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Nine Bright Γ Doradus Variables Discovered With Ground-Based Photometry, Gregory W. Henry, Francis C. Fekel, Michael H. Williamson
Nine Bright Γ Doradus Variables Discovered With Ground-Based Photometry, Gregory W. Henry, Francis C. Fekel, Michael H. Williamson
Information Systems and Engineering Management Research Publications
We have used precise photometric and high-dispersion spectroscopic observations to study nine candidate γ Doradus (γ Dor) stars, identified as optically variable comparison stars in our photometric studies of Sun-like stars. In this paper, we confirm these nine candidates as new γ Dor variables. All exhibit sinusoidal variability with amplitudes between 6 and 65 mmag in Johnson B and periods from 0.28 to 1.13 days. All lie in the same region of the H-R diagram as our previously confirmed γ Dor stars. Of the nine systems, one is a single-lined spectroscopic binary (SB1), two are double-lined spectroscopic binaries (SB2), and …
The Expres Stellar Signals Project Ii. State Of The Field In Disentangling Photospheric Velocities, Lily L. Zhao, Debra A. Fischer, Eric B. Ford, Alex Wise, Michaël Cretignier, Suzanne Aigrain, Oscar Barragan, Megan Bedell, Lars A. Buchhave, João D. Camacho, Heather M. Cegla, Jessi Cisewski-Kehe, Andrew Collier Cameron, Zoe L. De Beurs, Sally Dodson-Robinson, Xavier Dumusque, João P. Faria, Christian Gilbertson, Charlotte Haley, Justin Harrell, David W. Hogg, Parker Holzer, Ancy Anna John, Baptiste Klein, Marina Lafarga, Florian Lienhard, Vinesh Maguire-Rajpaul, Annelies Mortier, Belinda Nicholson, Michael L. Palumbo Iii, Victor Ramirez Delgado, Christopher J. Shallue, Andrew Vanderburg, Pedro T. P. Viana, Jinglin Zhao, Norbert Zicher, Samuel H. C. Cabot, Gregory W. Henry, Rachael M. Roettenbacher, John M. Brewer, Joe Llama, Ryan R. Petersburg, Andrew E. Szymkowiak
The Expres Stellar Signals Project Ii. State Of The Field In Disentangling Photospheric Velocities, Lily L. Zhao, Debra A. Fischer, Eric B. Ford, Alex Wise, Michaël Cretignier, Suzanne Aigrain, Oscar Barragan, Megan Bedell, Lars A. Buchhave, João D. Camacho, Heather M. Cegla, Jessi Cisewski-Kehe, Andrew Collier Cameron, Zoe L. De Beurs, Sally Dodson-Robinson, Xavier Dumusque, João P. Faria, Christian Gilbertson, Charlotte Haley, Justin Harrell, David W. Hogg, Parker Holzer, Ancy Anna John, Baptiste Klein, Marina Lafarga, Florian Lienhard, Vinesh Maguire-Rajpaul, Annelies Mortier, Belinda Nicholson, Michael L. Palumbo Iii, Victor Ramirez Delgado, Christopher J. Shallue, Andrew Vanderburg, Pedro T. P. Viana, Jinglin Zhao, Norbert Zicher, Samuel H. C. Cabot, Gregory W. Henry, Rachael M. Roettenbacher, John M. Brewer, Joe Llama, Ryan R. Petersburg, Andrew E. Szymkowiak
Information Systems and Engineering Management Research Publications
Measured spectral shifts due to intrinsic stellar variability (e.g., pulsations, granulation) and activity (e.g., spots, plages) are the largest source of error for extreme-precision radial-velocity (EPRV) exoplanet detection. Several methods are designed to disentangle stellar signals from true center-of-mass shifts due to planets. The Extreme-precision Spectrograph (EXPRES) Stellar Signals Project (ESSP) presents a self-consistent comparison of 22 different methods tested on the same extreme-precision spectroscopic data from EXPRES. Methods derived new activity indicators, constructed models for mapping an indicator to the needed radial-velocity (RV) correction, or separated out shape- and shift-driven RV components. Since no ground truth is known when …
Expres. Iii. Revealing The Stellar Activity Radial Velocity Signature Of Ε Eridani With Photometry And Interferometry, Rachael M. Roettenbacher, Samuel H. C. Cabot, Debra A. Fischer, John D. Monnier, Gregory W. Henry, Robert O. Harmon, Heidi Korhonen, John M. Brewer, Joe Llama, Ryan R. Petersburg, Lily L. Zhao, Stefan Kraus, Jean-Baptiste Le Bouquin, Narsireddy Anugu, Claire L. Davies, Tyler Gardner, Cyprien Lanthermann, Gail Schaefer, Benjamin Setterholm, Catherine A. Clark, Svetlana G. Jorstad, Kyler Kuehn, Stephen Levine
Expres. Iii. Revealing The Stellar Activity Radial Velocity Signature Of Ε Eridani With Photometry And Interferometry, Rachael M. Roettenbacher, Samuel H. C. Cabot, Debra A. Fischer, John D. Monnier, Gregory W. Henry, Robert O. Harmon, Heidi Korhonen, John M. Brewer, Joe Llama, Ryan R. Petersburg, Lily L. Zhao, Stefan Kraus, Jean-Baptiste Le Bouquin, Narsireddy Anugu, Claire L. Davies, Tyler Gardner, Cyprien Lanthermann, Gail Schaefer, Benjamin Setterholm, Catherine A. Clark, Svetlana G. Jorstad, Kyler Kuehn, Stephen Levine
Information Systems and Engineering Management Research Publications
The distortions of absorption line profiles caused by photospheric brightness variations on the surfaces of cool, main-sequence stars can mimic or overwhelm radial velocity (RV) shifts due to the presence of exoplanets. The latest generation of precision RV spectrographs aims to detect velocity amplitudes ≲ 10 cm s−1, but requires mitigation of stellar signals. Statistical techniques are being developed to differentiate between Keplerian and activity-related velocity perturbations. Two important challenges, however, are the interpretability of the stellar activity component as RV models become more sophisticated, and ensuring the lowest-amplitude Keplerian signatures are not inadvertently accounted for in flexible …
Establishing Α Oph As A Prototype Rotator: Precision Orbit With New Keck, Chara, And Rv Observations, Tyler Gardner, John D. Monnier, Francis C. Fekel, Michael H. Williamson, Fabien Baron, Sasha Hinkley, Michael Ireland, Adam L. Kraus, Stefan Kraus, Rachael M. Roettenbacher, Gail Schaefer, Judit Sturmann, Laszlo Sturmann, Theo A. Ten Brummelaar
Establishing Α Oph As A Prototype Rotator: Precision Orbit With New Keck, Chara, And Rv Observations, Tyler Gardner, John D. Monnier, Francis C. Fekel, Michael H. Williamson, Fabien Baron, Sasha Hinkley, Michael Ireland, Adam L. Kraus, Stefan Kraus, Rachael M. Roettenbacher, Gail Schaefer, Judit Sturmann, Laszlo Sturmann, Theo A. Ten Brummelaar
Information Systems and Engineering Management Research Publications
Alpha Ophiuchi (Rasalhague) is a nearby rapidly rotating A5IV star that has been imaged by infrared interferometry. α Oph is also part of a known binary system, with a companion semimajor axis of ∼430 mas and a high eccentricity of 0.92. The binary companion provides the unique opportunity to measure the dynamical mass to compare with the results of rapid rotator evolution models. The lack of data near periastron passage limited the precision of mass measurements in previous work. We add new interferometric data from the MIRC combiner at the CHARA Array as well as new Keck adaptive optics imaging …
California Legacy Survey. Ii. Occurrence Of Giant Planets Beyond The Ice Line, Benjamin J. Fulton, Lee J. Rosenthal, Lea A. Hirsch, Howard Isaacson, Andrew W. Howard, Cayla M. Dedrick, Ilya A. Sherstyuk, Sarah C. Blunt, Erik A. Petigura, Heather A. Knutson, Aida Behmard, Ashley Chontos, Justin R. Crepp, Ian J. M. Crossfield, Paul A. Dalba, Debra A. Fischer, Gregory W. Henry, Stephen R. Kane, Molly Kosiarek, Geoffrey W. Marcy, Ryan A. Rubenzahl, Lauren M. Weiss, Jason T. Wright
California Legacy Survey. Ii. Occurrence Of Giant Planets Beyond The Ice Line, Benjamin J. Fulton, Lee J. Rosenthal, Lea A. Hirsch, Howard Isaacson, Andrew W. Howard, Cayla M. Dedrick, Ilya A. Sherstyuk, Sarah C. Blunt, Erik A. Petigura, Heather A. Knutson, Aida Behmard, Ashley Chontos, Justin R. Crepp, Ian J. M. Crossfield, Paul A. Dalba, Debra A. Fischer, Gregory W. Henry, Stephen R. Kane, Molly Kosiarek, Geoffrey W. Marcy, Ryan A. Rubenzahl, Lauren M. Weiss, Jason T. Wright
Information Systems and Engineering Management Research Publications
We used high-precision radial velocity measurements of FGKM stars to determine the occurrence of giant planets as a function of orbital separation spanning 0.03–30 au. Giant planets are more prevalent at orbital distances of 1–10 au compared to orbits interior or exterior of this range. The increase in planet occurrence at ∼1 au by a factor of ∼4 is highly statistically significant. A fall-off in giant planet occurrence at larger orbital distances is favored over models with flat or increasing occurrence. We measure ${14.1}_{-1.8}^{+2.0}$ giant planets per 100 stars with semimajor axes of 2–8 au and ${8.9}_{-2.4}^{+3.0}$ giant planets per …
The California Legacy Survey. I. A Catalog Of 178 Planets From Precision Radial Velocity Monitoring Of 719 Nearby Stars Over Three Decades, Lee J. Rosenthal, Benjamin J. Fulton, Lea A. Hirsch, Howard Isaacson, Andrew W. Howard, Cayla M. Dedrick, Ilya A. Sherstyuk, Sarah C. Blunt, Erik A. Petigura, Heather Knutson, Aida Behmard, Ashley Chontos, Justin R. Crepp, Ian J. M. Crossfield, Paul A. Dalba, Debra A. Fischer, Gregory W. Henry, Stephen R. Kane, Molly Kosiarek, Geoffrey W. Marcy, Ryan A. Rubenzahl, Lauren M. Weiss, Jason T. Wright
The California Legacy Survey. I. A Catalog Of 178 Planets From Precision Radial Velocity Monitoring Of 719 Nearby Stars Over Three Decades, Lee J. Rosenthal, Benjamin J. Fulton, Lea A. Hirsch, Howard Isaacson, Andrew W. Howard, Cayla M. Dedrick, Ilya A. Sherstyuk, Sarah C. Blunt, Erik A. Petigura, Heather Knutson, Aida Behmard, Ashley Chontos, Justin R. Crepp, Ian J. M. Crossfield, Paul A. Dalba, Debra A. Fischer, Gregory W. Henry, Stephen R. Kane, Molly Kosiarek, Geoffrey W. Marcy, Ryan A. Rubenzahl, Lauren M. Weiss, Jason T. Wright
Information Systems and Engineering Management Research Publications
We present a high-precision radial velocity (RV) survey of 719 FGKM stars, which host 164 known exoplanets and 14 newly discovered or revised exoplanets and substellar companions. This catalog updated the orbital parameters of known exoplanets and long-period candidates, some of which have decades-longer observational baselines than they did upon initial detection. The newly discovered exoplanets range from warm sub-Neptunes and super-Earths to cold gas giants. We present the catalog sample selection criteria, as well as over 100,000 RV measurements, which come from the Keck-HIRES, APF-Levy, and Lick-Hamilton spectrographs. We introduce the new RV search pipeline RVSearch (https://california-planet-search.github.io/rvsearch/) that we …
Precise Transit And Radial-Velocity Characterization Of A Resonant Pair: The Warm Jupiter Toi-216c And Eccentric Warm Neptune Toi-216b, R. I. Dawson, C. X. Huang, R. Brahm, K. A. Collins, M. J. Hobson, A. Jordán, J. Dong, J. Korth, T. Trifonov, L. Abe, A. Agabi, I. Bruni, R. P. Butler, M. Barbieri, K. I. Collins, D. M. Conti, J. D. Crane, N. Crouzet, G. Dransfield, P. Evans, N. Espinoza, T. Gan, T. Guillot, T. Henning, J. J. Lissauer, Eric L. N. Jensen, W. M. Sainte, D. Mékarnia, G. Myers, S. Nandakumar, H. M. Relles, P. Sarkis, P. Torres, S. Shectman, F.-X. Schmider, A. Shporer, C. Stockdale, J. Teske, A. H. M. J. Triaud, S. X. Wang, C. Ziegler, G. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. Winn, J. M. Jenkins, L. G. Bouma, J. A. Burt, D. Charbonneau, A. M. Levine, S. Mcdermott, B. Mclean, M. E. Rose, A. Vanderburg, B. Wohler
Precise Transit And Radial-Velocity Characterization Of A Resonant Pair: The Warm Jupiter Toi-216c And Eccentric Warm Neptune Toi-216b, R. I. Dawson, C. X. Huang, R. Brahm, K. A. Collins, M. J. Hobson, A. Jordán, J. Dong, J. Korth, T. Trifonov, L. Abe, A. Agabi, I. Bruni, R. P. Butler, M. Barbieri, K. I. Collins, D. M. Conti, J. D. Crane, N. Crouzet, G. Dransfield, P. Evans, N. Espinoza, T. Gan, T. Guillot, T. Henning, J. J. Lissauer, Eric L. N. Jensen, W. M. Sainte, D. Mékarnia, G. Myers, S. Nandakumar, H. M. Relles, P. Sarkis, P. Torres, S. Shectman, F.-X. Schmider, A. Shporer, C. Stockdale, J. Teske, A. H. M. J. Triaud, S. X. Wang, C. Ziegler, G. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. Winn, J. M. Jenkins, L. G. Bouma, J. A. Burt, D. Charbonneau, A. M. Levine, S. Mcdermott, B. Mclean, M. E. Rose, A. Vanderburg, B. Wohler
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TOI-216 hosts a pair of warm, large exoplanets discovered by the TESS mission. These planets were found to be in or near the 2:1 resonance, and both of them exhibit transit timing variations (TTVs). Precise characterization of the planets' masses and radii, orbital properties, and resonant behavior can test theories for the origins of planets orbiting close to their stars. Previous characterization of the system using the first six sectors of TESS data suffered from a degeneracy between planet mass and orbital eccentricity. Radial-velocity measurements using HARPS, FEROS, and the Planet Finder Spectrograph break that degeneracy, and an expanded TTV …
Tess Delivers Five New Hot Giant Planets Orbiting Bright Stars From The Full-Frame Images, J. E. Rodriguez, S. N. Quinn, G. Zhou, A. Vanderburg, L. D. Nielsen, R. A. Wittenmyer, R. Brahm, P. A. Reed, C. X. Huang, S. Vach, D. R. Ciardi, R. J. Oelkers, K. G. Stassun, C. Hellier, B. S. Gaudi, J. D. Eastman, K. A. Collins, A. Bieryla, S. Christian, D. W. Latham, I. Carleo, D. J. Wright, E. Matthews, E. J. Gonzales, C. Ziegler, C. D. Dressing, S. B. Howell, T.-G. Tan, J. Wittrock, P. Plavchan, K. K. Mcleod, D. Baker, G. Wang, D. J. Radford, R. P. Schwarz, M. Esposito, G. R. Ricker, R. K. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, B. Addison, D. R. Anderosn, T. Barclay, T. G. Beatty, P. Berlind, F. Bouchy, M. Bowen, B. P. Bowler, C. E. Brasseur, C. Briceño, D. A. Caldwell, M. L. Calkins, S. Cartwright, P. Chaturvedi, G. Chaverot, S. Chimaladinne, J. L. Christiansen, K. I. Collins, I. J. M. Crossfield, K. Eastridge, N. Espinoza, G. A. Esquerdo, D. L. Felix, T. Fenske, W. Fong, T. Gan, S. Giacalone, H. Gill, L. Gordon, A. Granados, N. Grieves, E. W. Guenther, N. Guerrero, T. Henning, C. E. Henze, K. Hesse, M. J. Hobson, J. Horner, D. J. James, Eric L. N. Jensen, M. Jimenez, A. Jordán, S. R. Kane, J. Kielkopf, K. Kim, R. B. Kuhn, N. Latouf, N. M. Law, A. M. Levine, M. B. Lund, A. W. Mann, S. Mao, R. A. Matson, M. W. Mengel, J. Mink, P. Newman, T. O’Dwyer, J. Okumura, E. Palle, J. Pepper, E. V. Quintana, P. Sarkis, A. B. Savel, J. E. Schlieder, C. Schnaible, A. Shporer, R. Sefako, J. V. Seidel, R. J. Siverd, B. Skinner, M. Stalport, D. J. Stevens, C. Stibbards, C. G. Tinney, R. G. West, D. A. Yahalomi, H. Zhang
Tess Delivers Five New Hot Giant Planets Orbiting Bright Stars From The Full-Frame Images, J. E. Rodriguez, S. N. Quinn, G. Zhou, A. Vanderburg, L. D. Nielsen, R. A. Wittenmyer, R. Brahm, P. A. Reed, C. X. Huang, S. Vach, D. R. Ciardi, R. J. Oelkers, K. G. Stassun, C. Hellier, B. S. Gaudi, J. D. Eastman, K. A. Collins, A. Bieryla, S. Christian, D. W. Latham, I. Carleo, D. J. Wright, E. Matthews, E. J. Gonzales, C. Ziegler, C. D. Dressing, S. B. Howell, T.-G. Tan, J. Wittrock, P. Plavchan, K. K. Mcleod, D. Baker, G. Wang, D. J. Radford, R. P. Schwarz, M. Esposito, G. R. Ricker, R. K. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, B. Addison, D. R. Anderosn, T. Barclay, T. G. Beatty, P. Berlind, F. Bouchy, M. Bowen, B. P. Bowler, C. E. Brasseur, C. Briceño, D. A. Caldwell, M. L. Calkins, S. Cartwright, P. Chaturvedi, G. Chaverot, S. Chimaladinne, J. L. Christiansen, K. I. Collins, I. J. M. Crossfield, K. Eastridge, N. Espinoza, G. A. Esquerdo, D. L. Felix, T. Fenske, W. Fong, T. Gan, S. Giacalone, H. Gill, L. Gordon, A. Granados, N. Grieves, E. W. Guenther, N. Guerrero, T. Henning, C. E. Henze, K. Hesse, M. J. Hobson, J. Horner, D. J. James, Eric L. N. Jensen, M. Jimenez, A. Jordán, S. R. Kane, J. Kielkopf, K. Kim, R. B. Kuhn, N. Latouf, N. M. Law, A. M. Levine, M. B. Lund, A. W. Mann, S. Mao, R. A. Matson, M. W. Mengel, J. Mink, P. Newman, T. O’Dwyer, J. Okumura, E. Palle, J. Pepper, E. V. Quintana, P. Sarkis, A. B. Savel, J. E. Schlieder, C. Schnaible, A. Shporer, R. Sefako, J. V. Seidel, R. J. Siverd, B. Skinner, M. Stalport, D. J. Stevens, C. Stibbards, C. G. Tinney, R. G. West, D. A. Yahalomi, H. Zhang
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We present the discovery and characterization of five hot and warm Jupiters—TOI-628 b (TIC 281408474; HD 288842), TOI-640 b (TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC 409794137), and TOI-1601 b (TIC 139375960)—based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (RP = 1.01–1.77 RJ) and have masses that range from 0.85 to 6.33 MJ. The host stars of these systems …
Speckle Imaging Characterization Of Radial Velocity Exoplanet Systems, Paul A. Dalba, Stephen R. Kane, Steve B. Howell, Elliott P. Horch, Zhexing Li, Lea A. Hirsch, Jennifer Burt, Timothy D. Brandt, Teo Močnik, Gregory W. Henry, Mark E. Everett, Lee J. Rosenthal, Andrew W. Howard
Speckle Imaging Characterization Of Radial Velocity Exoplanet Systems, Paul A. Dalba, Stephen R. Kane, Steve B. Howell, Elliott P. Horch, Zhexing Li, Lea A. Hirsch, Jennifer Burt, Timothy D. Brandt, Teo Močnik, Gregory W. Henry, Mark E. Everett, Lee J. Rosenthal, Andrew W. Howard
Information Systems and Engineering Management Research Publications
We conducted speckle imaging observations of 53 stellar systems that were members of long-term radial velocity (RV) monitoring campaigns and exhibited substantial accelerations indicative of planetary or stellar companions in wide orbits. Our observations were made with blue and red filters using the Differential Speckle Survey Instrument at Gemini-South and the NN-Explore Exoplanet Stellar Speckle Imager at the WIYN telescope. The speckle imaging identifies eight luminous companions within 2'' of the primary stars. In three of these systems—HD 1388, HD 87359, and HD 104304—the properties of the imaged companion are consistent with the RV measurements, suggesting that these companions may …
Physical Parameters Of The Multiplanet Systems Hd 106315 And Gj 9827*†, Molly R. Kosiarek, David A. Berardo, Ian J. M. Crossfield, Cesar Laguna, Caroline Piaulet, Joseph M. Akana Murphy, Steve B. Howell, Gregory W. Henry, Howard Isaacson, Benjamin Fulton, Lauren M. Weiss, Erik A. Petigura, Aida Behmard, Lea A. Hirsch, Johanna Teske, Jennifer A. Burt, Sean M. Mills, Ashley Chontos, Teo Močnik, Andrew W. Howard, Michael Werner, John H. Livingston, Jessica Krick, Charles Beichman, Varoujan Gorjian, Laura Kreidberg, Caroline Morley, Jessie L. Christiansen, Farisa Y. Morales, Nicholas J. Scott, Jeffrey D. Crane, Sharon Xuesong Wang, Stephen A. Shectman, Lee J. Rosenthal, Samuel K. Grunblatt, Ryan A. Rubenzahl, Paul A. Dalba, Steven Giacalone, Chiara Dane Villanueva, Qingtian Liu, Fei Dai, Michelle L. Hill, Malena Rice, Stephen R. Kane, Andrew W. Mayo
Physical Parameters Of The Multiplanet Systems Hd 106315 And Gj 9827*†, Molly R. Kosiarek, David A. Berardo, Ian J. M. Crossfield, Cesar Laguna, Caroline Piaulet, Joseph M. Akana Murphy, Steve B. Howell, Gregory W. Henry, Howard Isaacson, Benjamin Fulton, Lauren M. Weiss, Erik A. Petigura, Aida Behmard, Lea A. Hirsch, Johanna Teske, Jennifer A. Burt, Sean M. Mills, Ashley Chontos, Teo Močnik, Andrew W. Howard, Michael Werner, John H. Livingston, Jessica Krick, Charles Beichman, Varoujan Gorjian, Laura Kreidberg, Caroline Morley, Jessie L. Christiansen, Farisa Y. Morales, Nicholas J. Scott, Jeffrey D. Crane, Sharon Xuesong Wang, Stephen A. Shectman, Lee J. Rosenthal, Samuel K. Grunblatt, Ryan A. Rubenzahl, Paul A. Dalba, Steven Giacalone, Chiara Dane Villanueva, Qingtian Liu, Fei Dai, Michelle L. Hill, Malena Rice, Stephen R. Kane, Andrew W. Mayo
Information Systems and Engineering Management Research Publications
HD 106315 and GJ 9827 are two bright, nearby stars that host multiple super-Earths and sub-Neptunes discovered by K2 that are well suited for atmospheric characterization. We refined the planets' ephemerides through Spitzer transits, enabling accurate transit prediction required for future atmospheric characterization through transmission spectroscopy. Through a multiyear high-cadence observing campaign with Keck/High Resolution Echelle Spectrometer and Magellan/Planet Finder Spectrograph, we improved the planets' mass measurements in anticipation of Hubble Space Telescope transmission spectroscopy. For GJ 9827, we modeled activity-induced radial velocity signals with a Gaussian process informed by the Calcium II H&K lines in order to more accurately …
A Collage Of Small Planets From The Lick–Carnegie Exoplanet Survey: Exploring The Super-Earth And Sub-Neptune Mass Regime, Jennifer Burt, Fabo Feng, Bradford Holden, Eric E. Mamajek, Chelsea X. Huang, Mickey M. Rosentha, Songhu Wang, R. Paul Butler, Steve S. Vogt, Gregory Laughlin, Gregory W. Henry, Johanna K. Teske, Sharon X. Wang, Jeffrey D. Crane, Steve A. Shectman
A Collage Of Small Planets From The Lick–Carnegie Exoplanet Survey: Exploring The Super-Earth And Sub-Neptune Mass Regime, Jennifer Burt, Fabo Feng, Bradford Holden, Eric E. Mamajek, Chelsea X. Huang, Mickey M. Rosentha, Songhu Wang, R. Paul Butler, Steve S. Vogt, Gregory Laughlin, Gregory W. Henry, Johanna K. Teske, Sharon X. Wang, Jeffrey D. Crane, Steve A. Shectman
Information Systems and Engineering Management Research Publications
Analysis of new precision radial velocity (RV) measurements from the Lick Automated Planet Finder and Keck HIRES has yielded the discovery of three new exoplanet candidates orbiting the nearby stars HD 190007 and HD 216520. We also report new velocities from the APF and the Planet Finder Spectrograph and updated orbital fits for the known exoplanet host stars GJ 686 and HD 180617. Of the newly discovered planets, HD 190007 b has a period of P = 11.72 days, an RV semiamplitude of K = 5.64 ± 0.55 m s−1, a minimum mass of Mpl = 16.46 ± 1.66 M⊕, …
Kelt-25 B And Kelt-26 B: A Hot Jupiter And A Substellar Companion Transiting Young A Stars Observed By Tess, R. R. Martínez, R. R. Martínez, B. S. Gaudi, J. E. Rodriguez, G. Zhou, J. Labadie-Bartz, S. N. Quinn, K. Penev, T.-G. Tan, D. W. Latham, L. A. Paredes, J. F. Kielkopf, B. Addison, D. J. Wright, J. Teske, S. B. Howell, D. Ciardi, C. Ziegler, K. G. Stassun, M. C. Johnson, J. D. Eastman, R. J. Siverd, T. G. Beatty, L. Bouma, T. Bedding, J. Pepper, J. Winn, M. B. Lund, S. Villanueva Jr., D. J. Stevens, Eric L.N. Jensen, C. Kilby, J. D. Crane, A. Tokovinin, M. E. Everett, C. G. Tinney, M. Fausnaugh, David H. Cohen, D. Bayliss, A. Bieryla, P. A. Cargile, K. A. Collins, D. M. Conti, K. D. Colón, I. A. Curtis, D. L. Depoy, P. Evans, D. L. Feliz, J. Gregorio, J. Rothenberg, D. J. James, M. D. Joner, R. B. Kuhn, M. Manner, S. Khakpash, J. L. Marshall, K. K. Mcleod, M. T. Penny, P. A. Reed, H. M. Relles, D. C. Stephens, C. Stockdale, M. Trueblood, P. Trueblood, X. Yao, R. Zambelli, R. Vanderspek, S. Seager, J. M. Jenkins, T. J. Henry, H.-S. James, W.-C. Jao, S. X. Wang, P. Butler, I. Thompson, S. Schectman, R. Wittenmyer, B. P. Bowler, J. Horner, S. R. Kane, M. W. Mengel, T. D. Morton, J. Okumura, P. Plavchan, H. Zhang, N. J. Scott, R. A. Matson, A. W. Mann, D. Dragomir, M. Günther, E. B. Ting, A. Glidden, E. V. Quintana
Kelt-25 B And Kelt-26 B: A Hot Jupiter And A Substellar Companion Transiting Young A Stars Observed By Tess, R. R. Martínez, R. R. Martínez, B. S. Gaudi, J. E. Rodriguez, G. Zhou, J. Labadie-Bartz, S. N. Quinn, K. Penev, T.-G. Tan, D. W. Latham, L. A. Paredes, J. F. Kielkopf, B. Addison, D. J. Wright, J. Teske, S. B. Howell, D. Ciardi, C. Ziegler, K. G. Stassun, M. C. Johnson, J. D. Eastman, R. J. Siverd, T. G. Beatty, L. Bouma, T. Bedding, J. Pepper, J. Winn, M. B. Lund, S. Villanueva Jr., D. J. Stevens, Eric L.N. Jensen, C. Kilby, J. D. Crane, A. Tokovinin, M. E. Everett, C. G. Tinney, M. Fausnaugh, David H. Cohen, D. Bayliss, A. Bieryla, P. A. Cargile, K. A. Collins, D. M. Conti, K. D. Colón, I. A. Curtis, D. L. Depoy, P. Evans, D. L. Feliz, J. Gregorio, J. Rothenberg, D. J. James, M. D. Joner, R. B. Kuhn, M. Manner, S. Khakpash, J. L. Marshall, K. K. Mcleod, M. T. Penny, P. A. Reed, H. M. Relles, D. C. Stephens, C. Stockdale, M. Trueblood, P. Trueblood, X. Yao, R. Zambelli, R. Vanderspek, S. Seager, J. M. Jenkins, T. J. Henry, H.-S. James, W.-C. Jao, S. X. Wang, P. Butler, I. Thompson, S. Schectman, R. Wittenmyer, B. P. Bowler, J. Horner, S. R. Kane, M. W. Mengel, T. D. Morton, J. Okumura, P. Plavchan, H. Zhang, N. J. Scott, R. A. Matson, A. W. Mann, D. Dragomir, M. Günther, E. B. Ting, A. Glidden, E. V. Quintana
Physics & Astronomy Faculty Works
We present the discoveries of KELT-25 b (TIC 65412605, TOI-626.01) and KELT-26 b (TIC 160708862, TOI-1337.01), two transiting companions orbiting relatively bright, early A stars. The transit signals were initially detected by the KELT survey and subsequently confirmed by Transiting Exoplanet Survey Satellite (TESS) photometry. KELT-25 b is on a 4.40 day orbit around the V = 9.66 star CD-24 5016 (${T}_{\mathrm{eff}}={8280}_{-180}^{+440}$ K, Msstarf = ${2.18}_{-0.11}^{+0.12}$ M⊙), while KELT-26 b is on a 3.34 day orbit around the V = 9.95 star HD 134004 (${T}_{\mathrm{eff}}$ = ${8640}_{-240}^{+500}$K, Msstarf = ${1.93}_{-0.16}^{+0.14}$M⊙), which is likely an Am star. We have confirmed the …
Expres. I. Hd 3651 As An Ideal Rv Benchmark, John M. Brewer, Debra A. Fischer, Ryan T. Blackman, Samuel H. C. Cabot, Allen B. Davis, Gregory Laughlin, Christopher Leet, J. M. Joel Ong, Ryan R. Petersburg, Andrew E. Szymkowiak, Lily L. Zhao, Gregory W. Henry, Joe Llama
Expres. I. Hd 3651 As An Ideal Rv Benchmark, John M. Brewer, Debra A. Fischer, Ryan T. Blackman, Samuel H. C. Cabot, Allen B. Davis, Gregory Laughlin, Christopher Leet, J. M. Joel Ong, Ryan R. Petersburg, Andrew E. Szymkowiak, Lily L. Zhao, Gregory W. Henry, Joe Llama
Information Systems and Engineering Management Research Publications
The next generation of exoplanet-hunting spectrographs should deliver up to an order of magnitude improvement in radial velocity (RV) precision over the standard 1 ${\rm{m}}\ {{\rm{s}}}^{-1}$ state-of-the-art spectrographs. This advance is critical for enabling the detection of Earth-mass planets around Sun-like stars. New calibration techniques such as laser frequency combs and stabilized etalons ensure that the instrumental stability is well characterized. However, additional sources of error include stellar noise, undetected short-period planets, and telluric contamination. To understand and ultimately mitigate error sources, the contributing terms in the error budget must be isolated to the greatest extent possible. Here, we introduce …
Toi-1235 B: A Keystone Super-Earth For Testing Radius Valley Emergence Models Around Early M Dwarfs, R. Cloutier, J. E. Rodriguez, J. Irwin, D. Charbonneau, K. G. Stassun, A. Mortier, D. W. Latham, H. Isaacson, A. W. Howard, S. Udry, T. G. Wilson, C. A. Watson, M. Pinamonti, F. Lienhard, P. Giacobbe, P. Guerra, K. A. Collins, A. Bieryla, G. A. Esquerdo, E. Matthews, R. A. Matson, S. B. Howell, E. Furlan, I. J. M. Crossfield, J. G. Winters, C. Nava, K. Ment, E. D. Lopez, G. Ricker, R. Vanderspek, S. Seager, J. M. Jenkins, E. B. Ting, P. Tenenbaum, A. Sozzetti, L. Sha, D. Ségransan, J. E. Schlieder, D. Sasselov, A. Roy, P. Robertson, K. Rice, E. Poretti, G. Piotto, D. Phillips, J. Pepper, F. Pepe, E. Molinari, T. Mocnik, G. Micela, M. Mayor, A. F. Martinez Fiorenzano, F. Mallia, J. Lubin, C. Lovis, M. López-Morales, M. R. Kosiarek, J. F. Kielkopf, S. R. Kane, Eric L.N. Jensen, G. Isopi, D. Huber, M. L. Hill, A. Harutyunyan, E. Gonzales, S. Giacalone, A. Ghedina, A. Ercolino, X. Dumusque, C. D. Dressing, M. Damasso, P. A. Dalba, R. Cosentino, D. M. Conti, K. D. Colón, K. I. Collins, A. Collier Cameron, D. Ciardi, J. Christiansen, A. Chontos, M. Cecconi, D. A. Caldwell, C. Burke, L. Buchhave, C. Beichman, A. Behmard, C. Beard, J. M. Akana Murphy
Toi-1235 B: A Keystone Super-Earth For Testing Radius Valley Emergence Models Around Early M Dwarfs, R. Cloutier, J. E. Rodriguez, J. Irwin, D. Charbonneau, K. G. Stassun, A. Mortier, D. W. Latham, H. Isaacson, A. W. Howard, S. Udry, T. G. Wilson, C. A. Watson, M. Pinamonti, F. Lienhard, P. Giacobbe, P. Guerra, K. A. Collins, A. Bieryla, G. A. Esquerdo, E. Matthews, R. A. Matson, S. B. Howell, E. Furlan, I. J. M. Crossfield, J. G. Winters, C. Nava, K. Ment, E. D. Lopez, G. Ricker, R. Vanderspek, S. Seager, J. M. Jenkins, E. B. Ting, P. Tenenbaum, A. Sozzetti, L. Sha, D. Ségransan, J. E. Schlieder, D. Sasselov, A. Roy, P. Robertson, K. Rice, E. Poretti, G. Piotto, D. Phillips, J. Pepper, F. Pepe, E. Molinari, T. Mocnik, G. Micela, M. Mayor, A. F. Martinez Fiorenzano, F. Mallia, J. Lubin, C. Lovis, M. López-Morales, M. R. Kosiarek, J. F. Kielkopf, S. R. Kane, Eric L.N. Jensen, G. Isopi, D. Huber, M. L. Hill, A. Harutyunyan, E. Gonzales, S. Giacalone, A. Ghedina, A. Ercolino, X. Dumusque, C. D. Dressing, M. Damasso, P. A. Dalba, R. Cosentino, D. M. Conti, K. D. Colón, K. I. Collins, A. Collier Cameron, D. Ciardi, J. Christiansen, A. Chontos, M. Cecconi, D. A. Caldwell, C. Burke, L. Buchhave, C. Beichman, A. Behmard, C. Beard, J. M. Akana Murphy
Physics & Astronomy Faculty Works
Small planets on close-in orbits tend to exhibit envelope mass fractions of either effectively zero or up to a few percent depending on their size and orbital period. Models of thermally driven atmospheric mass loss and of terrestrial planet formation in a gas-poor environment make distinct predictions regarding the location of this rocky/nonrocky transition in period–radius space. Here we present the confirmation of TOI-1235 b (P = 3.44 days, ${r}_{{\rm{p}}}={1.738}_{-0.076}^{+0.087}$ ${R}_{\oplus }$), a planet whose size and period are intermediate between the competing model predictions, thus making the system an important test case for emergence models of the rocky/nonrocky transition …
A Pair Of Tess Planets Spanning The Radius Valley Around The Nearby Mid-M Dwarf Ltt 3780, R. Cloutier, J. D. Eastman, J. E. Rodriguez, N. Astudillo-Defru, X. Bonfils, A. Mortier, C. A. Watson, M. Stalport, M. Pinamonti, F. Lienhard, A. Harutyunyan, M. Damasso, D. W. Latham, K. A. Collins, R. Massey, J. Irwin, J. G. Winters, D. Charbonneau, C. Ziegler, E. Matthews, I. J. M. Crossfield, L. Kreidberg, S. N. Quinn, G. Ricker, R. Vanderspek, S. Seager, J. Winn, J. M. Jenkins, M. Vezie, S. Udry, J. D. Twicken, P. Tenenbaum, A. Sozzetti, D. Ségransan, J. E. Schlieder, D. Sasselov, N. C. Santos, K. Rice, B. V. Rackham, E. Poretti, G. Piotto, D. Phillips, F. Pepe, E. Molinari, L. Mignon, G. Micela, C. Melo, J. R. De Medeiros, M. Mayor, R. A. Matson, A. F. Martinez Fiorenzano, A. W. Mann, A. Magazzú, C. Lovis, M. López-Morales, E. Lopez, J. J. Lissauer, S. Lépine, N. Law, J. F. Kielkopf, J. A. Johnson, Eric L.N. Jensen, S. B. Howell, E. Gonzales, A. Ghedina, T. Forveille, P. Figueira, X. Dumusque, C. D. Dressing, R. Doyon, R. F. Díaz, L. Di Fabrizio, X. Delfosse, R. Cosentino, D. M. Conti, K. I. Collins, A. C. Cameron, D. Ciardi, D. A. Caldwell, C. Burke, L. Buchhave, C. Briceño, P. Boyd, F. Bouchy, C. Beichman, É. Artigau, J. M. Almenara
A Pair Of Tess Planets Spanning The Radius Valley Around The Nearby Mid-M Dwarf Ltt 3780, R. Cloutier, J. D. Eastman, J. E. Rodriguez, N. Astudillo-Defru, X. Bonfils, A. Mortier, C. A. Watson, M. Stalport, M. Pinamonti, F. Lienhard, A. Harutyunyan, M. Damasso, D. W. Latham, K. A. Collins, R. Massey, J. Irwin, J. G. Winters, D. Charbonneau, C. Ziegler, E. Matthews, I. J. M. Crossfield, L. Kreidberg, S. N. Quinn, G. Ricker, R. Vanderspek, S. Seager, J. Winn, J. M. Jenkins, M. Vezie, S. Udry, J. D. Twicken, P. Tenenbaum, A. Sozzetti, D. Ségransan, J. E. Schlieder, D. Sasselov, N. C. Santos, K. Rice, B. V. Rackham, E. Poretti, G. Piotto, D. Phillips, F. Pepe, E. Molinari, L. Mignon, G. Micela, C. Melo, J. R. De Medeiros, M. Mayor, R. A. Matson, A. F. Martinez Fiorenzano, A. W. Mann, A. Magazzú, C. Lovis, M. López-Morales, E. Lopez, J. J. Lissauer, S. Lépine, N. Law, J. F. Kielkopf, J. A. Johnson, Eric L.N. Jensen, S. B. Howell, E. Gonzales, A. Ghedina, T. Forveille, P. Figueira, X. Dumusque, C. D. Dressing, R. Doyon, R. F. Díaz, L. Di Fabrizio, X. Delfosse, R. Cosentino, D. M. Conti, K. I. Collins, A. C. Cameron, D. Ciardi, D. A. Caldwell, C. Burke, L. Buchhave, C. Briceño, P. Boyd, F. Bouchy, C. Beichman, É. Artigau, J. M. Almenara
Physics & Astronomy Faculty Works
We present the confirmation of two new planets transiting the nearby mid-M dwarf LTT 3780 (TIC 36724087, TOI-732, V = 13.07, K s = 8.204, R s = 0.374 R ⊙, M s = 0.401 M ⊙, d = 22 pc). The two planet candidates are identified in a single Transiting Exoplanet Survey Satellite sector and validated with reconnaissance spectroscopy, ground-based photometric follow-up, and high-resolution imaging. With measured orbital periods of P b = 0.77, P c = 12.25 days and sizes r p,b = 1.33 ± 0.07, r p,c = 2.30 ± 0.16 R ⊕, the two planets span …
Absolute Dimensions Of The Unevolved F-Type Eclipsing Binary Bt Vulpeculae, Guillermo Torres, Claud H. Sandberg Lacy, Francis C. Fekel, Matthew W. Muterspaugh
Absolute Dimensions Of The Unevolved F-Type Eclipsing Binary Bt Vulpeculae, Guillermo Torres, Claud H. Sandberg Lacy, Francis C. Fekel, Matthew W. Muterspaugh
Information Systems and Engineering Management Research Publications
We report extensive differential V-band photometry and high-resolution spectroscopy for the 1.14 day, detached, double-lined eclipsing binary BT Vul (F0+F7). Our radial-velocity monitoring and light-curve analysis lead to absolute masses and radii of ${M}_{1}=1.5439\pm 0.0098\,{{ \mathcal M }}_{\odot }^{{\rm{N}}}$ and ${R}_{1}=1.536\pm 0.018\,{{ \mathcal R }}_{\odot }^{{\rm{N}}}$ for the primary, and ${M}_{2}=1.2196\pm 0.0080\,{{ \mathcal M }}_{\odot }^{{\rm{N}}}$ and ${R}_{2}=1.151\pm 0.029\,{{ \mathcal R }}_{\odot }^{{\rm{N}}}$ for the secondary. The effective temperatures are 7270 ± 150 K and 6260 ± 180 K, respectively. Both stars are rapid rotators, and the orbit is circular. A comparison with stellar evolution models from the MESA Isochrones …
Updated Parameters And A New Transmission Spectrum Of Hd 97658b, Xueying Guo, Ian J. M. Crossfield, Diana Dragomir, Molly Kosiarek, Joshua Lothringer, Thomas Mikal-Evans, Lee J. Rosenthal, Björn Benneke, Heather Knutson, Paul A. Dalba, Eliza M. R. Kempton, Gregory W. Henry, Peter R. Mccullough, Travis Barman, Sarah C. Blunt, Ashley Chontos, Jonathan J. Fortney, Benjamin Fulton, Lea A. Hirsch, Andrew W. Howard, Howard Isaacson, Jaymie Matthews, Teo Mocnik, Caroline Morley, Erik A. Petigura, Lauren M. Weiss
Updated Parameters And A New Transmission Spectrum Of Hd 97658b, Xueying Guo, Ian J. M. Crossfield, Diana Dragomir, Molly Kosiarek, Joshua Lothringer, Thomas Mikal-Evans, Lee J. Rosenthal, Björn Benneke, Heather Knutson, Paul A. Dalba, Eliza M. R. Kempton, Gregory W. Henry, Peter R. Mccullough, Travis Barman, Sarah C. Blunt, Ashley Chontos, Jonathan J. Fortney, Benjamin Fulton, Lea A. Hirsch, Andrew W. Howard, Howard Isaacson, Jaymie Matthews, Teo Mocnik, Caroline Morley, Erik A. Petigura, Lauren M. Weiss
Information Systems and Engineering Management Research Publications
Recent years have seen increasing interest in the characterization of sub-Neptune-sized planets because of their prevalence in the Galaxy, contrasted with their absence in our solar system. HD 97658 is one of the brightest stars hosting a planet of this kind, and we present the transmission spectrum of this planet by combining four Hubble Space Telescope transits, 12 Spitzer/IRAC transits, and eight MOST transits of this system. Our transmission spectrum has a higher signal-to-noise ratio than those from previous works, and the result suggests that the slight increase in transit depth from wavelength 1.1–1.7 μm reported in previous works on …
Orbital Refinement And Stellar Properties For The Hd 9446, Hd 43691, And Hd 179079 Planetary Systems, Michelle L. Hill, Teo Močnik, Stephen R. Kane, Gregory W. Henry, Joshua Pepper, Natalie R. Hinkel, Paul A. Dalba, Benjamin Fulton, Keivan Stassun, Lee J. Rosenthal, Andrew W. Howard, Steve B. Howell, Mark E. Everett, Tabetha S. Boyajian, Debra A. Fischer, Joseph E. Rodriguez, Thomas G. Beatty, David J. James
Orbital Refinement And Stellar Properties For The Hd 9446, Hd 43691, And Hd 179079 Planetary Systems, Michelle L. Hill, Teo Močnik, Stephen R. Kane, Gregory W. Henry, Joshua Pepper, Natalie R. Hinkel, Paul A. Dalba, Benjamin Fulton, Keivan Stassun, Lee J. Rosenthal, Andrew W. Howard, Steve B. Howell, Mark E. Everett, Tabetha S. Boyajian, Debra A. Fischer, Joseph E. Rodriguez, Thomas G. Beatty, David J. James
Information Systems and Engineering Management Research Publications
The Transit Ephemeris Refinement and Monitoring Survey is a project that aims to detect transits of intermediate-long period planets by refining orbital parameters of the known radial velocity planets using additional data from ground-based telescopes, calculating a revised transit ephemeris for the planet, then monitoring the planet host star during the predicted transit window. Here we present the results from three systems that had high probabilities of transiting planets: HD 9446 b and c, HD 43691 b, and HD 179079 b. We provide new radial velocity (RV) measurements that are then used to improve the orbital solution for the known …
Optical And X-Ray Studies Of 10 X-Ray-Selected Cataclysmic Binaries, John R. Thorstensen, Jules Halpern
Optical And X-Ray Studies Of 10 X-Ray-Selected Cataclysmic Binaries, John R. Thorstensen, Jules Halpern
Dartmouth Scholarship
We report on ground-based optical observations of 10 cataclysmic binaries that were discovered through their X-ray emission. Time-resolved radial velocity spectroscopy yields unambiguous orbital periods for eight objects and ambiguous results for the remaining two. The orbital periods range from 87 minutes to 9.38 hr. We also obtained time-series optical photometry for six targets, four of which have coherent pulsations. These periods are 1218 s for 1RXS J045707.4+452751, 628 s for AX J1740.2–2903, 477 s for AX J1853.3–0128, and 935 s for IGR J19267+1325. A total of seven of the sources have coherent oscillations in X-rays or optical, indicating that …
A Detailed Kinematic Map Of Cassiopeia A'S Optical Main Shell And Outer High-Velocity Ejecta, Dan Milisavljevic, Robert A. Fesen
A Detailed Kinematic Map Of Cassiopeia A'S Optical Main Shell And Outer High-Velocity Ejecta, Dan Milisavljevic, Robert A. Fesen
Dartmouth Scholarship
We present three-dimensional (3D) kinematic reconstructions of optically emitting material in the young Galactic supernova remnant Cassiopeia A (Cas A). These Doppler maps have the highest spectral and spatial resolutions of any previous survey of Cas A and represent the most complete catalog of its optically emitting material to date. We confirm that the bulk of Cas A’s optically bright ejecta populate a torus-like geometry tilted approximately 30◦ with respect to the plane of the sky with a − 4000 to +6000 km s−1 radial velocity asymmetry. Near-tangent viewing angle effects and an inhomogeneous surrounding circumstellar material/ interstellar medium environment …
Subaru High-Resolution Spectroscopy Of Star G In The Tycho Supernova Remnant, Wolfgang E. Kerzendorf, Brian P. Schmidt, M. Asplund, Ken'ichi Nomoto, Ph. Podsiadlowski, Anna Frebel, Robert A. Fesen, David Yong
Subaru High-Resolution Spectroscopy Of Star G In The Tycho Supernova Remnant, Wolfgang E. Kerzendorf, Brian P. Schmidt, M. Asplund, Ken'ichi Nomoto, Ph. Podsiadlowski, Anna Frebel, Robert A. Fesen, David Yong
Dartmouth Scholarship
It is widely believed that Type Ia supernovae (SNe Ia) originate in binary systems where a white dwarf accretes material from a companion star until its mass approaches the Chandrasekhar mass and carbon is ignited in the white dwarf's core. This scenario predicts that the donor star should survive the supernova (SNe) explosion, providing an opportunity to understand the progenitors of SNe Ia. In this paper, we argue that rotation is a generic signature expected of most nongiant donor stars that is easily measurable. Ruiz-Lapuente et al. examined stars in the center of the remnant of SN 1572 (Tycho SN) …
De Canum Venaticorum: A Bright, Eclipsing Red Dwarf–White Dwarf Binary, E. J. M. Van Den Besselaar, R. Greimel, L. Morales-Rueda, G. Nelemans, J. R. Thorstensen
De Canum Venaticorum: A Bright, Eclipsing Red Dwarf–White Dwarf Binary, E. J. M. Van Den Besselaar, R. Greimel, L. Morales-Rueda, G. Nelemans, J. R. Thorstensen
Dartmouth Scholarship
Close white dwarf - red dwarf binaries must have gone through a common-envelope phase during their evolution. DE CVn is a detached white dwarf - red dwarf binary with a relatively short (~8.7 hours) orbital period. Its brightness and the presence of eclipses makes this system ideal for a more detailed study. From a study of photometric and spectroscopic observations of DE CVn we derive the system parameters which we discuss in the frame work of common-envelope evolution. Photometric observations of the eclipses are used to determine an accurate ephemeris. From a model fit to an average low-resolution spectrum of …
Hs 2331+3905: The Cataclysmic Variable That Has It All, S. Araujo-Betancor, B. T. Gänsicke, H.-J. Hagen, T. R. Marsh, E T. Harlaftis, J Thorstensen
Hs 2331+3905: The Cataclysmic Variable That Has It All, S. Araujo-Betancor, B. T. Gänsicke, H.-J. Hagen, T. R. Marsh, E T. Harlaftis, J Thorstensen
Dartmouth Scholarship
We report detailed follow-up observations of the cataclysmic variable HS 2331+3905, identified as an emission- line object in the Hamburg Quasar Survey. An orbital period of 81.08 min is unambiguously determined from the detection of eclipses in the light curves of HS 2331+3905. A second photometric period is consistently detected at P ≃ 83.38 min, ∼2.8% longer than Porb, which we tentatively relate to the presence of permanent superhumps. High time resolution photometry exhibits short-timescale variability on time scales of ≃5−6 min which we interpret as non-radial white dwarf pulsations, as well as a coherent signal at 1.12 min, which …
A Photometric And Spectroscopic Study Of The Cataclysmic Variable Sx Leonis Minoris In Quiescence And Superoutburst, R. Mark Wagner, John R. Thorstensen, R. K. Honeycutt, S. B. Howell
A Photometric And Spectroscopic Study Of The Cataclysmic Variable Sx Leonis Minoris In Quiescence And Superoutburst, R. Mark Wagner, John R. Thorstensen, R. K. Honeycutt, S. B. Howell
Dartmouth Scholarship
We present CCD imaging, CCD photometry on long and short timescales, and time-resolved spectroscopy of SX LMi, a new SU Ursae Majoris type dwarf nova. The quiescent optical spectrum shows broad double-peaked Balmer, He I, and He II emission lines, similar to other quiescent dwarf novae. Absorption lines from a late-type secondary are not detected. Time-resolved spectra obtained in quiescence reveal radial velocity variations of the Balmer emission lines on a period of 0.06717 ± 0.00011 days, or 96.72 ± 0.16 minutes, with only a slight possibility of a daily cycle-count error. Optical photometry obtained between 1987 and 1991 shows …
The Spectroscopic-Speckle Triple System Hr 6469, Colin D. Scarfe, David J. Barlow, Francis C. Fekel, Richard F. Rees, R. W. Lyons, Charles Thomas Bolton, Harold A. Mcalister, William I. Hartkopf
The Spectroscopic-Speckle Triple System Hr 6469, Colin D. Scarfe, David J. Barlow, Francis C. Fekel, Richard F. Rees, R. W. Lyons, Charles Thomas Bolton, Harold A. Mcalister, William I. Hartkopf
Information Systems and Engineering Management Research Publications
HR 6469 consists of an evolved G star and a close pair of stars, believed to be on the main sequence, the brighter of which is an early F star. Shallow eclipses have been detected in the close pair and the components of the wide system have been resolved over most of the orbit by speckle interferometry (McAlister & Hartkopf, Second Catalog of Interferometric Observations of Binary Stars, Center for High Angular Resolution Astronomy, Contribution No. 2 (CHARA), 1988). This paper presents radial velocities, obtained at the David Dunlap, McDonald, Kitt Peak and Dominion Astrophysical Observatories, for the G star …
Spot On Rs Cvn From Spectroscopy And Photometry, Joel A. Eaton, Gregory W. Henry, Coretta Bell, Albert Okorogu
Spot On Rs Cvn From Spectroscopy And Photometry, Joel A. Eaton, Gregory W. Henry, Coretta Bell, Albert Okorogu
Information Systems and Engineering Management Research Publications
We have used contemporaneous spectra and V light curves to form spot models for RS CVn in 1991 and 1992. More than two spots are needed to fit all the properties of the observations. In fact, moderately small spots (22 x 28 deg in latitude and longitude) having only a slight effect on the rotational light curve were eclipsed in both years, and we find that a collection of 6-8 such moderate spots is required to fit the line profiles in each year. These groups of spots also account naturally for a difference in level of light between the two …
Lithium And Rapid Rotation In Chromospherically Active Single Giants, Francis C. Fekel, Suchitra C. Balachandran
Lithium And Rapid Rotation In Chromospherically Active Single Giants, Francis C. Fekel, Suchitra C. Balachandran
Information Systems and Engineering Management Research Publications
The rotational velocities presently obtained via spectroscopic observations of a group of moderately rapidly rotating, chomospherically active single giants indicate that Gray's (1989) rotostat hypothesis requires modification. Their rapid rotation appears to be due to high Li abundances, and results in increased chromospheric activity. A scenario is projected in which the surface convection zone reaches the rapidly rotating core just as a star begins its first ascent of the giant branch, and dredges both high angular momentum material and freshly synthesized Li to the surface.
Speckle And Spectroscopic Orbits Of The Early A-Type Triple System In Virginis, William I. Hartkopf, Harold A. Mcalister, Xinxing Yang, Francis C. Fekel
Speckle And Spectroscopic Orbits Of The Early A-Type Triple System In Virginis, William I. Hartkopf, Harold A. Mcalister, Xinxing Yang, Francis C. Fekel
Information Systems and Engineering Management Research Publications
Eta Virginis is a bright (V = 3.89) triple system of composite spectral type A2 IV that has been observed for over a dozen years with both spectroscopy and speckle interferometry. Analysis of the speckle observations results in a long period of 13.1 yr. This period is also detected in residuals from the spectroscopic observations of the 71.7919 day short-period orbit. Elements of the long-period orbit were determined separately using the observations of both techniques. The more accurate elements from the speckle solution have been assumed in a simultaneous spectroscopic determination of the short- and long-period orbital elements. The magnitude …
Hr 266=Ads 784: An Early Type Spectroscopic, Speckle Astrometric Multiple System, Warren A. Cole, Francis C. Fekel, William I. Hartkopf, Harold A. Mcalister, Jocelyn Tomkin
Hr 266=Ads 784: An Early Type Spectroscopic, Speckle Astrometric Multiple System, Warren A. Cole, Francis C. Fekel, William I. Hartkopf, Harold A. Mcalister, Jocelyn Tomkin
Information Systems and Engineering Management Research Publications
The detection and nature of a 'speckle astrometric' system are reported with attention given to alternative interpretations of the system components. The HR 226 = ADS 784 system is described as a short-period binary (with a period of 4.241148 +/- 0.000008 d) orbiting an unseen companion (with a period of 1769 +/- 10 d), and the triple's visual orbit is 83.10 +/- 0.20 yr. The elements of the various orbits taken from spectroscopic data are employed to develop the model scenarios. The masses and spectral types of the components are developed and used to calculate the inclinations of the short-, …
The 11 Year History Of Starspots On V1149 Ori=Hd 37824, Douglas S. Hall, Francis C. Fekel, Gregory W. Henry, William S. Barksdale
The 11 Year History Of Starspots On V1149 Ori=Hd 37824, Douglas S. Hall, Francis C. Fekel, Gregory W. Henry, William S. Barksdale
Information Systems and Engineering Management Research Publications
All available radial-velocity measures, published and unpublished, yield an improved period and a new (assumed circular) solution. The period is 53.58 d +/- 0.02 d, and conjunction (K1 giant in front) was at 2 444 325.93 +/- 0.12 d. Eleven years of V-band photometry, published and unpublished, between 1978-1979 and 1989-1990 are analyzed. Eighteen data groups are fit with a two-spot light-curve-modeling technique. Six spots existing sometime during the 11 years are identified, and the 4-percent range of their rotation periods is used to estimate a differential rotation coefficient of k = 0.08 +/- 0.02. Observed lifetimes of those six …