astro-init - 用户贡献 [zh-cn]

Topic:Ve4e10ccfh3ajm37

2020-01-02T14:46:17Z

Richardjcx（讨论 | 贡献）已评论"国际奥赛成绩更新"的话题(yck同学喜提2019APAO银牌镇爷快点更[滑稽])

CZAO

2019-11-24T05:17:38Z

Richardjcx：

捷克天文奥林匹克竞赛(Český '''Astronomická Olympiáda''')是捷克的国家天文奥赛，由捷克教育部资助。迄今（2019-2020年度）已举办17届。

[[2018-19年度捷克天文奥林匹克竞赛]]

官网：olympiada.astro.cz

CZAO

2019-11-20T13:11:05Z

Richardjcx：创建页面，内容为“捷克天文奥林匹克竞赛(Český '''Astronomická Olympiáda''')是捷克的国家天文奥赛，由捷克教育部资助。迄今（2019-2020年度）已举…”

捷克天文奥林匹克竞赛(Český '''Astronomická Olympiáda''')是捷克的国家天文奥赛，由捷克教育部资助。迄今（2019-2020年度）已举办17届。

[[2018-19年度捷克天文奥林匹克竞赛]]

官网：[[olympiada.astro.cz]]

用户:Richardjcx

2019-10-24T22:43:15Z

Richardjcx：

我

萌新

膜大佬

啥都不会

英语还凑合

等着某人女装

CNAO

新疆乌鲁木齐·云南昆明/玉溪·北京顺义·山东威海·山西太原·新疆伊宁·浙江绍兴·贵州平塘·广东汕头？

IAO

中国威海·斯里兰卡科伦坡·罗马尼亚皮亚特拉-尼亚姆茨

用户:Richardjcx

2019-10-24T22:42:12Z

Richardjcx：创建页面，内容为“我萌新膜大佬啥都不会英语还凑合等着某人女装 CNAO 新疆乌鲁木齐·云南昆明/玉溪·北京顺义·山东威海·山西太原·新疆…”

我
萌新
膜大佬
啥都不会
英语还凑合
等着某人女装

CNAO
新疆乌鲁木齐·云南昆明/玉溪·北京顺义·山东威海·山西太原·新疆伊宁·浙江绍兴·贵州平塘·广东汕头？

IAO
中国威海·斯里兰卡科伦坡·罗马尼亚皮亚特拉-尼亚姆茨

USAAAO2019

2019-10-24T20:17:29Z

Richardjcx：创建页面，内容为“=== 初赛 === ==== 英文题目 ==== Time Limit: 75 Minutes 1. (1 point) Which of the following relates the intrinsic luminosity of a spiral galaxy with its asymp…”

=== 初赛 ===

==== 英文题目 ====
Time Limit: 75 Minutes

1. (1 point) Which of the following relates the intrinsic luminosity of a spiral galaxy with its asymptotic rotation velocity?

A. The Fundamental Plane

B. The Tully-Fisher Relation

C. The Press-Schechter Formalism

D. The Faber-Jackson Relation

2. (1 point) Which of the following correctly gives the location of Population I vs. Population II stars in the Milky Way?

A. Population I - Thin Disk, Spiral Arms; Population II - Halo, Bulge

B. Population I - Thin Disk, Bulge; Population II - Spiral Arms, Halo

C. Population I - Halo, Bulge; Population II - Thin Disk, Spiral Arms

D. Population I - Halo, Thin Disk; Population II - Bulge, Spiral Arms

3. (1 point) A quasar with a bolometric flux of approximately 10−12 erg s−1 cm−2 is observed at a redshift of 1.5, i.e. its comoving radial distance is about 4.4 Gpc. What is the bolometric luminosity of the quasar?

A. 6.0 ·1011 L B. 3.8 ·1012 L �C. 2.4 ·1013 L �D. 6.3 ·1014 L�

4. (1 point) Now, let’s assume that the quasar in the previous question is observed to have a companion galaxy which is 5 arcseconds apart. What is the projected linear separation of the companion galaxy from the quasar?

A. 107 kpc B. 29 kpc C. 74 kpc D. 43 kpc

5. (1 point) An observer is standing atop the Burj Khalifa, the tallest building on earth (height = 830m, latitude = 25.2N, longitude = 55.3E). Which of the following options is the closest to the shortest and longest shadow on the ground at the local noon time due to the building in a given year?

A. 10m, 1050m B. 25m, 950m C. 35m, 850m D. 45m, 750m

6. (1 point) Which of the following is closest to the ratio of the farthest distance to the horizon that can be seen by an observer standing top of the Mount Everest on Earth (height = 8.8 km) and Olympus Mons on Mars (height = 25 km)?

A. 0.1 B. 1 C. 5 D. 10

7. (1 point) An observer measures the black-body spectrum for a variety of bodies as a function of temperature and wavelength in the long wavelength limit ( hc λ � kBT) and finds that his data approximately fits the relationship log(I) = a+b log(T)+c log(λ)). Here, I is the spectral intensity in terms of wavelength, T is the temperature of the body and λ is the wavelength. Which of the following are the expected values of b and c?

A. 1,-4 B. 1,4 C. 4,1 D. -4,1

8. (1 point) Suppose a spacecraft were orbiting in a low Earth orbit at an altitude of 400 km. The spacecraft makes a single orbital maneuver to place it into a Mars transfer orbit. Delta-v (∆v) refers to the change in velocity during an orbital maneuver. What is the ∆v required for this trans-Mars injection? The semimajor axes of the orbits of Earth and Mars are 1.496 × 108 km and 2.279 × 108 km, respectively.

A. 2.94 km/s B. 3.57 km/s C. 6.12 km/s D. 10.85 km/s E. 11.24 km/s

9. (1 point) After entering Mars orbit, the spacecraft finds that over the course of the martian year, the position of Star A varies by 613.7 milliarcseconds (mas) due to the movement of the spacecraft around the sun. Determine the distance to Star A.

A. 1.629 pc B. 2.482 pc C. 3.259 pc D. 4.965 pc E. 6.518 pc

10. (1 point) Star A, of mass 3.5 M�, shows radial velocity variations 24.2 m/s in amplitude and 23.22 years in period, suggesting the presence of an orbiting exoplanet. Which of the following is closest to the mass of the exoplanet in terms of Jupiter’s masses (MJ )? Assume the exoplanet’s orbit is circular and has inclination 90◦ . The mass of Jupiter is 1.898 × 1027 kg. Assume the mass of the planet is much smaller than that of Star A.

A. 0.7 MJ B. 2.1 MJ C. 5.6 MJ D. 9.9 MJ E. 13.2 MJ

11. (1 point) Whether or not a diffraction-limited optical system is able to resolve two points as distinct can be determined by the Rayleigh criterion. β Pictoris b is one of the first exoplanets discovered using direct imaging. The star system is located 19.44 pc away, and β Pictoris b is located 9.2 AU from the host star. When viewing in infrared (λ = 1650 nm), what is the minimum telescope diameter that is able to resolve β Pictoris and its exoplanet under the Rayleigh criterion?

A. 0.719 m B. 0.877 m C. 1.142 m D. 1.438 m E. 1.755 m

12. (1 point) The celestial coordinates of the Orion Nebula are RA 05h35m, dec − 05◦230 . Which of the following is closest to the time (local solar time) when the Orion Nebula would cross the meridian on the night of February 1st 2019? The date of the vernal equinox of 2019 is March 20th.

A. 08:40 PM B. 10:22 PM C. 12:00 AM D. 01:38 AM E. 03:20 AM

13. (1 point) A yellow hypergiant located 1.04 kpc away has an apparent visual magnitude of 1.49 and a B − V color excess of 0.29. Assuming RV , the ratio of V -band extinction to B − V color excess, is 3.1, determine the absolute visual magnitude of the star.

A. -9.5 B. -8.9 C. -8.6 D. -8.3 E. -7.7

14. (1 point) The pp chain is a primary energy generation mechanism in the Sun. Each run of the process 2H + e → D + ν releases 26.73 MeV of energy. Calculate the neutrino flux on the surface of Mars (in neutrinos per m2 ), assuming that the pp chain is responsible for 100% of the Sun’s energy generation. (Mars is at a distance of 1.52 AU)

A. 2.54 × 1013 B. 3.17 × 1016 C. 1.37 × 1014 D. 5.94 × 1012 E. 4.45 × 1015

15. (1 point) A relation between which of the following pairs of properties of Cepheids variables makes Cepheids variables, specifically, useful objects for determining stellar distances?

A. Mass and Temperature

B. Period and Luminosity

C. Temperature and Period

D. Mass and Luminosity

E. Period and Radius

16. (1 point) Assuming that the Chandrasekhar Limit is 1.4 Solar masses, estimate the maximum average density (in kg/m3 ) of a Chandrashekhar mass black hole.

A. 1.5 × 1022 B. 4.7 × 1014 C. 8.2 × 1010 D. 9.4 × 1018 E. 7.1 × 1026

17. (1 point) The Sun’s differential rotation can be estimated with the equation ω = X+Y sin2 (φ)+ Zsin4 (φ), where ω is the angular velocity in degrees per day, φ is solar latitude, and X, Y , and Z are constants (equal to 15, -2.5, and -2 degrees per day respectively). Two sunspots are spotted along the same solar meridian, one at 0◦ and the other at 40◦ . Assuming that the sunspots do not disappear or change latitude and move with the same velocity as the surface of the sun, after how many days will the sunspots be aligned once again? Round your answer to the nearest day.

A. 142 B. 202 C. 262 D. 312 E. 372

18. (1 point) An observer generates a light curve of a binary system, and notices two different minima that repeat periodically (in an alternating fashion). The time between when the light curve reaches the first minima and the second minima is 285.7 days. In solar masses, estimate the total mass of the binary system if the two stellar bodies are separated by a mean distance of 4.1 AU.

A. 0.0002 B. 0.0008 C. 28 D. 56 E. 112

19. (1 point) Eltanin, the brightest star in Draco, has the approximate coordinates RA: 17h 56m, Dec: +51.5◦ . Given that at the observer’s location, the latitude is +50◦ and the local sidereal time is 14:00, how far above the horizon will Eltanin appear? Round your answer to the nearest degree.

A. 26 B. 54 C. 59 D. 89 E. The star is below the horizon

20. (1 point) Stellar bodies located in the top left of a Hertzsprung-Russell diagram necessarily have which properties?

A. Low absolute magnitude, Low effective temperature

B. Low absolute magnitude, High effective temperature

C. High absolute magnitude, High effective temperature

D. High absolute magnitude, Low effective temperature

E. Intermediate absolute magnitude, Intermediate effective temperature

21. (1 point) Which of the following correctly orders the following distance indicators from the smallest to largest scale?

A. Stellar parallax, spectroscopic parallax, RR Lyrae variables, Hubble constant

B. Spectroscopic parallax, stellar parallax, RR Lyrae variables, Hubble constant

C. Stellar parallax, RR Lyrae variables, spectroscopic parallax, Hubble constant

D. Stellar parallax, spectroscopic parallax, Hubble constant, RR Lyrae variables

E. Spectroscopic parallax, stellar parallax, Hubble constant, RR Lyrae variables

22. (1 point) As seen from Mars, what phase will Earth appear to be in when Mars is at quadrature from Earth?

A. New B. Crescent C. Quarter D. Gibbous E. Full

23. (1 point) Which of the following stars is almost always never visible to observers in the Northern hemisphere?

A. Alpha Aurigae B. Gamma Cygni C. Alpha Lyrae D. Sigma Octantis E. Beta Orionis

24. (1 point) Two amateur astronomers A and B living in Ecuador are standing on the Equator at the Galapagos Islands (height 0 m, longitude 91◦ W) and Volcan Cayambe (height 5790 m, longitude 78◦ W) respectively. What are the differences (in degrees) of the altitudes from the horizon and zenith distances of the Sun measured by these two astronomers on March 20, 2019 when it is local noon for observer B? Neglect refraction and give your answer to the nearest degree.

A. Difference in altitudes: 15, Difference in zenith distances: 13.

B. Difference in altitudes: 13, Difference in zenith distances: 13.

C. Difference in altitudes: 13, Difference in zenith distances: 15.

D. Difference in altitudes: 11, Difference in zenith distances: 13.

25. (1 point) The spectra of two stars A and B peak at wavelengths 500 nm and 250 nm respectively. What is the ratio of their luminosities if they form black holes with Schwarzschild radii in the ratio 8:1? Assume that their densities were uniform and identical before they collapsed to form a black holes and that they did not lose any mass while forming the black holes.

A. 2:1 B. 4:1 C. 1:4 D. 1:2

26. (1 point) Two stationary observers at a distance 100 AU from the sun observe transits of Mercury across the diameter of the Sun’s disk when Mercury is at perihelion and aphelion respectively. Which of the following is closest to the ratio of the aphelion transit time to the perihelion transit time? You are given that the semi-major axis and eccentricity of Mercury’s orbit are 0.387 AU and 0.21 respectively.

A. 1:1 B. 2:1 C. 4:1 D. 8:1

27. (1 point) Find the total sum of the binary system of the star Capella, if semi-major axis between them is 0.85 AU, and period of 0.285 years.

A. 5.5 solar masses B. 6.5 solar masses C. 7.6 solar masses D. 8.5 solar masses E. 9.5 solar masses

28. (1 point) The New Horizons spacecraft completed a flyby of 2014 MU69 on New Year’s day of this year. 2014 MU69 is a Kuiper Belt Object with a semi-major axis of 44.58 AU. Estimate the maximum temperature at the surface of 2014 MU69, in Kelvin, assuming the object has zero albedo.

A. 41.7 Kelvin B. 58.9 Kelvin C. 83.3 Kelvin D. 117.9 Kelvin

29. (1 point) HD 209458b is an extrasolar gas giant planet with a radius of 1.38 Jupiter radii and a mass of 0.69 Jupiter masses (1 Jupiter radius = 6.99·107 m, 1 Jupiter mass = 1.90·1027 kg). Which of the following is closest to the pressure at the very center of HD 209458b, in bars?

A. 109 bars B. 106 bars C. 105 bars D. 103 bars

30. (1 point) Imagine that our Sun was suddenly replaced by an M-dwarf with a mass half that of the Sun. If our Earth kept the same semi-major axis during this change, what would Earth’s new orbital period be around the M-dwarf?

A. 0.707 years B. 1 year C. 1.414 years D. 2 years

==== 中文题目 ====
欠缺

==== 解答 ====
BABDB BABDC BAACB DCCBB ACDDC BCBBC

=== 决赛 ===

==== 英文题目 ====
The maximum score is 153 points. The test must be completed within 2.5 hours (150 minutes).

===== 短问题 =====
1. (7 points) Assuming that the present density of baryonic matter is ρb0 = 4.17*10^28 kg/m3 , what was the density of baryonic matter at the time of Big Bang nucelosynthesis (when T = 10^10 K)? Assume the present temperature, T0 to be 2.7 K.

2. (7 points) On the night of January 21st, 2019, there was a total lunar eclipse during a supermoon. At the time, the moon was close to perigee, at a distance of 351837 km from the earth, which was 1.4721*10^8 km from the sun. The gamma (γ) of a lunar eclipse refers to the closest distance between the center of the moon and the center of the shadow, expressed as a fraction of the earth’s radius. For this eclipse, γ = 0.3684. Given this information, find the closest estimate for the duration of totality of the eclipse.

3. (7 points) You are in the northern hemisphere and are observing rise of star A with declination δ = -8 degrees , and at the same time a star B with declination δ = +16 degrees is setting. What will happen first: next setting of the star A or rising of the star B?

4. (7 points) Consider a star with mass M and radius R. The star’s density varies as a function of radius r according to the equation ρ(r) = ρ(center)(1-sqrt(r/R)), where ρcenter is the density at the center of the star. Derive an expression for dP{dr in terms of G, M, R, and r, where P is the pressure at a given radius r.

===== 中问题 =====
5. (15 points) An alien spaceship from the planet Kepler 62f is in search of a rocky planet for a remote base. They’re attracted to Earth because of a fortunate coincidence: its axis of rotation points directly at their home planet. That means they can have uninterrupted communication with home by planting fixed transmitters on The North Pole. But first, they need to find out if Earth’s axis will always point in the same direction or if it undergoes precession. They can’t know without years of observation, so they hope that we, its now-extinct intelligence, have left behind the answer. While orbiting Earth, they see a few remarkable structures, including the Hoover Dam in Nevada. Zooming in on the dam, a colorful plaza with peculiar markings on its floor catches their attention. Descending on the plaza, they realize the markings are a map of the sky when the dam was built, left to indicate the date to posterity. Figure 1 is an overhead architectural map of this plaza. The center-point depicts the north ecliptic pole, and the large circle represents the path of the Earth’s axis throughout its counter-clockwise procession. As they interpret the map, they’re dismayed to realize that their star has not been and will not be Earth’s north star for very long.
[[文件:Figure 1 for USAAAO2019 Final Q5.jpg|缩略图|Figure 1: Overhead architectural plan of the Hoover Dam plaza depicting Polaris as north star]]
For the purpose of this question, assume that the Earth’s axial tilt is a constant i = 23.5 degrees and its axis precesses at a constant rate.

a) Using the values on the map, and knowing that the aliens used carbon-aging to determine that the dam is 12,000 years old, find all possible values for the period of Earth’s axial precession.

b) Using the most optimistic answer (longest period) from part (a), calculate how many arcseconds the Earth’s axis precesses each day. Use the period you calculate here in the next two sections.

c) If they hadn’t been lucky enough to come across the star map and decided to build a radio interferometer to observe the movement of the celestial pole over the course of 30 days instead, how many kilometers would the baseline of their telescope array have to be, assuming it operated at a 20cm wavelength?

d) As a last resort, to keep Earth’s axis fixed, the aliens decide to counter the forces that cause the Earth’s precession by building giant nuclear thrusters on the Earth’s surface. Assume Earth’s precession is caused by external forces alone and calculate the average force (in kN) that a strategically positioned thruster would have to exert to counter them.

6. (15 points)
[[文件:USAAAO 2019 Final Fig 2.jpg|缩略图|Figure 2 shows a full-phase light curve (“phase curve”) of the exoplanet HD 189733b taken by the Spitzer space telescope.]]
Use this figure to answer the following questions.

The star HD 189733 has an effective temperature of 4785 K and a radius of 0.805 Solar radii.

a) Use the depth of the planet’s transit to estimate the radius of HD 189733b, in Jupiter radii.

b) Use the depth of the eclipse of the planet by the host star to estimate the ratio of the flux of the planet HD 189733b to that of the host star HD 189733.

c) HD 189733b is so close-in to its host star that it is expected to be tidally locked. Use the phase curve to estimate the ratio of the dayside flux emitted by the planet to the nightside flux emitted by the planet.

d) This phase curve also noticeably has a phase curve offset, that is, the maximum in planet and star flux does not occur exactly at secondary eclipse. What process that occurs in a planetary atmosphere could cause such a phase curve offset?

7. (15 points)

a) Mass-Radius Relation Stellar physics often involves guessing the equation of state for stars, which is typically a relation between the pressure P and the density ρ. A family of such guesses are known as polytopes and go as follows

P = K*ρ^γ (1)

where K is a constant and the exponent γ is fixed to match a certain pressure and core temperature of a star. Given this, show that one can obtain a crude power-law scaling between the mass M of a polytopic star and its radius R of the form M9Rα. Find the exponent α for polytopic stars (justify all steps in your argument). Also, indicate the exponent γ for which the mass is independent of the radius R. Bonus: Why is this case interesting?

b) Black Holes as Blackbodies The mass radius relation for ideal non-rotating, uncharged black holes is known from relativity to be

R = 2GM/c^2 (2)

Moreover, Stephen Hawking showed that a black hole behaves like a blackbody, where its temperature (known as the Hawking temperature) is given by

T = ħc^3/8πkGM (3)

Given this information, show that the lifetime of a black hole (justify this phrase!) t ˚ scales with its mass M as

t* is proportional to Mβ (4)

where you should find the exponent β

c) Minimal Black Holes Using the information of the previous part, and Wien’s displacement law, estimate the smallest possible mass of a black hole. State any possible flaws with this estimate.

8. (15 points) In a rather weird universe, the gravitational constant G varies as a function of the scale factor aptq. G “ G0fpaq (5) Consider the model fpaq “ e bpa´1q where b “ 2.09. a) Assuming that the universe is flat, dark energy is absent, and the only constituent is matter, estimate the present age of this weird universe according to this model. Assume that the Friedmann equation: Hpaq 2 “ H2 0 pΩm ` Ωr ` Ωk ` ΩΛq (6) still holds in this setting. b) What is the behaviour of the age of the universe t as the scale factor aptq Ñ 8 ? Note that all parameters with subscript 0 indicate their present value. Take the value of Hubble’s constant as H0 “ 67.8 kms´1Mpc´1 Hint: You might need the following integrals ż 8 0 x 2 e ´x 2 dx “ ? π 4 ż 1 0 x 2 e ´x 2 dx « 0.189471 (7) 9. (15 points) a) Find the shortest distance from Boston (42.36010 N, 71.05890 W) to Beijing (39.90420 N, 116.40740 E)traveling along the Earth’s surface. Assume that the Earth is a uniform sphere of radius 6371 km. b) What fraction of the path lies within the Arctic circle (north of 66.56080 N)?

===== 长问题 =====

文件:USAAAO 2019 Final Fig 2.jpg

2019-10-24T19:41:15Z

Richardjcx：

This is the picture involved in the final round of USAAAO 2019.

文件:Figure 1 for USAAAO2019 Final Q5.jpg

2019-10-24T19:35:07Z

Richardjcx：

The figure involved in the final of USAAAO 2019 Q5.

2019年CNAO预赛选择题

2019-07-27T19:48:25Z

Richardjcx：

==题目==
01. 梅西叶天体M44位于（　　）的天区内。

（A）巨蟹座　（B）猎户座

（C）大犬座　（D）金牛座

02. 大角星的视星等为（　　）。

（A）2等　　（B）1等

（C）0等　　（D）-1等

03. 以下哪一项不是天文学的星座名？（　　）

（A）杜鹃座　（B）天平座

（C）天炉座　（D）水蛇座

04. 一般认为，望远镜是荷兰的商人发明的，而首位将望远镜用于天文观测的人是（　　）。

（A）牛顿　　（B）开普勒

（C）伽利略　（D）哥白尼

05. 以下哪颗行星没有卫星？（　　）

（A）金星　　（B）火星

（C）木星　　（D）土星

06. 2019年1月12日，中国天文学会和北京天文馆在京联合宣布启动国际天文学联合会（IAU）发起的“同一天空下”全球天文行动（中国大陆地区），以纪念IAU成立（　　）周年。

（A）60　　（B）80

（C）100　　（D）200

07. “七月流火”是《诗经·豳风·七月》中的第一句，描述的是古人对天象的观察结果，其中的“火”是指（　　）。

（A）火星

（B）火流星

（C）某种大气现象

（D）大火星

08. 半人马座α星距离我们大约（　　）。

（A）2.8光年　（B）4.3光年

（C）16.7光年　（D）8.6万光年

09.（　　）在2017年记录到的中微子来自一个名为TXS 0506+056的星系。星系中心超大质量黑洞所产生的两道喷流中有一道正好对准了地球，它会产生辐射和高能粒子，其中就包括了这次探测到的中微子和带电宇宙线。

（A）地中海中微子天文台

（B）南极冰立方中微子天文台

（C）钱德拉X射线天文台

（D）康普顿伽马射线天文台

10. 2019年唯一的一次日全食在哪个大洲可见？（　　）

（A）欧洲　　（B）非洲

（C）亚洲　　（D）南美洲

11. 一位天文学家准备在今晚观测星团NGC6633，已知它大约在地方时刚过午夜后升起，且在本次竞赛预赛的所有考点都能被观测到，那么它可能位于以下哪个星座？（　　）

（A）蛇夫座　（B）乌鸦座

（C）麒麟座　（D）宝瓶座

12. 下列流星雨中，2019年极大期间的观测受月光影响最小的是（　　）。

（A）四月天琴座流星雨

（B）宝瓶座η流星雨

（C）猎户座流星雨

（D）双子座流星雨

13. 以下哪一项不是中国传统的天文仪器？（　　）

（A）象限仪　（B）浑仪

（C）简仪　　（D）圭表

14. 以下哪一项是2018年辞世的理论物理学家斯蒂芬·霍金最著名的理论？（　　）

（A）黑洞辐射理论

（B）宇宙大爆炸理论

（C）提出希格斯粒子

（D）量子纠缠理论

15. 美国航天局（NASA）于2019年宣布超期服役的（　　）火星探测器结束使命。

（A）机遇号　（B）勇气号

（C）水手1号　（D）朱雀号

16. 在地球表面观测，使用天文望远镜无法看到（　　）。

（A）火星卫星　（B）水星相位

（C）太阳日冕　（D）月面莫斯科海

17. 太阳绕银心运动的轨道速度是（　　）。

（A）7.9km/s　（B）16.7km/s

（C）52km/s　（D）210km/s

18. 中国古人用测量正午时太阳影长的方式来确定二十四节气的日期，请问在哪一个节气观测到的日影长度最短？（　　）

（A）秋分　　（B）立冬

（C）冬至　　（D）夏至

19. 仙女星系M31未来会与银河系合为一体，预计汇合的时间约为（　　）。

（A）400万年　（B）4000万年

（C）40亿年　（D）400亿年

20. 以下说法不正确的是？（　　）

（A）2018年6月，隼鸟2号探测器抵达小行星“龙宫”上空，随后，巡视器MINERVA-II1成功着陆于其表面并传回照片，成为首次成功着陆小行星上的巡视器。

（B）2018年8月，帕克太阳探测器发射升空，这也是NASA第一次以还在世者的名字来命名探测器。

（C）2018年10月，迄今为止第三个金星探测器贝比科隆博号（BepiColombo）发射升空，并将在7年后抵达相应轨道。

（D）2018年11月，旅行者2号穿过了太阳风边界，继旅行者1号后成为第二个正式进入星际空间的探测器。

21. 到目前为止，在距离我们太阳系10pc的范围之内，天文观测已经证实存在的数目最多的是以下哪类恒星（　　）。

（A）O型　　（B）G型

（C）M型　　（D）褐矮星

22. 下列恒星核聚变反应可以形成的元素中，最重的是（　　）。

（A）Si　（B）Ca　（C）Fe　（D）Au

23. 2019年1月3日，嫦娥四号探测器成功着陆在月球背面内（　　）的冯·卡门撞击坑内。随后，嫦娥四号着陆器与巡视器玉兔二号顺利分离，玉兔二号抵达月球表面。这是人类首次在月球背面成功软着陆和巡视探测的航天器。

（A）金牛-利特罗峡谷

（B）南极-艾特肯盆地

（C）东海盆地

（D）坚忍环形山

24. 中国古代曾发展出自己独特的天文体系，我们现在所说的“农历”就是指过去数千年来我国一直沿用的历法系统，“农历”是什么类型的历法？（　　）

（A）阳历　　（B）阴阳合历

（C）阴历　　（D）和现在的公历相同

25. 在中国古典神话故事《西游记》中，孙悟空手持一根如意金箍棒，重一万三千五百斤。平时孙悟空会把金箍棒变成“绣花针”大小放在耳朵里。与这根“绣花针”的密度最为接近的天体是（　　）。

（A）参宿四

（B）天狼星伴星

（C）蟹状星云中心星

（D）织女星

26. 由欧空局主导研制的GAIA探测器是由以下哪种火箭发射入轨的？（　　）

（A）俄罗斯Soyuz火箭

（B）欧洲Ariane火箭

（C）美国Falcon火箭

（D）中国长征火箭

27. 以下关于银河系的说法正确的是？（　　）

（A）银心黑洞的质量约为40万个太阳质量。

（B）天文学家通过对恒星的观测发现银河系外盘有惊人的翘曲结构。

（C）太阳位于银河系的英仙臂上。

（D）银心位于半人马座方向。

28. 以下哪一架望远镜没有用来做与搜寻地外文明有关的项目？（　　）

（A）FAST望远镜

（B）阿雷西沃(Arecibo)望远镜

（C）绿堤(Green Bank)望远镜

（D）SOHO望远镜

29. 哈雷彗星最远可以到达（　　）。

（A）木星与土星轨道之间

（B）土星与天王星轨道之间

（C）天王星与海王星轨道之间

（D）海王星轨道外侧

30. 在地球表面观测，以下哪个波段的大气透过率最高？（　　）

（A）可见光　（B）近红外

（C）射电　　（D）远红外

31. 氢元素在宇宙中不可能存在的形态包括（　　）。

（A）H II　　（B）H I

（C）H2　　（D）H III

32. 位于巴西里约热内卢（西经43°12'，南纬22°54'）的一位天文爱好者，在清晨大约6点抬头看到月亮位于头顶正上方，这天最可能是农历的（　　）。

（A）初九　　（B）十七

（C）廿三　　（D）廿八

33. 位于北京（东经116°20'，北纬39°56'）的一位天文爱好者，当面向正南方向观测时，在以下哪个星座范围内能够看到地球同步轨道卫星？（　　）

（A）盾牌座　（B）海豚座

（C）天琴座　（D）南鱼座

34. 以下哪一项表述最接近人类目前对系外行星卫星的探测情况？（　　）

（A）已经探测到超过1万颗系外行星卫星。

（B）系外行星卫星亮度太低，人类不可能探测到。

（C）最新发射的空间探测器将有能力探测系外行星卫星。

（D）系外行星卫星不存在。

35. 某个望远镜的极限星等是20等，那么它能探测到的类太阳恒星的最远距离是（　　）。

（A）520光年

（B）8400光年

（C）36000光年

（D）450000光年

==答案==
01-05 ACBCA

06-10 CDBBD

11-15 ABAAA

16-20 DDDCC

21-25 CCBBB

26-30 ABDDC

31-35 DCACC

==解答==

*[[2019年CNAO预赛第35题-星等]]

[[分类:选择题]]

分类:望远镜

2019-07-27T19:46:44Z

Richardjcx：

[[分类:按知识点索引]]
望远镜（一般指光学望远镜），是天文学中重要的观测设备，主要有反射式、折射式和折反射式三种构型。

分类:星等

2019-07-27T19:45:03Z

Richardjcx：

[[分类:按知识点索引]]
星等在天文学中被用来衡量天体的亮度。对于一颗特定的恒星，我们定义其在距地球10pc处的视星等为其绝对星等。两颗恒星的视星等有如下换算关系：$$M_1-M_2=-2.5lg(\frac{F_1}{F_2})$$。此公式同样适用于绝对星等的计算。

2019年CNAO决赛第18题-垂直发射的炮弹

2019-07-27T14:22:22Z

Richardjcx：

{{需要解答}}
==题目==
18、（高年组）垂直发射的炮弹

垂直发射的炮弹是否会落回炮口，这是很久以前曾出现过的争论。

考虑在赤道处从地面垂直向上发射一颗炮弹，忽略空气影响，则：

（1）当弹丸落回地面时，落点会正好位于炮口、位于其东侧、还是位于其西侧，列出判断依据。

（2）设弹丸发射的初速为V0，弹丸飞行高度远小于地球半径。推导落点到炮口的距离与V0的关系，请列出过程。
[[文件:CNAO2019-18.jpg|缩略图|图1]]
【提示】

在推导中你可能用到以下参数：

*地球自转角速度ω0
*地球半径R
*重力加速度g

还可能用到以下公式：

*开普勒定律
*<nowiki>$$\frac{1}{1+x}\simeq 1-x$$</nowiki>
*<nowiki>$$\frac{1}{(1+x)^2}\simeq1-2x$$</nowiki>

[[分类:天体力学]]

分类:恒星时

2019-07-27T14:21:32Z

Richardjcx：

[[分类:按知识点索引]]
恒星时是对于特定观测地的特定时刻，上中天恒星的时角。它每23小时56分钟4.1秒循环一次，即为恒星日。

分类:射电望远镜

2019-07-27T14:18:32Z

Richardjcx：

[[分类:按知识点索引]]
射电望远镜是工作频率在射电波段的望远镜，通常采用反射式设计。

分类:会合周期

2019-07-27T14:16:14Z

Richardjcx：

[[分类:按知识点索引]]
会合周期是行星系统中两颗行星间再次回到同一相对位置时的周期。其计算公式为：$$\frac{1}{T_E}-\frac{1}{T_P}=\frac{1}{T_会}$$

分类:会合周期

2019-07-27T14:14:19Z

Richardjcx：

[[分类:按知识点索引]]
$$\frac{1}{T_E}-\frac{1}{T_P}=\frac{1}{T_会}$$

IOAA2018

2019-07-27T14:10:11Z

Richardjcx：/* 中国队参赛名单 */

{{内容需要完善}}

第12届IOAA于2018年11月3日-11日在北京举办。
[[文件:IOAA2018.jpg|缩略图|IOAA2018]]
==理论考试==
[[2018年IOAA理论第5题-恒星时]]

[[2018年IOAA理论第6题-用FAST观测太阳]]

==实测考试==

==观测考试==

==中国队参赛名单==
{| class="wikitable"
|+
!姓名
!组别
!地区
!奖项
|-
|钱江源
|高
|河北
|一等
|-
|吴泓毅
|高
|广东
|一等 BP
|-
|徐潇彤
|高
|浙江
|一等
|-
|岳泽世
|高
|山东
|二等
|-
|庞彬
|高
|广东
|二等
|-
|侯志鹏
|高
|安徽
|二等
|-
|邱子健
|高
|广东
|三等
|-
|张瀚
|高
|北京
|二等
|-
|杨雨涵
|高
|浙江
|鼓励
|-
|刘亦辰
|高
|北京
|三等
|}
 
==参与国家==

==相关链接==
[http://www.bjp.org.cn/art/2018/11/16/art_19_6293.html 2018国际天文与天体物理奥林匹克竞赛圆满落幕]

[http://www.hf168.net/home/Detail/200/10372 浩瀚星空起帆远航——热烈祝贺合肥一六八中学高三（4）班侯志鹏同学入选IOAA国家队]

[[Category:按赛事索引]]

APAO2017

2019-07-27T14:08:42Z

Richardjcx：/* 中国队参赛名单 */

{{内容需要完善}}
[[文件:APAO2017.gif|缩略图|200x200像素|APAO2017]]
第13届APAO于2017年11月22日-29日在俄罗斯新西伯利亚举办

==理论考试==

==实测考试==

==观测考试==

==中国队参赛名单==
{| class="wikitable"
|+
!姓名
!级别
!地区
!奖项
|-
|贾淞寓
|高
|北京
|一等 BR
|-
|郭京松
|低
|北京
|一等 BR
|-
|于澄楷
|低
|北京
|一等 BT
|-
|徐舶洋
|低
|北京
|二等
|-
|汪尧
|低
|江苏
|二等
|-
|赵泉博
|高
|甘肃
|二等 BO
|-
|黄盛骞
|高
|广东
|二等
|-
|张志云
|高
|广东
|二等
|}

==参与国家==
中国、俄罗斯（主队、客队）、韩国、哈萨克斯坦

==相关链接==

[[Category:按赛事索引]]