Five new hot-Jupiter transits investigated with Swift-UVOT Lia Corrales, Sasikrishna Ravi, George W. King, Erin May, Emily Rauscher, Mark Reynolds Short wavelength exoplanet transit measurements have been used to probe mass-loss in exoplanet atmospheres. We present the Swift-UVOT transit light curves for five hot Jupiters orbiting UV-bright F-type stars: XO-3, KELT-3, WASP-3, WASP-62, and HAT-P-6. We report one positive transit detection of XO-3b and one marginal detection of KELT-3b. We place upper limits on the remaining three transit depths. The planetary radii derived from the NUV transit depths of both potential detections are 50-100% larger than their optical radius measurements. We examine the ratio RNUV/Ropt for trends as a function of estimated mass-loss rate, which we derive from X-ray luminosity obtained from the Swift-XRT, or XMM-Newton in the case of WASP-62. We find no correlation between the energy-limited photoevaporative mass-loss rate and the RNUV/Ropt ratio. We also search for trends based on the equilibrium temperature of the hot Jupiters. We find a possible indication of a transition in the RNUV/Ropt ratio around Teq=1700 K, analogous to the trends found for NIR water features in transmission spectra. This might be explained by the formation of extended cloud decks with silicate particles ≤1 μm. We demonstrate that the Swift-UVOT filters could be sensitive to absorption from aerosols in exoplanet atmospheres.
Women of Color (WoC) – particularly Black, indigenous, and Latinx minorities – are the most underrepresented demographic from high paying industries, including software engineering. Yet WoC are flush with the talent, creativity, and social insight to solve complex problems and lead in the software industry. This program seeks to unite WoC and other members of minoritized groups, to battle feelings of isolation and marginalization that are prevalent in educational institutions and industry settings. Using a dedicated Slack space and cohorts of 4-5 people, we will create a peer mentoring network for WoC and members of other minoritized groups to engage, receive feedback, and troubleshoot issues around their participation in open source software communities.
X-ray imaging and spectroscopy can provide a powerful tool for measuring the large end of the dust grain size distribution — important for interpretting infrared extinction as well as understanding grain growth in the diffuse interstellar medium (ISM). In addition, X-ray photoelectric absorption edges observed in high resolution spectra of Galactic X-ray binaries directly reveal the mineral composition of interstellar dust. I will review open problems in the field of astromineralogy, as probed by X-ray extinction. I will describe how observations from the next two X-ray missions — XARM and ARCUS — will answer some of those questions. Finally, I will discuss synergistic opportunities for X-ray telescopes and JWST to provide a more complete picture of dust grain evolution in the diffuse ISM. Click here for a link to the pdf version of the poster.
The X-ray energy band is sensitive to absorption by all abundant metals in the interstellar medium (ISM) — carbon, oxygen, neon, silicon, magnesium, and iron — whether they are in gas or dust form. Photoelectric edges seen in high resolution X-ray spectra of Galactic X-ray point sources allow us to measure absolute abundances of gas and solid phase metals in the ISM, with fewer underlying assumptions. X-ray absorption fine structure (XAFS) in the photoelectric edge also reveals dust grain mineralogies and grain sizes. We review open problems in the field of astromineralogy, including problems in reconciling X-ray absorption spectroscopy with ISM observations at other wavelengths. In the future, high resolution imaging spectroscopy enabled by micro-calorimeters can probe the constituent elements of large dust grains, which are relatively invisible in absorption. Gratings spectroscopy is also necessary to obtain high resolution spectra at soft energies, required for probing the state of neutral carbon and oxygen — the two most abundant interstellar metals and the two most important actors in the field of astromineralogy. Click here for a link to the presentation slides.
With accurate cross-sections and higher signal-to-noise, X-ray spectroscopy can directly measure Milky Way gas and dust-phase metal abundances with few underlying assumptions. The X-ray energy band is sensitive to absorption by all abundant interstellar metals — carbon, oxygen, neon, silicon, magnesium, and iron — whether they are in gas or dust form. High resolution X-ray spectra from Galactic X-ray point sources can be used to directly measure metal abundances from all phases of the interstellar medium (ISM) along singular sight lines. We show our progress for measuring the depth of photoelectric absorption edges from neutral ISM metals, using all the observations of bright Galactic X-ray binaries available in the Chandra HETG archive. The cross-sections we use take into account both the absorption and scattering effects by interstellar dust grains on the iron and silicate spectral features. However, there are many open problems for reconciling X-ray absorption spectroscopy with ISM observations in other wavelengths. We will review the state of the field, lab measurements needed, and ways in which the next generation of X-ray telescopes will contribute. Click here for a link to the talk
We posted a statement, On the US Presidential Election, on the CSMA blog: Astronomy in Color. An except is below. “The undersigned express our solidarity with the people in the astronomy community who are directly and negatively affected by the outcome of this election. We are keeping you in our thoughts, we are feeling your pain, and we are here to support you and to fight for you in whatever way we can. We ask that our colleagues take concrete actions to affirm and validate the needs of the most marginalized members in our community.”
We are pleased to announce “Women in Astronomy IV: The Many Faces of Women Astronomers”, a conference sponsored by the National Radio Astronomy Observatory (NRAO) and the American Astronomical Society (AAS) to take place June 9 – 11, 2017, following the 2017 AAS Summer Meeting in Austin, Texas. Through extensive use of workshops, panels, and small group discussions, WiA IV will focus on issues that affect a broad spectrum of women in astronomy. It will address the challenges specific to women and what institutions can do to create welcoming, equitable workplaces. Workshops and breakout sessions will be structured with the aim of producing policy white papers, tool kits, and resource lists. We encourage interested parties to visit our website (go.nrao.edu/wiaiv) to view the formal announcement. Please pre-register (http://tinyurl.com/wiaivprereg) to indicate your interests and topic preferences and to receive updates about the conference. Responses that arrive by November 18, 2016, will be considered as we finalize the program. Help spread the word by circulating this announcement to your departments and networks. Astronomy professionals at all career levels and in all settings are invited to participate. Questions can be addressed to firstname.lastname@example.org. We look forward to seeing you at WiA IV! Nancy Morrison on behalf of the Women in Astronomy IV organizing committee
I was interviewed for a Nature news piece about the Fisher vs University of Texas case and the call for broader reforms to the academic environment. Turning Point: Diversity Ruling (V. Gerwin, Nature)
I curated an open letter to the Supreme Court of the United States, in response to comments made by Chief Justice John Roberts and Justice Antonin Scalia during the Fisher vs University of Texas case. I mailed physical copies of the letter to each of the eight Supreme Court justices hearing the case. An Open Letter to SCOTUS from professional physicists, drafted by the Equity and Inclusion in Physics and Astronomy group
This summer a group of roughly one hundred astronomers, activists, and social scientists got together for the first ever Inclusive Astronomy meeting at Vanderbilt University. The goal of the conference: “Help define recommendations and actions that will make the astronomical community more diverse and inclusive.” View at FOLD.cm