Spectroscopic confirmation of young planetary-mass companions on wide orbits
Abstract
We present moderate-resolution (R ∼ 4000-5000) near-infrared integral field spectroscopy of the young (1-5 Myr) 6-14 M {sub Jup} companions ROXs 42B b and FW Tau b obtained with Keck/OSIRIS and Gemini-North/NIFS. The spectrum of ROXs 42B b exhibits clear signs of low surface gravity common to young L dwarfs, confirming its extreme youth, cool temperature, and low mass. Overall, it closely resembles the free-floating 4-7 M {sub Jup} L-type Taurus member 2MASS J04373705+2331080. The companion to FW Tau AB is more enigmatic. Our optical and near-infrared spectra show strong evidence of outflow activity and disk accretion in the form of line emission from [S II], [O I], Hα, Ca II, [Fe II], Paβ, and H{sub 2}. The molecular hydrogen emission is spatially resolved as a single lobe that stretches ≈0.''1 (15 AU). Although the extended emission is not kinematically resolved in our data, its morphology resembles shock-excited H{sub 2} jets primarily seen in young Class 0 and Class I sources. The near-infrared continuum of FW Tau b is mostly flat and lacks the deep absorption features expected for a cool, late-type object. This may be a result of accretion-induced veiling, especially in light of its strong and sustained Hαmore »
- Authors:
-
- California Institute of Technology, Division of Geological and Planetary Sciences, 1200 East California Boulevard, Pasadena, CA 91101 (United States)
- Institute for Astronomy, University of Hawai'i, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
- Publication Date:
- OSTI Identifier:
- 22351472
- Resource Type:
- Journal Article
- Journal Name:
- Astrophysical Journal
- Additional Journal Information:
- Journal Volume: 784; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ACCRETION DISKS; EMISSION; GRAVITATION; HYDROGEN; INFRARED SPECTRA; MASS; ORBITS; RESOLUTION; SPECTROSCOPY; STARS; SURFACES; VISIBLE RADIATION
Citation Formats
Bowler, Brendan P., Liu, Michael C., Mann, Andrew W., and Kraus, Adam L., E-mail: bpbowler@caltech.edu. Spectroscopic confirmation of young planetary-mass companions on wide orbits. United States: N. p., 2014.
Web. doi:10.1088/0004-637X/784/1/65.
Bowler, Brendan P., Liu, Michael C., Mann, Andrew W., & Kraus, Adam L., E-mail: bpbowler@caltech.edu. Spectroscopic confirmation of young planetary-mass companions on wide orbits. United States. https://doi.org/10.1088/0004-637X/784/1/65
Bowler, Brendan P., Liu, Michael C., Mann, Andrew W., and Kraus, Adam L., E-mail: bpbowler@caltech.edu. 2014.
"Spectroscopic confirmation of young planetary-mass companions on wide orbits". United States. https://doi.org/10.1088/0004-637X/784/1/65.
@article{osti_22351472,
title = {Spectroscopic confirmation of young planetary-mass companions on wide orbits},
author = {Bowler, Brendan P. and Liu, Michael C. and Mann, Andrew W. and Kraus, Adam L., E-mail: bpbowler@caltech.edu},
abstractNote = {We present moderate-resolution (R ∼ 4000-5000) near-infrared integral field spectroscopy of the young (1-5 Myr) 6-14 M {sub Jup} companions ROXs 42B b and FW Tau b obtained with Keck/OSIRIS and Gemini-North/NIFS. The spectrum of ROXs 42B b exhibits clear signs of low surface gravity common to young L dwarfs, confirming its extreme youth, cool temperature, and low mass. Overall, it closely resembles the free-floating 4-7 M {sub Jup} L-type Taurus member 2MASS J04373705+2331080. The companion to FW Tau AB is more enigmatic. Our optical and near-infrared spectra show strong evidence of outflow activity and disk accretion in the form of line emission from [S II], [O I], Hα, Ca II, [Fe II], Paβ, and H{sub 2}. The molecular hydrogen emission is spatially resolved as a single lobe that stretches ≈0.''1 (15 AU). Although the extended emission is not kinematically resolved in our data, its morphology resembles shock-excited H{sub 2} jets primarily seen in young Class 0 and Class I sources. The near-infrared continuum of FW Tau b is mostly flat and lacks the deep absorption features expected for a cool, late-type object. This may be a result of accretion-induced veiling, especially in light of its strong and sustained Hα emission (EW(Hα) ≳ 290 Å). Alternatively, FW Tau b may be a slightly warmer (M5-M8) accreting low-mass star or brown dwarf (0.03-0.15 M {sub ☉}) with an edge-on disk. Regardless, its young evolutionary stage is in stark contrast to its Class III host FW Tau AB, indicating a more rapid disk clearing timescale for the host binary system than for its wide companion. Finally, we present near-infrared spectra of the young (∼2-10 Myr) low-mass (12-15 M {sub Jup}) companions GSC 6214-210 B and SR 12 C and find they best resemble low-gravity M9.5 and M9 substellar templates.},
doi = {10.1088/0004-637X/784/1/65},
url = {https://www.osti.gov/biblio/22351472},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 784,
place = {United States},
year = {Thu Mar 20 00:00:00 EDT 2014},
month = {Thu Mar 20 00:00:00 EDT 2014}
}