Vertical flows and mass flux balance of sunspot umbral dots

T. L. Riethmüller; S. K. Solanki; M. Van Noort; S. K. Tiwari

doi:10.1051/0004-6361/201321075

Vertical flows and mass flux balance of sunspot umbral dots

T. L. Riethmüller
, S. K. Solanki
, M. Van Noort
, S. K. Tiwari

Research output: Contribution to journal › Article › peer-review

28 Citations (Scopus)

Abstract

A new Stokes inversion technique that greatly reduces the effect of the spatial point spread function of the telescope is used to constrain the physical properties of umbral dots (UDs). The depth-dependent inversion of the Stokes parameters from a sunspot umbra recorded with Hinode SOT/SP revealed significant temperature enhancements and magnetic field weakenings in the core of the UDs in deep photospheric layers. Additionally, we found upflows of around 960 m/s in peripheral UDs (i.e., UDs close to the penumbra) and ≈600 m/s in central UDs. For the first time, we also detected systematic downflows for distances larger than 200 km from the UD center that balance the upflowing mass flux. In the upper photosphere, we found almost no difference between the UDs and their diffuse umbral background.

Original language	English
Article number	A53
Journal	Astronomy and Astrophysics
Volume	554
DOIs	https://doi.org/10.1051/0004-6361/201321075
Publication status	Published - 2013

Bibliographical note

Funding Information:
Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ, NASA, and STFC (UK) as partners. This work has been partly supported by the WCU grant No. R31-10016 funded by the Korean Ministry of Education, Science & Technology.

Keywords

Sun: photosphere
Sunspots
Techniques: polarimetric

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10.1051/0004-6361/201321075

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title = "Vertical flows and mass flux balance of sunspot umbral dots",

abstract = "A new Stokes inversion technique that greatly reduces the effect of the spatial point spread function of the telescope is used to constrain the physical properties of umbral dots (UDs). The depth-dependent inversion of the Stokes parameters from a sunspot umbra recorded with Hinode SOT/SP revealed significant temperature enhancements and magnetic field weakenings in the core of the UDs in deep photospheric layers. Additionally, we found upflows of around 960 m/s in peripheral UDs (i.e., UDs close to the penumbra) and ≈600 m/s in central UDs. For the first time, we also detected systematic downflows for distances larger than 200 km from the UD center that balance the upflowing mass flux. In the upper photosphere, we found almost no difference between the UDs and their diffuse umbral background.",

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author = "Riethm{\"u}ller, \{T. L.\} and Solanki, \{S. K.\} and \{Van Noort\}, M. and Tiwari, \{S. K.\}",

note = "Funding Information: Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ, NASA, and STFC (UK) as partners. This work has been partly supported by the WCU grant No. R31-10016 funded by the Korean Ministry of Education, Science \& Technology.",

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doi = "10.1051/0004-6361/201321075",

language = "English",

volume = "554",

journal = "Astronomy and Astrophysics",

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TY - JOUR

T1 - Vertical flows and mass flux balance of sunspot umbral dots

AU - Riethmüller, T. L.

AU - Solanki, S. K.

AU - Van Noort, M.

AU - Tiwari, S. K.

N1 - Funding Information: Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ, NASA, and STFC (UK) as partners. This work has been partly supported by the WCU grant No. R31-10016 funded by the Korean Ministry of Education, Science & Technology.

PY - 2013

Y1 - 2013

N2 - A new Stokes inversion technique that greatly reduces the effect of the spatial point spread function of the telescope is used to constrain the physical properties of umbral dots (UDs). The depth-dependent inversion of the Stokes parameters from a sunspot umbra recorded with Hinode SOT/SP revealed significant temperature enhancements and magnetic field weakenings in the core of the UDs in deep photospheric layers. Additionally, we found upflows of around 960 m/s in peripheral UDs (i.e., UDs close to the penumbra) and ≈600 m/s in central UDs. For the first time, we also detected systematic downflows for distances larger than 200 km from the UD center that balance the upflowing mass flux. In the upper photosphere, we found almost no difference between the UDs and their diffuse umbral background.

AB - A new Stokes inversion technique that greatly reduces the effect of the spatial point spread function of the telescope is used to constrain the physical properties of umbral dots (UDs). The depth-dependent inversion of the Stokes parameters from a sunspot umbra recorded with Hinode SOT/SP revealed significant temperature enhancements and magnetic field weakenings in the core of the UDs in deep photospheric layers. Additionally, we found upflows of around 960 m/s in peripheral UDs (i.e., UDs close to the penumbra) and ≈600 m/s in central UDs. For the first time, we also detected systematic downflows for distances larger than 200 km from the UD center that balance the upflowing mass flux. In the upper photosphere, we found almost no difference between the UDs and their diffuse umbral background.

KW - Sun: photosphere

KW - Sunspots

KW - Techniques: polarimetric

UR - https://www.scopus.com/pages/publications/84878640217

U2 - 10.1051/0004-6361/201321075

DO - 10.1051/0004-6361/201321075

M3 - Article

AN - SCOPUS:84878640217

SN - 0004-6361

VL - 554

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - A53

ER -

Vertical flows and mass flux balance of sunspot umbral dots

Abstract

Bibliographical note

Keywords

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