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Vanderbilt Meeting Speakers and Abstracts

Speakers and Abstracts

 

Author: Franz-Josef (Josch) Hambsch
Co-Authors:
​Type: Oral
Title: From YY Boo (eclipsing binary) via J1407 (ringed companion) to WD 1145+017 (white dwarf with debris disk)
Abstract Description: 

Several years ago by accident I observed YY Boo outside of an eclipse and was very surprised to see a short term periodic variation of about 0.1 mag. That was completely unexpected and it initiated an international campaign by amateurs to identify the cause of these variations. It turned out that YY Boo showed a pulsation period of about 88 min in addition to being an Algol type eclipsing binary. Hence it turned out that YY Boo has become a new member of a class of pulsating eclipsing binary systems with at that time the second largest amplitude after BO Her [1].

Since August 2011, I have a remote observatory (ROAD) under pristine skies in Chile. It has been a production facility since day 1 of operation. Via the AAVSO Alert Notice 462 from June 25, 2012, I came to know about the interesting star 1SWASP J140747.93-394542.6 ("J1407"; V=12.3 mag), which underwent a series of deep eclipsing events during April/May 2007. The event lasted about 52 days with changes in brightness of the star by 0.5 to 3 magnitudes according to the Alert Notice. Nightly observations were asked, which I started on June 27 and continued ever since. A first paper [2] where observations from ROAD were taken up gave a possible period in the range of 3.5-13.8 years. Hence the coming years will be crucial to keep up observations of this interesting object.

Finally in 2015 I was asked by B. GÌ_nsicke (U. Warvick) to observe the interesting object WD 1145+017. In this context I also got to know Bruce Gary who had observed this object already for some time and joined the pro-am team to contribute observations from Chile. WD 1145+017 was observed in the period 2015 November to 2016 July to characterize the transiting behavior of the white dwarf by dust clouds produced by an asteroid orbiting the star [3]. The object was discovered by Kepler and the observed activity was enhanced drastically during the observing period.


 

Author: Tom Calderwood
Co-Authors: Jim Kay
​Type: Oral
Title: The Vega Project, Part I
Abstract Description: 

Vega is a key target for spectrophotometric calibration, hence confidence in its constancy is of great importance.  However, decades of claims and counter-claims in professional studies have left open the possibility that Vega is, at a significant level, a variable star.  We present a plan for a new photometric study and some preliminary results.


 

Author: Marco Ciocca
Co-Authors:
​Type: Oral
Title: BV observations of the eclipsing binary XZ Andromedae at the EKU Observatory
Abstract Description: 

XZ Andromedae is an Algol-type eclipsing binary.  It has been the subject of many observing campaign, all aiming at determining the mechanisms responsible for its period variation.  Results have been inconsistent and the period changes did not seem to have a common explanation between authors.  The latest of these observations (Y. –G. Yang, New Astronomy 25 (2013) 109–113) concluded that a third companion may be present and that mass transfer from the secondary to the primary companion may be occurring.  We performed measurements in the Bessel band pass B and V and measured several T.O.M and developed a model, using Binary Maker 3, that matches well the observations and includes mass transfer by adding a hot spots on the primary (the cool, more evolved companion) and a “cold” spot on the secondary (hooter, but smaller companion).  The data were collected at the EKU observatory with a Celestron C14 telescope and a SBIG STL-6303 camera.


 

Author: Dennis Conti
Co-Authors:
​Type: Oral
Title: Looking for Zebras When There Are Only Horses
Abstract Description: 

How many times have each of us thought we had made a “scientific discovery” only to realize that we were the victim of our own operational, instrumentation, or processing errors? With amateur astronomers  contributing more and more to pro/am collaborations, the quality and credibility of our participation is becoming even more important.

This keynote presentation will review some of the common pitfalls in producing research-grade photometry results and will give examples of some “horses” that we thought were really “zebras.” In addition, it will present some procedures and new techniques for obtaining higher precision photometry.  These will be especially useful in helping amateur astronomers better identify false positives in support of the upcoming TESS exoplanet mission.


 

Author: Dan Burger
Co-Authors: Keivan G. Stassun;Chandler Barnes;Sara Beck;Stella Kafka;Kenneth Li
​Type: Oral
Title: AAVSO Target Tool: A Web-Based Service for Tracking Variable Star Observations
Abstract Description: 

The AAVSO Target Tool is a web-based interface for bringing stars in need of observation to the attention of AAVSO's network of amateur and professional astronomers. The site tracks over 700 targets of interest, collecting data from them on a regular basis from AAVSO's servers and sorting them based on priority. While the target tool does not require a login, users can obtain visibility times for each target by signing up and entering a telescope location. Other key features of the site include filtering by AAVSO observing section, sorting by different variable types, formatting the data for printing, and exporting the data to a CSV file. The AAVSO Target Tool builds upon seven years of experience developing web applications for astronomical data analysis, most notably on Filtergraph (Burger et al. 2013), and is built using the Web2py web framework based on the Python programming language. The target tool is available at http://filtergraph.com/aavso


 

Author: Koji Mukai
Co-Authors: Stella Kafka;Laura Chomiuk;Ray Li;Tom Finzell;Justin Linford;Jeno Sokoloski;Tommy Nelson;Michael Rupen;Amy Mioduszewski;Jennifer Weston
​Type: Oral
Title: Nova eruptions from radio to gamma-rays - with AAVSO data in the middle
Abstract Description: 

Novae are among the longest-known class of optical transients. In recent years, V1369 Cen in the south reached magnitude 3.3 in late 2013, and had repeated (but not periodic) cycles of re-brightening. Earlier in 2013, V339 Del almost reached magnitude 4.0 during the northern summer. An expanding ball of gas, at about 10,000 K, expelled by a nuclear explosion on the surface of a white dwarf, can explain much of the visible light outputs of novae. But these spectacular visible light displays turn out to be just a small part of the show. Novae are also transient objects in the radio through gamma-rays - in addition to the warm, visible light-emitting gas, we need cold dust particles that emit in the infra-red, 10 million degree shock-heated gas that emits hard X-rays, and the exposed surface of the nuclear-burning white dwarf that emits soft X-rays. Last but not least, we need an exotic process of particle acceleration to explain the gamma-rays and some radio data.

In recent years, using data from satellites (such as Swift) and ground-based telescopes (including the Jansky VLA), we have made significant progress cataloging and understanding the messy process of mass ejection in novae. But we still know very little about how exactly novae produce gamma-rays. We plan to collect more gamma-ray data using the Fermi satellite over the next several years, of course continuing our multi-wavelength observations from the radio to the X-rays as well.

For that, we need the AAVSO community to (1) discover novae, as early as possible, and alert us; and (2) monitor novae, particularly brighter ones that are suitable for gamma-ray observations. Even in the era of ASAS-SN and other professional surveys, amateur astronomers are competitive in terms of nova discovery. Once discovered, the sheer number of small telescopes operated by the AAVSO community will provide the optical light curves and, increasingly, optical spectra that are the centerpiece of any study of novae.


 

Author: Michael D. Joner
Co-Authors: Eric G. Hintz;Denise C. Stephens
​Type: Oral
Title: Observations of Transiting Exoplanet Candidates Using BYU Facilities
Abstract Description: 

During the past five years, faculty and student observers at Brigham Young University have actively participated in observations of candidate objects as part of the follow-up network of observers for the KELT transiting exoplanet survey. These observations have made use of several small telescopes at the main campus Orson Pratt Observatory and adjacent observing deck, as well as the more remote West Mountain Observatory. Examples will be presented in this report to illustrate the wide variety of objects that have been encountered while securing observations for the KELT Follow-up Network. Many of these observations have contributed to publications that include both faculty and students researchers as coauthors.


 

Author: Knicole Colon
Co-Authors: @nasa.gov
​Type: Oral
Title: Chasing Exoplanets from NASA's K2 and TESS Missions
Abstract Description: 

NASA’s K2 mission has discovered a plethora of transiting exoplanets along the ecliptic plane, and NASA’s Transiting Exoplanet Survey Satellite (TESS) mission will surpass these discoveries in its all-sky search for transiting exoplanets. The discoveries from both K2 and TESS are important for identifying key exoplanet targets that should be characterized in detail with NASA’s James Webb Space Telescope (JWST) and other advanced facilities. I will present the latest results from an ongoing program to use the 3.5-meter WIYN telescope at Kitt Peak National Observatory for near-infrared transit photometry of K2 exoplanets and candidates. This program of high-precision, high-cadence, high-spatial-resolution near-infrared transit photometry is providing improved measurements of the orbital and physical properties of K2 exoplanets and candidates as well as identifying false positives (like eclipsing binaries) within the K2 candidate list.  I will also describe upcoming observations that I will conduct with WIYN in January 2018 as part of a campaign to observe exoplanet transits in the near-infrared simultaneously with the Kepler spacecraft during K2 Campaign 16. This campaign is a unique opportunity for all ground-based observers to point their telescopes at the same part of the sky where K2 will be observing and to simultaneously collect light curves at different wavelengths for all types of astronomical objects. Furthermore, the TESS mission is expected to launch in March 2018, and ground-based studies of K2 objects are great preparation for the follow-up that TESS will need.


 

Author: D. E. Cowall
Co-Authors: A. P. Odell
​Type: Oral
Title: Period Variation in BW Vulpeculae
Abstract Description: 

BW Vulpeculae (BW Vul) has the largest amplitude of the β Cephei stars.  An observing campaign on this star using the AAVSOnet’s Bright Star Monitor (BSM) telescopes was begun in December of 2015 and has yielded 66 nights of observations to date. A period analysis will be presented using the BSM data set in combination with unpublished data from the Lowell Observatory.  Over almost 80 years of observations, BW Vul has closely followed a parabolic ephemeris (period increasing by 2.4 seconds/century) plus a light-travel-time effect. This parabola with excursions on either side also could be viewed as a sequence of straight lines (constant period) with abrupt period increases.  The first paradigm predicted a necessary change in slope around 2004, which did not occur.  Instead, the period decreased abruptly in 2009. That maximum occurred 250 minutes early compared to the first paradigm, and about 25 minutes early compared to the straight-line paradigm from 1982-2009.


 

Author: Bert Pablo
Co-Authors:
​Type: Oral
Title: The Exciting World of Binary Stars: Not Just Eclipses Anymore​
Abstract Description: 

Binary stars have always been essential to astronomy. Their periodic eclipses are the most common and efficient method for determining precise masses and radii of stars. Binaries are known for their predictability and have been observed for hundreds if not thousands of years. As such, they are often ignored by observers as uninteresting, however, nothing could be further for the truth. In the last 10 years alone the importance of binary stars, as well of our knowledge of them has changed significantly. In this talk, I will introduce you to this new frontier of heartbeats, mergers, and evolution, while hopefully motivating a change in the collective thinking of how this unique class of objects is viewed. Most importantly, I will highlight areas in which anyone who wants can contribute to the understanding and enhancement of our astronomical knowledge base. 


 

Author: Kristine Larsen
Co-Authors:
​Type: Oral
Title: Transits, Spots, and Eclipses: The Sun’s Role in Pedagogy and Outreach
Abstract Description: 

While most people observe variable stars at night, the observers of the AAVSO Solar Division make a single observation per day, but only if it is sunny, because our variable is the Sun itself. While the Sun can play an important role in astronomy outreach and pedagogy in general, as demonstrated by the recent 2017, it can also serve as an ambassador for variable stars. This talk will examine how our sun can be used as a tool to explain several types of variable star behaviors, including transits, spots, and eclipses.


 

Author: Matt Craig
Co-Authors:
​Type: Oral
Title: Python for Variable Star Astronomy 
Abstract Description: 

Open source Python packages that are useful for data reduction, photometry and other tasks relevant to variable star astronomy have been developed over the last 3-4 years as part of the Astropy project. Using this software, it is relatively straightforward to reduce images, automatically detect sources and match them to catalogs. Over the last year browser-based tools for performing some of those tasks have been developed that minimize or eliminate the need to write any of your own code. After providing an overview of the current state of the software, an application that calculates transformation coefficients on a frame-by-frame basis by matching stars in an image to the APASS catalog will be described.


 

Author: Paul Benni
Co-Authors: Artem Burdanov;Vadim Krushinsky;Eugene Sokov;KPS;SOPHIE 
​Type: Oral
Title: Discovery of KPS-1b, a Transiting Hot-Jupiter, with an Amateur Telescope Setup
Abstract Description: 

Using readily available amateur equipment, a wide-field telescope (Celestron RASA, 279 mm f/2.2) coupled with a SBIG ST-8300M camera, was set up at a private residence in a fairly light polluted suburban town 30 miles outside of Boston, MA, USA.  This telescope participated in the Kourovka Planet Search (KPS) prototype survey, along with a MASTER-II Ural wide field telescope near Yekaterinburg, Russia.  One goal was to determine if higher resolution imaging (~2 arcsec/pixel) with much lower sky coverage can practically detect exoplanet transits compared to the successful very wide-field exoplanet surveys (KELT, XO, WASP, HATnet, TrES, Qatar, etc.) which used an array of small aperture telescopes coupled to CCDs.
The RASA telescope was pointed in the direction of HIP 53535 in Ursa Major and stared at the same point in the sky every clear night between January to April 2015.  The image field of view was 1.67 x 1.25 degrees, with drift corrected by autoguiding.  Image exposures were 50 seconds, taken with a Rc filter.  About 115 hours of data were collected and processed by K-pipe data reduction pipeline software, consisting of sequential scripts for astrometry, instrumentation + differential photometry, and Box-fitting Least Squares (BLS) periodic transit search.
Rather serendipitously, a 13.0 magnitude star (GSC0414800138, 2MASS    11004017+6457504 at coordinates RA 11 00 40.150, DEC +64 57 50.09), with periodic 10 mmag transits was detected.  Follow-up with a narrow-field telescope (Celestron 1100 EdgeHD with SBIG ST-8XME camera) confirmed the transits were real and also achromatic with different filters.  The Hot-Jupiter exoplanet was validated by RV measurements from the SOPHIE spectrograph.  KPS-1b is similar in mass and radius to Jupiter (Mp = 1.14 +/- 0.15 Mjup,  Rp = 0.96 +/- 0.10 Rjup) and has an orbital period of 1.70645 +/- 0.00004 days.  The host star is similar to our sun with mass and radius (M* = 0.93  +/-  0.07 M_Sun, R* = 0.96 +/- 0.08 R_Sun).
From this initial success, the RASA telescope was upgraded with a larger CCD size camera, and multi-field imaging capability was added to increase the survey field of view to 8.0 x 2.5 degrees.  With this setup, the Galactic Plane Exoplanet Survey (GPX) was started to survey high-density star fields of the Milky Way.  Over the past year, several high quality exoplanet candidates were identified and are awaiting validation.


 

Author: Keivan G. Stassun
Co-Authors:
​Type: Oral
Title: The Royal Road, Redux: Eclipses and Transits in the Era of Gaia and TESS
Abstract Description: 

In his 1946 inauguration of the lectureship that now bears his name, Henry Norris Russell described eclipses as a "royal road" that "repays its followers richly." In this talk, I describe how eclipsing binary stars serve as independent, empirical benchmarks for trigonometric parallaxes---with an accuracy of 200 micro-arcseconds or better that does not degrade with distance---and show an application of such a test to the first Gaia parallaxes. I then describe an approach by which the Gaia parallaxes, together with observations of planetary transits of stars, permit the radii and masses of stars and planets to be measured with an accuracy of better than 5%, in an entirely empirical fashion. Already with the first Gaia parallaxes it is possible to assess the true masses of evolved planet-host stars. I briefly summarize key results from the KELT transit survey and its implications for the science yield from the upcoming TESS mission specifically for massive stars, which are underrepresented in current planet surveys. Finally, returning to Henry Norris Russell's famous H-R diagram as an example, I conclude with some remarks on the role of data visualization in scientific discovery, and describe new efforts to quantify neuro-diverse visuo-cognitive capabilities in order to teach humans and machines to visualize data autistically.


 

Author: J. Allyn Smith
Co-Authors: Melissa Butner, Douglas Tucker, Sahar Allam
​Type: Oral
Title: Searching for Variable Stars in the SDSS Calibration Fields
Abstract Description: 

We are searching the Sloan Digital Sky Survey (SDSS) calibration fields for variable stars.  This long neglected data set, taken with a 0.5m telescope, contains nearly 200,000 stars in more than 100 fields which were observed over the course of 8+ years during the observing portion of the SDSS-I and SDSS-II surveys.  During the course of the survey, each field was visited from ~10 to several thousand times, so our initial pass is just to identify potential variable stars.  Our initial “quick-look” effort shows several thousand potential candidates and includes at least one nearby supernova.  We are present our plans for a follow-up observational program for further identification of variable types and period determinations.


 

Author: Andy Block
Co-Authors:

​Type: Poster
Title: Detecting Moving Sources In Astronomical Images
Abstract Description: 

Source detection in images is an important part of analyzing astronomical data. This project discusses an implementation of image detection in Python, as well as a processes for performing photometry in Python. Application of these tools to looking for moving sources is also discussed.​ 


 

Author: Erin Aadland
Co-Authors:
​Type: Poster
Title: Variable Stars in the Field of TrES-3b
Abstract Description: 

The star field around the exoplanet TrES-3b has potential for finding unknown variable stars.  The field was observed over several nights using Minnesota State University Moorhead’s Feder Observatory.  A light curve for each star was created and  are being evaluated for variability and periodicity.  A python program is in development to help complete the analysis by automating some of the process.  Several stars in the field appear to be variable and are being further analyzed to determine a period and to classify the  type of variable.


 

Author: Jane Glanzer
Co-Authors:
​Type: Poster
Title: Calculating Galactic Distances Through Supernova Light Curve Analysis
Abstract Description: 
 

The purpose of this project is to experimentally determine the distance to the galaxy M101 by using data that was taken on the type Ia supernova SN 2011fe at the Paul P. Feder Observatory. Type Ia supernovae are useful for determining distances in astronomy because they all have roughly the same luminosity at the peak of their outburst. Comparing the apparent magnitude to the absolute magnitude allows a measurement of the distance. The absolute magnitude is estimated in two ways: using an empirical relationship from the literature between the rate of decline and the absolute magnitude, and using sncosmo, a python package used for supernova light curve analysis that fits model light curves to the photometric data.


 

Author: Jamin Welch
Co-Authors: J. Allyn Smith
​Type: Poster
Title: Searching for variable stars in the field of Dolidze 35
Abstract Description: 

We are conducting a study of the open cluster Dolidze-35. We have a data set which contains several nights and spans four years.  One step of our survey is to search these data to identify candidate local standards and potential variable stars.  We present early results of the variable search effort.


 

Author: Rachid El Hamri
Co-Authors: Mel Blake
​Type: Poster
Title: A Search for Variable Stars in Ruprecht 134 
Abstract Description: 

Contact binary stars have been found in many old open clusters.  These stars are useful for obtaining the distances to these star clusters and for understanding  the stellar populations and evolution of the old clusters.  Ruprecht 134 is a relatively neglected, old open cluster with an age of about 1 Gyrs.  We have obtained observations of Ruprecht 134 using the 1m telescope at Cerro Tololo Interamerican Observatory for the purpose of identifying candidate contact binaries.   We present the preliminary results of this search and discuss future observations.


 

Author: Michael Lund
Co-Authors:
​Type: Oral
Title: 
A Century of Light: Insights into Boyajian's Star with Archival Data
Abstract Description: 

In late 2015, the Planet Hunters project announced one of the most surprising finds from NASA's Kepler mission. Officially designated KIC 8462852, the star has also been known as the "WTF star", "Tabby's Star", "Boyajian's Star", and even more fancifully, "the one with the alien megastructure." In the short time frame since its discovery, it has been a frequent target of observations, and Kepler data provides very precise observations from 2009 to 2013 and the explanation of the irregular and sometimes very significant dimmings that the star undergoes has been elusive. However, the archival data that has been preserved at facilities such as by Harvard's DASCH project have provided the opportunity to study the star's behavior for more than a century. This timescale of observation is infrequently an option in astronomy, and allows us to constrain long-term behavior even as we seek explanations for short-term phenomena.


 

Author: Joseph Rodriguez
Co-Authors:
​Type: Oral
Title: 
The Great PDS 110 Eclipse: Back to the Drawing Board
Abstract Description: 

Our understanding of the evolution from circumstellar material to the thousands of planetary systems discovered to date, is limited. One means to constrain the size and composition of this planet-forming material is to observe a YSO being eclipsed by circumstellar material. These events are rare but have led to such insights as Saturn-like rings and gaps in the disk surrounding the a young planet. One such candidate, PDS 110, displayed two separate 0.3 mag deep, 14 day long dimming events attributed to an occultation of the host star by a sub-stellar companion with a circumsecondary disk. From our analysis of the 2008 and 2011 eclipses, we predicted that PDS 110 would undergo another dimming event in September of 2017. In this talk, I will present the results of our worldwide campaign to observed the 2017 eclipse of PDS 110, and discuss how it has impacted our understanding of the system. 


 

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