPECTROSCOPY; BINARY STARS; BRIGHTNESS; COSMIC DUST; ECLIPSE; FLUCTUATIONS; JUPITER PLANET; MASS; NEBULAE; PHOTOMETRY; PROTOSTARS; REFLECTION; SPACE; STAR CLUSTERS; TELESCOPES; VISIBLE RADIATION

Citation Formats

Dahm, S. E., and Hillenbrand, L. A.. Interpretation of a Variable Reflection Nebula Associated with HBC 340 and HBC 341 in NGC 1333. United States: N. p., 2017. Web. doi:10.3847/1538-3881/AA89EB.
Dahm, S. E., & Hillenbrand, L. A.. Interpretation of a Variable Reflection Nebula Associated with HBC 340 and HBC 341 in NGC 1333. United States. doi:10.3847/1538-3881/AA89EB.
Dahm, S. E., and Hillenbrand, L. A.. Wed . "Interpretation of a Variable Reflection Nebula Associated with HBC 340 and HBC 341 in NGC 1333". United States. doi:10.3847/1538-3881/AA89EB.
@article{osti_22663131,
title = {Interpretation of a Variable Reflection Nebula Associated with HBC 340 and HBC 341 in NGC 1333},
author = {Dahm, S. E. and Hillenbrand, L. A.},
abstractNote = {We present multi-epoch, R -band imaging obtained from the Palomar Transient Factory of a small, fan-shaped reflection nebula in NGC 1333 that experiences prominent brightness fluctuations. Photometry of HBC 340 (K7e) and HBC 341 (M5e), a visual pair of late-type, young stellar objects lying near the apex of the nebula, demonstrates that while both are variable, the former has brightened by more than two magnitudes following a deep local minimum in 2014 September. Keck high-dispersion ( R  ∼ 45,000–66,000), optical spectroscopy of HBC 340 suggests that the protostar is a spectroscopic binary (HBC 340Aa + HBC 340Ab). Both HBC 340 and HBC 341 exhibit strong H α and forbidden line emission, consistent with accretion and outflow. We conclude that the brightness fluctuations in the reflection nebula represent light echos produced by varying incident radiation emanating from HBC 340. The short-term variability observed in the protostar is attributed to irregular accretion activity, while correlated, dipping behavior on a several hundred day timescale may be due to eclipse-like events caused by orbiting circumstellar material. Archival Hubble Space Telescope imaging of the region reveals a second, faint (F814W ∼ 20.3 mag) companion to HBC 340 that lies 1.″02 (∼235 au) east of the protostar. If associated, this probable substellar mass object (20–50 Jupiter masses), HBC 340B, is likely unrelated to the observed brightness variations. The sustained brightening of HBC 340 since late 2014 can be explained by an EXor-like outburst, the recovery from a long duration eclipse event caused by obscuring circumstellar dust, or by the gradual removal of extincting material from along the line of sight. Our analysis here favors one of the extinction scenarios.},
doi = {10.3847/1538-3881/AA89EB},
journal = {Astronomical Journal (Online)},
number = 5,
volume = 154,
place = {United States},
year = {Wed Nov 01 00:00:00 EDT 2017},
month = {Wed Nov 01 00:00:00 EDT 2017}
}