Zobrazeno 1 - 10
of 63
pro vyhledávání: '"Fraser, Helen J."'
Autor:
Greaves, Jane S., Rimmer, Paul B., Richards, Anita M. S., Petkowski, Janusz J., Bains, William, Ranjan, Sukrit, Seager, Sara, Clements, David L., Silva, Clara Sousa, Fraser, Helen J.
Publikováno v:
MNRAS 2022
New analysis is presented of the 1.1 mm wavelength absorption lines in Venus' atmosphere that suggested the presence of phosphine. We retrieve a sulphur dioxide observation from the JCMT archive that was simultaneous within a few days of the PH3 1-0
Externí odkaz:
http://arxiv.org/abs/2108.08393
Autor:
Greaves, Jane S., Richards, Anita M. S., Bains, William, Rimmer, Paul B., Clements, David L., Seager, Sara, Petkowski, Janusz J., Sousa-Silva, Clara, Ranjan, Sukrit, Fraser, Helen J.
Publikováno v:
Nature Astronomy 5.7 (2021): 636-639
We recover PH3 in the atmosphere of Venus in data taken with ALMA, using three different calibration methods. The whole-planet signal is recovered with 5.4{\sigma} confidence using Venus bandpass self-calibration, and two simpler approaches are shown
Externí odkaz:
http://arxiv.org/abs/2104.09285
Autor:
Greaves, Jane S., Bains, William, Petkowski, Janusz J., Seager, Sara, Sousa-Silva, Clara, Ranjan, Sukrit, Clements, David L., Rimmer, Paul B., Fraser, Helen J., Mairs, Steve, Currie, Malcolm J.
Publikováno v:
Nature Astronomy 5.7 (2021): 726-728
We published spectra of phosphine molecules in Venus' clouds, following open-science principles in releasing data and scripts (with community input leading to ALMA re-processing, now benefiting multiple projects). Some misconceptions about de-trendin
Externí odkaz:
http://arxiv.org/abs/2012.05844
Autor:
Greaves, Jane S., Richards, Anita M. S., Bains, William, Rimmer, Paul B., Clements, David L., Seager, Sara, Petkowski, Janusz J., Sousa-Silva, Clara, Ranjan, Sukrit, Fraser, Helen J.
Publikováno v:
Nature Astronomy 5.7 (2021): 636-639
We first respond to two points raised by Villanueva et al. We show the JCMT discovery spectrum of PH3 can not be re-attributed to SO2, as the line width is larger than observed for SO2 features, and the required abundance would be an extreme outlier.
Externí odkaz:
http://arxiv.org/abs/2011.08176
Autor:
Greaves, Jane S., Richards, Anita M. S., Bains, William, Rimmer, Paul B., Sagawa, Hideo, Clements, David L., Seager, Sara, Petkowski, Janusz J., Sousa-Silva, Clara, Ranjan, Sukrit, Drabek-Maunder, Emily, Fraser, Helen J., Cartwright, Annabel, Mueller-Wodarg, Ingo, Zhan, Zhuchang, Friberg, Per, Coulson, Iain, Lee, E'lisa, Hoge, Jim
Publikováno v:
Greaves, J. S., Richards, A. M., Bains, W., Rimmer, P. B., Sagawa, H., Clements, D. L., ... & Hoge, J. (2020). Phosphine gas in the cloud decks of Venus. Nature Astronomy, 1-10
Measurements of trace-gases in planetary atmospheres help us explore chemical conditions different to those on Earth. Our nearest neighbor, Venus, has cloud decks that are temperate but hyper-acidic. We report the apparent presence of phosphine (PH3)
Externí odkaz:
http://arxiv.org/abs/2009.06593
Autor:
Gärtner, Sabrina, Gundlach, Bastian, Headen, Thomas F., Ratte, Judy, Oesert, Joachim, Gorb, Stanislav N., Youngs, Tristan G. A., Bowron, Daniel T., Blum, Jürgen, Fraser, Helen J.
Models and observations suggest that ice-particle aggregation at and beyond the snowline dominates the earliest stages of planet-formation, which therefore is subject to many laboratory studies. However, the pressure-temperature gradients in proto-pl
Externí odkaz:
http://arxiv.org/abs/1710.02074
Autor:
Suutarinen, Aleksi N., Kristensen, Lars E., Mottram, Joseph C., Fraser, Helen J., van Dishoeck, Ewine F.
Water in outflows from protostars originates either as a result of gas-phase synthesis from atomic oxygen at T > 200 K, or from sputtered ice mantles containing water ice. We aim to quantify the contribution of the two mechanisms that lead to water i
Externí odkaz:
http://arxiv.org/abs/1402.7214
In the quest to understand the formation of the building blocks of life, amorphous solid water (ASW) is one of the most widely studied molecular systems. Indeed, ASW is ubiquitous in the cold interstellar medium (ISM), where ASW-coated dust grains pr
Externí odkaz:
http://arxiv.org/abs/1402.3517
Publikováno v:
Hei{\ss}elmann, D., Fraser, H., & Blum, J. 2007, Proc. 58th Int. Astronautical Congress 2007 (Paris: Int. Astronautical Federation), IAC-07-A2.1.02
To reveal the formation of planetesimals it is of great importance to understand the collision behavior of the dusty and icy aggregates they have formed from. We present an experimental setup to investigate the aggregation properties in low-velocity
Externí odkaz:
http://arxiv.org/abs/1106.4760
In this paper we present results of two novel experimental methods to investigate the collisional behavior of individual macroscopic icy bodies. The experiments reported here were conducted in the microgravity environments of parabolic flights and th
Externí odkaz:
http://arxiv.org/abs/0908.3424