RISPOSTE ASTRONOMIA
1. What does the escape speed from a celestial body depend on?
The mass and the radius of the celestial body
2. Mark the correct definition oh hour angle
Distance of the star from the local meridian along the equator measured clockwise
3. Venus has
A mass similar to that of the earth
4. How long is the orbital period of jupiter
About 12 terrestrial years
5. What is the main comnent of earth atmosphere
Nitrogen
6. Mark the wrong sentence regarding the definition of magnitude
The magnitude of a star increases linearly with the increase in its flux density
7. Mark the wrong sentence regarding the magnitude of star
The absorption caused by material between the star and the observe does not affect the
magnitude
8. Mark the wrong sentence regarding the different definitions of temperature of a gas or surface
Kinetic temperature: temperature of a blackbody with the same speed of the molecules in a gas
9. Mark the incorrect sentence
The perihelion happens during the northern summer precisely the 3rd of july
10. Mark the wrong sentence regarding the asymptotic giant phase in stellar evolution (intermediatemass stars)
The outcome of this phase will be a white dwars either made of carbon and oxygen ora just helium
11. Two reference systems have the east-west axis in common
Horizontal and equatorial systems
12. Mark the wrong sentence regarding neutron stars and pulsars
Only a small number of neutron stars emits a radio beam sweeping the sky regularly and they take
the name of pulsars
13. Mark the wrong sentence regarding the formation of protostars
During the protostar phase, the central temperature in the core is high enough for hydrogen fusion
14. Mark the wrong sentence regarding the core collapse of a massive star
Neutronization and photo-disintegration increase the pressure in the core slowing down the
collapse
15. Mark the correct definition
Distance at which one astronomical unit subtends an angle of one arc second
16. Mark the wrong sentence regarding the rotation of the sun
The separation zone between the outer convective zone and the atmosphere is called tachocline
and it is studied using helioseismology
17. What is the main component of venus atmosphere
Carbon dioxide
18. Mark the correct definition of right ascension
Distance of the tar from the vernal point along the equator measured anti-clockwise
19. Mark the incorrect sentence
The elliptical orbit of earth has no influence on the equation of time
20. What does the roche limit depend
The distance between the two bodies times the cubic root of the ratio of the densities of the two
bodies
21. Mark the correct sentence regarding the transition between energy levels
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
Absorption is a bound-bound transition
Where do short period comets come from
The kuiper belt
What if the frost line
The boundary between inner and outer planets
Mark the wrong sentence regarding white dwarfs
White dwarfs are very cold, so they are dim (low luminosity) despite their large size (several solar
radii)
Mark the wrong sentence regarding stellar spectral classification
F-G-K stars do not show any feature in their spectra
The original classification by Secchi was based on distance color and luminosity of the stars
Classes are grouped in early-solar-and late-type according to their age
Mark the wrong sentence regarding exoplanet detection from space
PLATO (ESA) will study the atmosphere of 1000 planets mostly detected by ARIEL (ESA) using lowresolution transmission spectroscopy
Select teh topocentric reference system
Horizontal system
Mark the wrong sentence regarding the atmosphere of the sun
He solar corona can be abserves using a telescope with an H-alpha filter, while the photosphere can
be observes only during an eclipse
Mark the dynamical effect with incorrect amplitude and period
Polar motion, amplitude 0.3 arcminutes, 10 months
Mark the wrong sentence regarding the main sequence phase
In the color-magnitude diagram, main sequence stars are randomly scattered all across the diagram
Mark the wrong sentence regarding stellar clusters and association
Open clusters and associations are randomly distributed in the galactic disk so they do not provide
any information on the shape of the milky way
Mark the definition of Houur Angel
Distance of the star from the Local Meridian along the Equator, measured clockwise
Mark the incorrect sentence, assuming that we are in the north hemisphere.
During the summer the sun rises/sets closer to south than during the winter
Two reference systems have the east-west axis common:
Horizontal and equatorial system
Mark he incorrect sentence regarding the meridian telescope.
A meridian telescope is fixed in declination and can be moved only in right ascension
Mark the only sentence that correctly describes the effect of annual aberration for a star with
ecliptic latitude equal to 45 degrees:
The star describes an ellipsis with one axis perpendicular to the ecliptic
Mark the dynamical effect with incorrect amplitude and period
Polar motion, amplitude 0.3 arcminutes, 10 months
Mark the only cause of perturbations of coordinates that is not related to the movements of the
earth.
Refraction
Mark the incorrect sentence
The elliptical orbit of earth has no influence on the equation of time
What is the main component of the jovian planets?
Helium and hydrogen
Where do short period comets come from?
The Kuiper belt
42. What if the frost line?
The boundary between inner and outer planets
43. Venus has:
A mass similar to that of the earth
44. How much greater is the mass of Jupiter as respect to that of the earth?
317 times
45. How does the cometary dust tail from?
Interaction between cometary dust and solar radiation pressure
46. The atmospheric equilibrium temperature of a planet depends on
Its albedo
47. What is the main component of venus atmosphere?
Carbon dioxide
48. Mark the wrong sentence regarding the propagation of radiation in a medium (radiative transfer)
There are no conditions for which the radiation of a medium is equal to the blackbody radiation.
49. Mark the wrong sentence regarding molecular spectra
Rotational transitions are more energetic than vibrational ones
50. Mark the wrong sentence regarding the magnitude of star
The absorption caused by material between the star and the observer does not affect the
magnitude.
51. Mark the element that is not required for the operational definition of an apparent magnitude :
Properties of calibration stars(position, proper motion and parallax of each calibrator)
52. Mark the wrong sentence regarding different kind of spectrographs
Multi- object spectrographs uses grism to simultaneously take spectra of all the object in the focal
plane.
53. Mark the wrong sentence regarding slit spectroscopy.
The width of the slit does not have any influence on the spectral resolution.
54. Mark the wrong sentence regarding hydrostatic equilibrium in stars:
Hydrostatic equilibrium is naturally realised without requiring any source of energy.
55. Mark the wrong sentence regarding the main sequence phase.
In the colour-magnitude diagram, main sequence stars are randomly scattered all across the
diagram.
56. Mark the wrong sentence regarding the horizontal branch phase in stellar evolution (intermediatemass stars)
During this phase, nuclear reactions are happening only in the core, and the rest of the stars is
unaffected.
57. Mark the wrong sentence regarding the asymptotic giant phase in stellar evolution (intermediatemass stars).
The outcome of this phase will be a white dwarf either made of carbon and oxygen or just
exclusively helium.
58. Mark the wrong sentence regarding neutron stars
The totally of the mass of the stellar remnant is converted to neutrons, forming as homogeneous
ensemble of neutrons
59. Mark the wrong sentence regarding the magnetic activity of the sun
Flares consist of a sudden decrease of energy stored in the magnetic field. They are the least
energetic events on the sun and go mostly unnoticed.
60. Mark the wrong sentence regarding stellar clusters and association
The messier and NGC catalogues include a careful selection of open and globular cluster, with all
possible constellations and asterisms cleaned out.
61. Mark the wrong sentence regarding exoplanet detection
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
With transits it is easier to detect small planets around large stars than large planets around small
stars
Mark the correct definition of the Vogt-Russel theorem:
The structure of a star, under given approximations, is uniquely determined by its mass and
composition
Mark the category of exoplanets that I just invented
Nano-earths: planets slightly larger and more massive than dwarf planets (like pluto) but smaller
than earth, with rocky composition and no atmosphere.
Mark differences between inner and outer planets
Inner planets are made of rocks and metals, outer planets of a gas (He,H) and ice
Mark the INCORRECT sentence
When a star is crossing the Local Meridian, its Hour Angle is equal to the sidereal time
What is the most unusual property od Uranus
The inclination of its axis
Mark the wrong sentence regarding exoplanet detection
With transits it is easier to detect small planets around large stars than large planets around small
stars
The atmospheric equilibrium temperature of a planet depends on
its albedo
how long is the orbital period of Jupiter
about 12 terrestrial years
Mark the wrong sentence regarding slit spectroscopy
The width of the lit does not have any influence on the spectral resolution
Mark the wrong sentence regarding the definition of magnitude
The magnitude of a star increases linearly with the increase in its flux density
Mark the INCORRECT definition among the proposed ones
Sidereal year time between two consecutive passages of the vernal point on a given star
Mark the wrong sentence regarding the photometric color index of a star
The color index is strongly affected by the stellar radius or the distance of the star
Mark the INCORRECT sentence
The mean sidereal time is obtained by averaging the apparent sidereal time over one year
One of these elements is not required to define a celestial coordinate system
The radius of the sphere where the celestial objects are projected
Mark the INCORRECT sentence
The mean solar time is equal to the right ascension of the sun minus 12 hours
Mark the correct definition of parsec
Distance at which one astronomical unit subtends an angle of one arc second
Mark the INCORRECT sentence
UT1, TAI and UTC are all continuous time standards, whitout discontinuities
The difference between primary and secondary planetary atmosphere is
The primary atmosphere is made of hydrogen and helium
How does the cometary ion tail from
Interaction between cometary ions and solar wind
What is the percentage of the main components of the primordial solar nebula
Hydrogen and helium 98%
Mark the only sentence that correctly describes the effect of annual aberration for a star with
ecliptic latitude equal to zero degrees
The star will move along a line parallel to the ecliptic
What is the main components of mars atmosphere
Carbon dioxide
84. The third kepler’s law gives the possibility to determine
The mass of an object from the distance and orbital period of a satellite
85. Which planet among the eight ones of the SS has the lowest density
Saturn
86. Why are the outer planets bigger than the inner planets
Outer planets formed in a region in which more material condensed
87. Mark the physical that is not concurring to luni-solar precession and nutation
The moon always showing the same side to earth
88. Which element is not part of world geodetic system
A reference plane normal to the surface
89. Mark the incorrect sentence, assuming that we are in the north hemisphere
A star is circumpolar if its declination is lower than zenith angle of the north pole (e anche
EQUATOR)
90. The velocity of a planet on its orbit is
Maximum at perihelion and minimum at aphelion
91. The calendar actually in use
Is the Gregorian calendar
92. Mark the wrong sentence regarding the helium burning phase in stellar evolution (massive stars)
The blue super giant phase is extremely slow and the probability of observing it in the hertzprungrussell diagram is high
93. Where is the main belt
Between the orbit of mars and Jupiter
94. Mark the wrong sentence regarding the proprieties of light
A photon has energy momentum and mass but no electric charge
95. Mark the wrong sentence regarding the different spectroscopic techniques
In gratings both the spectral resolution and the intensity decrease with increasing order
96. Mark the wrong sentence regarding the mass-temperature relationship in stars
The CNO cycle is less sensitive to temperature si in massive stars nuclear reactions occur at a much
slower rate
97. Mark the wrong sentence regarding the nuclear fusion reactions in stars
The CNO cycle causes a noticeable variation of the abundances of “metals” in the core of the stars
98. Mark the wrong sentence regarding the carbon burning phase and beyond in stellar evolution
(massive stars)
Neutrino losses play only a minor contribution to the energy loss of the star, since they don’t have
any mass
99. Mark the wrong sentence regarding the structure and lifetime of intermediate-mass stars
Energy in the core is produced by proton-proton cycle and carbon-nitrogen-oxygen in equal parts
100.
Mark the wrong sentence regarding the Chandrasekar limit
Photo-disintegration and neutronization provide pressure to the core and allow white dwarfs to be
above this limit
101.
Mark the wrong sentence regarding exoplanets
A planet is in the habitable zone (HZ) if water has been observed on its surface. HZ gets closer to
the star with increasing mass and temperature of the star
102.
Mark the wrong sentence regarding these techniques for exoplanet characterization
During the transit part of the stellar radio and gamma radiation are blocked by the planet,
providing insights on its internal composition
103.
Mark the wrong sentence regarding blackbody radiation
Both the intensity and the peak wavelength of a blackbody decrease with increasing temperature
104.
Mark the wrong sentence regarding the measurement of radiation
NON METTERE the specific….
105.
Mark the sentence regarding photometric system
A modern photometric system is completely defined by the description of the filter response as a
function of wavelength
106.
Mark the wrong sentence regarding the life of a star radiating as the sun
Without any internal pressure to counterbalance gravity, a star would collapse in 15 minutes E
ANCHE nuclear
107.
Mark the wrong sentence regarding the giant phase in stellar evolution
Stars in the giant phase have the same size and luminosity regardless of their mass during the main
sequence phase
108.
Mark the wrong sentence regarding black holes and compact objects
Form the outside we would see the local clock of someone falling into a black hole increasing its
speed exponentially
109.
mark the wrong sentence regarding false positive scenarios in exoplanet detection
object of interest: the planet hase been detected by three independent techniques, one of..
110.
Mark the correct sentence regarding the apparent and bolometric magnitude of a star
The apparent magnitude is obtained by comparing the flux density of different stars the same
wavelength
111.
Mark the wrong sentence regarding black holes
A supernova remnant will always become a black hole regardless of the ejected mass during the
supernova explosion
112.
Mark the correct sentence regarding the electromagnetic spectrum
At increasing frequency of a photon corresponds increasing energy
113.
Mark the wrong sentence regarding the magnetic activity of the sun
The lifetime of a single spot can be of several years. Spots appear and disappear randomly on the
surface of the sun
114.
Mark the sentence regarding the structure and lifetime of low-mass stars
At the end of their life low-mass stars will evolve into carbon-oxygen white dwarf and slowly cool
down
115.
Mark the wrong sentence regarding the sun
The sun has a convective core, extended up to 0.4 solar radii from the center, surrounded by a
radiative envelope
116.
Mark the correct definition of an isochrone
Luminosity and temperature of an ensemble of stars with age chemical composition over a wide
range of mass