Abstract
We use the Wide Field Camera 3 on the Hubble Space Telescope to spectrophotometrically monitor the young L7.5 companion HD 203030B. Our time series reveal photometric variability at 1.27 and 1.39 μm on timescales compatible with rotation. We find a rotation period of 7.5-0.5 +0.6 hr: Comparable to those observed in other brown dwarfs and planetary-mass companions younger than 300 Myr. We measure variability amplitudes of 1.1% ± 0.3% (1.27 μm) and 1.7% ± 0.4% (1.39 μm), and a phase lag of 56° ± 28° between the two light curves. We attribute the difference in photometric amplitudes and phases to a patchy cloud layer that is sinking below the level where water vapor becomes opaque. HD 203030B and the few other known variable young late-L dwarfs are unlike warmer (earlier-type and/or older) L dwarfs, for which variability is much less wavelength-dependent across the 1.1-1.7 μm region. We further suggest that a sinking of the top-most cloud deck below the level where water or carbon monoxide gas become opaque may also explain the often enhanced variability amplitudes of even earlier-type low-gravity L dwarfs. Because these condensate and gas opacity levels are already well-differentiated in T dwarfs, we do not expect the same variability amplitude enhancement in young versus old T dwarfs.
| Original language | English (US) |
|---|---|
| Article number | 181 |
| Journal | Astrophysical Journal |
| Volume | 883 |
| Issue number | 2 |
| DOIs | |
| State | Published - Oct 1 2019 |
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ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
Cloud Atlas : Variability in and out of the Water Band in the Planetary-mass HD 203030B Points to Cloud Sedimentation in Low-gravity L Dwarfs. / Miles-Paéz, Paulo A.; Metchev, Stanimir; Apai, Dániel; Zhou, Yifan; Manjavacas, Elena; Karalidi, Theodora; Lew, Ben W.P.; Burgasser, Adam J.; Bedin, Luigi R.; Cowan, Nicolas; Lowrance, Patrick J.; Marley, Mark S.; Radigan, Jacqueline; Schneider, Glenn.
In: Astrophysical Journal, Vol. 883, No. 2, 181, 01.10.2019.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Cloud Atlas
T2 - Variability in and out of the Water Band in the Planetary-mass HD 203030B Points to Cloud Sedimentation in Low-gravity L Dwarfs
AU - Miles-Paéz, Paulo A.
AU - Metchev, Stanimir
AU - Apai, Dániel
AU - Zhou, Yifan
AU - Manjavacas, Elena
AU - Karalidi, Theodora
AU - Lew, Ben W.P.
AU - Burgasser, Adam J.
AU - Bedin, Luigi R.
AU - Cowan, Nicolas
AU - Lowrance, Patrick J.
AU - Marley, Mark S.
AU - Radigan, Jacqueline
AU - Schneider, Glenn
PY - 2019/10/1
Y1 - 2019/10/1
N2 - We use the Wide Field Camera 3 on the Hubble Space Telescope to spectrophotometrically monitor the young L7.5 companion HD 203030B. Our time series reveal photometric variability at 1.27 and 1.39 μm on timescales compatible with rotation. We find a rotation period of 7.5-0.5 +0.6 hr: Comparable to those observed in other brown dwarfs and planetary-mass companions younger than 300 Myr. We measure variability amplitudes of 1.1% ± 0.3% (1.27 μm) and 1.7% ± 0.4% (1.39 μm), and a phase lag of 56° ± 28° between the two light curves. We attribute the difference in photometric amplitudes and phases to a patchy cloud layer that is sinking below the level where water vapor becomes opaque. HD 203030B and the few other known variable young late-L dwarfs are unlike warmer (earlier-type and/or older) L dwarfs, for which variability is much less wavelength-dependent across the 1.1-1.7 μm region. We further suggest that a sinking of the top-most cloud deck below the level where water or carbon monoxide gas become opaque may also explain the often enhanced variability amplitudes of even earlier-type low-gravity L dwarfs. Because these condensate and gas opacity levels are already well-differentiated in T dwarfs, we do not expect the same variability amplitude enhancement in young versus old T dwarfs.
AB - We use the Wide Field Camera 3 on the Hubble Space Telescope to spectrophotometrically monitor the young L7.5 companion HD 203030B. Our time series reveal photometric variability at 1.27 and 1.39 μm on timescales compatible with rotation. We find a rotation period of 7.5-0.5 +0.6 hr: Comparable to those observed in other brown dwarfs and planetary-mass companions younger than 300 Myr. We measure variability amplitudes of 1.1% ± 0.3% (1.27 μm) and 1.7% ± 0.4% (1.39 μm), and a phase lag of 56° ± 28° between the two light curves. We attribute the difference in photometric amplitudes and phases to a patchy cloud layer that is sinking below the level where water vapor becomes opaque. HD 203030B and the few other known variable young late-L dwarfs are unlike warmer (earlier-type and/or older) L dwarfs, for which variability is much less wavelength-dependent across the 1.1-1.7 μm region. We further suggest that a sinking of the top-most cloud deck below the level where water or carbon monoxide gas become opaque may also explain the often enhanced variability amplitudes of even earlier-type low-gravity L dwarfs. Because these condensate and gas opacity levels are already well-differentiated in T dwarfs, we do not expect the same variability amplitude enhancement in young versus old T dwarfs.
UR - http://www.scopus.com/inward/record.url?scp=85073755510&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85073755510&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/ab3d25
DO - 10.3847/1538-4357/ab3d25
M3 - Article
AN - SCOPUS:85073755510
VL - 883
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 181
ER -