Search Publications
Are Starspots and Plages Co-located on Active G and K Stars?
Hawley, Suzanne L.; Agol, Eric; Agüeros, Marcel A. +4 more
We explore the connection between starspots and plages of three main-sequence stars by studying the chromospheric and photospheric activity over several rotation periods. We present simultaneous photometry and high-resolution (R ∼ 31500) spectroscopy of KIC 9652680, a young, super-flare-producing G1 star with a rotation period of 1.4 days. Its Kep…
HAT-TR-318-007: A Double-lined M Dwarf Binary with Total Secondary Eclipses Discovered by HATNet and Observed by K2
Latham, D. W.; Bhatti, W.; Fulton, B. J. +11 more
We report the discovery by the HATNet survey of HAT-TR-318-007, a P=3.34395390+/- 0.00000020 day period detached double-lined M dwarf binary with total secondary eclipses. We combine radial velocity (RV) measurements from TRES/FLWO 1.5 m and time-series photometry from HATNet, FLWO 1.2 m, BOS 0.8 m, and NASA K2 Campaign 5, to determine the masses …
A New, Long-lived, Jupiter Mesoscale Wave Observed at Visible Wavelengths
de Pater, Imke; Wong, Michael H.; Fletcher, Leigh N. +12 more
Small-scale waves were observed along the boundary between Jupiter’s North Equatorial Belt (NEB) and North Tropical Zone, ∼16.°5 N planetographic latitude in Hubble Space Telescope data in 2012 and throughout 2015-2018, observable at all wavelengths from the UV to the near-IR. At peak visibility, the waves have sufficient contrast (∼10%) to be obs…
Kinematics of the Horsehead Nebula and IC 434 Ionization Front in CO and C+
Bally, John; Stanke, Thomas; Zinnecker, Hans +5 more
Stratospheric Observatory for Infrared Astronomy [C II] 157 µm, APEX 860 µm J = 3-2 CO, and archival James Clerk Maxwell Telescope J = 2-1 CO and 13CO observations of the Horsehead Nebula are presented. The photon-dominated region (PDR) between the Orion B molecular cloud and the adjacent IC 434 H II region is used to study …
Ultraviolet Observations of Coronal Mass Ejection Impact on Comet 67P/Churyumov-Gerasimenko by Rosetta Alice
Parker, Joel Wm.; Bertaux, Jean-Loup; Stern, S. Alan +13 more
The Alice ultraviolet spectrograph on the European Space Agency Rosetta spacecraft observed comet 67P/Churyumov-Gerasimenko in its orbit around the Sun for just over two years. Alice observations taken in 2015 October, two months after perihelion, show large increases in the comet’s Lyβ, O I 1304, O I 1356, and C I 1657 Å atomic emission that init…
Searching for Cool Dust. II. Infrared Imaging of The OH/IR Supergiants, NML Cyg, VX Sgr, S Per, and the Normal Red Supergiants RS Per and T Per
Gehrz, Robert D.; Humphreys, Roberta M.; Jones, Terry J. +6 more
New MMT/MIRAC (9-11 µm), SOFIA/FORCAST (11-37 µm), and Herschel/PACS (70 and 160 µm) infrared (IR) imaging and photometry is presented for three famous OH/IR red supergiants (NML Cyg, VX Sgr, and S Per) and two normal red supergiants (RS Per and T Per). We model the observed spectral energy distributions (SEDs) using radiative-tr…
The Double Dust Envelopes of R Coronae Borealis Stars
Evans, A.; Clayton, Geoffrey C.; Matsuura, M. +5 more
The study of extended, cold dust envelopes surrounding R Coronae Borealis (RCB) stars began with their discovery by the Infrared Astronomical Satellite. RCB stars are carbon-rich supergiants characterized by their extreme hydrogen deficiency and their irregular and spectacular declines in brightness (up to 9 mag). We have analyzed new and archival…
Optical Dimming of RW Aur Associated with an Iron-rich Corona and Exceptionally High Absorbing Column Density
Schneider, P. C.; Birnstiel, T.; Principe, D. A. +7 more
RW Aur is a binary system composed of two young, low-mass stars. The primary, RW Aur A, has undergone visual dimming events (ΔV = 2-3 mag) in 2011, 2014-16, and 2017-2018. Visual and IR observations indicate a gray absorber that moved into the line of sight. This dimming is also associated with changes in the outflow. In 2017, when the optical bri…
Toward the ICRF3: Astrometric Comparison of the USNO 2016A VLBI Solution with ICRF2 and Gaia DR1
Dorland, Bryan N.; Makarov, Valeri V.; Johnson, Megan C. +2 more
The VLBI USNO 2016A (U16A) solution is part of a work-in-progress effort by USNO toward the preparation of the ICRF3. Most of the astrometric improvement with respect to the ICRF2 is due to the re-observation of the VCS sources. Our objective in this paper is to assess U16A’s astrometry. A comparison with ICRF2 shows statistically significant offs…
Is the Young Star RZ Piscium Consuming Its Own (Planetary) Offspring?
Kastner, J. H.; Punzi, K. M.; Melis, C. +4 more
The erratically variable star RZ Piscium (RZ Psc) displays extreme optical dropout events and strikingly large excess infrared emission. To ascertain the evolutionary status of this intriguing star, we obtained observations of RZ Psc with the European Space Agency’s X-ray Multi-Mirror Mission (XMM-Newton), as well as high-resolution optical spectr…