A calculated methane line list for characterizing exoplanets and brown dwarfs

用于表征系外行星和褐矮星的计算甲烷线列表

• 批准号: ST/I001050/1
• 负责人: Jonathan Tennyson
• 金额: $ 48.51万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FI001050%2F1
• 关键词: calculated; methane; line; list; characterizing

The discovery of over 400 orbiting other stars has opened a whole new field of astronomy. Astronomers are now beginning to ask questions about these new worlds: what are they like? what are they made of? and of course, are there any signs of life? Characterizing these exoplanets, as they are called, requires the use novel observational techniques as it is rarely possible to separate the planet from its nearby and very bright parent star. It transpires that about 70 of the planets detected so far pass in front of their star when viewed from earth. Observation of the slight dimming of the star for different colours of light is beginning to yield valuable information on the composition of exoplanets. However to do understand these observations requires building atmospheric models to simulate how the planet interacts with the light coming from the planet's parent star. This is in turn requires huge quantities of laboratory data. However in many cases the laboratory data required is often simply not available; this is particularly true for the most commonly observed class of exoplanets 'hot Jupiters', which are gas giant planets who orbit close to their parent star. It is also true for similar studies of brown dwarfs and cool stars. The most glaring omission in all this work is reliable data for methane. Methane has been detected in exoplanets and is a major atmospheric species in brown dwarfs and cool carbon stars. However models of these and other astronomical objects are hampered by the lack of laboratory data on methane. How a molecule such as methane absorbs and emits light is very complicated since, particularly at elevated temperatures, it requires knowledge of the position and strength of probably many billions of individual transition lines. This proposal will use first principles quantum mechanical calculations to provide a comprehensive and reliable rotation-vibration line list for methane. These calculations will be compared with the much more limited available laboratory studies of the problem, which will if necessary be used to help improve the accuracy of the resulting computed line list. The new line list will allow astronomers and other scientists to model how methane absorbs or emits light as a function of temperature. This line list will be made widely available via a new web portal, www.exomol.com, and using other web-based distribution methods methods.

超过400个绕着其他恒星的发现开辟了一个全新的天文学领域。天文学家现在开始询问有关这些新世界的问题：它们是什么样的？他们是用什么？当然，有生命的迹象吗？被称为这些系外行星的表征，需要使用新颖的观察技术，因为很少将行星与附近和非常明亮的父恒星分开。它的进展使大约70个行星在从地球上看时在他们的恒星面前被检测到的。观察恒星对不同颜色的光线的轻微变暗开始，开始产生有关系外行星组成的有价值的信息。但是，要理解这些观察结果需要建立大气模型，以模拟地球与地球的父恒星的光线相互作用。反过来，这需要大量的实验室数据。但是，在许多情况下，所需的实验室数据通常根本不可用。对于最常见的系外行星“热木星”的类别是，这是气体巨型行星，它们绕着亲近父母的恒星旋转。对于棕色矮人和酷星的类似研究也是如此。在所有这项工作中，最明显的遗漏是甲烷的可靠数据。甲烷已在系外行星中检测到，是棕色矮人和凉爽碳星的主要大气物种。但是，由于缺乏甲烷的实验室数据，这些模型和其他天文对象的模型受到了阻碍。甲烷等分子如何吸收并发出光非常复杂，因为尤其是在升高的温度下，它需要了解可能数十亿个单个过渡线的位置和强度。该提案将使用第一原理量子机械计算，为甲烷提供全面可靠的旋转振动线列表。这些计算将与对问题的可用实验室研究更为有限，如果有必要，则可以帮助提高所得计算线列表的准确性。新的线列表将使天文学家和其他科学家能够建模甲烷如何吸收或发出光作为温度的函数。此行列表将通过新的Web门户网站www.exomol.com和其他基于Web的分发方法进行广泛提供。

项目成果

ExoMol line lists - III. An improved hot rotation-vibration line list for HCN and HNC

• DOI: 10.1093/mnras/stt2011
• 发表时间: 2014-01-01
• 期刊: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
• 影响因子: 4.8
• 作者: Barber, R. J.;Strange, J. K.;Tennyson, Jonathan
• 通讯作者: Tennyson, Jonathan

METHANE IN THE ATMOSPHERE OF THE TRANSITING HOT NEPTUNE GJ436B?

• DOI: 10.1088/0004-637x/731/1/16
• 发表时间: 2011-04-10
• 期刊: ASTROPHYSICAL JOURNAL
• 影响因子: 4.9
• 作者: Beaulieu, J. -P.;Tinetti, G.;Aylward, A.
• 通讯作者: Aylward, A.

ExoMol line lists - VIII. A variationally computed line list for hot formaldehyde

ExoMol 系列列表 - VIII。

• DOI: 10.1093/mnras/stv091
• 发表时间: 2015
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Al-Refaie A

Dissociative recombination of N 2 + : An ab initio study

N 2 的解离重组：从头开始研究

• DOI: 10.1103/physreva.90.052705
• 发表时间: 2014
• 期刊: Physical Review A
• 影响因子: 2.9
• 作者: Little D

Temperature-dependent molecular absorption cross sections for exoplanets and other atmospheres

• DOI: 10.1016/j.icarus.2012.07.028
• 发表时间: 2013-11-01
• 期刊: ICARUS
• 影响因子: 3.2
• 作者: Hill, Christian;Yurchenko, Sergei N.;Tennyson, Jonathan
• 通讯作者: Tennyson, Jonathan