News

The paper "SpecpolFlow: a new software package for spectropolarimetry using Python" published on July 19, 2025 was authored by 5 current student of the research group (Shaquann Seadrow, Patrick Stanley, Tali Natan, Federico Villadiego Forero, and Marisol Catalan Olais) including Dr. Pettit. 

Tali  explained a little bit about this paper: 

"Previous spectropolarimetry tools have been based in legacy codes and are only available through subscriptions or if you know a user. Without adequate documentation and version control, these codes are difficult to approach if you are new to the field. SpecpolFlow leverages the accessibility and large user base of Python to develop and maintain a spectropolarimetry for the community."

This paper was a group effort but Tali's primary contribution to the code was developing and testing SpecpolFlow tutorials with Patrick. She said "Our goal was to make these tutorials accessible to students and seasoned researchers alike with plenty of helpful hints and comments."

The SpecpolFlow dev team had researchers that span low- and high-mass star physics; this collaboration allows us to tackle science cases outside our specific niche.

Read the paper here.

The exam has the form of a 3000+ word research paper followed by a research presentation and defense in front of a committee similar to a masters thesis or masters literature review defense.

Patrick's paper, titled "Magnetic Upper Limits of the MiMeS Classical Be Star Sample," investigates the magnetic properties of Be type stars. Unlike other massive stars, of which about 10% are magnetic, no Be stars have been found to exhibit magnetic fields. "We found that this upper limit is not consistent with the magnetic fields of the other massive stars indicating that Be stars are indeed not strongly magnetic as is observed in other massive stars."

The RRE paper was a preliminary work (only half the sample were used), the finished results will be published once the rest of the analysis is finished. Below is one of the key figures from the work. The thick blue line is the upper limit of Be stars in this sample, the thick black is the upper limit of massive O-type stars, and the thin lines are the known magnetic field strengths of O and B stars. Since the thick lines are similar we can say that the upper limits of Be stars are similar to O stars, but since the thick blue line is shifted to lower Bpole values than the thin lines we can say that if Be stars had magnetic fields similar to magnetic O and B stars they could have been detected. However, we have not detected magnetic Be stars so we can conclude there are no strongly magnetic Be stars.

On August 10th, I presented at the Undergraduate Summer Symposium as a part of the McNair Scholars Program. I learned a lot about creating a research poster and creating a pitch to talk about my work to people who are not in my field of study. Throughout the day, I attended various poster sessions and talked to plenty of other undergraduate researchers about their summer work and individual experiences. It’s truly amazing what people all around campus are working on.

Although I was initially very nervous to present my work, once I started talking to people who were interested in my work, it felt really nice to share my work with others. It gave me an opportunity to convey my work to a larger audience. One of my favorite interactions I had was someone telling me their mind was blown because they didn’t know stars could have magnetic fields.

This experience definitely got me out of my comfort zone, but I really enjoyed it and look forward to doing more poster presentations in the future!

~ Marisol Catalan Olais

Spindown of Magnetic Massive Stars Calculated from ZDI Maps

Angular momentum loss in massive main sequence stars is due, in part, by the strength and structure of surface magnetic fields (Ud-Doula et al. 2008). The torque created by a surface magnetic field can be calculated through integration of a ZDI map (Shultz et al. in prep). To characterize how the scale of magnetic structures affect the spindown of the star, the ZDI maps are decomposed into spherical harmonics in a method described by Kochukhov & Wade (2015). From these, we can calculate the torque associated with each harmonic number. In this work, we looked at three massive fast rotators, CU Vir (HD124224), 36 Lyn (HD79158), and σ Ori E (HD37479), as well as the slowly rotating early B-type star, τ Sco (HD149438). From these, we see that the loss of angular momentum in massive stars is primarily due to large structures in the surface magnetic field. This result agrees with consensus that the surface magnetic fields of massive stars are dominated by simple geometry.

Shaquann  was awarded a graduate fellowship from the NASA Delaware Space Grant Consortium for 2023-24. This fellowship supports graduate students whose reasearch aligns with NASA core objectives. In this case, Shaquann's studies of NGC 1624-2 and his work toward the science verification of utilizing SPIRou to study massive stars aligns with the NASA core objectives.

Congratulations Shaquann!!

Read more about the Delaware Space Grant consortium here. 

Mount Cuba Astronomical Observatory hosts various events during the summer for the public in addition to facility tours for groups such as the scouts or schools. Generally they are three times of events, Family Nights which are usually telescope observing or a planetarium shows if the weather is bad, Public Nights which are for adults and students 5th grade and up are usually lectures or talks on something related to astronomy, and Children's Shows which are more interactive or activity-oriented shows for young children. 

This summer Patrick has already given one show so far titled "International Astronomy Day" which was a show focusing on how the sky isn't static but instead changes over short and long periods of time. Unfortunately two other shows were canceled due to bad weather. 

Upcoming events featuring Patrick:

July 7th- Family Nights

July 14th- Children's Shows

In August he will be giving a Public Night show called "Solar System Mysteries" 

A recent article in the UDaily featured Dr. Veronique Petit teaching. This is part of series of articles aimed at courses typically taken by first year students. The course she discussed is called “Concepts of the Universe,”  certainly an intimidating title, but her goal is to expose students to astronomy. If you have ever wondered what are gravitational waves or what really are exoplanets, this is the course for you! This course is taught online and is offered to the Delaware high school students in the Early College Credit (ECC) Program.  The course comes highly recommended by past students! 

You can read the entire article here.

Dr. Das et. al findings were featured in NICER Nuggets this month. Each week, the NICER team summarizes important scientific activities or results utilizing data from the NICER mission. These summaries are called science nuggets and it is always fun to see one of our team's papers get picked.

Barnali Das and Veronique Petit and their team conducted a detailed study regarding the X-ray properties of the unique stellar system Epsilon Lupi. Read the paper here.

Marisol is joining us again this summer as a McNair fellow. She is a rising Junior and is currently  working on creating PDFs of graphs of that display the LSD profiles of different model spectra and determining how accurate the masks are at matching the observed spectra. 

Marisol- "So far, I’ve learned a lot about different coding features, such as making a python path for packages and using GitHub to access various repositories." 

Here are some of the graphs she has been working on!

Barnali Das and Veronique Petit and their team conducted a detailed study regarding the X-ray properties of the unique stellar system Epsilon Lupi.

This is the only known binary system with two magnetic massive stars whose magnetospheres overlap at all times. This raises the possibility of inter-stellar magnetospheric interaction which is likely to produce distinct X-ray signatures. Using the Neutron Star Interior Composition Explorer Mission (NICER) onboard the International Space Station (ISS), they obtained the first evidence that indeed such magnetospheric interactions are present in the system. To know about more please check out the paper.

The Astronomical Society of India just announced the winner for outstanding thesis in 2022 to be our very own Dr. Das We are very proud of her achievement.

Dr. Das' PhD research was on coherent radio emission from magnetic massive stars. This research was carried out under the supervision of Prof. Poonam Chandra at the National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, India. Such stars (which can produce coherent radio emission) were thought to be extremely rare at the time the research began. By conducting a systematic survey using the upgraded Giant Metrewave Radio Telescope, they showed that the phenomenon is very likely ubiquitous among the population of hot magnetic stars, solving a two-decades old puzzle about these stars. In addition, they also carried out ultra-wideband radio observations of these stars for the first time, which led to the realization that coherent radio emission is a treasure-trove of information about massive stars’s magnetospheres, and has the potential to become a unique stellar magnetospheric probe.

This year the whole group attended the Mid-Atlantic APS meeting in December. We had forgotten how much fun it is to go to conferences in person, having in person conversations and attend presentations of others in the group. Bottom line, the conference was a great success! Barnali, Victor, Shaquann, and Patrick gave great presentations. Read a little bit about each presentation below. 

Patrick Stanley presenting: "Investigating the Magnetic Incidence of Be Stars". It was a progress report on our study of a non-magnetic subgroup of massive stars known as Be stars with a novel technique that used both synthetic (modeled) and observed data. Patrick- “I find Be stars incredibly interesting because they seemingly go against the ~10% magnetic incidence found for other massive stars and we don't yet know why this is the case.”

Victor Ramirez presenting: “Exploring the IBF of massive  stars by simulating magnetic detectability in star clusters”. Victor- “I presented my work on trying to explain the 10% incidence of magnetic massive stars by generating a synthetic stellar cluster and simulating that if all these stars are magnetic and are located at a certain distance from us how many of them we would detect as being magnetic. Assuming a log-normal IBF I find that throughout the millions of years that I evolved the cluster, I obtained a 92% observational incidence of magnetic stars. While this is far off from the 10% we observe, this result still shows that due to our observational limits we wouldn’t be able to detect a magnetic field for all stars specially for stars of low luminosity and slow rotational speeds. I really enjoyed working on this project and getting the opportunity to present it, and I look forward to continuing to explore this interesting question of why only 10% massive stars are magnetic.”

Shaquann Seadrow  presenting: “Revising the Rotational Period of NGC 1624-2” He explains “ In a gist, it is about using variational analysis techniques on optical spectral lines to measure the rotation rate of that star. I've found it fascinating that this property that we can’t directly measure for most stars, which adds to how cool magnetic massive stars are.”

This summer Shaquan and Victor got to spend a week at the Mesa Summer School. Below is a quick recap of the highlights from Victor.

Victor- “I spent the an exciting week at the campus of UCSB for the MESA Summer School 2022. Everyday consisted of hands on experience using the MESA software, where we spent hours coding up the tutorials the organizers prepared. While it was quite exhausting at times trying to gather all of the information they presented at us, I learned a lot and improved my skills using MESA. I also enjoyed connecting with other grad students, post-docs and professors of institutions across the US and Europe, and hearing about their research. One of my favorite memories was of the conference was the barbecue we had on the beach the day before the end of the Summer School. The views were incredible specially thanks to the sunset!”

Sounds like it comes highly recommended for anyone else interested to attend.

The last week of July, AstroPhilly22, a regional symposium bringing together physicists and astronomers to share their summer research took place at the Villanova University. This symposium consists of both talks and posters and Patrick brought his poster on "Studying Titan with a Simple Climate Model"

Abstract: Saturn's moon Titan is a scientifically rich and interesting body and has captivated the minds of people for decades. Titan's thick atmosphere is vastly important in the investigation of climate and atmospheric energy transport under exotic conditions. Titan is also relevant to paleoclimatology as a young Earth likely possessed an antigreenhouse effect that should have kept Earth in an ice age (faint young sun problem). Additionally, with NASA’s upcoming

mission to send a quadcopter to Titan ( the Dragonfly mission), the study of Titan‚ Äôs atmosphere is even more important. To study the climate of Titan, a 2D time-dependent radiative energy balance equation was numerically solved to find the surface temperature as a function of the latitude, longitude, and time, taking into account atmospheric gravitational tides and antigreenhouse haze. The model was then compared to Cassini observations and more complex models, namely GCMs, to assess how well the simple model stacks up to reality

Read more about the symposium here.

During the 40th meeting of the Astronomical Society of India on March 20, 2022, Dr Barnali received an honorable mention for the best thesis presentation. The announcement can be found at this link. The title of the thesis is 'Coherent Radio Emission from Hot Magnetic Stars'.

Congratulations!!! Great way to start the year!

We are excited to welcome Dr. Barnali Das to our research group as our newest postdoc. 

Dr. Barnali Das recently obtained her PhD from the National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, India. During her PhD, she worked with Prof. Poonam Chandra on coherent radio emission from hot magnetic stars. The primary objective was to find out why this phenomenon (of production of coherent radio emission) is so rare among these stars. What they discovered was that the phenomenon is probably ubiquitous among the population of hot magnetic stars provided they are observe at the right time and frequency. They also conducted the first ultra-wideband observation of these stars (0.4-4.0 GHz) that resulted into several new discoveries including the fact that this radio emission carries a vast amount of information regarding the stellar magnetospheres.

During Dr. Barnali Das post-doc at the University of Delaware in our group, she will attempt to probe the stellar magnetospheres by combining information from multi-waveband analysis.