Calendar

Nov
17
Fri
Colloquium: Larisza Krista (Host: James McAteer)
Nov 17 @ 3:15 pm – 4:15 pm

The statistical study of solar dimmings and their eruptive counterparts

Larisza Krista, Cu/CIRES, NOAA/NCEI

Picture1Results are presented from analyzing the physical and morphological properties of 154 dimmings (transient coronal holes) and the associated flares and coronal mass ejections (CMEs). Each dimming in the catalog was processed with the semi-automated Coronal Dimming Tracker (CoDiT) using Solar Dynamics Observatory AIA 193 Å observations and HMI magnetograms. Instead of the typically used difference images, the transient dark regions were detected “directly” in extreme ultraviolet (EUV) images. This allowed us to study dimmings as the footpoints of CMEs—in contrast with the larger, diffuse dimmings seen in difference images that represent the projected view of the rising, expanding plasma. Studying the footpoint-dimming morphology allowed us to better understand the CME structure in the low corona. While comparing the physical properties of dimmings, flares, and CMEs, the relationships between the different parts of this complex eruptive phenomenon were identified: larger dimmings were found to be longer-lived, which suggests that it takes longer to “close down” large open magnetic regions. During their growth phase, smaller dimmings were found to acquire a higher magnetic flux imbalance (i. e., become more unipolar) than larger dimmings. Furthermore, the EUV intensity of dimmings (indicative of local electron density) was found to correlate with how much plasma was removed and how energetic the eruption was. Studying the morphology of dimmings (single, double, fragmented) also helped identify different configurations of the quasi-open magnetic field.

BIO

Dr Larisza Krista received an MSc degree in astrophysics in 2007 from Eotvos Lorand University, in Budapest, Hungary. She did her PhD at Trinity College Dublin (Ireland) as a Government of Ireland Scholar, on “The Evolution and Space Weather Effects of Solar Coronal Holes”. She moved to Boulder in 2011 to accept a research scientist position at CU/CIRES in residence at NOAA/SWPC. She has also been a long-term scientific visitor at the High Altitude Observatory, where she collaborates with Dr Scott McIntosh. Her main interests involve the evolution of open solar magnetic field regions over the solar cycle as well as the related heliospheric structures and geomagnetic effects.

 

 

Observatory Open House
Nov 17 @ 7:00 pm – 8:00 pm
Observatory Open House

Your hosts for the November Campus Observatory Open House are Chris Churchill, Sean Sellers, Sam Schonfeld, and Sarah Kovac.

 

The Calendar of Astronomical Events for November 2017

November Night Sky Chart.

Nov
27
Mon
Pizza Lunch: Rachel Marra and Trevor Picard
Nov 27 @ 12:30 pm – 1:30 pm
Pizza Lunch: Rachel Marra and Trevor Picard @ AY 119

ASTR 598 Talk

Dec
1
Fri
Colloquium: Laura Keating (Host: Kristian Finlator)
Dec 1 @ 3:15 pm – 4:15 pm
Colloquium: Laura Keating (Host: Kristian Finlator) @ BX102

Colloquium Title

Colloquium Speaker Name, Affiliation

Abstract text

Dec
4
Mon
Pizza Lunch: Karen Kinemuchi
Dec 4 @ 12:30 pm – 1:30 pm
Pizza Lunch: Karen Kinemuchi @ AY 119

Life at Apache Point Observatory

Dec
8
Fri
Colloquium – Dean Pesnell (Host: James McAteer)
Dec 8 @ 3:15 pm – 4:15 pm
Colloquium - Dean Pesnell (Host: James McAteer) @ BX102

SDO, the Sun, the Universe

Dean Pesnell, NASA / GSFC

ABSTRACT: The Sun is our best example for how stars evolve and behave. It is the only star whose surface is well-resolved in time and space. It is the only star which local helioseisomology can look into and through. One tool we to study the Sun is the Solar Dynamics Observatory (SDO), a NASA satellite that has been returning data for seven years. SDO focuses on the variations in the Sun caused by changes in the magnetic field generated by the convection zone.I will describe some aspects of SDO science that can be directly related to Sun-like stars. First are spectral irradiance measurements in extreme ultraviolet wavelengths that contribute to the loss of planetary atmospheres. Next are failed filament eruptions that fall back onto the surface as a form of accretion. Finally, how the magnetic field evolves from solar minimum to maximum and back is giving us clues about predicting that magnetic field. Please come and have a look at how studying the Sun informs our knowledge of stars.

Observatory Open House
Dec 8 @ 7:00 pm – 8:00 pm
Observatory Open House

Your hosts for the December Campus Observatory Open House are Anatoly Klypin, Gordon MacDonald, Xander Thelen, and Minje Beom.

 

The Winter Solstice

December Night Sky Chart.

Jan
24
Wed
Colloquium Thesis Proposal: Laurel Farris
Jan 24 @ 2:30 pm – 3:30 pm
Colloquium Thesis Proposal: Laurel Farris @ Science Hall, Room 110

Characterizing the oscillatory response of the chromosphere during solar flares

Laurel Farris; NMSU Astronomy Department

Quasi-periodic pulsations (QPPs) are observed in the emission of solar flares over a wide range of wavelengths,

particularly in the radio and hard x-ray regimes where non-thermal emission dominates. These pulsations are

considered to be an intrinsic feature of flares, yet the exact mechanism that triggers them remains unclear.

There have been reports of an increase in the oscillatory power at 3-minute periods (the local acoustic

cutoff frequency) in the solar chromosphere associated with flaring events. I propose to investigate the

chromospheric response to flares by inspecting the spatial and temporal onset and evolution of the 3-minute

oscillatory power, along with any QPP patterns that may appear in chromospheric emission. The analysis

will be extended to multiple flares, and will include time before, during, and after the main event. To test

initial methods, the target of interest was the well-studied 2011 February 15 X-class flare. Data from two

instruments on board the Solar Dynamics Observatory (SDO) were used in the preliminary study, including

continuum images from the Helioseismic and Magnetic Imager (HMI) and UV images at 1600 and 1700

Angstroms from the Atmospheric Imaging Assembly (AIA). Later, spectroscopic data from the Interface

Region Imaging Spectrometer (IRIS) will be used to examine velocity patterns in addition to intensity.

Jan
26
Fri
Colloquium: Zheng Cai (Host: Kristian Finlator)
Jan 26 @ 3:15 pm – 4:15 pm
Colloquium: Zheng Cai (Host: Kristian Finlator) @ BX102

Colloquium Title

Colloquium Speaker Name, Affiliation

Abstract text

Observatory Open House
Jan 26 @ 7:00 pm – 8:00 pm
Observatory Open House

Your hosts for the January 2018 Campus Observatory Open House are Rene Walterbos, Jeremy Emmett, and Caitlin Doughty.